Fam. 4. Brahmaeidae.—The species forming the genus Brahmaea have been placed in various families, and are now treated by Hampson as a family apart, distinguished from Saturniidae by the presence of a proboscis. They are magnificent, large moths, of sombre colours, but with complex patterns on the wings, looking as if intended as designs for upholstery. About fifteen species are recognised; the geographical distribution is remarkable; consisting of a comparatively narrow belt extending across the Old World from Japan to West Africa, including Asia Minor and the shores of the Caspian Sea. Little has been recorded as to the life-histories of these Insects. The larva is said to have the second and third segments swollen and armed with a pair of lateral spines projecting forwards. A cocoon is not formed.
Fam. 5. Ceratocampidae.—This is a small family. They are fine moths peculiar to the New World, and known principally by scattered notices in the works of North American entomologists. Seven genera and about sixty species are known. The chief genus is Citheronia. Some of the larvae are remarkable, being armed with large and complex spines. A cocoon is not formed.
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 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.
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 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]]
