INSECTS OR HBXAPOnA. 



141 



are headless (Onion Fly maggot). Oruh is the term generally 

 given to the larvae of some beetles (Weevils) and Hymenoptera 

 (such as "Wasp grubs). In the larval stage the insect often 

 feeds with great voracity. Several ecdyses take, place, the skin 

 splitting after stretching to a certain limit ; the larva ceases to 

 feed during this period of moulting. Frequently after each 

 moult, of which there are four or more, the larva presents a 

 different coloration. The internal anatomy of the larva of 

 insects that undergo a complete metamorphosis is different to 

 that of the adult. Fig. 67 shows the digestive tract of the 

 larva of one of the Daddy Long-legs {Tipula), which will be 



Fin. 65. — Pup.^ or Insects. 

 A, Puparia of Dipteron ; b, pnpa of moth ; o, chrysalis of butterfly. 



seen to be of quite a different type to that given in fig. 41. 

 There are considerable differences in the digestive tract of 

 insects. We shall observe much variation in the length of 

 larval life when studying this group : some larvae 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 condition the larva either enters the ground and forms a 

 cell in the earth, or spins a silken cocoon, or attaches itself by 

 silk to some object (fig. 65, a), or finds some shelter in which 

 to pupate. Typically the pupal stage is a period of rest, no 



