Chapter VIII: Hemiptera, or Bugs—anoplura 532 (16)

FAM. 6. BOMBYCIDAE.—In entomological literature this name has a very uncertain meaning, as it has been applied to diverse groups; even at present the name is frequently used for the Lasiocampidae. We apply it to the inconsiderable family of true silkworm moths. They are comparatively small and uninteresting Insects in both the larval and imaginal instars; but the cocoons formed by the well-known silkworm are of great value, and some other species form similar structures that are of more or less value for commercial purposes. The silkworm has been domesticated for an enormous period, and is consequently now very widely spread over the earth's surface; opinions differ as to its real home, some thinking it came originally from Northern China, while others believe Bengal to have been its native habitat. The silkworm is properly called _Bombyx mori_, but perhaps it is as often styled _Sericaria mori_. Besides being of so great a value in commerce, this Insect has become an important object of investigation as to anatomy, physiology and development. Its domestication has probably been accompanied by a certain amount of change in habits and instincts, the creature having apparently lost its appreciation of freedom and its power of flight; it is also said to be helpless in certain respects when placed on trees in the larval state; but the importance of these points has been perhaps somewhat exaggerated.[245]

Although the family Bombycidae is very widely distributed in the warmer regions of the world, it includes only 15 or 20 {376}genera, and none of them have many species. The Mustiliidae of some entomologists are included here. Like the Saturniidae, the Bombycidae are destitute of proboscis and of frenulum to the wings, but they possess two or three internal nervures on the hind wing instead of the single one existing in Saturniidae.

FAM. 7. EUPTEROTIDAE (Striphnopterygidae of Aurivillius).—This family has only recently been separated from Lasiocampidae; its members, however, possess a frenulum; while none is present in the larger family mentioned. Its limits are still uncertain, but it includes several extremely interesting forms. The larvae of the European processionary moth, _Cnethocampa processionea_, are social in habits; they sometimes occur in very large numbers, and march in columns of peculiar form, each band being headed by a leader in front, and the column gradually becoming broader. It is thought that the leader spins a thread as he goes on, and that the lateral leaders of the succeeding files fasten the threads they spin to that of the first individual, and in this way all are brought into unison. The hairs of these caterpillars are abundant, and produce great irritation to the skin and mucous membrane of any one unlucky enough to come into too close contact with the creatures. This property is, however, not confined to the hairs of the processionary moths, but is shared to a greater or less extent by the hairs of various other caterpillars of this division of Lepidoptera. In some cases the irritation is believed to be due to the form of the hair or spine, which may be barbed or otherwise peculiar in form. It is also thought that in some cases a poisonous liquid is contained in the spine.

The larvae of other forms have the habit of forming dense webs, more or less baglike, for common habitation by a great number of caterpillars, and they afterwards spin their cocoons inside these receptacles. This has been ascertained to occur in the case of several species of the genus _Anaphe_, as has been described and illustrated by Dr. Fischer,[246] Lord Walsingham,[247] and Dr. Holland.[248] The structures are said to be conspicuous objects on trees in some parts of Africa. The common dwelling of this kind formed by the caterpillars of _Hypsoides radama_ in Madagascar is said to be several feet in length; but the structures of most of the other species are of much smaller size.

{377}The larvae of the South American genus _Palustra_, though hairy like other Eupterotid caterpillars, are aquatic in their habits, and swim by coiling themselves and making movements of extension; the hair on the back is in the form of dense brushes, but at the sides of the body it is longer and more remote; when the creatures come to the surface—which is but rarely—the dorsal brushes are quite dry, while the lateral hairs are wet. The stigmata are extremely small, and the mode of respiration is not fully known. It was noticed that when taken out of the water, and walking in the open air, these caterpillars have but little power of maintaining their equilibrium. They pupate beneath the water in a singular manner: a first one having formed its cocoon, others come successively and add theirs to it so as to form a mass.[249] Another species of _Palustra_, _P. burmeisteri_, Berg,[250] is also believed to breathe by means of air entangled in its long clothing; it comes to the surface occasionally, to renew the supply; the hairs of the shorter brushes are each swollen at the extremity, but whether this may be in connexion with respiration is not known. This species pupates out of the water, between the leaves of plants.

_Dirphia tarquinia_ is remarkable on account of the great difference of colour and appearance in the two sexes. In the Australian genus _Marane_ the abdomen is densely tufted at the extremity with hair of a different colour.

FAM. 8. PEROPHORIDAE.—The moths of the genus _Perophora_ have for long been an enigma to systematists, and have been placed as abnormal members of Psychidae or of Drepanidae, but Packard now treats them as a distinct family. The larvae display no signs of any social instincts, but, on the contrary, each one forms a little dwelling for itself. Some twenty species of _Perophora_ are now known; they inhabit a large part of the New World, extending from Minnesota to Buenos Aires. The habits of _P. melsheimeri_ have been described by Harris, Packard[251] and Newman, and those of _P. batesi_ by Newman.[252] The larva is very peculiar; there is a flexible pair of appendages on the {378}head, the use of which is unknown;[253] they arise by slender stalks behind and above the eyes, are about as long as the head, and are easily broken off. After hatching, the young larva, when it begins to feed, fastens two leaves together with silk threads, and so feeds after the fashion of a Tortricid, rather than a case-making, larva. Subsequently, however, the caterpillar entirely detaches two pieces of leaves and fastens them together at the edges, thus constructing a case that it lives in, and carries about; it can readily leave the case and afterwards return to it. When at rest, the larva relieves itself from the effort of supporting this case by the device of fastening it to a leaf with a few silken threads; when the creature wished to start again, "it came out and bit off these threads close to the case." Subsequently it changes inside the case to a pupa armed with transverse rows of teeth, like so many other pupae that are capable of a certain amount of movement. The larva is of broad, short, peculiar form, and is said to be very bold in defending itself when attacked. The moth is somewhat like the silkworm moth, though of a more tawny colour. Newman does not allude to any cephalic appendages as existing in the larva of _P. batesi_. If we accept the eggs figured and described by Snellen,[254] as those of _P. batesi_, it is possible that this Insect possesses a peculiar mode of oviposition, the eggs being placed one on the other, so as to form an outstanding string; but we think this example probably abnormal; the mode is not shared by _P. melsheimeri_. The genus _Lacosoma_ is considered by Packard to be an ally of _Perophora_. The caterpillar of _L. chiridota_ doubles a leaf at the mid-rib and fastens the two edges together, thus forming an unsymmetrical case. Many larvae of Microlepidoptera do something like this, but the _Lacosoma_ cuts off the habitation thus formed and carries it about. Packard says it may have descended from ancestors with ordinary habits and that certain peculiar obsolete markings on the body of the caterpillar may be indications of this.[255]

{379}

The Argentinian Insect _Mamillo curtisea_[256] is also probably an ally of _Lacosoma_. The caterpillar of this moth spins a dwelling for itself, and is remarkable from the bright colour of the thoracic segments, the following somites being colourless; the head bears a pair of large processes, quite different from those figured by Harris. The moth itself is very Geometrid-like in colour and form. This species is now assigned to _Perophora_, but it seems to be very doubtful whether many of the species placed in this genus really belong to it. The diversity of habits and instincts evinced by these moths of exceptional modes of life, but considered to be closely allied, is very interesting. The most remarkable of all is the Hammock-moth, _Perophora sanguinolenta_, of the centre of South America, the larva of which constructs its portable habitations out of its own {380}excrement, which is of peculiar form, specially suitable for the purpose. The caterpillar, when wishing to enlarge its case, builds it up from excrement "flattened at the sides, so as to adapt it for building purposes."[257]

FAM. 9. SPHINGIDAE (_Hawk-moths_).—A very important family of moths of large or moderate size. They have a proboscis which is frequently very long; there is a frenulum; the body is stouter than in most other Lepidoptera, and the wings are of small superficies in comparison with it; the antennae are somewhat peculiar, having a thick, solid appearance, pointed at the tip. This is usually somewhat hooked, and bears a few hairs. In the males the antennae are formed in a manner specially characteristic of the family. In section, each joint shows a chitinous process on the under side (Fig. 189, A), forming with that of the other joints a continuous ridge, and on each side of this ridge there exists a series of short, delicate "cilia" arranged in a very beautiful manner (Fig. 189, B). This structure, with some modifications, appears to be usually present in the family; it attains a very perfect development in cases where the tips of two rows of cilia bend towards one another, meeting so as to form an arched cavity. This structure is different from what occurs in the males of other families of Lepidoptera, for though cilia are very common, they are usually placed either on two projections from the body of the antennae (instead of on the two sides of a single projection), or there is but a single whorl, or set, of them on each joint (_Catocala_, etc.). The front wings are usually pointed at the tip, and are long in proportion to their width; but in the Smerinthini they are of different form, with the outer margin scalloped; the hind wings are remarkably small; the abdomen is frequently pointed, but in the Macroglossini, or Humming-bird hawk-moths, it is furnished at the {381}tip with a tuft, or with two tufts, of dense, long scales, capable of expansion.

The larvae are remarkable for their colours and form. The anterior segments are attenuated, but are capable of great retraction, so that in repose (Fig. 190, A) this shape is concealed by the curious attitudes that are assumed. There is in nearly all cases a conspicuous horn on the eleventh segment, and the body at the extremity behind the horn is so much modified that the terminal two segments look like little more than a pair of large claspers. In the Choerocampini, the thoracic segments are retractile, and can be withdrawn into the more or less inflated fourth segment, and give the creature somewhat the appearance of a miniature hooded snake. The larvae of Sphingidae do not bear any conspicuous hairs—except during the first instar. They do not spin cocoons, but bury themselves in the earth. The pupa is remarkable from the deep cleft that exists to admit air to the first spiracle, and for a deep depression on each side of the anterior part of abdominal segments 5-7; in some cases the proboscis projects on the breast somewhat like the handle of a pitcher.

A great deal has been written on the colours, markings, and attitudes of Sphingid larvae, and many interesting facts have been brought to light. We may refer the reader to the writings of Weismann[258] and Poulton,[259] without, however, recommending him to place an implicit confidence in their somewhat metaphysical disquisitions; for the views there shadowed will {382}necessarily became much modified with the advance of exact knowledge. It is certain that the position assumed by the same individual varies much according to age, and to the interval since the last moult; sometimes the attitude is much more remarkable than that shown in Figure 190, A, for the anterior segments are held erect, as well as contracted, the front part of the body being curled, and the Insect supported by the claspers and two pairs only of the abdominal feet. There is, too, a considerable difference in colour before and after an ecdysis. Piepers, who has had a long experience among Sphingid larvae in Java, considers that much of what has been written as to the protective value of their colours and attitudes, is mere fancy, and wild generalisation.[260]

Sphingidae have been recorded as capable of producing sounds in the larval and pupal, as well as in the perfect, instars; but the method in which this is done has not been ascertained, except in the case of the imago of the Death's-head moth, which is well known to emit a very audible cry when not on the wing; in this case it is highly probable that the method is the friction of the palpi against the proboscis, as stated by Réaumur and Landois; the inner face of the palp is said to be marked in this case with fine ridges or striae.

FAM. 10. COCYTIIDAE.—A single genus constitutes this family, and there are only three or four species known; they come from the region of New Guinea, whence the first was brought by D'Urville nearly a hundred years ago. They are still amongst {383}the rarest of Insects. Nothing is known as to their life-histories. In appearance they somewhat remind us of the Bee-hawk moths and Zygaenidae. Butler says[261] the family is characterised by the palpi, which differ much in the two sexes, and by the antennae resembling those of Castniidae or Hesperiidae. The form, transparency, and coloration of the wings reminds one vividly of the Sphingid genus _Hemaris_; the nervuration is somewhat like that of _Hemaris_, but has certain features of Zygaenidae. Butler places the family between Agaristidae and Zygaenidae.

FAM. 11. NOTODONTIDAE (_Prominents_, _Puss-moths_, etc.).—This is one of the most extensive of the families of Bombyces; it consists in larger part of obscure-coloured moths, somewhat like the ordinary Noctuidae of temperate regions; to which family the Notodonts are indeed considered to be very closely allied. The family contains, however, some very remarkable forms. _Tarsolepis_ has an elongate body, terminated (in the female of _T. fulgurifera_) by a very conspicuous tuft of enormously long, battledore scales; while in the male of _T. sommeri_ the hind legs are provided with an appendage of beautiful, roseate hairs. A few of the larger kinds bear a considerable resemblance in form and proportions to the Sphingidae. Some of the larvae are most interesting objects; the Puss-moth caterpillar, the Lobster, and the Dragon larvae are of such strange forms that they have already interested several generations of observers. The Puss-moth is common in the southern half of England; its caterpillar (Fig. 192) has, instead of the claspers, a pair of tubes in which are concealed {384}two long, flexible whips, capable of being thrust out, and withdrawn, with rapidity. The structure and the mode of action of these flagella have been well elucidated by Professor Poulton.[262] The flagella are to be considered as actual prolongations of the receptacle in which each is placed, though they are of very different texture therefrom; they are everted by blood-pressure and drawn in by muscular action; this latter function is very perfectly accomplished, the amount of relaxation and contraction of the muscle being very great. It has been maintained that the whips have arisen as arms of protection against the attacks of Ichneumon flies; observation shows, however, that the proportion of these "protected" Insects destroyed by enemies of this sort is quite as large as it is in the case of forms that are not so protected. The Puss-moth larva is also believed to be protected by terrifying attitudes,[263] as well as by ejection (like so many other larvae and insects generally) of fluid. There is no reason for believing that these larvae are less eaten than others, and consequently a further hypothesis has been proposed, to the effect that if they had not acquired these means of defence they would have been exterminated altogether. This supposition is considered to account for their acquiring the defence by means of natural selection; realising the dictum of D. O'Phace, Esq.—

Some flossifers think that a fakkilty's granted,
The minnit it's proved to be thoroughly wanted.

When the Puss-moth caterpillar is full grown it spins a peculiar cocoon of a solid and impervious nature, which it manages to make look very like the spots, crevices, or other places amongst which it is located; in this prison the creature remains for nine or ten months—by far the larger part of its existence. When it has changed to a moth it has to escape from the cell in which it so effectually confined itself. This is effected by the cocoon being thinner in front of the head of the moth, and by the emission from the alimentary canal of a fluid that softens the cocoon at the spot alluded to. Mr. Latter has ascertained[264] that this fluid is strongly alkaline, and contains potassium hydroxide. The front of the head of the moth is provided with a shield, consisting of a portion of the pupa shell, which enables the moth to {385}push through in safety, and at the same time protects the head from the emitted fluid. Figure 192 shows the great change that occurs in the period of a few hours in the size of the head of the larva, as well as in that of the spiracles: in A the old spiracles are seen surrounded by the much larger new orifices, which are at the moment of moulting quite visible through the skin that is about to be cast off.

The caterpillar of the Lobster-moth, _Stauropus fagi_, is more remarkable than that of the Puss-moth, but is unfortunately very rare. It has remarkably long thoracic legs, the abdomen is swollen at the tip, and instead of the terminal claspers has two long slender processes. The effect of these peculiarities is greatly enhanced by the extraordinary attitude assumed by the caterpillar, which holds the first five segments erect, with the second and third pairs of thoracic legs outstretched; the swollen terminal segment is also held erect. Hermann Müller states[265] that when seen from the front this caterpillar looks like a spider, and also that when alarmed it moves the long legs after the fashion of an Arachnid. He believes that it is thus effectually protected from the attacks of Ichneumons. Birchall says[266] that the young larva, when at rest, closely resembles, in colour and outline, one of the twigs of beech with unopened buds, on which it frequently stations itself; and that, when feeding, its likeness to a great earwig or to a _Staphylinus_ is very striking. Others say that this caterpillar resembles a dead and crumpled beech leaf.

The larva of _Hybocampa milhauseri_—the Dragon of old Sepp—is highly remarkable. When young it has grand lateral horns in front, and a dorsal row; as it grows the lateral horns disappear. Dr. Chapman says[267] that he could not understand at first why any larva should have such remarkable angular outlines, curiously conspicuous corners and humps. But he afterwards found that the creature exactly resembled a curled oak leaf, eaten and abandoned by a _Tortrix_ larva. This caterpillar also constructs an elaborate cocoon from which the moth escapes by an operation performed by the pupa, which is provided with two hard spines, called by Dr. Chapman sardine-openers. "By a lateral rotatory movement of the pupa, which obtains its fulcrum {386}from the tightness with which it is grasped by the cocoon, it traverses over and over again" the same part of the cocoon till it is cut through; at the same time the spines act as guides to a fluid which is emitted so as to soften the part that has to be sundered.

Though many other larvae of Notodontidae are of most curious form and assume remarkable attitudes, yet this is not the case with all, and some are quite ordinary and like the caterpillars of common Noctuidae. This is the case with the species _Rhegmatophila alpina_ we have selected to illustrate the metamorphosis of the Order (Fig. 157). Those who wish to form an idea of the variety of larval forms in this family will do well to refer to Packard's beautiful volume on the North American forms.[268] The family has a very wide distribution, but is absent from New Zealand and Polynesia, and appears to be but poorly represented in Australia. In Britain we have about two dozen species.

FAM. 12. CYMATOPHORIDAE.—A small family of nocturnal moths that connect the Bombyces with the Noctuids; they are usually associated with the latter, but are widely separated in Hampson's arrangement because of a slight difference of nervuration, nervule 5 being nearer to 6 than to 4, whereas in Noctuidae the reverse is the case. The Insects, however, in certain respects approach the Notodontidae, and are of interest if only as showing that the linear sequences we adopt in books are necessarily conventional, and to some extent deceptive. We have three genera in Britain; our pretty Peach-blossom, _Thyatira batis_, and the very different Buff-arches, _T. derasa_, being among them. Meyrick denies any connexion of this group with Noctuidae, and in his nomenclature _Cymatophora_ becomes _Polyploca_, and the family, consequently, Polyplocidae.

FAM. 13. SESIIDAE or AEGERIIDAE (_Clear-wings_).—A family of comparatively small extent; its members have frequently one or both pairs of wings in large part free from scales, the tip of the body tufted, the hind legs of one sex peculiar. The size is usually small, but in the largest forms the measurement may be but little less than two inches across the expanded wings. The pupa is of the kind classed as "incompletae" by Chapman, the appendages not being firmly glued to the body, and much {387}mobility existing; an "eye-collar" is present, and the segments of the abdomen are armed with series of teeth. The larva is a concealed feeder, nearly naked and colourless, but with the legs normal in number—three thoracic, four abdominal pairs of feet, and the terminal claspers; these are sometimes but poorly developed; the larvae have a greater or less resemblance to those of Longicorn beetles, the habits of which they share. The family was formerly associated with the Sphingidae, with which it has no true relationship; it is more closely allied to the Tineidae. Some of the species have a certain resemblance to Hymenoptera, which is probably in most, if not in all cases merely incidental. The proper position of the family was pointed out by Butler,[269] but he did not distinguish it from Tinaegeriidae. Meyrick calls the family Aegeriadae, and places it in his series Tineina.

We have two genera of these Clear-wings in Britain. They are _Trochilium_ (called variously _Sesia_, _Sphecia_, and _Aegeria_), with two species of comparatively large size, and _Sesia_ (called variously _Trochilium_ and _Aegeria_), with nearly a dozen species of smaller size. A third genus, _Sciapteron_, is doubtfully native with us. They are much prized by collectors on account of the rarity of the Insects and their great difference in appearance from our other native Lepidoptera.

FAM. 14. TINAEGERIIDAE. This is one of the least known of the families of Lepidoptera, and has only recently been distinguished from Sesiidae. It is entirely exotic, and our knowledge of it is principally due to Lord Walsingham.[270] Nothing is known as to the life-histories, except that it has been stated by Stainton that a larva feeds in webs on shoots of a shrub of the genus _Clerodendron_. The family is widely distributed, but its metropolis will probably prove to be the tropics of Africa. It is of considerable interest as showing that the Sesiidae really {388}belong to the Tineid series of moths. The species we figure (Fig. 193) has a character otherwise peculiar to Sesiidae in the wings being inserted on the thorax remote from the head—a feature we do not find in the Tineidae proper; while on the other hand it has the long wing-fringes, and the shape of the wings that are characteristic of Tineidae. It is worth mentioning that though these Insects are of excessive rarity and very peculiar, there exists in the Solomon Islands[271] a species distinct from, though at first sight excessively similar to, the S. African one we figure.

FAM. 15. SYNTOMIDAE.—This family has usually been associated with the Zygaenidae. It includes a large number of moths having, as a rule, in external appearance little to distinguish them from the family named. Many of them are of gaudy colours, and probably of diurnal, but somewhat sedentary, habits. The wings are less ample than usual, the hind pair frequently very small, so that the Insects have somewhat the proportions of Hymenoptera. In some cases the resemblance is made more remarkable by the fact that the wings are transparent and bare of scales, or have scales only at the margins, so as to be like the wings of Hymenoptera. Not less remarkable is the fact that these Insects use the body itself for the purposes of adornment or display; thus adopting a system prevalent in the Hymenoptera, rather than that of their own Order, where the rule is that the wings are more ornamented than the body. In many cases the shape of the body is so very different from the normal that the disposition of the organs of life in the interior of the body must be materially affected. In some genera, such as _Andrenimorpha_, the form, colour and attitude of the body and some of the limbs are plainly similar to Hymenoptera. These Insects have a highly-developed frenulum, retinaculum, and proboscis; bipectinate antennae in the male, a complex organ at the base of the abdomen on each side, and are in fact highly-developed forms, except perhaps as regards the structures in connexion with flight.

Unfortunately little or nothing is known as to the habits and metamorphoses of these extraordinary creatures, but it is no doubt to them Seitz referred in saying, "How far one may be deceived by appearances of a mimetic nature can only be comprehended by visiting the tropics; in this part of the world {389}[Europe] one is prepared by knowledge gained from books for the appearance _Sesia_ presents. Had one no knowledge of this sort as to Sesiidae he would actually in the field [in Brazil] overlook dozens of these little creatures without being aware of his deception. The surprise at finding a quite different being in the net from what one believes he has caught occurs daily in Brazil, so rich in Lepidoptera."[272] The same intelligent observer says[273] that a species of _Macrocneme_ was observed by him to be exactly like one of the blue wasps of the genus _Pepsis_.

One remarkable point in these Hymenopteroid Syntomids is their complete dissimilarity from their immediate allies. They resemble very different Hymenoptera; and not only stinging Hymenoptera; the Sessiliventres have a large share of their attentions; the numerous species of _Dycladia_ partaking the appearance of the South American Sawflies in a wonderful manner. Bees, Wasps of the most different kinds, and a variety of Sawflies are beautifully paralleled, if one may use such an expression, by these Syntomids. That shown in Fig. 194 has the abdomen formed like that of a Petiolate Hymenopteron; the base of this part, moreover, resembles in a remarkable manner the "median segment" of that Order. The constriction is, however, placed not at the base of the abdomen but beyond the second segment. Thus the structure is not morphologically similar to that of the Hymenoptera, for the median segment of Aculeate Hymenoptera consists of only one abdominal segment, while in this moth the corresponding part is formed of two segments. Though anatomically inexact, the resemblance is, as to proportions, correct; and those who delight in the use of the imagination will see that had the moth used only one segment for the imitation, the result would have been less successful owing to insufficient size. In his very interesting account of some Brazilian Syntomids,[274] Seitz describes a species of _Trichura_ provided with a long appendage that is held straight backwards during life; and he informs us that this creature resembles a female Ichneumon, the long process looking like the elongate ovipositor of the Hymenopteron. Possibly the species from Demerara we figure may resemble an Ichneumon we are not acquainted with, though its colour and form rather suggest a likeness to an Aculeate. {390}This case of resemblance is of the most noteworthy character, for an appendage of this kind in a Lepidopterous Insect is without parallel, and is almost equivalent to the production of a new structure. An interesting feature of the case is that Ichneumonidae do not sting, and there is no evident reason why the enemies of the moth should be particularly afraid of an ovipositor.

The larvae appear to be in form somewhat like those of Zygaenidae; but with the same sort of remarkable clothing, in the form of tufts and brushes, that we find in Lymantriidae. A cocoon is formed. In Britain no member of this family is to be met with, but _Naclia ancilla_ may formerly have been a native; _Syntomis phegea_ has occurred here; probably an escaped example that had been introduced in one of its earlier stages.

FAM. 16. ZYGAENIDAE (_Burnet-Moths_).—This family is one about the limits and characters of which much difference of opinion prevails. As exemplified by our Burnet-moths it is characterised (in addition to the points given in the table) by the peculiar, flexible antennae; these are a little thicker before the tip, but are curved and pointed at the extremity, and without pectinations in the male. There is an elongate proboscis; bladder-like organs at the sides of the first abdominal segment are not present. The pupa is softer than is usual in the Macrolepidoptera, and the parts are less firmly fixed together, so that unusual mobility exists; six of the intersegmental membranes {391}are free, and the abdomen has much power of movement; there is no eye-collar; the antennae, hind legs, and proboscis-tips stretch backwards as far as the fifth or sixth abdominal segment, the tips being quite free; on the dorsal plates of the abdomen there are rows of minute elevations reminding one of the teeth existing in pupae that live in stems or galleries. This is altogether a peculiar pupa; it lives closely enclosed in a small hard cocoon, and its great capacity for movement is perhaps connected with the fact that the pupa itself manages to force its way through the cocoon in anticipation of the emergence of the moth. This cocoon is fastened tightly to a stem, and is covered with a substance that gives it a glazed appearance. The larvae are objects of a baggy nature, with inferior coloration, consisting of large dark blotches on a light ground, and without any remarkable development of their somewhat feeble system of hairs. Numerous small moths from the tropics are assigned to the family; they are most of them conspicuously marked and coloured, and like our Burnets are probably diurnal.

The family Chalcosiidae is reduced by Hampson to the position of a sub-family of Zygaenidae. It consists of a large variety of diurnal moths of varied and brilliant colours, with an expanse of wing large in comparison with the typical Zygaenae, and with the antennae pectinate or flabellate to the tip. Some of these Insects (which are as conspicuous as possible in appearance, at any rate in a cabinet, the East Indian _Cadphises moorei_ _e.g._) are considered to be destitute of any special "protection." _Histia_ is a genus of remarkable cruciform moths, of a mixture of black and metallic colours, with carmine-tinted bodies. _Hampsonia pulcherrima_ (East India) is a curious moth of butterfly form and coloration, red and black with yellow patches, and with some of the nervules distorted, as if they had been forced apart in certain spots in order to accommodate these patches.

Two or three hundred species of Chalcosiidae are recorded. They are specially characteristic of the Indo-Malayan region.

{392}FAM. 17. HIMANTOPTERIDAE (THYMARIDAE of some authorities) are placed by Hampson in the sub-family Phaudinae of Zygaenidae characterised by the absence of the mouth-parts. The Himantopteridae are small moths, and have the scales on the wings very imperfect and hair-like; the hind wings form long slender tails, so that the Insects scarcely look like moths. They are peculiar to India and Africa. In the South African genus _Dianeura_ (belonging really to Phaudinae) also the wings are scaleless and nearly transparent.

FAM. 18. HETEROGYNIDAE.—Consists of the single genus _Heterogynis_ which has hitherto been found only in the south of Europe. This is an important form connecting Zygaenidae and Psychidae. The larvae resemble those of Zygaena, and construct an oval cocoon for their metamorphosis. The male issues as a small moth of smoky colour, the scales being but imperfect; the female chrysalis shows no trace of any appendages, and the imago is practically a maggot, and never leaves the cocoon; in it she deposits her eggs, and the young larvae hatch there.[275]

FAM. 19. PSYCHIDAE.—Small, or moderate-sized moths, with imperfect scales, and little or no colour beyond certain shades of duskiness; the sexes very different, the female being wingless and sometimes quite maggot-like; the male often with remarkable, bipectinate antennae, the branches sometimes very long and flexible. Larva inhabiting a case that it carries about. This family consists of Insects unattractive in appearance but presenting some points of great interest. It is frequently stated that the Psychidae are destitute of scales, but Heylaerts states[276] that, in addition to hairs, scales of a more or less imperfect formation are present in all, but that they are, like those of some Sphingidae (_Macroglossa_), very easily detached. There is much difference in the females, some having well-developed legs, while others are not only apterous, but are bare and destitute of appendages like a maggot, while in certain cases (Fig. 196, G), the head is reduced in size and is of peculiar form so as to make the Insect look really like the larva of one of the parasitic Diptera. These females never leave their cases, but deposit their eggs {393}therein, and inside, also, their former pupa-skin; and here the young hatch; the peculiar little larvae are very numerous, and it is suggested that they make a first meal on the body of their parent, but this we believe has not been satisfactorily ascertained. Great differences as to the condition of the legs, antennae, etc., are said to exist in species of the same genus. There is also a remarkable diversity in the pupae of the females; the male sex being normal in this respect. Some of the female pupae are destitute of wing-sheaths and all other appendages, while others are said to possess them, though there are no wings at all in the imago (_Fumea_, _e.g._).[277] Great difficulties attend the study of these case-bearing Insects, and several points require careful reconsideration, amongst them the one we have just mentioned. The males fly rapidly in a wild manner, and may sometimes be met with in swarms; their lives are believed to be very brief, rarely exceeding a couple of days, and sometimes being limited to a few hours.

The larvae are called basket-worms, and their baskets or cases are well worthy of attention. Their variety is remarkable; the most extraordinary are some of the genus _Apterona_ Fig. 197, B, which perfectly resemble the shells of Molluscs such as snails; indeed, the specimens in the collection at the British Museum were sent there as shells. This case is not, like those of other Psychidae, constructed of earth or vegetable matter, but is of silk and is in texture and appearance exactly {394}like the surface of a shell. _Psyche helix_ is, according to Ingenitzky,[278] found in great numbers near Lake Issyk-kul in Central Asia, where the larvae feed, in their snail-shell-like cases, on a grass, just like snails. Only females could be reared from these larvae. The case of _Chalia hockingi_ (Fig. 197, C) consists of little pieces of wood cut to the proper lengths, and spirally arranged, so as to form a construction that would be quite a credit to our own species. In some of the Canephorinae we meet with long cylindrical cases, like those of Caddis-worms, or of Tineid larvae.

Riley has given an account of several points in the structure and natural history of one of the North American basket- or bag-worms, _Thyridopteryx ephemeraeformis_; one of his points being the manner in which the newly hatched larva forms its case.[279] This question has also been discussed by Packard.[280] The larvae when hatched in unnatural conditions will make use of fragments of paper, cork, etc., for the case; the act of construction takes one or two hours, and the larva does not eat till the case is completed. It walks in a peculiar manner, the legs of the third pair being moved forwards together, as if they were the prongs of a fork.

This family is already one of considerable extent, but its study, as already remarked, is but little advanced. Some naturalists are inclined to place it among the Tineidae, but it is connected with Zygaenidae by means of Heterogynidae. Mr. Meyrick divides it, placing _Psyche_ and _Sterrhopteryx_ (the forms representing, according to his ideas, the family Psychidae in Britain) in the series Psychina which includes Zygaenidae. He {395}removes the other British genera, _Fumea_, and _Epichnopteryx_, to Tineidae near _Solenobia_ and _Taleporia_. The group Canephorinae, to which the two genera in question belong, was long since separated from Psychidae by Herrich-Schäffer, but this course was condemned by Heylaerts. Parthenogenesis has been thought by some to occur in numerous species in this family, but Heylaerts says that it is limited to _Apterona crenulella_ var. _helix_, and even of this species males are found in certain localities.

FAM. 20. COSSIDAE (_Goat-Moths_, or _Carpenter-Worms_).—Moths of moderate, or rather large size, without proboscis, frequently with a dense covering of matted, imperfect scales; the pattern being vague. The larvae bore into trees in which they often make large burrows, leaving holes from which sap exudes. Our common Goat-moth is a good specimen of this family, which is a very widely distributed one. The Australian genus _Ptilomacra_ has very large, pectinated antennae in the male. The larvae of Cossidae are nearly bare of clothing and are unadorned; they form a slight cocoon of silk mixed with gnawed wood. The pupa of the Goat-moth is remarkable for the great development of the rows of teeth on the dorsal aspects of the segments of the abdomen, and for the absence of consolidation in this part, six of the intersegmental incisions being free, and the ventral aspect almost membranous. Very little is known as to other pupae of the family. It is believed that the generations of these Insects are fewer than usual, the growth of the larva occupying a period of two or three years. The larva of _Zeuzera aesculi_ forms a temporary cocoon in which it passes a winter-sleep, before again feeding in the spring.[281] It is a moot question whether the Zeuzeridae should be separated from the Cossidae or not. The group includes our Wood-leopard moth, which, like many other Zeuzerids, is spotted in a very striking but inartistic manner. The position the family Cossidae should occupy in an arrangement of the Lepidoptera is a very difficult question. Some consider the Insects to be allied to Tortricidae. The wing-nervuration of _Cossus_ is very peculiar and complex, there being four or five cells on the front wing, and three on the hind one. Meyrick places Zeuzeridae as a family of his series Psychina, but separates Cossidae proper (he calls them Trypanidae) as a family of the series Tortricina.

{396}FAM. 21. ARBELIDAE.—Closely allied to Cossidae, but without frenulum, and with less complex wing-nervures. A small family believed to be similar to Cossidae in the life-history. The tropical African Arbelidae are considered by Karsch to be a distinct family, Hollandiidae.

FAM. 22. CHRYSOPOLOMIDAE.—This family has been established by Dr. Aurivillius[282] for an African genus, allied in wing-nervuration to Cossidae; the Insects are like Lasiocampidae.

FAM. 23. HEPIALIDAE (_Ghost-_ and _Swift-Moths_).—Moths of very diverse size, some gigantic; wings not fitting together well at the bases; without a frenulum; no proboscis; the scales imperfect; the nervures complex. The Hepialidae are extremely isolated amongst the Lepidoptera; indeed, they have really no allies; the conclusion that they are connected with the Micropterygidae being certainly erroneous. Although but small in numbers—only about 150 species being known—they exhibit a remarkable variety in size and colour. Many are small obscure moths, while others are of gigantic size—six or seven inches across the wings—and are amongst the most remarkably coloured of existing Insects. The great _Charagia_ of Australia, with colours of green and rose, bearing white spots, are remarkable. The South African _Leto venus_ is of large size, and has an astonishing supply of glittering metallic splashes on the wings, making a barbaric but effective display. The South Australian _Zelotypia staceyi_, of enormous size, is also a handsome moth; but the majority of species of the family are adorned only in the feeblest manner.

Very little is known as to the larvae; they are either subterranean, feeding on roots, or they live in the wood of trees and shrubs. They are nearly bare, and are apparently the lowest type of Bombycid larva. At the same time, it would appear there is considerable variety amongst them. Packard says[283] the young larva of _Hepialus mustelinus_ has the arrangement of setae that is normal in Tineidae. The larva of _H. humuli_ seems to be a very simple form, but _H. hectus_ shows a considerable amount of divergence from it. They probably live for several years; the larva of _H. argenteo-maculatus_ in North America lives for three years, at first eating the roots of Alder and then entering the {397}stems. The pupae are also peculiar. They are of unusually elongate, cylindrical form, with comparatively feeble integument, but with a considerable development of chitinous, elevated, toothed ridges, on the dorsal aspect, and a very strong ridge of this kind on the ventral surface of the seventh segment; the wing-sheaths are short; it is very difficult to distinguish the full number of abdominal segments. These pupae are remarkably agile, and by wriggling and kicking are able to move a considerable distance; it is said that they can force themselves to the surface even when the superficial soil is quite hard. We cannot consider this pupa naturally placed amongst either the pupae obtectae or incompletae of Chapman.

We have already remarked that little is known as to the life-histories. The species are probably prolific, a female of _H. thule_ having been known to deposit more than 2000 eggs. Of the Australian forms little more is known[284] than that they live in the wood of trees and shrubs, and are rapidly disappearing; we may fear that some are extinct without ever having been discovered, and others, also unknown but still existing, may disappear only too soon; the wasteful destruction of timber in Australia having been deplorable.

The peculiar habits of the Hepialidae are not likely to bring the Insects to the net of the ordinary collector, and we believe they never fly to light, hence it is probable that we are acquainted with only a small portion of the existing species; their distribution is very wide, but Australia seems to be their metropolis, and in New Zealand twelve species are known. The genera as at present accepted are remarkable for their wide distribution. _Leto_ is said to occur in South Africa and in the {398}Fiji Islands; but we must repeat that the study of these interesting Insects is in a very primitive state, and our present knowledge of their distribution may be somewhat misleading.

The habits of the European _Hepialus_ in courtship have been observed to a considerable extent and are of great interest, an astonishing variety and a profound distinction in the methods by which the sexes are brought together having been revealed.

_H. humuli_, our Ghost-moth, is the most peculiar. Its habits were detected by Dr. Chapman.[285] The male is an Insect of exceptional colour, being white above, in consequence of a dense formation of imperfect scales; the female is of the brownish tints usual in Swift-moths. In the month of June the male selects a spot where he is conspicuous, and hovers persistently there for a period of about twenty minutes in the twilight; his colour has a silvery-white, glistening appearance, so that the Insect is really conspicuous notwithstanding the advanced hour. Females may be detected hovering in a somewhat similar manner, but are not conspicuous like the male, their colour being obscure; while so hovering they are ovipositing, dropping the eggs amongst the grass. Females that have not been fertilised move very differently and dash about in an erratic manner till they see a male; they apparently have no better means of informing the hovering male of their presence than by buzzing near, or colliding with him. Immediately this is done, the male abandons his hovering, and coupling occurs. There can be little doubt that the colour of the male attracts the female; but there is a variety, _hethlandica_, of the former sex coloured much like the female, and in some localities varieties of this sort are very prevalent, though in others the species is quite constant. This variation in the colour of the males is very great in Shetland,[286] some being quite like the females. In _H. hectus_ the two sexes are inconspicuously and similarly coloured. The male hovers in the afternoon or evening in a protected spot, and while doing so diffuses an agreeable odour—said by Barrett to be like pine-apple—and this brings the female to him, much in the same manner as the colour of _H. humuli_ brings its female. The hind legs of the male {399}are swollen, being filled with glands for secreting the odorous matter.[287] This structure has led to the suggestion of the generic name _Phymatopus_ for the Insect. Turning to other species of the genus, we find that the normal relative rôles of the sexes are exhibited, but with considerable diversity in the species. In _H. lupulinus_ the males fly about with rapidity, while the female sits on a stem and vibrates her wings; she thus attracts the males, but they do not perceive her unless happening to come within three or four feet, when they become aware of her proximity, search for and find her. It is doubtful whether the attraction is in this case the result of an odour; it would appear more probable that it may be sound, or that the vibration of the wings may be felt by the male.

In _H. sylvinus_, _H. velleda_ and _H. pyrenaicus_ less abnormal modes of attracting the males occur, the individuals of this latter sex assembling in great numbers at a spot where there is a female. In the first of the three species mentioned the female sits in the twilight on the stem of some plant and vibrates the wings with rapidity; she does not fly; indeed, according to Mr. Robson, she does not till after fertilisation move from the spot where she emerged. In _H. pyrenaicus_ the female is quite apterous, but is very attractive to the males, which as we have said, assemble in large numbers near her. Thus within the limits of these few allied forms we find radically different relations of the sexes.

1. The male attracts the female—(A) by sight (_H. humuli_); (B) by odour
(_H. hectus_).

2. The female attracts the male—(A) by vibration of wings (_H. lupulinus_
and _H. sylvinus_); (B) without vibration, but by some means acting at a
distance (_H. velleda_, _H. pyrenaicus_).

Little or nothing is known as to the habits of the great majority of the more remarkable forms of the family. The gigantic Australian forms are believed to be scarcely ever seen on the wing.

The Hepialidae differ from other Lepidoptera by very important anatomical characters. The absence of most of the {400}mouth-parts is a character common to them and several other divisions of Lepidoptera; but the labial palpi are peculiarly formed in this family, being short and the greater portion of their length consisting of an undivided base, which probably represents some part of the labium that is membranous in normal Lepidoptera. The thoracic segments are remarkably simple, the three differing less from one another than usual, and both meso- and meta-notum being much less infolded and co-ordinated. The wings are remarkable for the similarity of the nervuration of the front and hind wings, and by the cell being divided by longitudinal nervules so as to form three or four cells. On the inner margin of the front wing there is near the base an incision marking off a small prominent lobe, the jugum of Prof. Comstock. Brandt mentions the following anatomical peculiarities,[288] viz. the anterior part of the alimentary canal is comparatively simple; the respiratory system is in some points like that of the larva; the heart is composed of eight chambers; the appendicular glands of the female genitalia are wanting. The testes remain separate organs throughout life. The chain of nerve ganglia consists of the supra- and infra-oesophageal, three thoracic, and five abdominal, ganglia, while other Lepidoptera have four abdominal.

FAM. 24. CALLIDULIDAE.—A small family of light-bodied diurnal moths having a great resemblance to butterflies. In some the frenulum is present in a very rudimentary condition, and in others it is apparently absent. _Cleosiris_ and _Pterodecta_ are very like butterflies of the Lycaenid genus _Thecla_. Although fifty species and seven or eight genera are known, we are quite ignorant of the metamorphoses. Most of the species are found in the islands of the Malay Archipelago, but there are a few in East India.

FAM. 25. DREPANIDAE (or DREPANULIDAE). (_Hook-tips_).—The larger moths of this family are of moderate size; many of the species have the apex of the front wing pointed or even hooked; some have very much the appearance of Geometrid moths; they resemble very different members of that family. _Oreta hyalodisca_ is remarkable on account of the very large, transparent patch on each front wing, though the other species of the genus have nothing of the sort. In the genus _Deroca_ we {401}find Insects with the scales imperfect, they being few and small and approximating in form to hairs; in _D. hyalina_ scales are nearly entirely absent. In other genera, _e.g._ _Peridrepana_, _Streptoperas_, there is only a very inferior state of scale-formation. The few larvae that are known are peculiar; they are nearly bare of hair, without the pair of terminal claspers, while the body is terminated by a long tubular process. They form a slight cocoon among leaves.

The members of the family were formerly much misunderstood, and were assigned to various positions in the Order. There are now about 30 genera, and 150 species known, the geographical distribution of the family being very wide. In Britain we have half a dozen species. _Cilix glaucata_ (better known as _C. spinula_) is said "to undoubtedly imitate" the excrement of birds. No doubt the Insect resembles that substance so as to be readily mistaken for it. This Insect has a very wide distribution in North America, Europe and East India, and is said to vary so much in the structure of its organs as to justify us in saying that the one species belongs to two or three genera.

FAM. 26. LIMACODIDAE (or EUCLEIDAE).—These are somewhat small moths, of stout formation, sometimes very short in the body, and with rather small wing-area. The family includes however at present many Insects of diverse appearance; there are numerous forms in which apple-green is a prominent colour; some bear a certain resemblance to the Swifts, others to Noctuids; some, _Rosema_ and _Staetherinia_, are of extraordinary shapes; certain very small forms, _Gavara_, _Ceratonema_, resemble Tortricids or Tineids; a few even remind one of Insects of other Orders; so that the group is a mimetic one. _Nagoda nigricans_ (Ceylon) has the male somewhat like a Psychid, while the female has a different system of coloration and wing-form. In _Scopelodes_ the palpi are in both sexes remarkable; elongated, stiff, directed upwards and brush-like at the tip. Altogether there are about 100 genera and 400 species known; the distribution of the family is very wide {402}in both hemispheres, but these Insects do not occur in insular faunas. In Britain we have two genera, _Heterogenea_ and _Apoda_ (better known as _Limacodes_[289]), each with a single species.