FamilyGeometridæ.
Selidosema panagrata(PlateXI., fig. 7 ♂, 7a ♀, 7b larva).
One of our commonest moths, occurring in great numbers in the forest throughout the whole summer.
The larvæ (Fig. 7b) are extremely variable, the most usual colouring being that of the individual figured, but when very young they are all of a uniform green with a conspicuous white dorsal line; as age advances the caterpillars become dark olive brown of varying degrees of intensity in different specimens, some retaining a considerable amount of their original green colouring, especially those feeding on the kawakawa (Piper excelsum), whose hue consequently harmonizes with that of the plant. These larvæ often select a forked twig to rest in, where they lie curled round with the head and tail close together. They are very voracious, and are the primary cause of the riddled appearance which the leaves of the kawakawa almost invariably present. Other food-plants are the "currant" (A. racemosa), and theMyrtus bullata; those taken from the latter have a strong pinkish tint, and are consequently very inconspicuous amongst the young shoots where they generally feed. The burrows ofHepialus virescensare frequently utilized by the larvæ which feed on the "currant," as convenient retreats during the winter, a large number being often found in a single hole. When full-grown they descend to the ground and construct, on the under-side of fallen leaves, loose cocoons of silk and earth from which the perfect insects emerge in about a month's time. The autumnal larvæ, however, either hibernate or remain in the pupa state throughout the winter. This moth is even more variable than the last species (S. dejectaria), which it occasionally somewhat resembles. The sexes are very different, the colouring of the male consisting of variousshades of warm brown (Fig. 7), while in the female the prevailing hue is slaty brown or even grey (Fig. 7a). Many specimens are much suffused with ochre and reddish-brown, while the stigma near the centre of the fore-wing, although sometimes almost obsolete, is often very conspicuous and black, white, or even yellow in colour. It would be of great interest to learn, by rearing a large number of these insects, whether the many varieties existing in the larval and perfect states could be traced to differences in food-plant, or some other external circumstance.
FamilyGeometridæ.
Selidosema productata(PlateXII., fig. 1 ♂, 1a ♀, 1b larva).
Abundant in the forest, where it may be dislodged from ferns and undergrowth during the day or captured flying about in the evening. Its larva is rather attenuated, and possesses a large hump on the second abdominal segment. In colour it is dark reddish brown, mottled with creamy white and pale green, and is sparsely supplied with a few isolated hairs (Fig. 1b). It feeds on the white rata (Metrosideros scandens), and when in its usual position—i.e., sticking straight out from a branch—absolutely defies detection. Specimens, however, may be readily procured with a lantern at night, when they may be found walking about and eating. The pupa state is spent in the earth, about two inches below the surface, the moth appearing in three or four weeks' time, this period, however, being extended in the case of autumnal larvæ, to as many months. It is extremely variable, scarcely two individuals being found exactly alike. The colouring, as in the caterpillar, is chiefly protective, consisting of a delicate tracery of browns and greys, which render the insect quite invisible when resting on the trunk of a tree, with its pale yellowish hind-wings concealed, a position it invariably assumesduring the daytime (Fig. 1 male, 1a female). The curious and interesting "Tatosomas," with their enormously elongated bodies, are closely allied to the present insect; one of them (Tatosoma agrionata) being found in similar situations, although in much more limited numbers; as, however, I know nothing of their transformations, I am forced reluctantly to pass them by.
FamilyGeometridæ.
Hydriomena deltoidata(PlateXIII., fig. 1, 1a larva).
One of our commonest moths, appearing in great numbers during January and February, in all open situations. It is especially abundant on the fern-hills.
The larva (Fig. 1a) feeds on the plantain. It is very sluggish, and lives all through the winter, becoming full-grown in September, when it changes into a pupa, among the roots of its food-plant. In colour it is a uniform dark brown.
The moth is extremely variable, but the figure may be taken as representing a fairly typical specimen. It is a pretty insect, and may be often seen resting on fences with its fore-wings folded backwards and forming together a triangle, whence its name ofdeltoidata. Any unusual-looking specimens of this species should always be netted, in order to form a thoroughly representative series, as many of the varieties are very interesting. A rather uncommon and remarkable-looking form occasionally occurs, in which the dark central band of the fore-wings is completely divided near the middle.
FamilyGeometridæ.
Asthena schistaria(PlateXII., fig. 2, 2a larva).
This delicate little insect may be often taken at rest on fences and tree-trunks during the day, and is aconspicuous moth when flying in the evening, owing to its light colour. The larva (Fig. 2a), which feeds on the manuka (Leptospermum ericoides), is very ornamental. Its general colour is light green, with black dorsal and lateral stripes, and a series of diagonal markings bordered with crimson; the legs and prolegs are also crimson, and the segments are divided by brilliant yellow rings, a white line extending down each side of the larva. It is difficult to find, as it remains closely concealed amongst the dense manuka foliage, from which it can only be dislodged by vigorous and continued beating. The caterpillars allow themselves to fall a short distance, hanging suspended by a silken thread, which they rapidly ascend when the danger is passed. The pupa is rather attenuated, dark-brown, and much pointed at its posterior extremity. It is found buried about an inch in the earth, and the moth appears in a month's time. This insect varies much in intensity of markings. The males are generally considerably darker than the females, but are more certainly distinguished by their attenuated bodies.
The pearly whiteAsthena pulchrariaoccurs in October and April; it is a most beautiful insect, and may be found amongst the foliage of the kawakawa (P. excelsum), on which its larva will probably be found to feed.
FamilyPyralidæ.
Scoparia hemiplaca(PlateXII., fig. 4).
This pretty little moth was reared from a larva found feeding amongst moss during the winter of 1885, but unfortunately I neglected to make a drawing until it was too late. Doubtless many of the other Pyrales we meet with in the New Zealand forest have similar habits, their larvæ probably feeding on different kinds of mosses. These can always be examined during the winter months,when the entomologist is usually in want of work, and thus much information may be obtained regarding this interesting but little-known family.
FamilyPyralidæ.
Scoparia sabulosella(PlateXIII., fig. 4, 4a larva).
This is that extremely abundant, though dull-coloured little insect, that rises in such multitudes from every field before one's footsteps during the early summer.
Its larva (Fig. 4a) feeds on various mosses, forming numerous silken galleries amongst the roots in which it resides. These caterpillars are very active, and consequently rather difficult to obtain, as they move either backwards or forwards in their galleries with equal rapidity.
They feed during the whole of the autumn and winter, changing into pupæ about September, from which the moths emerge in a month or six weeks' time.
The habits of the numerous other species belonging to this genus and the closely allied genusXeroscopa(Meyr) probably do not materially differ from those of the species here described.
FamilyPyralidæ.
Crambus flexuosellus(PlateXII., fig. 5).
An extremely abundant insect, occurring in swarms over meadows during the summer, where it may be captured in the daytime or taken by hundreds at the attracting lamp in the evening. Its larva is at present unknown, but probably feeds on the roots of grasses.
Closely allied isCrambus tahulalis, found in similar situations, but appearing rather later in the season, the earliest specimens being met with about January, whileC. flexuosellusis on the wing throughout the summer.
FamilyPyralidæ.
Siculodes subfasciata(PlateXII., fig. 3, 3a larva, 3b pupa).
This curious insect may be occasionally taken flying round patches ofMuhlenbeckia adpressa, which grows freely amongst brushwood in many parts of the country.
Its larva (Fig. 3a), is very stout and sluggish, resembling the caterpillar of an ordinary Pyrale in general appearance. It feeds in the stems of the creeper, causing large swellings therein, which readily betray its presence, and should therefore be cut off and kept until the moth emerges, as specimens obtained in this way are far superior to any captured in the open. The pupa is dark brown, and shining; it lies in the centre of one of the swellings, the larva having previously prepared a safe outlet for the moth in the form of a small burrow leading to the air, its extreme end remaining closed by a thin pellicle of the original bark, which effectually prevents the inmate's resting-place being discovered from the exterior (see Fig. 3b, the small circle marked * represents the outlet).
The perfect insect appears about December, flying rapidly in the hottest sunshine. It varies greatly, both in size and colour, some of the small males being very much suffused with dark brown, while the females usually resemble the figure (3), and are often more than twice the size of their mates. This insect is generally placed in a family called theSiculidæ, but I think without sufficient reason, and have therefore located it among the Pyralidæ, with which it has unquestionably a great affinity.
FamilyTortricidæ.
Isonomeutis amauropa(PlateXIII., fig. 2, 2a larva).
This odd little moth may be occasionally seen basking in openings in the forest, and usually flies awaywith lightning speed when an attempt is made to capture it.
The larva lives under the scaly bark of the matai-tree, feeding on the soft, juicy inner bark and sap. In colour it is light yellowish white, darker on the back, some specimens becoming quite pink on the dorsal surface. When full-grown it encloses itself in a tough silken cocoon, covered on the outside with fragments of wood, from which the moth emerges in about a fortnight's time.
The sexes differ considerably in appearance, the male having much broader wings, and darker in colour than those in the female from which the illustration (Fig. 2) is taken.
This insect is probably single-brooded, as the larva may be found feeding in the trees during the whole of the winter.
FamilyTortricidæ.
Cacoecia excessana(PlateXIII., fig. 5, 5a larva).
This is the commonest species ofTortricidæin New Zealand, and may be found almost without interruption during the whole of the year.
The larva (Fig. 5a) feeds on a great variety of plants, the common manuka being probably the most usual food for the species when in a state of nature. It now, however, eats numerous European plants, including honeysuckle and occasionally the fruit of the apple, but further evidence is required on the latter subject before we can really consider it as actually injurious in that direction.
In colour this caterpillar is light green with a yellow line on each side, but varies considerably; it feeds between several rolled-up leaves, in which it is afterwards converted into a pupa whence the moth emerges in about three weeks' time.
The perfect insect is also excessively variable and is often more or less suffused with yellow. It is most abundant inthe middle of summer, and may be taken at light, or in the daytime at rest on fences and trees.
FamilyTortricidæ.
Ctenopseustis obliquana(PlateXII., fig. 6).
This little moth is occasionally noticed at rest on garden fences during the autumn. Its larva inhabits the interior of the peach, feeding on the kernel, which appears to exactly meet its requirements, the caterpillar being full-grown as soon as it has completely devoured the nut. Before assuming the pupa state this insect provides a ready means of escape for the future moth by drilling a small hole through the hard shell and pulp of the peach to the air; it also spins a slight cocoon inside the stone, the pupa resting in the place formerly occupied by the kernel, in which position it is often discovered. The only noticeable mischief produced by this insect is delay in the ripening of the fruit. In fact all the infected specimens which I have seen were quite hard and green, whilst other fruit from the same tree had reached complete perfection.
FamilyTineidæ.
Endrosis fenestrella(PlateXII., fig. 7, 7a larva, 7b pupa).
This common species may be observed in almost any house in New Zealand, and is often mistaken for the dreaded "clothes moth" (Tinea tapezella), which it somewhat resembles in general appearance. Its larva (Fig. 7a) is very destructive, feeding on dried peas, amongst which it creates great havoc, drilling numerous holes through them and spinning a large number together, in the centre of which the caterpillar undergoes its change into a pupa (Fig. 7b), from which the moth emerges in about a fortnight's time. This insect should be destroyed whenever seen, as there is no doubt that much loss will be caused by its ravages in the future. It also infests bee-hives.
FamilyTineidæ.
Œcophora scholæa(PlateXIII., fig. 6, 6a larva).
This dull-coloured insect is extremely abundant during the early summer.
The larva feeds on the roots of various plants, forming numerous white silken galleries in the earth where it resides. In colour it is dark chocolate-brown with a yellowish head and white markings. It is very large, considering the size of the future moth, full-grown specimens often measuring as much as 10½ lines in length. About the end of September these caterpillars are transformed into pupæ, and the moths emerge in a month or six weeks' time.
The perfect insect may be often disturbed amongst brushwood. It is very sluggish on the wing and usually drops to the ground, where it is very inconspicuous. It also has a habit of running into any crevice immediately on the approach of an enemy. This peculiarity is shared by the other members of the genusŒcophora, of which there are large numbers in New Zealand.
FamilyTineidæ.
Semiocosma platyptera(PlateXII., fig. 8, 8a larva, 8b pupa).
This is one of the largest of theTineidæfound in New Zealand, measuring fully fifteen lines across the expanded wings. Its larva (Fig. 8a) is abundant under the bark of dead henau trees (Eleocarpus dentatus), feeding on the soft inner surface, but leaving the hard wood untouched. In colour it is pale yellow, the head and prothorax are dark brown and corneous, and the remaining segments are provided with two horny warts, from which numerous hairs arise; its legs are all very small, and the caterpillar is considerably attenuated posteriorly; it is very active, wriggling about with great violence when disturbed.
The pupa (Fig. 8b) is enclosed in a compact cocoon, constructed of minute fragments of wood, firmly woven together with silk, and attached to the inner surface of the bark, where it may be soon found by careful searching, and the finest specimens may thus be easily reared in captivity.
The perfect insect appears about November, and may be often observed at rest on the trunks of trees; its pale hind-wings are completely concealed by the dark upper pair, which render its discovery very difficult. The sexes may be at once distinguished by their size, the males being much smaller than the female (Fig. 8) and usually lighter in colour.
CHAPTER VII
The Neuroptera.
The Order Neuroptera, as here considered, is a very limited one, consisting only of the seven small families, which comprise the Lace-wings, Ant-lions, Caddis-flies, and a few others. It forms a most convenient passage from the insects undergoing a complete metamorphosis with a quiescent pupa, to those which are active during the whole of their life, as the larvæ are widely different from the adults, but the pupæ, although incapable of walking or eating, approximate very closely in structure to the perfect insects. I regret that my observations have been at present restricted to three families only,i.e., theHemerobiidæ,Sialidæ, andPhryganidæ, which will consequently have to represent the entire series. I understand, however, from Mr. A. S. Atkinson, that a species ofMyrmeleontidæ(Ant-lion) is not uncommon round Nelson, and doubtless future investigation will reveal insects belonging to the other families.
FamilyPhryganidæ.
Oxyethira albiceps(?) (McLach.) (PlateXIV., fig. 3, 3a larva, 3b pupa).
This insect occurs in the neighbourhood of ponds and streams during the summer. Its larva may be foundcommonly in the green, slimy weed floating in large masses on all stagnant waters. Being very small it is rather difficult to detect, and is best procured by washing a small quantity of the weed in a saucer of water, when the little insects will be at once seen walking about at the bottom. On examination with the microscope the case will first arrest attention, being of a most unique structure. Its shape is best described as closely resembling that of a minute pocket-flask, very much flattened at the lower end and almost transparent. Its surface is slightly corrugated, and the neck of the flask constructed of a much denser material than the body. It is open at both ends, the posterior end being perforated by a long shallow slit, which extends for nearly the whole width of the case, thus admitting a free circulation of water round the larva, which is also able to turn round and project its head and anterior segments through the lower aperture, thus occupying the reverse position to that shown in the illustration (Fig. 3a). It is, however, prevented from actually leaving the case by its abdomen, which is too large to be withdrawn from either end. The head and thorax of the larva are very horny in comparison with those portions permanently retained in the case, the legs being constructed to fold up into the smallest possible compass, a cavity existing in each joint for the reception of the preceding one—a structure which is almost universal among the caddis-worms. The two organs, situated on the posterior segments, are doubtless respiratory in their function, a large air-tube taking its rise from each and ramifying through the body in all directions. When alarmed these insects retreat into their cases with lightning rapidity, remaining concealed until the danger is passed. Their food probably consists of the green weed, although they are perhaps carnivorous, feeding on the rotifers and other animalculæ, which swarm in the water where they are found.
With regard to the method employed by the young larva in constructing, and subsequently enlarging, its case, I can give no positive information, although it is undoubtedly made of a viscous fluid, secreted by the insect, which hardens when exposed to the water; this secretion is no doubt analogous to the silk of caterpillars, which always exists in the form of a gummy fluid before being spun.
When about to change, the insect fixes its case down by four ligaments, two at each end, the extremities of these being firmly fastened to a stone; it then closes the small aperture, and constructs a curious arch-shaped partition, of dense material, a short distance from the broad end (Fig. 3b). In about a week's time the larva is transformed into a pupa, having the limbs, &c., free from the body but incapable of motion. The fixing down of the case prior to the change may be easily performed from each of the apertures, which are no doubt left open till the last for this purpose. Before the final transformation the pupa breaks through the partition at the broad end of the case and rises to the surface, the imago (Fig. 3) ascending a blade of grass to dry and expand its wings. The little exuvia of the pupa may be often noticed floating on the water, and the empty cases are very conspicuous on the sides of a glass aquarium, where the insects generally fix them down when in captivity.
FamilyHemerobiidæ.
Stenosmylus incisus(PlateXIV., fig. 2).
This lovely insect is figured as an example of this family, being found occasionally in the New Zealand forest, but is rather scarce as a rule. I regret that nothing is at present known of its transformations.
Family Sialidæ.
Chauliodes diversus(PlateXIV., fig. 1, 1a larva, 1b pupa).
During still warm weather, from December till March, this large insect is frequently observed flying lazily over water at dusk, when it may be readily captured with the ordinary net. Its larva is aquatic, living under stones in running streams, where it devours large quantities of Ephemeræ and other insect larvæ, which are always abundant in those situations. It is very ferocious and will bite violently when disturbed, being furnished with a pair of powerful mandibles. The curious filaments on each side are gills, and it will be noticed that they are situated exactly where the spiracles of the perfect insect afterwards appear (see Fig. 1a).
This larva probably lives over a year, its growth proceeding very slowly, but mature specimens are not infrequently met with quite as large as the illustration. When full-grown it leaves the water and forms an oval cell in the mud, usually under a large stone; its gills then gradually shrivel up, and in ten days or a fortnight it is transformed into the curious pupa, shown at Fig. 1b, from which the perfect insect proceeds in about six weeks' time. The sexes of this species may be readily distinguished by their size, the male being considerably smaller than the female (Fig. 1), and possessing longer antennæ.
CHAPTER VIII
The Orthoptera.
This Order, although including a comparatively small number of species, comprises some of the largest and most conspicuous insects inhabiting New Zealand, many of them reminding one of the denizens of the tropics in their gigantic size and striking appearance. They may be conveniently divided into the three following groups:—TheAquatic group, or those whose larvæ inhabit the water, including the Dragonflies, Mayflies, and Perlidæ; theTerrestrial group, including all the typical Orthoptera, Termites, and Mallophaga; and theEuplexoptera, including the Earwigs. We start our observations with the Aquatic group, as these exhibit the greatest affinity with the Neuroptera.
AquaticGroup.
FamilyLibellulidæ.[19]
Uropetala carovei(PlateXV., fig. 1 ♂, 1a larva.)
This magnificent insect occurs in all swampy situations during January and February, when it may be seen dashing about with amazing rapidity intent on catchingthe various flies which constitute its food. Its curious larva is represented at Fig. 1a, the drawing having been taken from a singularly perfect exuvia, which I had the good fortune to discover, clinging to the stem of a fuchsia-tree in a swamp, the rent through which the perfect insect escaped having almost closed up. In this state it no doubt feeds on various aquatic animals, which it procures with a prehensile instrument similar in structure to the "mask" of British dragonfly larvæ, but much larger.
The female of this species may be at once recognized by the absence of the two peculiar leaf-like appendages at the anal extremity, from which the insect takes its name. Her abdomen is also much stouter. My experience leads me to believe either that she is very retired in her habits or else that there are at least six males to one female.
Closely allied, and much commoner than the above insect, isCordulia Smithii, found almost everywhere, its rapid and continuous flight frequently taking it many miles away from any water. The specimen figured is a male (PlateXV., fig. 2), the female possessing a pair of slender sickle-shaped hooks, attached to the end of her body. She may occasionally be seen depositing her eggs in stagnant streams, the abdomen being violently beaten against the surface of the water during the operation. I have not yet met with the larva, which probably lives concealed in the mud. One specimen, taken near Lake Wairarapa, is remarkable in possessing a cloudy brown patch near the tip of each wing, but it is no doubt only a variety of the ordinary insect.
FamilyLibellulidæ.
Lestes colensonis(PlateXV., fig. 3, 3a larva).
Extremely abundant in all damp situations from September till May, being one of the last insects to disappear in the autumn. The larva is found under stones, &c., inevery stream, feeding on various aquatic insects and crustaceans. When very young the wing-cases are scarcely discernible, but gradually become more distinct at each moult, until the larva assumes the form shown in the illustration (Fig. 3a), which is taken from a specimen about a week before the emergence of the perfect insect. In all these insects it would be much more convenient to regard the metamorphosis as consisting of only two stages, viz., larva and imago, as there is really no condition analogous to the quiescent pupa of other orders. The female is rather stouter than the male, which is the sex figured, and her abdomen is of a dull bronze colour, instead of metallic blue. The only other dragonfly found in my neighbourhood (Wellington) is the pretty littleTelebasis zealandica(Fig. 4), which occurs in similar situations to the last, but is not quite so common. The male is of a brilliant red colour, the female being bronzy green, but she may be readily distinguished from the same sex inLestes colensonisby her smaller size. The larva of this species is rather more attenuated than that of the previous insect, and is of course considerably smaller.
FamilyEphemeridæ.
Ephemera, n.s., nearColoburus[20](PlateXVI., fig. 4, 4a larva).
The well-known mayflies are very extensively represented in New Zealand, hovering in swarms over running water during the summer evenings.
The larva of the present species (Fig. 4a) occurs abundantly under stones in rapid streams. It may be immediately distinguished from its numerous congeners by its large head and conspicuous black eyes. It is carnivorous,feeding on various small insects, chiefly those belonging to the present family, but in lack of these it will even devour individuals of its own species. It is consequently a most difficult insect to rear, and it was a long time before I succeeded in obtaining a single imago in captivity. When mature the insect leaves the water, and an apparently perfect imago escapes through a rent in the thorax in the usual way. In a few hours, however, a second moult occurs, the wings gaining additional size and beauty, and the anal setæ becoming very much more elongated than before (Fig. 4). This second change, which has so perplexed some entomologists, is merely anapparentdeparture from the general rule, a careful examination of the exuviæ of the dragonflies, and pupa shells of many other insects, revealing a delicate membrane within, which invests the imago, and is cast off at the same time as the harder external envelope. In the case of the mayflies, the retention of this internal membrane some two or three hours longer than usual, will fully explain its apparently unique metamorphosis.
FamilyPerlidæ.
Stenoperla prasina(PlateXVI., fig. 3, 3a larva).
This is the green gauzy-winged insect which we see flying feebly over running water, during the twilight, throughout the summer.
Its larva (Fig. 3a) is aquatic, hiding itself under stones, and devouring the unfortunateEphemeræfound in similar situations. Towards the end of its career the rudimentary wings become very conspicuous, at which time it is a most interesting object. The curious appendages on each side of the abdomen are gills, which the larva is constantly vibrating, in order to obtain a fresh supply of aërated water. When mature, it ascends the stem of some aquatic plant, the skin becomes dry and brittle, and finally bursting, allows the perfect insect to escape,and in a few hours its wings are sufficiently hardened for flight. Several other species occur in New Zealand, one of the commonest beingPerla cyrene, a black insect much resemblingS. prasina, but considerably smaller; its larva may be occasionally found, and is at once known by its dark colour.
TerrestrialGroup.
FamilyPsocidæ.
Psocus zealandicus, n.s. (PlateXVI., fig. 2, 2a larva).
During the hottest days in summer every one must have noticed numbers of minute active insects assembled on garden fences in groups, ranging from ten to fifty, immediately dispersing when disturbed. These are individuals ofPsocus zealandicus(Fig. 2), a curious little species, closely allied to the renowned "Book Tick" (Atropos pulsatorium), whose ravages in museums and libraries need no description. Its larva (2a) may be found in the same situations as the imago, and often assembles in similar groups. Its food probably consists of rotten wood and other decaying vegetable matter, and in its later stages it is provided with wing-cases, thus differing from the Book Tick (A. pulsatorium), which remains apterous during the whole of its life.
FamilyTermitidæ.
Stolotermes ruficeps(PlateXVI., fig. 1 ♂, 1a ♀, 1b "soldier," 1c "worker").
The termites, or white ants, which occur in such great numbers in the tropics, are represented in New Zealand by several small species, the commonest in this neighbourhood beingStolotermes ruficeps.
This species inhabits rotten logs, excavating extensive burrows, resembling in a very humble manner thewonderfully elaborate nests constructed by the African and other species, about which so much has been written, and so much remains to be discovered. The present insect appears in the perfect state during January and February. It is seldom noticed flying about, but may be readily obtained by opening the nests, where a large number are frequently seen huddled together in the main galleries. At this time the community consists of three classes of individuals, viz., males, females, and workers, which last are in all probability nothing more than the larvæ. After pairing they shed their wings and return to the nest, the female becoming very much distended with eggs. About March she commences to lay. This is continued for several months, and during this time the female is queen of the nest. She resides in a capacious chamber, from which numerous galleries diverge in all directions, some extending as far as eighteen or twenty inches, but the most populous portion of the nest is contained within a radius of six inches from the queen's apartment. The "soldiers" (Fig. 1b) now appear in considerable numbers. They are chiefly stationed in the royal chamber, and furiously attack any intruders; but the workers which stream in and out, carrying the eggs from the queen, they treat with the greatest gentleness. I have never seen soldiers in a nest containing winged insects, nor indeed later in the spring than October, when they seem to have all disappeared. With regard to the nature of these individuals I am unable to supply any positive information, but it appears probable that they are abortive males, in the same way that the neuters of the bees and ants are abortive females. As none of these insects have yet been reared, many points of great interest remain to be discovered in connection with their economy, and a rigid investigation of a number of nests kept in captivity, is the only mode by which we can hope to become fully acquainted with the habits of this interesting family.
FamilyBlattidæ.
Periplaneta fortipes(PlateXVII., fig. 5).
Few people who cut up old wood remain unacquainted with this species for very long, its insufferable odour immediately betraying its presence independently of anything else. It is very common under the bark of rimu, henau, and other large trees, where specimens may be found in all stages of growth; the mature individuals only differing from the young in the matter of size and the possession of rudimentary wing-cases. I have never found the females of this species carrying their eggs, but have, on several occasions, discovered the closely allied, but smaller,Periplaneta undulivittathus engaged under stones on the hills round Nelson. This is a much more agreeable insect to study thanP. fortipes, not possessing the disgusting odour so characteristic of the latter species.
The only wingedBlattidæfound round Wellington areBlatta conjuncta, andPeriplaneta orientalis. The former (Fig. 6), may be occasionally noticed under the scaly bark of rimu and matai trees, but a sharp eye and hand are needed to effect a capture, the insect running with marvellous rapidity. The latter species I have not yet noticed, but as it is the ordinary "cockroach" of Europe its habits have already been amply described.
FamilyMantidæ.
Tenodera intermedia(PlateXVII., fig. 2).
A local species confined, I believe, to the South Island, and occurring in some numbers round Nelson, where my specimens were obtained. It seldom flies, but crawls stealthily about the trunks of trees, in the hottest sunshine, capturing and destroying great quantities of insects, its green colouring and leaf-like form rendering it very inconspicuousto its victims. The purple spots on the tibiæ of this insect are very noticeable, and resemble small drums in structure, hence they are regarded by Mr. A. H. Swinton ("Insect Variety," page 239), as the organs of hearing. These curious drums may be also found in insects belonging to nearly all the remaining families of the Orthoptera, but, as we find no auditory organs occupying asimilarsituation in any other groups of insects, I think that Mr. Swinton's explanation of their function must be regarded at present as a somewhat doubtful one.[21]
FamilyPhasmidæ.
Acanthoderus horridus(PlateXIX.).
The curious Stick Insects are familiar to most people from their remarkable similarity to the twigs of trees.
The present species is one of the largest, the mature insect frequently attaining a length of five inches. It is best taken at night, when it may be readily discovered, feeding on the leaves of shrubs, and suddenly becoming perfectly motionless when the lantern is turned upon it. The favourite plant for this (and indeed most of the species) is the white rata, upon which they are often seen in large numbers when the entomologist is collecting Lepidoptera in autumn. One of the commonest species found in this way isBacillus(hookeri?) chiefly remarkable for its great sexual disparities, the male resembling a very slender stick about twenty-eight lines long, while the female is nearly half as long again (thirty-eight lines), and much more stoutly built. A more systematic investigation of this family is needed before we can pretend to correctly determine the various species, as there is little doubt that in other cases the sexes will be found quite as divergent. In addition to thisthe insects are most variable in colour, and their completely apterous character rendering the distinction between larva and imago a matter of considerable difficulty, it is very probable that some of the smaller species may be only immature specimens of the larger ones.
Stick insects are easily kept in captivity, and will not be found devoid of interest. They are great eaters, and grow with considerable rapidity, frequently casting their skin, a task of no easy accomplishment, which I once had the pleasure of watching in the case of a specimen ofAcanthoderus prasinuswhich I had under observation for several months.
The insect first suspends itself by its hind pair of legs, keeping the others in the same position as when walking, the head is bent in, and the antennæ are placed along the breast, the long abdomen hanging over backwards. The skin then splits along the back of the thorax, and the head and thorax are gradually pushed out. The front and middle legs are immediately afterwards extracted, the long femora and tibiæ easily passing the sharp angles in the exuvia, owing to their complete flexibility. When these are finally clear, the insect reaches forwards with its fore-legs and draws the abdomen and hind-legs out of the old skin, which remains attached to the branch until dislodged by some accident.
During the spring months great quantities of little stick insects may be noticed on the parasitic ferns covering the tree stems in the forest; they are curious little animals, their antics when simulating inanimate twigs being often most amusing, and if the reader wishes to investigate a comparatively untouched branch of entomology he cannot do better than keep a number of these until mature, when he will doubtless contribute much to our scanty knowledge of this curious family.
FamilyAchetidæ.
Acheta fuliginosa(PlateXVIII., fig. 1).
This destructive insect is not indigenous to New Zealand, having been introduced from Australia into the Nelson district many years ago. Strange to say it has never been seen in Wellington, where specimens must be constantly landed amongst produce, &c., but appear to be unable to effect a settlement, owing, probably, to some peculiarity of the climate which renders the place unsuitable for them. The larvæ may be first observed about December, when they are often seen hopping about the vegetation. They are extremely obnoxious, devouring everything, and frequently entering houses, where they consume provisions, clothes, and even boots. During the summer of 1875 the farmers round Nelson were fairly eaten out by this insect, the cattle absolutely starving for the want of food, but since that time the pest seems to have gradually diminished, although it is still very injurious to many garden plants.
The illustration (Fig. 1) is taken from a female, the male wanting the long ovipositor. These insects appear in the imago state about March, and continue in great abundance until the end of summer, the cold weather which generally sets in about the beginning of May rapidly destroying them.
FamilyGryllidæ.
Deinacrida megacephala(PlateXVIII., fig. 2 ♂,XVII., fig. 8 ♀).
This conspicuous species is especially interesting, as it may be regarded as the type of a very peculiar assemblage of apterous crickets, pre-eminently characteristic of New Zealand. It is very abundant round Wellington, and may be occasionally taken under logs, &c., but is best procuredfrom the hollow stems of various trees, where it is found inhabiting the deserted galleries of wood-boring species—frequently enlarging them to suit its own requirements.
The plant most usually selected by these insects is the mahoe (Melicytus ramiflorus), whose stems may be often seen pierced with large holes. Out of these the insects emerge at night to feed on the leaves. To extract a number of specimens, without injury, requires considerable care, and is best performed with a small axe, which should be first used to cut in about three-quarters through the trunk, just below one of the holes. Another notch is then cut about a foot lower down, and the intermediate wood split off in long pieces, until the tunnel is laid bare. On approaching an insect the first thing seen are two red threads, which are the antennæ, laid back as shown at Fig. 8. A deep notch is then cut into the trunk, some nine or ten inches below this point, and the piece bodily wrenched off. If the individual thus treated is a male he will cling firmly to the log, elevating his hind-legs in the air and biting viciously at anything within reach, but the females, in the majority of cases, endeavour to escape and hide themselves under the leaves, &c., on the ground. Both sexes when irritated emit a peculiar grating sound, which may be often heard at night in the forest, and is produced by the friction of the femur against a small file situated on each side of the second abdominal segment. They can also leap a short distance, but not so far as many of the smaller species (Libanasa macropathus, &c.). They are evidently strictly arboreal in their habits, as they exhibit great skill in walking along branches, and will climb up a thin stick with wonderful rapidity.
When in their burrows the posterior legs are extended behind the insect and push, while the anterior and intermediate ones are thrust forwards, the claws being firmly inserted, so as to enable the insect to pull itself along.Travelling along the burrow in this manner, they frequently evade all efforts to extract them, until they are stopped by arriving at the end of the gallery.
The sexes of this species are readily distinguishable, the male (PlateXVIII., fig. 2) possessing an immense head furnished with a pair of enormously powerful mandibles. The female (PlateXVII., fig. 8) is a more attractive insect, her gracefully curved ovipositor and smaller head having a much more pleasing appearance than the terribly menacing jaws of her mate. Both sexes are able to give severe bites, but it is extremely doubtful whether they would prove anything worse than slight mechanical injuries, as the insect is not likely to be poisonous. I am, however, unable tospeakfrom experience.
FamilyGryllidæ.
Xiphidium maoricum(PlateXVII., fig. 1).
This pretty insect may be found in great abundance round Nelson during the autumn, but is rarer in the Wellington Province. Its presence may be at once detected by the curious chirping heard in various directions shortly before sunset and lasting till eight or nine o'clock in the evening. This sound is produced with the wing-cases, which the male insects may be seen vigorously rubbing together. The females are quite mute, and they may be also distinguished by possessing a short curved ovipositor at the end of the body. The peculiarly leaf-like shape of the insect and its bright green colour render its discovery amongst the herbage a most difficult matter, even when its whereabouts is indicated by its cry—in fact, were it not for their music, there is little doubt that very few of these insects would ever be captured, as they are practically invisible, and are an instance of protective resemblance carried to great perfection.
When disturbed these crickets fly about twenty yardsand again settle in a bush or amongst herbage, carefully avoiding alighting on the ground where they would be readily visible. Their flight is somewhat feeble for such large insects. Great care must be taken, when capturing specimens for preservation, not to hold them by their powerful hind-legs, as they will not infrequently cast one off while endeavouring to escape.
I have not yet noticed the larva of this species, but should imagine it would closely resemble a wingless imago.
FamilyLocustidæ.
Caloptenus marginalis(PlateXVII., fig. 4).
This is the little grasshopper which rises before our footsteps in swarms on a hot summer's day; it is one of the last insects to leave us in the autumn, being frequently found in warm situations on fine days in the middle of winter. Owing to its great abundance this species must inflict considerable damage on the grass, as it has taken up its quarters like the English grasshopper in the cultivated fields, where an unlimited supply of food is always at hand. Formerly, no doubt, it was much less common round Wellington than at present, owing to the few open spots then existing, none of these grasshoppers being found in the forest.
The perfect insect may be recognized by the rudimentary wings which are present on the thorax, thus causing it to closely resemble the larval form of many of the winged species, and for which it might readily be mistaken were its true character unknown.
FamilyLocustidæ.
Œdipoda cinerascens(PlateXVII., fig. 3).
This large and conspicuous insect occurs abundantly in all open situations near Nelson, but is very rare in theWellington district, becoming, however, again common further north.
When disturbed it leaps into the air, spreads its wings, and flies away with great rapidity for thirty or forty yards, when it alights, and allows its pursuer to get within a few yards of his prize before again making off. This habit renders the capture of a good series of this insect a most arduous matter. The sexes may be readily distinguished by their size, the female being nearly twice as large as her mate.
This species is very variable in colour, some individuals being dark green whilst others are of a uniform drab.
The food of this insect consists of various domestic grasses, but I do not think it is at present sufficiently abundant to exercise any harmful influence on agriculture. By some entomologists, however, it is regarded as only a variety of the renowned migratory locust (Locusta migratoria), and as such its advent in large numbers might be viewed with serious apprehension.
It is also strange that although I have often seen large numbers of this species in the perfect state I have never observed the larva. I can only conjecture that the insect breeds in very secluded localities and then migrates in search of fresh food supplies.
GroupEuplexoptera.
FamilyForficulidæ.
Forficesila littorea(PlateXVII., fig. 7).
Abundant on the sea beach throughout the year, where it may be readily captured under stones and seaweed. It is a very bold insect, and when disturbed will grasp a blade of grass, or other object, very firmly with its powerful abdominal forceps, and allow itself to be lifted off the ground and carried away rather than relinquish its hold.