INSECTS 



257 



FIG. 135. Codling moth larva and its 

 work. (Fanners' Bulletin No. 283) 



stage. The pupa appears to 



be inactive and is sometimes 



referred to as a resting stage, 



but this is far from true. 



Great transformations are 



taking place inside the pupa 



skin. The wings are develop- 

 ing and the entire appearance of the body is changing. 



After these changes are complete, the fly appears in the 



mature stage. The pupa 

 stage lasts five to seven 

 days, and the larva stage 

 about as much longer, so 

 that a new generation 

 may be started every two 

 weeks. A single female 

 lays 120 to 160 eggs. It 

 is easy to see why flies be- 

 come so numerous in late summer. 



Each mosquito, codling moth and cotton-boll weevil 



passes through these four 



stages. Some insects do 



not pass through all these 



stages. Grasshoppers 



and some other insects 



grow continually from the 



time they hatch until they 



are mature. Some plant- 

 lice are born alive, so that 



they do not pass through 



Fio. 137. Mature cotton-boll weevil. 



the different stages. (After w. D. Hunter.) 



FIG. 136. Cotton-boll weevil larva at left; 

 pupa at the right. About five times natural 

 size. (Alter W. D. Hunter.) 



