Glass 3. Insecta. Order 6. Lepidoptera. 273 



On the long abdomen ttere are usually five pairs of prologs (one 

 pair on each of the segments three to six^ and one pair on segment 

 nine) J sometimes a smaller number, and then usually two pairs (in the 

 Geometers on segments six and nine), most rarely (in a single genus of 

 the Tineidse) six pairs. The prologs are provided at their lower ends 

 ■either, as in the Microlepidoptera, with a circle of movable hooks, 

 curved outwardly, with respect to the centre of the circle ; or in the 

 Macrolepidoptera, with a row of hooks on the inner side, and curved 

 inwards : the prolegs are thus adapted for clasping thin branches.* 

 ■Caterpillars may be distinguished from the very similar larvae of the 

 Tenthredinidee by the greater number of ocelli, the smaller number of 

 prolegs, and by the presence of hooks on the latter. The pupa is 

 characterised by the way in which all the appendages (wings, 

 legs, etc.) lie close to the body ; all the external surfaces are firmly 

 chitinised (whilst the surfaces lying against one another are but 

 feebly so), so that it looks as if it had been varnished. The larvee 

 possess spinning-glands, which open on to the labium, and many 

 ■of them before pupating either spin a complete cocoon; or form 

 a case by binding together various particles by means of the silk; 

 whilst others spin only a few threads ; not a few surround themselves 

 .still earlier with a saccular case, open at one end, which they carry 

 about with them. 



The Lepidoptera are allied to the Hymenoptera, especially to tlie Tentki-e- 

 dinidsB ; they agree with the latter in the form of the legs (metatarsus, coxa), in 

 the presence of a covering- scale at the root of the fore wing, in the feeble 

 •development of the prothorax, and in the structm-e of the larva. 



Sub-Order 1. Microlepidoptera. 



The prolegs of the larvae have a complete circle of hooks, the 

 head is directed forwards ; they live, for the most part, in conceal- 

 ment, either tunnelling in leaves, stems, or wood, or lying between 

 leaves held together by the threads which they spin, etc. The pupte 

 usually have transverse rows of spines on the dorsal side of the 

 abdomen. The adults are, with few exceptions, of small size, with 

 :slender bodies. 



1. Tineidse, small forms with naiTOw wings, bordered with a fringe of 

 hairs. The members of this group are numerous : they are often beauti- 

 fully coloured, but, as a, rule, very small. Among them ai-e the Olothes- 

 moths. Tinea pellionella, and T. iapezella ; the larva of the former species lives 

 upon fur and woollen materials ; it lies in a sac, open at both ends, formed of 

 pai-ticles gnawed ofE the material and spun together ; and here it pupates. The 



* The r o w of hooks corresponds with the inner portion of the circle, and the 

 unilateral type of foot may be derived from the other by supposing the outer half 

 of the circle to have disappeared. The last pair of prolegs in the Microlepidoptera, 

 "too, do not possess a complete circlej but a row in which the hooks are curved forward. 



