384 



APPLIED mOLOGT 



kept in a schoolroom, and much later if left outdoors. The habits 

 of the living moths should be observed. They will live but a short 

 time, for their alimentary canal is too imperfect to use food. This 

 is true only of some species of moths and butterflies. 



Larva, pupa, and adult of common butterflies and moths can be 

 identified by the figures in Dickerson's "Moths and Butterflies," 

 which also gives very readable accounts of the life-histories. 



325. The Reproductive Processes of Insects. The eggs 

 of the simplest and lowest insects (e.g., the silver-moth, Fig. 

 136) form young which at hatching are like the adults except 



insize. The young of 

 grasshoppers and numer- 

 ous other species are at 

 first without wings, and 

 they go through a number 

 of moltings before they 

 become adults. This con- 

 dition is called gradual met- 

 amorphosis, or incomplete 

 metamorphosis. The most 

 complicated development 

 is represented by the but- 

 terflies, moths, beetles, 

 flies, bees, and wasps. The 



and adult eggs of these hatch into 



worm-like tan* (popularly 

 called caterpillars, grubs, 

 maggots). These larvae are voracious feeders, and usually 

 grow rapidly to full size. Then while transforming from the 

 larva to the adult or imago stage, they undergo a period of 

 quiet in the pupa stage. In the butterflies the pupa stage is 

 often called a chrysalis. The larvae of some insects, like silk- 

 worm, spin a protective cocoon around themselves as they pass 

 into the pupa stage. After a period of quiet, during which 

 vast internal changes (complete metamorphosis) are taking 



FIG. 



