IX SECTS. 



171 



are hidden from enemies by their habits. The wood-boring beetle larva is 

 safe from all except the strong-billed woodpecker, while not many animals 

 care to disturb the maggot of the fly in his home in some decaying flesh. 



It is the duty of the larva to eat, and eat it docs. Most larva- arc fur- 

 nished with powerful jaws well adapted to cutting the substances on which 

 they feed, be it the most delicate plant of 

 the garden or the hardest wood of the 

 forest. The damage done by insects is 

 perfectly enormous; the farmer has con- 

 stantly to fight against their ravages, 

 while his wife at home is wrought up 

 to a high pitch of indignation at the dis- 

 cover}' that the moths or the 'buffalo- 

 bugs ' are in her carpets. And in almost 

 every instance it is the larva that does the 

 damage, but not in all. The larva eats 

 and grows, and even when he arrives at 

 his full size he apparently 

 differs but little from his 

 condition when he was much 

 smaller. Apparently — for 

 inside his skin marvellous FlG ' 153 

 changes have taken place — 



a new skin exists in outline inside the old, and on the sides 

 of the body are little round patches which are eventually 

 destined to become the wings. So with every other organ ; 

 it is being modified and changed inside the body. 



Sooner or later the time for the first change comes. The 

 larva knows it, and he crawls to some suitable place. Hi.- old 

 skin cracks, and out of it comes a body exceedingly unlike 

 the old. The strong jaws have disappeared, and there is 

 not a trace of a leg; stop a bit and look a little closer, and 

 you will see some things which will make you modify that 

 last statement. Notice those slender lines coming from the 



a butterfly, show- 

 ing the outlines of shoulders and folding over the breast ; those contain the 



the various parts O 



of the adult in- w s • beside them are the sheaths which contain the an- 



sect : e, eye; t, o ' 



tongue; w, wing; tenna3. while outside them, on either side of the body, are 



i, .i, d, legs. 



two broad plates in which the wings are folded up. 

 In some insects the pupa stage, just figured and described, hangs freely 

 in the open air ; in others it is enveloped in a silken case, or cocoon. In the 

 latter the larva, before it sheds its skin, begins to spin its silken thread- ; 



— Larva of Maia moth, with some of 

 the defensive spines enlarged. 



Fig. 154.— Chrysalis 



^P? a i tiis , e ' of last statement 



