INJURING THE LEAVES. 



195 



cabbage leaves by a handsome, purplish-brown moth 

 (Fig. 103, b), that appears early in summer. At first 

 the larvse are very dark, and feed together gregari- 

 ously, but as they develop they become lighter col- 

 ored, and disperse over the plant. When disturbed 

 they roll up and drop to the ground. They become 

 full grown (a) in three or four weeks, when they are 

 about two inches long, witli a wide, longitudinal, 

 velvet-black stripe upon the middle of the back, and 



Fig. 103. Zebra Caterpillar : a, larva ; 6, moth. 



two bright yellow stripes upon each side, which are 

 connected by fine, yellow, transverse lines. The cat- 

 erpillars now construct, slightly beneath the soil sur- 

 face, loose cocoons composed of particles of earth 

 fastened together by silken threads, within which 

 they change to pupae. About a fortnight later the 

 moths emerge, and deposit eggs for a second brood of 



