73 



crawling, they bend themselves in the shape 

 of a loop or arch in bringing the false and 

 true feet together, (Fig. 26). The silk spin- 

 ning caterpillars often aid their progression 

 by letting themselves drop from one branch 

 of a tree to another by means of a thread 

 spun from the mouth. The body of the 

 caterpillar consists of a head, three thoracic 

 segments and nine abdominal. Except in a 

 very few cases, they feed on plants and bite 



Fig. 26. 



their food by means of two powerful mand- 

 ibles or jaws, covering the opening of the 

 mouth at the sides. The mouth is further 

 protected above by two corneous pieces form- 

 ing the upper lip which is used to hold the 

 food fast. The substance forming the cover- 

 ing of the head is hard and horny and often 

 darker coloured than the rest of the body, 

 which is usually quite or almost naked, Fig. 25. 



though frequently covered more or less com- 

 pletely with hair, and ornamented with 



wart-like tubercles, the hairs themselves being gathered into bunches of various lengths 

 and colours, (Fig. 27). The caterpillars are most often of various shades of green and 



brown, like the leaves on which they feed 

 and the earth into which many enter to 

 form the pupa ; but not a few are grayish, 

 like the bark of the trees upon which they 

 often crawl, while their colouring is 

 almost always clearly protective and aids 

 their concealment from their enemies. 

 Not a few are internal feeders, living on 

 the pith or wood, and these are maggotty in 

 appearance, pale yellowish or flesh colour, 

 with dark heads, thus resembling the larvse 

 of beetles which inhabit similar localities. 

 A few are called " Sack-bearers " from 

 their living in a portable case made of silk 

 and twigs and bits of leaves, (Fig. 28). 

 The caterpillars of the Tineidce frequently 

 form mines on the leaves, eating out the 

 green and fleshy part of the leaf and leav- 

 ing the transparent pellicle as a protection. The pupa or chrysalis of butterflies and moths 

 is quiescent, covered with a horny skin, with the segments variously impressed or provided 



Fig. 27. 



