Certain nests which were furnished with two doors of the cork type were observed by Mr. S. S. Saunders in the Ionian Islands. The door at the surface of these nests was normal in position and structure, but the lower one was placed at the very bottom of the nest, and inverted, so that, though apparently intended to open downwards, it was permanently closed by the surrounding earth. The presence of a carefully constructed door in a situation which forbade the possibility of its ever being opened seemed, indeed, something difficult to account for. However, it occurred to Mr. Saunders that, as these nests were found in the cultivated ground round the roots of olive trees, they may occasionally have got turned topsy-turvy when the soil was broken up. The spider then, finding her door buried below in the ground and the bottom of the tube at the surface,would have either to seek new quarters or to adapt the nest to its altered position, and make an opening and door at the exposed end. In order to try whether one of these spiders would do this, Mr. Saunders placed a nest, with its occupant inside, upside down in a flower-pot. After the lapse of ten days a new door was made, exactly as he had conjectured it would be, and the nest presented two doors like those which he had found at first.
Certain nests which were furnished with two doors of the cork type were observed by Mr. S. S. Saunders in the Ionian Islands. The door at the surface of these nests was normal in position and structure, but the lower one was placed at the very bottom of the nest, and inverted, so that, though apparently intended to open downwards, it was permanently closed by the surrounding earth. The presence of a carefully constructed door in a situation which forbade the possibility of its ever being opened seemed, indeed, something difficult to account for. However, it occurred to Mr. Saunders that, as these nests were found in the cultivated ground round the roots of olive trees, they may occasionally have got turned topsy-turvy when the soil was broken up. The spider then, finding her door buried below in the ground and the bottom of the tube at the surface,would have either to seek new quarters or to adapt the nest to its altered position, and make an opening and door at the exposed end. In order to try whether one of these spiders would do this, Mr. Saunders placed a nest, with its occupant inside, upside down in a flower-pot. After the lapse of ten days a new door was made, exactly as he had conjectured it would be, and the nest presented two doors like those which he had found at first.
The most remarkable fact connected with these animals, if we regard their peculiar instinct from the standpoint of the descent theory, is the wide range of their geographical distribution. In all quarters of the globe species of trap-door spiders are found occurring in more or less localised areas; and as it is improbable that so peculiar an instinct should have arisen independently in more than one line of descent, we can only conclude that the wide dispersion of the species presenting it has been subsequent to the origin and perfecting of the instinct. This conclusion of course necessitates the supposition that the instinct must be one of enormous antiquity; and in this connection it is worthy of remark that we seem to have independent evidence to show that such is the case. It is a principle of evolution that the earlier any structure or instinct appears in the development of the race, the sooner will it appear in the development of the individual; and read by the light of this principle we should conclude, quite apart from all considerations as to the wide geographical distribution of trap-door spiders, that their instincts—as, indeed, is the case with the characteristic instincts of many other species of spiders—must be of immense age. Thus, again to quote Moggridge,—
It seems to be the rule with spiders generally that the offspring should leave the nest and construct dwellings for themselves when very young.Mr. Blackwall, speaking of British spiders, says:—'Complicated as the processes are by which these symmetrical nets are produced, nevertheless young spiders, acting under the influence of instinctive impulse, display, even in their first attempts to fabricate them, as consummate skill as the most experienced individuals.'Again, Mr. F. Pollock[85]relates of the young ofEpeira aurelia, which he observed in Madeira, that when seven weeks old they made a web the size of a penny, and that these nets have the same beautiful symmetry as those of the full-grown spider.
It seems to be the rule with spiders generally that the offspring should leave the nest and construct dwellings for themselves when very young.
Mr. Blackwall, speaking of British spiders, says:—'Complicated as the processes are by which these symmetrical nets are produced, nevertheless young spiders, acting under the influence of instinctive impulse, display, even in their first attempts to fabricate them, as consummate skill as the most experienced individuals.'
Again, Mr. F. Pollock[85]relates of the young ofEpeira aurelia, which he observed in Madeira, that when seven weeks old they made a web the size of a penny, and that these nets have the same beautiful symmetry as those of the full-grown spider.
And, speaking of trap-door spiders, Moggridge says,—
I cannot help thinking that these very small nests, built as they are by minute spiders probably not very long hatched from the egg, must rank among the most marvellous structures of this kind with which we are acquainted. That so young and weak a creature should be able to excavate a tube in the earth many times its own length, and know how to make a perfect miniature of the nest of its parents, seems to be a fact which has scarcely a parallel in nature.[86]
I cannot help thinking that these very small nests, built as they are by minute spiders probably not very long hatched from the egg, must rank among the most marvellous structures of this kind with which we are acquainted. That so young and weak a creature should be able to excavate a tube in the earth many times its own length, and know how to make a perfect miniature of the nest of its parents, seems to be a fact which has scarcely a parallel in nature.[86]
Regarding the steps whereby the instinct of building trap-doors probably arose, Büchner quotes Moggridge thus:—
To show, lastly, how various are the transitional forms and gradations so important in deciding upon the gradual origin of the forms of nests, Moggridge also alludes to the similar buildings made by other genera of spiders.Lycosa Narbonensis, a spider of Southern France much resembling the Apuleian tarantula, and belonging to the family of the wolf spiders, makes cylindrical holes in the earth, about one inch wide and three or four inches deep, in a perpendicular direction; when they have attained this depth they run further horizontally, and end in a three cornered room, from one to two inches broad, the floor of which is covered with the remnants of dead insects. The whole nest is lined within with a thick silken material, and has at its opening—closed by no door—an above-ground chimney-shaped extension, made of leaves, needles, moss, wood, &c., woven together with spider threads. These chimneys show various differences in their manner of building, and are intended chiefly, according to Moggridge, to prevent the sand blown about by the violent sea-winds from penetrating into the nests. During winter the opening is wholly and continuously woven over, and it is very well possible, or probable, that the process of reopening such a warm covering in the spring,after this opening was three-quarters completed, and was large enough to let the spider pass out, may have long ago awaked in the brain of some species of spider the idea of making a permanent and moveable door. But from this to the practical construction of so perfect a door as we have learned to know, and even to the building of the exceedingly complicated nest of theN. Manderstjernæ, through all the gradations which we already know, and which doubtless exist in far greater number, is no great or impossible step.
To show, lastly, how various are the transitional forms and gradations so important in deciding upon the gradual origin of the forms of nests, Moggridge also alludes to the similar buildings made by other genera of spiders.Lycosa Narbonensis, a spider of Southern France much resembling the Apuleian tarantula, and belonging to the family of the wolf spiders, makes cylindrical holes in the earth, about one inch wide and three or four inches deep, in a perpendicular direction; when they have attained this depth they run further horizontally, and end in a three cornered room, from one to two inches broad, the floor of which is covered with the remnants of dead insects. The whole nest is lined within with a thick silken material, and has at its opening—closed by no door—an above-ground chimney-shaped extension, made of leaves, needles, moss, wood, &c., woven together with spider threads. These chimneys show various differences in their manner of building, and are intended chiefly, according to Moggridge, to prevent the sand blown about by the violent sea-winds from penetrating into the nests. During winter the opening is wholly and continuously woven over, and it is very well possible, or probable, that the process of reopening such a warm covering in the spring,after this opening was three-quarters completed, and was large enough to let the spider pass out, may have long ago awaked in the brain of some species of spider the idea of making a permanent and moveable door. But from this to the practical construction of so perfect a door as we have learned to know, and even to the building of the exceedingly complicated nest of theN. Manderstjernæ, through all the gradations which we already know, and which doubtless exist in far greater number, is no great or impossible step.
Coming now to the general intelligence of spiders, I think there can be no reasonable doubt, from the force of concurrent testimony, that they are able to distinguish between persons, and approach those whom they have found to be friendly, while shunning strangers. This power of discrimination, it will be remembered, also occurs among bees and wasps, and therefore its presence in spiders is not antecedently improbable. I myself know a lady who has 'tamed' spiders to recognise her, so that they come out to be fed when she enters the room where they are kept; and stories of the taming of spiders by prisoners are abundant. The following anecdote recorded by Büchner is in this connection worth quoting:—
Dr. Moschkau, of Gohlis, near Leipsic, writes as follows to the author, on August 28, 1876:—'In Oderwitz(?), where I lived in 1873 and 1874, I noticed one day in a half-dark corner of the anteroom a tolerably respectable spider's web, in which a well-fed cross-spider had made its home, and sat at the nest-opening early and late, watching for some flying or creeping food. I was accidentally several times a witness of the craft with which it caught its victim and rendered it harmless, and it soon became a regular duty to carry it flies several times during a day, which I laid down before its door with a pair of pincers. At first this feeding seemed to arouse small confidence, the pincers perhaps being in fault, for it let many of the flies escape again, or only seized them when it knew that they were within reach of its abode. After a while, however, the spider came each time and took the flies out of the pincers and spun them over. The latter business was sometimes done so superficially, when I gave flies very quickly one after the other, thatsome of the already ensnared flies found time and opportunity to escape. This game was carried on by me for some weeks, as it seemed to me curious. But one day when the spider seemed very ravenous, and regularly flew at each fly offered to it, I began teasing it. As soon as it had got hold of the fly I pulled it back again with the pincers. It took this exceedingly ill. The first time, as I finally left the fly with it, it managed to forgive me, but when I later took a fly right away, our friendship was destroyed for ever. On the following day it treated my offered flies with contempt, and would not move, and on the third day it had disappeared.[87]
Dr. Moschkau, of Gohlis, near Leipsic, writes as follows to the author, on August 28, 1876:—'In Oderwitz(?), where I lived in 1873 and 1874, I noticed one day in a half-dark corner of the anteroom a tolerably respectable spider's web, in which a well-fed cross-spider had made its home, and sat at the nest-opening early and late, watching for some flying or creeping food. I was accidentally several times a witness of the craft with which it caught its victim and rendered it harmless, and it soon became a regular duty to carry it flies several times during a day, which I laid down before its door with a pair of pincers. At first this feeding seemed to arouse small confidence, the pincers perhaps being in fault, for it let many of the flies escape again, or only seized them when it knew that they were within reach of its abode. After a while, however, the spider came each time and took the flies out of the pincers and spun them over. The latter business was sometimes done so superficially, when I gave flies very quickly one after the other, thatsome of the already ensnared flies found time and opportunity to escape. This game was carried on by me for some weeks, as it seemed to me curious. But one day when the spider seemed very ravenous, and regularly flew at each fly offered to it, I began teasing it. As soon as it had got hold of the fly I pulled it back again with the pincers. It took this exceedingly ill. The first time, as I finally left the fly with it, it managed to forgive me, but when I later took a fly right away, our friendship was destroyed for ever. On the following day it treated my offered flies with contempt, and would not move, and on the third day it had disappeared.[87]
Jesse relates the following anecdote, which seems to display on the part of a spider somewhat remote adaptation of means to novel circumstances. He confined a spider with her eggs under a glass upon a marble mantelpiece. Having surrounded the eggs with web,—
She next proceeded to fix one of her threads to the upper part of the glass which confined her, and carried it to the further end of the piece of grass, and in a short time had succeeded in raising it up and fixing it perpendicularly, working her threads from the sides of the glass to the top and sides of the piece of grass. Her motive in doing this was obvious. She not only rendered the object of her care more secure than it would have been had it remained flat on the marble, but she was probably aware that the cold from the marble would chill her eggs, and prevent their arriving at maturity: she therefore raised them from it in the manner I have described.[88]
She next proceeded to fix one of her threads to the upper part of the glass which confined her, and carried it to the further end of the piece of grass, and in a short time had succeeded in raising it up and fixing it perpendicularly, working her threads from the sides of the glass to the top and sides of the piece of grass. Her motive in doing this was obvious. She not only rendered the object of her care more secure than it would have been had it remained flat on the marble, but she was probably aware that the cold from the marble would chill her eggs, and prevent their arriving at maturity: she therefore raised them from it in the manner I have described.[88]
Mr. Belt gives the following account of the intelligence which certain species of South American spiders display in escaping from the terrible hosts of the Eciton ants:—
Many of the spiders would escape by hanging suspended by a thread of silk from the branches, safe from the foes that swarmed both above and below.I noticed that spiders generally were most intelligent in escaping, and did not, like the cockroaches and other insects, take shelter in the first hiding-place they found, only to be driven out again, or perhaps caught by the advancing army of ants. I have often seen large spiders making off many yards in advance, and apparently determined to put a good distancebetween themselves and the foe. I once saw one of the false spiders, or harvest-men (Phalangidæ), standing in the midst of an army of ants, and with the greatest circumspection and coolness lifting, one after the other, its long legs, which supported its body above their reach. Sometimes as many as five out of its eight legs would be lifted at once, and whenever an ant approached one of those on which it stood, there was always a clear space within reach to put down another, so as to be able to hold up the threatened one out of danger.[89]
Many of the spiders would escape by hanging suspended by a thread of silk from the branches, safe from the foes that swarmed both above and below.
I noticed that spiders generally were most intelligent in escaping, and did not, like the cockroaches and other insects, take shelter in the first hiding-place they found, only to be driven out again, or perhaps caught by the advancing army of ants. I have often seen large spiders making off many yards in advance, and apparently determined to put a good distancebetween themselves and the foe. I once saw one of the false spiders, or harvest-men (Phalangidæ), standing in the midst of an army of ants, and with the greatest circumspection and coolness lifting, one after the other, its long legs, which supported its body above their reach. Sometimes as many as five out of its eight legs would be lifted at once, and whenever an ant approached one of those on which it stood, there was always a clear space within reach to put down another, so as to be able to hold up the threatened one out of danger.[89]
Mr. L. A. Morgan, writing to 'Nature' (Jan. 22, 1880), gives an account of a spider conveying a large insect from the part of the web where it was caught to the 'larder,' by the following means. The spider first went two or three times backwards and forwards between the head of the insect and the main strand of the web. After this he went about cutting all the threads around the insect till the latter hung by the head strands alone. The spider then fixed a thread to the tail end, and by this dragged the carcass as far on its way to the larder as the head strands would permit. As soon as these were taut, he made the tail rope fast, went back to the head rope and cut it; then he attached himself to the head and pulled the body towards the larder, until the tail rope was taut. In this way, by alternately cutting the head and tail ropes and dragging the insect bit by bit, he conveyed it safely to the larder.
But the practical acquaintance with mechanical principles which this observation displays is perhaps not so remarkable as that which is sometimes shown by spiders when they find that a widely spread web is not tightly enough stretched, and as a consequence is to an inconvenient extent swayed about by the wind. Under such circumstances these animals have been observed to suspend to their webs small stones or other heavy objects, the weight of which serves to steady the whole system. Gleditsch saw a spider so circumstanced let itself down to the ground by means of a thread, seize a small stone, remount, and fasten the stone to the lower part of its web, at a height sufficient to enable animals and men to walkbeneath it. After alluding to this case, Büchner observes (loc. cit., p. 318),—
But a similar observation was made by Professor E. H. Weber, the famous anatomist and physiologist, and was published many years ago in Müller's Journal. A spider had stretched its web between two posts standing opposite each other, and had fastened it to a plant below for the third point. But as the attachment below was often broken by the garden work, by passers-by, and in other ways, the little animal extricated itself from the difficulty by spinning its web round a little stone, and fastened this to the lower part of its web, swinging freely, and so to draw the web down by its weight instead of fastening it in this direction by a connecting thread. Carus ('Vergl. Psycho.,' 1866, p. 76) also made a similar observation. But the most interesting observation on this head is related by J. G. Wood ('Glimpses into Petland'), and repeated by Watson (loc. cit., p. 455). One of my friends, says Wood, was accustomed to grant shelter to a number of garden spiders under a large verandah, and to watch their habits. One day a sharp storm broke out, and the wind raged so furiously through the garden that the spiders suffered damage from it, although sheltered by the verandah. The mainyards of one of these webs, as the sailors would call them, were broken, so that the web was blown hither and thither, like a slack sail in a storm. The spider made no fresh threads, but tried to help itself in another way. It let itself down to the ground by a thread, and crawled to a place where lay some splintered pieces of a wooden fence thrown down by the storm. It fastened a thread to one of the bits of wood, turned back with it, and hung it with a strong thread to the lower part of its nest, about five feet from the ground. The performance was a wonderful one, for the weight of the wood sufficed to keep the nest tolerably firm, while it was yet light enough to yield to the wind, and so prevent further injury. The piece of wood was about two and a half inches long, and as thick as a goose-quill. On the following day a careless servant knocked her head against the wood, and it fell down. But in the course of a few hours the spider had found it and brought it back to its place. When the storm ceased, the spider mended her web, broke the supporting thread in two, and let the wood fall to the ground!
But a similar observation was made by Professor E. H. Weber, the famous anatomist and physiologist, and was published many years ago in Müller's Journal. A spider had stretched its web between two posts standing opposite each other, and had fastened it to a plant below for the third point. But as the attachment below was often broken by the garden work, by passers-by, and in other ways, the little animal extricated itself from the difficulty by spinning its web round a little stone, and fastened this to the lower part of its web, swinging freely, and so to draw the web down by its weight instead of fastening it in this direction by a connecting thread. Carus ('Vergl. Psycho.,' 1866, p. 76) also made a similar observation. But the most interesting observation on this head is related by J. G. Wood ('Glimpses into Petland'), and repeated by Watson (loc. cit., p. 455). One of my friends, says Wood, was accustomed to grant shelter to a number of garden spiders under a large verandah, and to watch their habits. One day a sharp storm broke out, and the wind raged so furiously through the garden that the spiders suffered damage from it, although sheltered by the verandah. The mainyards of one of these webs, as the sailors would call them, were broken, so that the web was blown hither and thither, like a slack sail in a storm. The spider made no fresh threads, but tried to help itself in another way. It let itself down to the ground by a thread, and crawled to a place where lay some splintered pieces of a wooden fence thrown down by the storm. It fastened a thread to one of the bits of wood, turned back with it, and hung it with a strong thread to the lower part of its nest, about five feet from the ground. The performance was a wonderful one, for the weight of the wood sufficed to keep the nest tolerably firm, while it was yet light enough to yield to the wind, and so prevent further injury. The piece of wood was about two and a half inches long, and as thick as a goose-quill. On the following day a careless servant knocked her head against the wood, and it fell down. But in the course of a few hours the spider had found it and brought it back to its place. When the storm ceased, the spider mended her web, broke the supporting thread in two, and let the wood fall to the ground!
If so well-observed a fact requires any further confirmation, I may adduce the following account, which is of the more value as corroborative evidence from the writernot appearing to be aware that the fact had been observed before. This writer is Dr. John Topham, whom the late Dr. Sharpey, F.R.S., assured me is a competent observer, and who publishes the account in 'Nature' (xi. 18):—
A spider constructed its web in an angle of my garden, the sides of which were attached by long threads to shrubs at the height of nearly three feet from the gravel path beneath. Being much exposed to the wind, the equinoctial gales of this autumn destroyed the web several times.The ingenious spider now adopted the contrivance here represented. It secured a conical fragment of gravel with its larger end upwards by two cords, one attached to each of its opposite sides, to the apex of its wedge-shaped web, and left it suspended as a moveable weight to be opposed to the effect of such gusts of air as had destroyed the webs previously occupying the same situation.The spider must have descended to the gravel path for this special object, and having attached threads to a stone suited to its purpose, must have afterwards raised this by fixing itself upon the web, and pulling the weight up to a height of more than two feet from the ground, where it hung suspended by elastic cords. The excellence of the contrivance is too evident to require further comment.
A spider constructed its web in an angle of my garden, the sides of which were attached by long threads to shrubs at the height of nearly three feet from the gravel path beneath. Being much exposed to the wind, the equinoctial gales of this autumn destroyed the web several times.
The ingenious spider now adopted the contrivance here represented. It secured a conical fragment of gravel with its larger end upwards by two cords, one attached to each of its opposite sides, to the apex of its wedge-shaped web, and left it suspended as a moveable weight to be opposed to the effect of such gusts of air as had destroyed the webs previously occupying the same situation.
The spider must have descended to the gravel path for this special object, and having attached threads to a stone suited to its purpose, must have afterwards raised this by fixing itself upon the web, and pulling the weight up to a height of more than two feet from the ground, where it hung suspended by elastic cords. The excellence of the contrivance is too evident to require further comment.
An almost precisely analogous case, with a sketch, is published by another observer in 'Land and Water,' Dec. 12, 1877.
Before quitting the Arachnida I must allude to some recent correspondence on the alleged tendency of the scorpion to commit suicide when surrounded by fire. This alleged tendency has long been recognised in popular fables, and has been used by Byron as a poetical metaphor in certain well-known lines. But until the publication of the correspondence to which I allude, no one supposed the tendency in question to have any existence in fact. This correspondence took place in 'Nature' (vol. xi.), and as the subject is an interesting one, I shall reproduce the more important contributions to itin extenso. It was opened by Mr. W. G. Biddie as follows:—
I shall feel obliged if you will record in 'Nature' a fact with reference to the common black scorpion of Southern India, which was observed by me some years ago in Madras.One morning a servant brought to me a large specimen of this scorpion, which, having stayed out too long in its nocturnal rambles, had apparently got bewildered at daybreak, and been unable to find its way home. To keep it safe the creature was at once put into a glazed entomological case. Having a few leisure minutes in the course of the forenoon I thought I would see how my prisoner was getting on, and to have a better view of it the case was placed in a window in the rays of the hot sun. The light and heat seemed to irritate it very much, and this recalled to my mind a story which I had read somewhere that a scorpion, on being surrounded with fire, had committed suicide. I hesitated about subjecting my pet to such a terrible ordeal, but taking a common botanical lens, I focussed the rays of the sun on its back. The moment this was done it began to run hurriedly about the case, hissing and spitting in a very fierce way. This experiment was repeated some four or five times with like results, but on trying it once again, the scorpion turned up its tail and plunged the sting, quick as lightning, into its own back. The infliction of the wound was followed by a sudden escape of fluid, and a friend standing by me called out, 'See, it has stung itself: it is dead;' and sure enough in less than half a minute life was quite extinct. I have written this brief note to show (1) that animals may commit suicide; (2) that the poison of certain animals may be destructive to themselves.
I shall feel obliged if you will record in 'Nature' a fact with reference to the common black scorpion of Southern India, which was observed by me some years ago in Madras.
One morning a servant brought to me a large specimen of this scorpion, which, having stayed out too long in its nocturnal rambles, had apparently got bewildered at daybreak, and been unable to find its way home. To keep it safe the creature was at once put into a glazed entomological case. Having a few leisure minutes in the course of the forenoon I thought I would see how my prisoner was getting on, and to have a better view of it the case was placed in a window in the rays of the hot sun. The light and heat seemed to irritate it very much, and this recalled to my mind a story which I had read somewhere that a scorpion, on being surrounded with fire, had committed suicide. I hesitated about subjecting my pet to such a terrible ordeal, but taking a common botanical lens, I focussed the rays of the sun on its back. The moment this was done it began to run hurriedly about the case, hissing and spitting in a very fierce way. This experiment was repeated some four or five times with like results, but on trying it once again, the scorpion turned up its tail and plunged the sting, quick as lightning, into its own back. The infliction of the wound was followed by a sudden escape of fluid, and a friend standing by me called out, 'See, it has stung itself: it is dead;' and sure enough in less than half a minute life was quite extinct. I have written this brief note to show (1) that animals may commit suicide; (2) that the poison of certain animals may be destructive to themselves.
The following corroborative evidence on the subject was then supplied by Dr. Allen Thomson, F.R.S. ('Nature,' vol. xx., p. 577):—
Doubts having been expressed at various times, even by learned naturalists, as to the reality of the suicide or self-destruction of the scorpion by means of its own poison, and these doubts having been again stated in 'Nature,' vol. xx., p. 553, by Mr. B. F. Hutchinson, of Peshawur, as the result of his own observations, I think it may be useful to give an articulate account of the phenomenon as it has been related to me by an eye-witness, which removes all possible doubt as to its occurrence under certain circumstances.While residing many years ago, during the summer months, at the baths of Sulla in Italy, in a somewhat damp locality, my informant together with the rest of the family was much annoyed by the frequent intrusion of small black scorpions intothe house, and their being secreted among the bedclothes, in shoes, and other articles of dress. It thus became necessary to be constantly on the watch for these troublesome creatures, and to take means for their removal and destruction. Having been informed by the natives of the place that the scorpion would destroy itself if exposed to a sudden light, my informant and her friends soon became adepts in catching the scorpions and disposing of them in the manner suggested. This consisted in confining the animal under an inverted drinking-glass or tumbler, below which a card was inserted when the capture was made, and then, waiting till dark, suddenly bringing the light of a candle near to the glass in which the animal was confined. No sooner was this done than the scorpion invariably showed signs of great excitement, running round and round the interior of the tumbler with reckless velocity for a number of times. This state having lasted for a minute or more, the animal suddenly became quiet, and turning its tail on the hinder part of its body over its back, brought its recurved sting down upon the middle of the head, and piercing it forcibly, in a few seconds became quite motionless, and in fact quite dead. This observation was repeated very frequently; in truth, it was adopted as the best plan of getting rid of the animals. The young people were in the habit of handling the scorpions with impunity immediately after they were so killed, and of preserving many of them as curiosities.In this narrative the following circumstances are worthy of attention:—(1) The effect of light in producing the excitement amounting to despair, which causes the animal to commit self-destruction;(2) The suddenness of the operation of the poison, which is probably inserted by the puncture of the head into the upper cerebral ganglion; and(3) The completeness of the fatal symptoms at once induced.I am aware that the phenomena now described have been observed by others, and they appear to have been familiarly known to the inhabitants of the district in which the animals are found. Sufficient confirmation of the facts is also to be found in the narratives of 'G. Biddie' and 'M. L.' contained in 'Nature,' vol. ix., pp. 29-47, and it will be observed that the circumstances leading the animal to self-destruction in these instances were somewhat similar to those narrated by my informant. It is abundantly clear, therefore, that the view takenby Mr. Hutchinson, viz., that the 'popular idea regarding scorpionic suicide is a delusion based on an impossibility,' is wholly untenable; indeed, the recurved direction of the sting, which he refers to as creating the impossibility of the animal destroying itself, actually facilitates the operation of inflicting the wound. I suppose Mr. Hutchinson, arguing from the analogy of bees or wasps, imagined that the sting would be bent forwards upon the body, whereas the wound of the scorpion is invariably inflicted by a recurvation of the tail over the back of the animal.
Doubts having been expressed at various times, even by learned naturalists, as to the reality of the suicide or self-destruction of the scorpion by means of its own poison, and these doubts having been again stated in 'Nature,' vol. xx., p. 553, by Mr. B. F. Hutchinson, of Peshawur, as the result of his own observations, I think it may be useful to give an articulate account of the phenomenon as it has been related to me by an eye-witness, which removes all possible doubt as to its occurrence under certain circumstances.
While residing many years ago, during the summer months, at the baths of Sulla in Italy, in a somewhat damp locality, my informant together with the rest of the family was much annoyed by the frequent intrusion of small black scorpions intothe house, and their being secreted among the bedclothes, in shoes, and other articles of dress. It thus became necessary to be constantly on the watch for these troublesome creatures, and to take means for their removal and destruction. Having been informed by the natives of the place that the scorpion would destroy itself if exposed to a sudden light, my informant and her friends soon became adepts in catching the scorpions and disposing of them in the manner suggested. This consisted in confining the animal under an inverted drinking-glass or tumbler, below which a card was inserted when the capture was made, and then, waiting till dark, suddenly bringing the light of a candle near to the glass in which the animal was confined. No sooner was this done than the scorpion invariably showed signs of great excitement, running round and round the interior of the tumbler with reckless velocity for a number of times. This state having lasted for a minute or more, the animal suddenly became quiet, and turning its tail on the hinder part of its body over its back, brought its recurved sting down upon the middle of the head, and piercing it forcibly, in a few seconds became quite motionless, and in fact quite dead. This observation was repeated very frequently; in truth, it was adopted as the best plan of getting rid of the animals. The young people were in the habit of handling the scorpions with impunity immediately after they were so killed, and of preserving many of them as curiosities.
In this narrative the following circumstances are worthy of attention:—
(1) The effect of light in producing the excitement amounting to despair, which causes the animal to commit self-destruction;
(2) The suddenness of the operation of the poison, which is probably inserted by the puncture of the head into the upper cerebral ganglion; and
(3) The completeness of the fatal symptoms at once induced.
I am aware that the phenomena now described have been observed by others, and they appear to have been familiarly known to the inhabitants of the district in which the animals are found. Sufficient confirmation of the facts is also to be found in the narratives of 'G. Biddie' and 'M. L.' contained in 'Nature,' vol. ix., pp. 29-47, and it will be observed that the circumstances leading the animal to self-destruction in these instances were somewhat similar to those narrated by my informant. It is abundantly clear, therefore, that the view takenby Mr. Hutchinson, viz., that the 'popular idea regarding scorpionic suicide is a delusion based on an impossibility,' is wholly untenable; indeed, the recurved direction of the sting, which he refers to as creating the impossibility of the animal destroying itself, actually facilitates the operation of inflicting the wound. I suppose Mr. Hutchinson, arguing from the analogy of bees or wasps, imagined that the sting would be bent forwards upon the body, whereas the wound of the scorpion is invariably inflicted by a recurvation of the tail over the back of the animal.
It will be perceived that these observations were not made by Dr. Allen Thomson himself, and that there are certain inherent discrepancies in the account which he has published—such, for instance, as the reason given for trying and repeating the experiment, the method being clearly a cumbersome one to employ if the only object were that of 'disposing of' the animals. Nevertheless, as Dr. Thomson is a high authority, and as I learn from him that he is satisfied regarding the capability and veracity of his informant, I have not felt justified in suppressing his evidence. Still I think that so remarkable a fact unquestionably demands further corroboration before we should be justified in accepting it unreservedly. For if it is a fact, it stands as a unique case of an instinct detrimental alike to the individual and to the species.
REMAINING ARTICULATA.
TheHymenoptera being so much the most intelligent order, not merely of insects, but of Invertebrata, and the Arachnida having been now considered, very little space need be occupied with the remaining classes of the Articulata.
Sir John Lubbock, in his first paper on Bees and Wasps, quotes the following case from Kirby and Spence, with the remarks which I append:—
The first of these anecdotes refers to a beetle (Ateuchus pilularius) which, having made for the reception of its eggs a pellet of dung too heavy for it to move, repaired to an adjoining heap, and soon returned with three of his companions. 'All four now applied their united strength to the pellet, and at length succeeded in pushing it out; which being done, the three assistant beetles left the spot and returned to their own quarters.' This observation rests on the authority of an anonymous German artist; and though we are assured that he was a 'man of strict veracity,' I am not aware that any similar fact has been recorded by any other observer.
The first of these anecdotes refers to a beetle (Ateuchus pilularius) which, having made for the reception of its eggs a pellet of dung too heavy for it to move, repaired to an adjoining heap, and soon returned with three of his companions. 'All four now applied their united strength to the pellet, and at length succeeded in pushing it out; which being done, the three assistant beetles left the spot and returned to their own quarters.' This observation rests on the authority of an anonymous German artist; and though we are assured that he was a 'man of strict veracity,' I am not aware that any similar fact has been recorded by any other observer.
Catesby, however, says:—
I have attentively admired their industry, and their mutual assisting of each other in rolling these globular balls from the place where they made them, to that of their interment, which is usually a distance of some yards, more or less. This they perform back foremost, by raising their hind parts and pushing away the ball with their hind feet. Two or three of them are sometimes engaged in trundling one ball, which from meeting with impediments, on account of the unevenness of the ground, is sometimes deserted by them. It is, however, attempted by others with success, unless it happen to roll into some deep hollow or ditch, where they are accustomed to leave it; butthey continue their work by rolling off the next ball that comes in their way. None of them seem to know their own balls, but an equal care for the whole appears to affect all the community. They form these pellets while the dung remains moist, and leave them to harden in the sun before they attempt to roll them. In their rolling of them from place to place, both they and the balls may frequently be seen tumbling about over the little eminences that are in their way. They are not, however, easily discouraged, and by repeating their attempts usually surmount the difficulties.[90]
I have attentively admired their industry, and their mutual assisting of each other in rolling these globular balls from the place where they made them, to that of their interment, which is usually a distance of some yards, more or less. This they perform back foremost, by raising their hind parts and pushing away the ball with their hind feet. Two or three of them are sometimes engaged in trundling one ball, which from meeting with impediments, on account of the unevenness of the ground, is sometimes deserted by them. It is, however, attempted by others with success, unless it happen to roll into some deep hollow or ditch, where they are accustomed to leave it; butthey continue their work by rolling off the next ball that comes in their way. None of them seem to know their own balls, but an equal care for the whole appears to affect all the community. They form these pellets while the dung remains moist, and leave them to harden in the sun before they attempt to roll them. In their rolling of them from place to place, both they and the balls may frequently be seen tumbling about over the little eminences that are in their way. They are not, however, easily discouraged, and by repeating their attempts usually surmount the difficulties.[90]
Büchner speaks of the fact that dung-beetles co-operate in their work as one that is well established, but gives no authorities or references.[91]A friend of my own, however, informs me that she has witnessed the fact; and in view of analogous observations made on other species of Coleoptera, I see no reason to doubt this one. Some of these observations I may here append.
Herr Gollitz writes to Büchner thus:—
Last summer, in the month of July, I was one day in my field, and found there a mound of fresh earth like a molehill, on which a striped black and red beetle, with long legs, and about the size of a hornet, was busy taking away the earth from a hole that led like a pit into the mound, and levelling the place. After I had watched this beetle for some time, I noticed a second beetle of the same kind, which brought a little lump of earth from the interior to the opening of the hole, and then disappeared again in the mound; every four or five minutes a pellet came out of the hole, and was carried away by the first-named beetle. After I had watched these proceedings for about half an hour, the beetle which had been working underground came out and ran to its comrade. Both put their heads together, and clearly held a conversation, for immediately afterwards they changed work. The one which had been working outside went into the mound, the other took the outside labour, and all went on vigorously. I watched the affair still for a little longer, and went away with the notion that these insects could understand each other just like men. Klingelhöffer, of Darmstadt (in Brehm,loc. cit., ix., p. 86), says:—A golden running beetle came to a cockchafer lying on its back in the garden, intending to eat it, but was unable to master it; it ran to the next bush, andreturned with a friend, whereupon the two overpowered the cockchafer, and pulled it off to their hiding-place.
Last summer, in the month of July, I was one day in my field, and found there a mound of fresh earth like a molehill, on which a striped black and red beetle, with long legs, and about the size of a hornet, was busy taking away the earth from a hole that led like a pit into the mound, and levelling the place. After I had watched this beetle for some time, I noticed a second beetle of the same kind, which brought a little lump of earth from the interior to the opening of the hole, and then disappeared again in the mound; every four or five minutes a pellet came out of the hole, and was carried away by the first-named beetle. After I had watched these proceedings for about half an hour, the beetle which had been working underground came out and ran to its comrade. Both put their heads together, and clearly held a conversation, for immediately afterwards they changed work. The one which had been working outside went into the mound, the other took the outside labour, and all went on vigorously. I watched the affair still for a little longer, and went away with the notion that these insects could understand each other just like men. Klingelhöffer, of Darmstadt (in Brehm,loc. cit., ix., p. 86), says:—A golden running beetle came to a cockchafer lying on its back in the garden, intending to eat it, but was unable to master it; it ran to the next bush, andreturned with a friend, whereupon the two overpowered the cockchafer, and pulled it off to their hiding-place.
Similarly, there is no doubt that the burying beetles (Nicrophorus) co-operate.
Several of them unite together to bury under the ground, as food and shelter for their young, some dead animal, such as a mouse, a toad, a mole, a bird, &c. The burial is performed because the corpse, if left above ground, would either dry up, or grow rotten, or be eaten by other animals. In all these cases the young would perish, whereas the dead body lying in the earth and withdrawn from the outer air lasts very well. The burying beetles go to work in a very well-considered fashion, for they scrape away the earth lying under the body, so that it sinks of itself deeper and deeper. When it is deep enough down, it is covered over from above. If the situation is stony, the beetles with united forces and great efforts drag the corpse to some place more suitable for burying. They work so diligently that a mouse, for instance, is buried within three hours. But they often work on for days, so as to bury the body as deeply as possible. From large carcasses, such as those of horses, sheep, &c., they only bury pieces as large as they can manage.[92]
Several of them unite together to bury under the ground, as food and shelter for their young, some dead animal, such as a mouse, a toad, a mole, a bird, &c. The burial is performed because the corpse, if left above ground, would either dry up, or grow rotten, or be eaten by other animals. In all these cases the young would perish, whereas the dead body lying in the earth and withdrawn from the outer air lasts very well. The burying beetles go to work in a very well-considered fashion, for they scrape away the earth lying under the body, so that it sinks of itself deeper and deeper. When it is deep enough down, it is covered over from above. If the situation is stony, the beetles with united forces and great efforts drag the corpse to some place more suitable for burying. They work so diligently that a mouse, for instance, is buried within three hours. But they often work on for days, so as to bury the body as deeply as possible. From large carcasses, such as those of horses, sheep, &c., they only bury pieces as large as they can manage.[92]
Lastly, Clarville gives a case of a burying beetle which wanted to carry away a dead mouse, but, finding it too heavy for its unaided strength, went off, like the beetles previously mentioned, and brought four others to its assistance.[93]
A friend of Gleditsch fastened a dead toad, which he desired to dry, upon the top of an upright stick. The burying beetles were attracted by the smell, and finding that they could not reach the toad, they undermined the stick, so causing it to fall with the toad, which was then buried safe out of harm's way.[94]
A converse exemplification of beetle-intelligence is given by G. Berkeley.[95]He saw a beetle carrying a dead spider up a heath plant, and hanging it upon a twig of the heath in so secure a position, that when the insect had left it Mr. Berkeley found that a sharp shake of the heather would not bring the dead spider down. As the buryingbeetle preserves its treasure by hiding it out of sight below ground, so this beetle no doubt secured the same end but by other means; 'seeing,' as Mr. Berkeley observes, 'that if it did not hang up its prey, it might fall into the hands of other hunters, it took all possible pains to find out the best store-room for it.'
The above instances of beetle-intelligence lead me to credit the following, which has been communicated to me by Dr. Garraway, of Faversham. On a bank of moss in the Black Forest he saw a beetle alight with a caterpillar which it was carrying, and proceed to excavate a cylindrical hole in the peat, about an inch and a half deep, into which, when completed, it dropped the caterpillar, and then flew away through the pines. 'I was struck,' says my correspondent, 'with the creature's folly in leaving the whole uncovered, as every curious wayfaring insect would doubtless be tempted to enter therein. However, in about a minute the beetle returned, this time carrying a small pebble, of which there were none in the immediate vicinity, and having carefully fitted this into the aperture, fled away into space.'
I must devote a short division of this chapter to the earwig. M. Geer describes a regular process of incubation as practised by the mother insect. He placed one with her eggs in a box, and scattered the eggs on the floor of the latter. The earwig, however, carried them one by one into a certain part of the box, and then remained constantly sitting upon the heap without ever quitting it for a moment. When the eggs were hatched, the young earwigs kept close to their mother, following her about everywhere, and often running under her abdomen, just as chickens run under a hen.[96]
A young lady, who objects to her name being published, informs me that her two younger sisters (children) are in the habit of feeding every morning with sugar an earwig, which they call 'Tom,' and which crawls up a certain curtain regularly every day at the same hour, with the apparent expectation of getting its breakfast. This resemblesanalogous instances which, have been mentioned in the case of spiders.
The gad-fly, whose eggs are hatched out in the intestines of the horse, exhibits a singular refinement of instinct in depositing them upon those parts of the horse which the animal is most likely to lick. For, according to Bingley and other writers, 'the inside of the knee is the part on which these flies principally deposit their eggs; and next to this they fix them upon the sides, and the back part of the shoulder; but almost always in places liable to be licked by the tongue.' The female fly deposits her eggs while on the wing, or at least scarcely appears to settle when she extends her ovidepositor to touch the horse. She lays only a single egg at a time—flying away a short distance after having deposited one in order to prepare another, and so on.
The following anecdote, which I quote from Jesse, seems to indicate no small degree of intelligence on the part of the common house-fly—intelligence, for instance, the same both in kind and degree as that which was displayed by Sir John Lubbock's pet wasp already mentioned:
Slingsby, the celebrated opera dancer, resided in the large house in Cross-deep, Twickenham, next to Sir Wathen Waller's, looking down the river. He was fond of the study of natural history, and particularly of insects, and he once tried to tame some house-flies, and preserve them in a state of activity through the winter. For this purpose, quite at the latter end of autumn, and when they were becoming almost helpless, he selected four from off his breakfast-table, put them upon a large handful of cotton, and placed it in one corner of the window nearest the fireplace. Not long afterwards the weather became so cold that all flies disappeared except these four, which constantly left their bed of cotton at his breakfast-time, came and fed at the table, and then returned to their home. This continued for a short time, when three of them became lifeless in their shelter, and only one came down. This one Slingsby had trained to feed upon his thumb-nail, by placing on it some moist, sugar mixed with a little butter. Although there had been at intervals several days of sharp frost, the fly never missed taking his daily meal in this way till after Christmas, when, his kindpreserver having invited a friend to dine and sleep at his house, the fly, the next morning, perched upon the thumb of the visitor, who, being ignorant that it was a pet of his host's, clapped his hand upon it, and thus put an end to Mr. Slingsby's experiment.[97]
Slingsby, the celebrated opera dancer, resided in the large house in Cross-deep, Twickenham, next to Sir Wathen Waller's, looking down the river. He was fond of the study of natural history, and particularly of insects, and he once tried to tame some house-flies, and preserve them in a state of activity through the winter. For this purpose, quite at the latter end of autumn, and when they were becoming almost helpless, he selected four from off his breakfast-table, put them upon a large handful of cotton, and placed it in one corner of the window nearest the fireplace. Not long afterwards the weather became so cold that all flies disappeared except these four, which constantly left their bed of cotton at his breakfast-time, came and fed at the table, and then returned to their home. This continued for a short time, when three of them became lifeless in their shelter, and only one came down. This one Slingsby had trained to feed upon his thumb-nail, by placing on it some moist, sugar mixed with a little butter. Although there had been at intervals several days of sharp frost, the fly never missed taking his daily meal in this way till after Christmas, when, his kindpreserver having invited a friend to dine and sleep at his house, the fly, the next morning, perched upon the thumb of the visitor, who, being ignorant that it was a pet of his host's, clapped his hand upon it, and thus put an end to Mr. Slingsby's experiment.[97]
There is no doubt that these are an intelligent group of animals, although I have been able to collect but wonderfully little information upon the subject. Mr. Moseley, F.R.S., in his very interesting work, 'Notes by a Naturalist on theChallenger,' says (p. 70):—
In the tropics one becomes accustomed to watch the habits of various species of crabs, which there live so commonly an aërial life. The more I have seen of them, the more have I been astonished at their sagacity.
In the tropics one becomes accustomed to watch the habits of various species of crabs, which there live so commonly an aërial life. The more I have seen of them, the more have I been astonished at their sagacity.
And again (pp. 48-9):—
A rock crab (Grapsus stringosus) was very abundant, running about all over the rocks, and making off into clefts on one's approach. I was astonished at the keen and long sight of this crab. I noticed some made off at full speed to their hiding-places at the instant that my head showed above a rock fifty yards distant. . . . .At Still Bay, on the sandy beach of which a heavy surf was breaking, I encountered a sand crab (Œcypoda ippeus), which was walking about, and got between it and its hole in the dry sand above the beach. The crab was a large one, at least three inches in breadth of its carapace. . . . . With its curious column-like eyes erect, the crab bolted down towards the surf as the only escape, and as it saw a great wave rushing up the shelving shore, dug itself tight into the sand, and held on to prevent the undertide from carrying it into the sea. As soon as the wave had retreated, it made off full speed for the shore. I gave chase, and whenever a wave approached, the crab repeated the manœuvre. I once touched it with my hand whilst it was buried and blinded by the sandy water, but the surf compelled me to retreat, and I could not snatch hold of it for fear of its powerful claws. At last I chased it, hard pressed, into the surf in a hurry, and being unable to get proper hold in time, it was washed into the sea. The crab evidently dreaded going into the sea. . . . . They soon die when kept a short time beneath the water.
A rock crab (Grapsus stringosus) was very abundant, running about all over the rocks, and making off into clefts on one's approach. I was astonished at the keen and long sight of this crab. I noticed some made off at full speed to their hiding-places at the instant that my head showed above a rock fifty yards distant. . . . .
At Still Bay, on the sandy beach of which a heavy surf was breaking, I encountered a sand crab (Œcypoda ippeus), which was walking about, and got between it and its hole in the dry sand above the beach. The crab was a large one, at least three inches in breadth of its carapace. . . . . With its curious column-like eyes erect, the crab bolted down towards the surf as the only escape, and as it saw a great wave rushing up the shelving shore, dug itself tight into the sand, and held on to prevent the undertide from carrying it into the sea. As soon as the wave had retreated, it made off full speed for the shore. I gave chase, and whenever a wave approached, the crab repeated the manœuvre. I once touched it with my hand whilst it was buried and blinded by the sandy water, but the surf compelled me to retreat, and I could not snatch hold of it for fear of its powerful claws. At last I chased it, hard pressed, into the surf in a hurry, and being unable to get proper hold in time, it was washed into the sea. The crab evidently dreaded going into the sea. . . . . They soon die when kept a short time beneath the water.
The land crabs of the West Indies and North America descend from their mountain home in May and June, to deposit their spawn in the sea. They travel in such swarms that the roads and woods are covered with them. They migrate in a straight line, and rather than allow themselves to be deflected from it, 'they scale the houses, and surmount every other obstacle that lies in their way' (Kirby). They travel chiefly by night, and when they arrive at the sea-shore they 'bathe three or four different times,' and then 'commit their eggs to the waves.' They return to the mountains by the same route, but only the most vigorous survive the double journey.
Prof. Alex. Agassiz details some interesting observations on the behaviour of young hermit crabs reared by himself 'from very young stages,' when first presented with shells of mollusks. 'A number of shells, some of them empty, others with the animal living, were placed in a glass dish with the young crabs. Scarcely had the shells reached the bottom before the crabs made a rush for the shells, turned them round and round, invariably at the mouth, and soon a couple of the crabs decided to venture in, which they did with remarkable alacrity.' The crabs which obtained for their share the shells still inhabited by living mollusks, 'remained riding round upon the mouth of their future dwelling, and, on the death of the mollusk, which generally occurred soon after in captivity, commenced at once to tear out the animal, and having eaten him, proceeded to take its place within the shell.'[98]
There is a species of small crustacean (Podocerus capillatus) described by Mr. Bates, which builds a nest to contain its eggs. The nest is in the form of a hollow cone, built upon seaweed, and composed of fine thread-like material closely interlaced. 'These nests,' says Mr. Bates, 'are evidently used as a place of refuge and security, in which the parent protects and keeps her brood of young until they are old enough to be independent of the mother's care.'
Dr. Erasmus Darwin tells us, on the authority of a friend on whose competency as an observer he relied, that the common crab during the moulting season stations assentinel an unmoulted or hard-shelled individual, to prevent marine enemies from injuring moulted individuals in their unprotected state. While thus mounting guard the hard-shelled crab is much more courageous than at other times, when he has only his own safety to consider. But these observations require to be corroborated.
In 'Nature' (xv., p. 415) there is a notice of a lobster (Homarus marinus) in the Rothesay Aquarium which attacked a flounder that was confined in the same tank with him, and having devoured a portion of his victim, buried the rest beneath a heap of shingle, on which he 'mounted guard.' 'Five times within two hours was the fish unearthed, and as often did the lobster shovel the gravel over it with his huge claws, each time ascending the pile and turning his bold defensive front to his companions.'
The following is quoted from Mr. Darwin's 'Descent of Man' (pp. 270-1):—
A trustworthy naturalist, Mr. Gardner, whilst watching a shore-crab (Gelasimus) making its burrow, threw some shells towards the hole. One rolled in, and three other shells remained within a few inches of the mouth. In about five minutes the crab brought out the shell which had fallen in, and carried it away to the distance of a foot; it then saw the three other shells lying near, and evidently thinking that they might likewise roll in, carried them to the spot where it had laid the first. It would, I think, be difficult to distinguish this act from one performed by man by the aid of reason.
A trustworthy naturalist, Mr. Gardner, whilst watching a shore-crab (Gelasimus) making its burrow, threw some shells towards the hole. One rolled in, and three other shells remained within a few inches of the mouth. In about five minutes the crab brought out the shell which had fallen in, and carried it away to the distance of a foot; it then saw the three other shells lying near, and evidently thinking that they might likewise roll in, carried them to the spot where it had laid the first. It would, I think, be difficult to distinguish this act from one performed by man by the aid of reason.
Mr. Darwin also alludes to the curious instinctive habits of the large shore-crab (Birgus latro), which feeds on fallen cocoa-nuts 'by tearing off the husk fibre by fibre; and it always begins at that end where the three eye-like depressions are situated. It then breaks through one of these eyes by hammering with its heavy front pincers, and turning round, extracts the albuminous core with its narrow posterior pincers.'
Remarkable cases occur of commensalism between certain crabs and sea-anemones, and they betoken much intelligence. Thus Professor Möbius says in his 'Beiträge zur Meeresfauna der Insel Mauritius' (1880) that there are two crabs belonging to different genera which havethe habit of firmly grasping a sea-anemone in each claw and carrying them about, presumably to secure some benefit to themselves. The more familiar case of the species of anemone which lives on the shells tenanted by hermit crabs is of special interest to us on account of a remarkable observation published by Mr. Gosse, F.R.S. (Zoologist, June, 1859). He found that on his detaching the anemone (Adamsia) from the shell, the hermit crab always took it up in its claws and held it against the shell 'for the space of ten minutes at a time, until fairly attached by a good strong base.' It was said by the late Dr. Robert Ball that when the commonSagartia parasiticais attached to a stone and a hermit crab is placed in its vicinity, the anemone will leave the stone and attach itself to the hermit's shell (Critic, March 24, 1860).
I shall now allude to some of the more interesting facts touching the psychology of insects when in their immature or larval state. This is an interesting topic from the point of view which we occupy as evolutionists, because a caterpillar is really a locomotive and self-feeding embryo, whose entire mental constitution is destined to undergo a metamorphosis no less complete and profound than that which is also destined to take place in its corporeal structure. Yet although the caterpillar has an embryo psychology, its instincts and even intelligence often seem to be higher or more elaborated than is the case with the imago form. Where such is the case the explanation of course must be that it is of more importance to the species that the larval form should be in a certain measure intelligent than that the imago form should be so. Every larva is a potential imago, or breeding individual; therefore its life is of no less value to the species during its larval than during its adult existence; and if certain instincts or grades of intelligence are of more use to it during the former than during the latter period, of course natural selection would determine the unusual event which we seem here in some cases to see—namely, that theembryo should stand on a higher level of psychological development than the adult.
I may most fitly begin under this heading with the remarkable instincts of the so-called 'ant-lion,' which is the larva of a neuropterous insect, the commonMyrmeleon(M. formicarium). I quote the following account of its habits from Thompson's 'Passions of Animals' (p. 258):—