ARTHROPODA 



303 



The caterpillars are usually voracious and may strip their food plant of its 

 leaves and buds. The majority of the larvae have become highly specialized in 

 their food habits, becoming restricted in some instances to one species or to a few 

 related species (as illustrated by the tomato worm, which feeds on tomato, potato, 



FIG. 145. 



C 



FIG. 145. The Cabbage Worm (Pieris rapcz). Natural size. Photo by Folsom. A and B, larvae; 



C, pupa. 



*". Questions on the figure. What is a larva? What is a pupa? Which is the 

 earlier stage? What is the color of this caterpillar in nature? See the next 

 figure for the adult. 



FIG. 146. 



FIG. 146. The adult Cabbage Butterfly (Pieris rapce). Natural size. Photo by Folsom. 



Questions on the figure. Why is the larva of this animal called the cabbage 

 worm? Why is the adult called the cabbage butterfly? What are its feeding 

 habits? 



and tobacco leaves; or the cabbage worm which eats the leaves of certain of the 

 cruciferous plants). The distribution of such species is thus clearly determined 

 by that of their host plants. The most injurious to vegetation are the "tent- 

 caterpillars" which occur gregariously and spin a web-like nest; the army- worm 

 so-called because it appears and moves from its hatching grounds in great numbers; 



