Fig 5. Entrance to wasp holeFig.5.
They make their nests of mud, etc., in crevices of walls, in banks, in plant stems, and oftenin most inconvenient places, such as keyholes, etc. Some of the solitary wasps have a very curious habit of making a tubular entrance to their hole. These may sometimes be seen projecting from sandy banks. The tube is composed of a series of little pellets of mud, which the wasp by degrees, with the help of its mouth secretions, sticks together till a sort of openwork curved tube of sometimes an inch long is formed (fig. 5). This curve is directed downwards, so that the wasp has to creep up it before reaching the actual orifice of the nest. It looks as if the first shower of rain would wash the whole structure away, and I have very little doubt that it often does so. The object of these tubes is difficult to appreciate. There is a bee on the continent which makes straight chimneys above its holes, so as to raise the entrance above the surrounding herbage; possibly these solitary wasps once requiredtheir tubes also for some such purpose, and have continued on truly conservative lines to build them long after all usefulness has passed away from the habit; anyhow they are very interesting and beautiful structures. I have found the tubes of one of our rarer species projecting perpendicularly out of the level sand, but even then the tubes were curved over at the end, so that the wasp had to go up and down again before entering its actual hole. The Rev. F. D. Morice in 1906 found the tubes of the same species in numbers projecting from the walls of an old stuccoed cottage situated close to the locality where I found mine, so it is evident that more than one situation suits its requirements. The solitary wasps provision their cells with caterpillars, stinging them in the same way as the fossors do. One very peculiar genus, of one species only in this country, has its body much narrowed at the waist by reason of the constricted form of the basal segment; it makes a little round nest of clay which it suspends from a twig of heather or other plant. This species is rarely met with except on the heathery commons of Surrey, Hants, Dorset, etc. Thesolitary wasps are subject to the attacks of cuckoos belonging to the jewel fly orChrysistribe; these behave differently from those belonging to the aculeate groups, as their larvæ do not eat the food laid up for the wasp, but wait till the wasp larva has finished feeding up, and then devour it. Unlike as these cuckoos are to their hosts in their brilliant metallic coloration, etc., they have structural characters curiously like theirs, so that even here a common parentage in bygone generations may be reasonably suspected. At present, however, they are placed, except by a few systematists, in quite distinct families of the Hymenoptera.
In general form these solitary wasps resemble the fossors more than the bees; they have mostly short tongues (I think all our British ones have), and their hairs are simple or more or less spirally twisted.
The social bees are certainly the most highly specialized of theAnthophila, and the social wasps of theDiplopteraor insects with folded wings. The ants occupy a less definite position: they would seem to be the outcome of specialization among the fossors, only they feed their young with vegetable juices and not with animal as the latter do. They are always kept as a separate tribe under the nameHeterogyna, but for our purposes the better known word "ant" will suffice.
The hive bee and the social wasps are the only British Hymenoptera which adopt the hexagonal cell-formation in their nests, the bee fashioning its cells in wax, the wasps and hornet in masticated wood or paper. The formation of ants' nests is far less regular, being composed of irregular passages, called galleries, and open spaces, no doubt built on a plan, but probablyin respect of plan no two nests are exactly alike. The humble bees again differ from either in their nesting habits: the female in the spring seeks out a mouse's nest or other suitable foundation of moss, etc., in or on the surface of the ground, according to the species. This she lines with wax, deposits a heap of pollen, and lays her eggs in it. She also makes waxen cells for honey, but these are not hexagonal and symmetrical as are those of the hive bee, but are more like little pots, and are known as "honey pots".
It must be borne in mind that the economic arrangements of the wasps and humble bees only last for a single season, whereas those of the ant and hive bee exist for many years. In consequence of this the swarming habits belong exclusively to the ants and hive bee. That of the hive bee is well known to all, and most people must have observed the swarms of male and female ants which fill the air on some sultry summer or autumn evening. Thousands of these must perish, but a certain number of the females accept the responsibility of starting a fresh nest, and so the ant population is kept up.It will be seen from these remarks that the three social groups are very distinct in their methods of nest making, and have really very little in common except the social habit. The humble bees have their cuckoos; one species of wasp has a cuckoo, and there is a possible case of a cuckoo amongst the continental ants, but this has not yet been observed in this country. The ants harbour so many species of insects in their nests besides their own family that it is difficult to form an idea as to whether the case in question is at all analogous to that of host and cuckoo in the other aculeates or not.
These little creatures are probably the most intelligent of all the insects—and yet at times they seem to wander about almost aimlessly. A worker may be found with an insect or something which it is eagerly dragging along and drops probably from fear. It appears anxious to regain its hold of it, but goes about in all sorts of wrong directions before it again finds it, it may be to make sure its enemy is clear away before it resumes operations, but the effect to the ordinary onlooker is one of sheer incapacity—at the same time the wonderful habits of the tribe, the way in which they keep plant lice for their larvæ, their methods of carrying each other, their nest-building, and the slave-making instincts of some of the species, show an intelligence surpassed by no other family of insects. Their nests are formed in very various ways: the same species even will sometimes nest under a stone and sometimes make ant hills; someof the large species make their nests of huge heaps of fir needles, and number 400 to 500 thousand in one nest—others live in quite small communities, nesting in bramble stems, old rotten wood, moss, etc. One little species, rare with us, lives in the walls of other ants' nests, just as mice live in the walls of our houses; another quite small species lives apparently on friendly terms with the common large red or horse ant, and may be found running about amongst them, on and in their nests, but, so far as I know, nothing is known as to how its young are reared. There is a curious division in the family between the ants that have true stings and those which have not. The large ants of our fir woods can bite and are able to eject poison through the apical opening of the body into the wound they create, but these as well as the larger and smaller black ants and some others have the sting undeveloped, whereas some of our small species have a sting which they can use with considerable effect; this difference in habit is accompanied by a difference in the structure in the basal segments of the body. In the stingless species the basal segment is reducedFig 6. Basal segments of antsFig.6to a flat upright transverse scale (fig. 6, 1); in the stinging ants two segments at the base are reduced to nodes (fig. 6, 3). There is an exception in the case of one little rare genus,Ponera, which has only the basal abdominal segment reduced to a scale although a much thicker scale than in the others (fig. 6, 2), and yet which has a distinct sting. These arrangements give the body very free movement so that the tail can be bent forward till it reaches the head. Another curious distinction between the stingers and non-stingers is that the larvæ of the former spin cocoons and those of the latter do not; the larvæ ofFormica fuscaoccasionally do not do so, but they are an exception to the rule. Cocoon spinning seems to involve the larvæ in some difficulties, as without the help of the worker ants they are often unable to extract themselves from their prison. This is a condition which does not, I believe, exist in other groups. In the stingless ants there is a curious difference in habit between thespecies of the genusFormica, where, according to Forel, the workers do not follow in line over unknown ground, and frequently carry one another, the one carried being rolled up under the head of the other, and the species ofLasius, where the workers follow one another in line, but never carry each other. Among the stinging ants another method of carrying occurs in certain genera. The porter seizes the one she wishes to carry by the external edge of one of her mandibles and then throws her over her back, so that she lies along the back of her porter with her ventral aspect uppermost and her legs and antennæ folded as in the nymph state. Neither of these methods sounds very comfortable, but then probably an ant's idea of comfort and our own may be very different.
Lord Avebury, in hisAnts, Bees and Wasps, tells us that he has known a male ofMyrmica ruginodislive for nine months, although no doubt, as he says, they generally die almost immediately, and he has known queen ants to live for seven years, and workers, which he had in his nest, for six years.
Of these we have only seven different kinds, and with the exception of the hornet they are all very much alike. One often hears people say that they have seen such a large wasp that they think it must have been a hornet, but no one who has ever seen a hornet could mistake a wasp for one. A hornet isred-brownwith yellow markings (pl. B, 13), a wasp isblackand yellow, and altogether a less formidable-looking creature (pl. B, 14). Even a queen wasp is not so large as a small worker hornet. The hornet nests in hollow trees, our three commoner wasps nest, as a rule, in the ground, but occasionally in outhouses, under roofs, etc. One of the others as a rule makes its nest in shrubs, but occasionally in the ground, another always nests in a bush or shrub, preferring a gooseberry or currant bush, and the only remaining one is a cuckoo of one of the ground species. The gooseberry-bushwasp is not a common species in the south, but in the midlands and north it is abundant. Wasps will eat most things, but are especially fond of syrups and sweets. One species,Vespa sylvestris, which seldom enters our houses, is very partial to the flowers ofScrophularia(Figwort). One rarely finds a plant of this in full blossom without finding its attendant wasps. I have seen other species of wasps also visiting it, butsylvestrisis practically sure to be there. The diet which wasps provide for their larvæ is probably a mixed one, but consists largely of insects. Dr. Ormerod says that a microscopic examination of the contents of a larval stomach shows "the mass to consist of scales, hairs and other fragments of insects, hairs of vegetables and other substances less easy of recognition."
Plate BPlate B.10.Colletes succinctus,female.11.Sphecodes subquadratus,female.12.Halictus leucozonius,female.13.Vespa crabro,female.14.Vespa vulgaris,female.15.Andrena fulva,male.16.Andrena fulva,female.17.Panurgus banksianus,female.18.Nomada ruficornis,var. signata,female.19.Epeolus rufipes,female.[face p. 36.
10.Colletes succinctus,female.11.Sphecodes subquadratus,female.12.Halictus leucozonius,female.13.Vespa crabro,female.14.Vespa vulgaris,female.15.Andrena fulva,male.16.Andrena fulva,female.17.Panurgus banksianus,female.18.Nomada ruficornis,var. signata,female.19.Epeolus rufipes,female.
[face p. 36.
Wasps do not store honey in their nest; the papery nature of their cells would make such storage impossible. I dare say some of my readers will have noticed wasps sitting in the sun on a wooden paling busily engaged apparently eating something—they are really pulling off little fibres of wood which they chew up into a substance fitted for the walls of their cells; they will also chew paper, and the experiment has been tried of giving them coloured papers, which resulted in stripes of colour appearing in their nests. The different species vary somewhat in the architecture of their nests; but they are built very much on the same general plan. The population of some underground nests is very large. The Rev. G. A. Crawshay estimated the number in a large nest ofVespa vulgaris, which he took on September 20, 1904, at about 12,000; of these he actually counted, including eggs and larvæ, 11,370, and estimated the rest as having left the nest and escaped, so that anyhow the computation cannot be far wrong. This, however, was probably a very large nest. The cuckoo wasp (Vespa austriaca), formerly known asV. arborea, is an associate ofVespa rufa; its habits had been suspected for a long time, but Mr. Robson set all doubts at rest by finding the nymphs of the cuckoo in the actual nest ofrufa. It is a rare species in the south, but far from uncommon as one goes north, and also in Ireland, where the relationship of the host and cuckoo have beencarefully studied by Prof. Carpenter and Mr. Pack Beresford.Vespa vulgarishas a beetle parasite, but this is somewhat of a rarity. This creatureMetœcus paradoxuslays its egg in the cell of the wasp, and enters the body of the larva, eventually entirely devouring it. The hornet also has a beetle associate, but this is a great rarity. It is a large black species of the "Devil's coach horse" or "Cock tail" tribe (Velleius dilatatus), but in what relation it stands to the hornet beyond inhabiting its nest is not known.
Of these beautiful creatures we have thirteen kinds in this country. Their velvety clothing and bright colours make them the favourites of most people. They are most industrious and may be seen on the wing from early morning often till quite late on summer evenings, whereas the solitary bees do not, as a rule, commence work till nine or ten in the morning, except in very hot weather, and generally retire about four or five p.m. There is an idea prevalent that humble bees do not sting, but this is fallacious. They can sting pretty severely, but I do not think they are so ready to use their defensive weapon as a wasp or hive bee is. The length of the tongue in these creatures makes them of great value to the farmer and gardener, as they can fertilize the red clover and probably other flowers which require a longer tongue to reach the nectary than is possessed by the hive bee.In New Zealand, when first the red clover was introduced from this country, it was found impossible to fertilize it, and humble bees had to be sent out. Now they are established there its fertilization is carried on quite successfully. The humble bees are divided into two natural groups, the underground species, i.e. those that make a subterranean nest, and the carder bees, as they have been called, which make a nest on the surface of the ground. The former live in much larger communities and are far more aggressive and pugnacious than the latter. They also feed their young, according to Mr. F. W. L. Sladen, of Ripple Court, in a different way. The carder bees "form little pockets or pouches of wax at the side of a wax-covered mass of growing larvæ into which the workers drop the pellets of pollen direct from their hind tibiæ. The pollen storers, on the contrary, store the newly gathered pollen in waxen cells, made for the purpose, or in old cocoons, specially set apart to receive it, from which it is taken and given to the larvæ mixed with honey through the mouths of the nurse-bees as required." As the author remarks, the methods of the undergroundspecies more resemble those of the hive bee than do those of the carder bees. Mr. Sladen has made many experiments in trying to domesticate humble bees, and succeeded so far withBombus terrestris(pl. D, 29, our common black and yellow banded species with a tawny tail) as to get it to breed in captivity, and in 1899 was able to show nests in full work at the Maidstone agricultural show, the bees coming in and out of the building to their nest. An interesting case of one of the carder bees (Bombus agrorum) is recorded by F. Smith. It invaded a wren's nest, heaping up its pollen, etc., amongst the eggs of the bird, till the parent bird was forced to desert the nest. The underground species are more subject to the attacks of cuckoos than the carder bees. Altogether the humble bees afford an excellent subject for study, as they appear to be amenable to treatment, and to any one who could give time and careful attention to them many interesting problems connected with them and not yet understood might have light thrown upon them. Dead humble bees are often found in numbers in a mutilated state, under lime trees. Thesehave been caught after they have filled themselves with honey, and become torpid in consequence, by the great tomtit and possibly other birds. The bird pecks a hole in the insect's thorax, enjoys the honey it has eaten and then drops the quivering body which falls to the ground. I once had the opportunity of seeing this slaughter going on, and was able to detect the great tomtit as the murderer.
In colour the humble bees vary remarkably, the variation occurring chiefly in the females. This variation is not so noticeable in this country, although in many species even here the variability is very great, but when we trace a common species such asterrestris, which varies very little here, over a large area such as the Palæarctic region its liveries are so diverse that its females have been treated as belonging to many different species. In the Siberian district its yellow bands become of a pale, almost whitish or straw colour, and the whole appearance of the insect is altered. If, instead of going north, we go to the Mediterranean region we find a large, fine form tolerably common, with bright yellow hairs on the legs. In Corsicaagain we find a quite different form; entirely black except for the bright red hairs on the apex of the body, and bright red tibiæ, clothed with red hairs. In the Canaries another coloration occurs: the whole insect is black with the exception of the apex of the body which is clothed with white hairs; but in all these the male varies comparatively little. In the Siberian and Canary forms it resembles the female, but in the others it varies very little from some varieties we find here. A rather similar series of varieties occurs inBombus hortorum, another species little liable to variation here. In Italy and south-east Europe a form with entirely black body and black wings occurs, and in Corsica a black form with reddish hairs on the apical segments. The male keeps throughout very constant to its normal coloration. The tendency to vary towards an entirely black form seems to exist in nearly all the species, although in Britain black varieties of some are very rare.
In this country we have only two genera in which the tongue is bifid at the apex, and on this account they are kept together as close allies in our classification. They are, however, very different in general appearance. One of these groups is calledColletes, on account of its habit of lining its cells with a gluey material, the other,Prosopis, on account of the markings on the face. The various kinds ofColletesare densely clothed on the head and thorax with brownish hairs, and the segments of the body have whitish bands composed of a dense, tight-fitting, duvet of hairs (pl. B, 10). There is in this country only one exception, a large insect like a hive bee, but rarely met with, its headquarters being the Wallasey Sandhills near Liverpool, and other localities in Lancashire. All the species tend to colonize; some building in huge coloniesin sandy cuttings, etc. They are preyed upon by a pretty little cuckoo bee calledEpeolus(pl. B, 19), which is black, ornamented with brownish red and whitish spots. One of our best known species,Colletes fodiens, can often be found in abundance on the heads of ragwort along the sea-coast in July.
The other genusProsopisis outwardly entirely unlikeColletes: its species are nearly all very small coal-black insects, with scarcely any noticeable hairs, rather unusually narrow and cylindrical in form; they emit a peculiar, agreeably scented fluid when handled; in the males the face is almost always white or yellow, in the females there is generally a yellow spot on each side near the eye. These little creatures are especially fond of burrowing in bramble stems. They like those which have been cut off in trimming the hedges, because in them the pith is exposed and they can burrow their way into it without gnawing through the wood. If any one, going along a hedge which has been trimmed, containing a lot of brambles, in the autumn or winter, would examine the cut-off ends they would soon find some with holes in them. Thesemay be the work ofProsopis, but there are other bees and fossors which also burrow in this way. So the stems should be brought home and opened. Then theProsopiscells may be known by the fine membranous pellicle which surrounds them, but possibly even then a little jewel-bee cuckoo may be found in possession of the cell, instead of the rightful owner. When these little bees emerge they are generally to be found on wild mignonette, bramble flowers or those of the wild parsley tribe. Some are very common, others of great rarity. The males of this genus seem to have a peculiar tendency to develop eccentricities in the shape of the first joint of the antennæ, or feelers, some having it expanded and concave, others rounded but thickened towards the apex; in only one British species,P. cornuta, does the female show any special peculiarity of form, but in this the face is produced on each side between the eyes into a distinct horn-shaped process. In the females there is scarcely any indication of pollen brush, and for this reason they used to be considered as possessors of cuckoo instincts, but there is now no doubt of their industrious habits; butthere is no other genus of industrious bees in this country, with the exception ofCeratina, with so little specialization for pollen collecting.
All the genera, except the two mentioned in the last chapter, belong to this section, which comprises a variety of very different styles of bees, beginning with the short spear-shape-tongued species and ascending to the long-tongued species, which are considered to culminate in the hive bee. The habits of these genera vary very greatly in some respects; special notice has been or will be given ofHalictus(pl. B, 12) andSphecodes(B, 11),Andrena(B, 15, 16),Nomada(B, 18) and the other cuckoos,Osmia(D, 28) andAnthophora(D, 24, 25) and the leaf-cutting bees, but there are several other genera which deserve a passing notice, although their habits are not so peculiar as those of the specially selected ones.Cilissa, which is a very close ally ofAndrena, is peculiar in having the hairs of the tongue erect and arranged almost in bottle-brush fashion. Its habits are much like those ofAndrena.Dasypoda, so called on account of the enormously long hairs of the pollen brushes of the legs in the female, is one of our most beautiful bees; it is of moderate size, a little more than half an inch long, with a brown haired thorax, and a black body with white apical bands on the segments; the hind legs are rather unusually long and the brush is composed of very long bright fulvous hairs, and when the bee returns home laden with pollen it is, as F. Smith says, "sufficiently singular to attract the attention of the most apathetic observer." It burrows in sandy places much after the fashion ofAndrena, etc. The male is a different looking insect, entirely covered with yellowish hairs.Panurgus(pl. B, 17) is a curious genus of coal-black bees, whose females have bright yellow pollen brushes on their hind legs; they visit yellow composite flowers and the males often sleep curled up amongst their rays; they are most active bees, and burrow generally in hard pathways. I was watching a large colony of one of the species near Chobham in the end of June—they were burrowing in a gravel path, under which the soil was of a black sandy nature; the path was scattered all over with little blackhillocks of sand, and seemed alive with bees. It was showery weather, and occasionally the hillocks were washed nearly flat and a lot of sand must have entered their burrows—however, as soon as the sun came out again they cleaned out their holes and returned to their work.Panurgusis most businesslike in its pollen collecting; it flies in a rapid headlong way into a flower, and seems to do its best to bury itself, with a remarkable amount of action as if it was in a great hurry, and often bustles out of it again almost immediately and goes on to the next. Its methods suggest that it does more work in five minutes than any other bee would do in ten.
Another genus,Anthidium(pl. D, 27), this time one of the long-tongued bees, is peculiar in having the male larger than the female. Both sexes are black, variegated with yellow markings and spots, but the male is more ornate in this respect than the female and also has a peculiarly shaped body, which is unusually flat, curving downwards towards the apex, which is armed with five teeth, two bent ones on the sixth segment and three on the seventh. The female collects pollen on the underside of its body and collects thedown off the stems of various plants, especially those of the dead nettle or "labiate" tribe, with which it invests its cells. I cannot do better than quote the following from F. Smith: "This is the social bee which White in his History of Selbourne has so well described in the following words: 'There is a sort of wild bee frequenting the Garden Campion for the sake of its tomentum, which probably it turns to some purpose in the business of nidification. It is very pleasant to see with what address it strips off the pubes running from the top to the bottom of a branch and shaving it bare with the dexterity of a hoop shaver; when it has got a vast bundle, almost as large as itself, it flies away, holding it secure between its chin and fore legs.'"
Fig 7. Leaf cut by beesFig. 7.
These are amongst the specially interesting of the bees in their habits. They are dull-brown coloured creatures rather like a stout hive bee in form (pl. C, 20). They all collect pollen on the underside of their body. They burrow either in decayed wood or in the ground, but they make their cells of pieces of leaves which they cut off from rose bushes or other plants; these cells when completed are wonderful works of art. Probably some of my readers may have noticed rose leaves with semicircular pieces cut out of them, and often with almost circular ones; this is the work of the leaf cutter (fig. 7).
Plate CPlate C.20.Megachile maritima,female. 21.Cœlioxys conoidea,male. 22.Cœlioxys conoidea,female. 23.Nest of Megachile willughbiella.[face p. 52.
20.Megachile maritima,female. 21.Cœlioxys conoidea,male. 22.Cœlioxys conoidea,female. 23.Nest of Megachile willughbiella.
[face p. 52.
She alights on a leaf, holds on to the edge of the piece she wants to cut off with her legs, and then cuts it out by means of her jaws, or mandibles; as soon as it is cut free she uses her wings and so prevents herself from falling, and goes off with the cut off piece safely held under her body by her legs. I have frequently seen bees flying home with their leafy burden, and once or twice I have seen them cutting the pieces out. They cut round the piece they select with great rapidity—the marvel is that they can arrange so exactly as not to fall when the last attachment is removed. The pieces they cut have to be of several shapes in order to build up the cell they require; some are more or less lozenge shaped, some almost circular; the cells they make are somewhat thimble-shaped. The lozenge-shaped pieces are used to build up the sides and lower end of the cell, and the circular pieces to close it in with at the top; it is all cemented together with a gluey substance excreted by the bee. The burrows of the leaf-cutters are made, as stated above, either in the ground or in rotten wood. I have never had a subterranean nest to examine, but have had several nests in rotten wood under my notice, one of which is now before me (pl. C, 23). It is in a piece of verysoft willow, almost in a touchwood condition. So that by carefully cutting away the wood I have been able to expose the whole series of cells. Two distinct burrows run almost parallel to each other; both of them are slightly curved and each has contained six cells; these are about half an inch long, and they fit one over another in the tube as closely as possible so as to look like two long thick green worms. Each cell is composed of many pieces of leaf, and the final plug which closes the cell is often made of several rounds of leaf one over the other. The amount of labour taken by the mother bee to make these cells must be enormous. The cells are provisioned like those of any other solitary bee with pollen, etc., and the egg is laid upon it. Most of the leaf-cutters have their attendant cuckoos, which are rather smaller than themselves, of a deep black with white bands on the sides of the body. The female has a very pointed tail, and the male's body ends in a series of spine-like projections (pl. C, 21, 22).
I have tried as much as possible to avoid scientific names, but the misfortune is that there are hardly any popular names in use which can be attached for certain to any particular species, and unless this can be done it is of no use using vague names like the "Carpenter Bee", the "Mason Bee", etc. There are many carpenter bees and many mason bees, and though their habits may be alike in this one particular they differ among themselves in the way they use their tools, and it is necessary to know which one we are talking about. It is a common thing to hear people inveighing against Latin names, etc., but they forget that there are no English ones in use, and what is more important, that Greek and Latin names are common property to all nations, so that we can all know what we are talking about, whereas if we call an insect by an English name and the Russianscall it by a Russian name, the difficulty of coming to a mutual understanding is very great. This is only an aside to justify the use of classical names. I quite feel that for popular use in this country a good series of English names might be useful, but we have not got one, and it would require a great deal of care and thought to frame a nomenclature which would really be useable by the persons who require it.
I have made these remarks here becauseOsmiais a genus whose members vary very much in their habits, and some species of which, like sensible beings, adapt their habits to their surroundings, so that no name such as carpenter bee, etc., would apply to all the species, or, as a rule, even to one.Osmia rufaespecially adopts several methods of nesting. This little bee is clothed more or less all over with yellowish hairs; it is compact in shape like all the other species ofOsmia, and like them collects its pollen on the underside of the body. It may sometimes be seen flying up and down the walls of a house looking for a crevice to build in, but it is not the least particular as to where to form its cells. In one memorable case the female selected a flutewhich had been left in a garden-arbour. The bee constructed fourteen cells in the tube of the instrument, commencing its first cell a quarter of an inch below the mouthhole. The flute is preserved in the Natural History Museum at South Kensington. At other times this species burrows in the ground, at others it makes its cells in crevices of old walls; it has been known to build in a lock, and is said sometimes to inhabit snail shells. Other species ofOsmiaalmost always burrow in banks, but in no case does a habit seem to be uniformly adopted by a species. One well known and rare species,Osmia leucomelana, is a regular bramble-stick species, tunnelling down the pith in the centre of the stalks, but I once found it to my surprise in fair numbers nesting in a sandy bank. Other species again, as a rule, select snail shells to build in; they find an old disused shell lying about in some sheltered place and adapt it to their purposes, commencing their cells singly in the narrow whorls of the shell and side by side as they approach its mouth, i.e. if the shell be a wide-mouthed one like the common garden snail (Helix aspersa). F. Smith, who gives a very interesting account of thesecreatures in hisCatalogue of British Hymenoptera in the British Museum, mentions a case where the bee finding the larger whorls of the shell too wide constructed two cells across the whorl. Another very interesting case given by Smith is of a nest of many cells of the rareOsmia inermis(which in his days was known asOsmia parietina). A slab of stone, 10 inches by 6, was brought to him with 230 cocoons of thisOsmiaattached to its under side; when found in the month of November, 1849, about a third of them were empty; in March of the following year a few males made their appearance and shortly afterwards a few females, and they continued to come out at intervals till the end of June, at which time he had 35 cocoons still unopened; in 1851 some more emerged, and he opened one or two of the closed ones and found that they still contained living larvæ; he closed them up again, and in April, 1852, examined them and found the larvæ still alive; at the end of May they changed to pupæ and appeared as perfect insects, the result being that some of the specimens were at least three years before reaching maturity.
There is a nest of yet another style adopted by one of our species (Osmia xanthomelana). This is formed of a series of pitcher-shaped cells made of mud, constructed at the roots of grass. The species which makes it is rare and seems to have its headquarters on the coasts of Wales, although it has occurred in the Isle of Wight and elsewhere. This species also is not constant in its habits, as it has been known to make its cells underground. A very curious habit was noticed some years ago by Mr. Vincent R. Perkins in another species of this genus (Osmia bicolor;pl. D, 28); the species nests in the ground or in snail shells, but, in the case under his observation, Mr. Perkins found that the little bees covered up all the snail shells in which they had built their cells with short pieces of "bents" so as to make a little hillock over each about two or three inches in height, somewhat resembling a miniature nest ofFormica rufa, the large horse ant, each mound containing hundreds of pieces. This is the only record I know of this habit, which must entail a large amount of labour for the bee.
These varying habits in the same speciesshow pretty clearly that these little creatures are not driven by any blind instinct in the adoption of their methods of nest building: they appear to have a distinct power of choice and adaptation according to their environment, unless of course it can be shown that the offspring of, say, a snail shell inhabitant follows its parents' habits, and that that of a ground borer does the same—but even that would not explain the case given by F. Smith, and quoted above, where anOsmiahad filled up the whorls of a shell and then, finding the final whorl too large, placed two cells horizontally to fill it: that seems to indicate distinct design on the part of the bee and would be hard to explain as due to instinct. Unfortunately, with the exception of a very few, the species ofOsmiaare rare in this country, so that few opportunities are available for studying their habits, which are certainly amongst the most interesting of any genus.
Plate DPlate D.24.Anthophora pilipes, male.25.Anthophora pilipes, female.26.Melecta armata, female.27.Anthidium manicatum, female.28.Osmia bicolor, female.29.Bombus terrestris, female.30.Bombus lapidarius. female.31.Psithyrus rupestris, female.[face p. 61.
24.Anthophora pilipes, male.25.Anthophora pilipes, female.26.Melecta armata, female.27.Anthidium manicatum, female.28.Osmia bicolor, female.29.Bombus terrestris, female.30.Bombus lapidarius. female.31.Psithyrus rupestris, female.
[face p. 61.
Anthophora pilipes(pl. D, 24, 25), one of our early spring bees, often forms enormous colonies. I have sometimes seen sandpits in which the sides were riddled all over with holes of this species, and where the insects were in such numbers that a distinct hum was audible from the vibration of their wings. In such colonies one is sure to detect some of their cuckoo associates,Melecta armata(pl. D, 26). They are deep black bees, much of the same size as their hosts but with more pointed tails and with a small spot of snow-white hairs on the side of each segment of the body; like other cuckoos they sail about in a more demure way than their hosts, but a more lively scene than a large colony ofAnthophoracan hardly be found. TheAnthophoraprovisions its cells with honey and pollen, and its egg in consequence floats on the top—thenumber of cells varies from five or six up to ten or eleven.
Anthophora pilipeshas a very close relative inAnthophora retusa, which also forms large colonies, but it is as a rule less common. These two species are exceedingly alike, in fact it requires some skill on the part of the observer to differentiate their females. They are both black and clothed with black hairs, and both have yellow pollen-brushes, but inretusathe hairs are shorter and not quite of such a deep black as those ofpilipes, and the spurs of the tibiæ are pale, whereas inpilipesthey are black. The males, however, differ widely, although much alike in colour; inpilipesthe feet of the middle pair of legs are clothed with enormously long hairs, the basal joint has a dense fringe of black hairs in front and some long black hairs behind (seepl. D, fig. 24); inretusathe basal joint of the middle pair of feet have a fan-shaped fringe of black hairs, and the rest of the joints are clothed with longer hairs, but not long enough to be specially noticeable.A. retusais visited by the same cuckoo asA. pilipesand also by its rare allyMelecta luctuosa, which only differs fromarmata(pl. D, 26) in the larger and squarer spots of the body and various small structural characters hardly appreciable except by specialists. The Anthophoras have other parasites besides their cuckoos; one is a beetle, which, however, is rare, and which lays its egg in theAnthophoracells; the other is a very minute member of the Hymenopterous family, whose larva when hatched feeds upon the larva of the bee. Notwithstanding these disadvantages both species are abundant, althoughretusais more local thanpilipes. A very interesting fact connected with this genus has just been communicated to me by the Rev. F. D. Morice. John Ray, who lived in the seventeenth century, mentions in his bookHistoria Insectorum(published posthumously in 1710), p. 243, that a large colony of a bee, which from his description was clearly anAnthophora, as he specially calls attention to the great difference between the males and females, inhabited a certain locality at Kilby near "Hill Morton" in Northamptonshire. Mr. Morice, who for many years resided at Rugby, knew Hillmorton, as it is now spelled, well, and tells me that a large colony ofAnthophorawas in that same locality when he knew it onlya few years ago. Of course there is no proof that it has been there throughout the intervening period, but there seems to be no reason to doubt it, and if so it is a most interesting case of a persistent colony.
Bees whether solitary or social enter flowers for the sake of the honey in their nectaries and the pollen on their anthers. In some cases the flowers automatically deposit pollen on the bees during the operation, which enables them to fertilize other flowers of the same species, but the pollen which the bee requires for its own use has to be worked for and collected on organs specially adapted for the purpose. These vary very much in the different families and genera; they exist only in the females, and, if the males get covered with pollen, as they often do, it is probably more by chance than purpose, and it is doubtful if it is of any value to the brood, although no doubt useful in fertilizing other flowers. All our bees, as has been pointed out before, are clothed more or less with branched or feather-like hairs, which would appear to be admirably adapted for the collecting of pollen.At the same time some species which have their bodies clothed with branched hairs have simple or spirally grooved hairs on the collecting organ—others collect on very much branched hairs—so that there seems to be no exact relationship between the plumosity of the hairs and their utility in collecting. The collecting brushes are either on the hind legs or, as in some cases, on the ventral surface of the body. In a femaleAndrena, the hind leg has a tuft of curled hairs near the base of the leg, and a more or less heavy brush on the outside of the tibia or shin (fig. 8). When a female returns after a collecting expedition these specially hairy regions are a mass of pollen grains, and the "beautiful yellow legs", so often remarked upon in some bees, are not always due to the colour of the hairs but to that of the grains of pollen adhering to them. The genera which collect on the under surface of the body have to visit flowers where the anthers lie in such a position that they can transfer the pollen on to it; the pea flower tribe are favourites with them, and also theCompositæ. All this section have long tongues so that they are able to reach the nectaries ofFig 8. Leg hairs of AndrenaFig.8.Fig 9. Corbicula of humble beeFig.9.plants with long tubular flowers. In visiting these the pollen is often deposited on the back of the bee; this it is able to transfer to its under side by means of the brushes on its feet or tarsi. The arrangements of the humble bees for pollen gathering are altogether different from those mentioned above. They have the hind shin outwardly shining and rather concave, with a series of long curved hairs running down each side of it and partly curving over it, so that they carry their mass of pollen in a sort of basket, scientifically called the "corbicula" (fig. 9); this would be impossible if the pollen were gathered dry, as it is by most of the solitary bees, so the bee moistens it on the flower with the nectar she has been sucking so as to make it sticky, and then transfers it into her basket by means of her foot brushes. The pollen therefore on the hind leg of a humble bee is all in one mass and can beremoved as such. When the bee reaches her nest this must of course save her the trouble which the solitary bee must have of cleaning off all the separate grains of pollen which are mixed up among the hairs.
A word or two may be convenient here on the combs and cleaning apparatus of bees. Any one who has watched a bee clean itself will have noticed that the front legs work more or less horizontally—a bee will lower its head and bring its front leg over it with a curved motion—and that it will clean the sides of the face with a sort of shaving-like action, also that the antennæ are apparently pulled through the foot-joint in a remarkable way, often many times in succession. Now the foot of a bee consists of five joints, and is clothed with bristly looking hairs. If these hairs be examined through a microscope they will be found to be more or less razor-shaped, having a thick back and a dilated wing or knife-like blade (fig. 10). In some the blade is of some width, and the edge is evidently very sharp: these hairs or spines no doubt do the cleaning work, and admirably adapted they are to the purpose. The antennæ-cleanerFig 10. Cleaning apparatus of beeFig. 10.Fig 11. Antenna cleaner of beeFig. 11.Fig 12. Cleaning apparatus of beeFig. 12.(it may possibly be used for other purposes too) is a still more wonderful adaptation; in the basal joint of the foot there is a semicircular incision, which, when examined under the microscope, is seen to be a small toothed comb. The foot itself fits into the tibia or shin, and at the apex of the latter is a modified spine which is dilated on one side into a wing, or knife-like blade; this shuts down on to the semicircular comb, and the insect by passing the antennæ between the two can clean off anything which may have stuck to it (fig. 11). When we come to examine the other legs we find that the inner surface of their tibiæ and tarsi, i.e. that which is nearest the body, is clothed with hairs which have the points dilated and spade-like (fig. 12), whichallowing for the different action of the hind legs makes them just as good cleaners as the razors of the front pair; the spurs at the apex of the tibiæ, which are known as thecalcaria, are also doubtless useful for cleaning purposes, and this is specially suggested by the beautiful saw-like form which they assume in some species; although there is no actual semicircular comb in the first joint of the tarsi, yet there can be little doubt that the spur and this joint in conjunction can act as a cleaning organ very much in the same way as the more elaborate arrangement in the front legs. Any one who has the opportunity of examining the hairs of bees under a microscope will be amply repaid for the trouble in noticing the beautiful shapes and structures which these organs assume. (Figs. 13-18; 17 showing pollen grains adhering.) At one time, when I was specially examining bee hairs, I shaved the various parts of a large number of species and mounted their hairs dry in microscopic slides, merely securing the cover glass with liquid glue; this was twenty years ago, and many are still quite good. It may seem a difficult operation to shave a bee, butthe hairs come off very easily, and with a sharp dissecting knife for a razor as many hairs as one wants are almost immediately at one's disposal.