INTR OD UCTION: xj 



prolegs or abdominal legs. The true legs consist of five parts, and are formed of short horny 

 cylinders which are connected by membranes. The prolegs are either claspers, or cylindrical, 

 or short wedge-shaped projections which end in a broad sole. The sole is more or less 

 surrounded with booklets at the edges. The points are directed inwards to form an organ of 

 prehension. Or the prolegs may be obtuse at the end with a fleshy, wart-like protuberance; 

 these legs are also surrounded by hooks, with the points directed outwards; they are generally 

 found in larvse which live in wood or which mine leaves, and serve merely as a support. 

 The number and position of the prolegs varies. The terminal segment of the abdomen differs 

 from the others in form, being rounded, obtuse, bifid or forked, and may have various appen- 

 dages. The skin of the caterpillar may be bare, or provided with obtuse elevations, such as 

 tubercles or warts, horny spines, soft fleshy hairy protuberances, and lappets or thin flat smooth 

 membranous appendages, which form a single or double row at the sides immediately above 

 the legs. The hairs are simple, plumose, or set with recurved hooks as in the processionary 

 caterpillars, or are knobbed at the extremity. They are placed singly or in clusters, so as to 

 form tufts or pencils. Larvas grow very quickly and from time to time the skin becomes too 

 small and is shed; this is called moulting. The old skin bursts open and the larva emerges 

 with a soft new skin, which, however, soon hardens. 



The pupa has a firm horny integument with an anterior immovable portion and a more 

 or less mobile posterior end, composed of separate rings. The anterior portion is divided into 

 several parts by longitudinal depressions on the upper surface. In front is the semicircular 

 covering of the head, which sometimes has a long or short appendage beneath, enclosing 

 the proboscis. Beside this are the coverings of the eyes. Next to the covering of the head 

 are those for the legs, antennae and thorax. Between those for the antennae and thorax are 

 those for the wings. Then come the abdominal segments, the last of which is obtuse or with 

 a pointed projection. Pupae are either bare and smooth, or provided with humps, spines or 

 hair. Those of butterflies have usually projecting angles and ridges, and are generally varied 

 with greenish, grey or golden. Some other pupae are wedge-shaped and they are usually 

 darkly coloured. Pupas may be suspended by a thread at the end of the body, attached by 

 a thread or threads round it, or they may be enclosed in a cocoon. 



The worst natural enemies of larvas are the ichneumon flies, a large section of the 

 Hymenoptera, which play an important part in the economy of nature, by keeping down the 

 numbers of injurious insects. They mostly search out the caterpillars and pierce them with 

 their ovipositors, laying their eggs in or on them, whilst other smaller species attack the eggs. 

 If laid on the larva, the maggots which emerge bore their way through the skin and feed on 

 the substance of the caterpillar. Many leave the larva before it passes into the pupa-state, 

 as does the small Microgasfa; which destroys the larvae of the White Butterfly. The maggots 

 of this species pupate in a small yellow cocoon in which they completely enclose the larva 

 of the butterfly; this dies and becomes shrivelled and dried up. Others, especially large 

 caterpillars, may reach the pupa-state, in which case the perfect ichneumons emerge from 

 the pupa. 



There are also flies {Diptera) which are injurious to caterpillars, especially Tachina, 

 which attacks the larger caterpillars in a similar manner. 



Larvae are also subject to various diseases and they are frequently destroyed in large 

 numbers by the effects of a wet and cold season. 



COLLECTING BUTTERFLIES AND MOTHS. 



Butterflies and moths are generally caught with a ring net, or occasionally with a forceps 

 net. The ring net (Figs. 3 and 4), in its best form, consists of an ordinary walking-stick with 

 a brass ferrule at the end containing a female screw, into which a screw with a large head. 



