124 



INSECTA OR HEXAPODA. 



undergo a complete metamorphosis is different to that of the 

 adult. Fig. 54: shows the digestive tract of the larva of one of 

 the Daddy Long-legs {Tipula), which will be seen to be of quite 

 a different type to that given in fig. 34. There are consider- 

 able differences in the digestive tract of insects. We shall 

 observe much variation in the length of larval life when study- 

 ing this group : some larvse live only a few days ; others, as 

 the Wireworm, as much as three or four years. Eventually 

 the " full-feed " state is reached, and the larva ceases to feed ; 

 it is then ready to assume the next stage — namely, the pupa, 

 chrysalis, or nymph. Prior to entering this stage the larva 

 either enters the ground and forms a cell in the earth, or spins 



Pig. 52.— PUP.E of Insects. 



A, Puparia of Dipteron; P, contained pupa, b, Pupa of moth; o, chrysalis of 

 butterfly. 



a silken cocoon, or finds some shelter in which to pupate. 

 Typically the pupal stage is a period of rest, no food being 

 taken. The pupal skin shows the general outline of the insect 

 — legs, antennae, wings, &c., being clearly defmed (fig. 52, b). 

 Chrysalis is the term generally used in Butterflies, which are 

 pale-coloured and more or less angular (o). In Flies, and some 

 Hymenoptera, the pupa is found in the old larval skin, which 

 hardens and forms a brown case, called the puparium — the 

 " flax-seed " stage of the Hessian Fly (a, i.) In some diptera the 

 pupae are spiny (fig. 53). During this pupal period the majority 

 of the larval organs are broken down into a granular soft mass. 



