INJURIOUS INSECTS. 



99 



single worm may devour a newly transplanted plant 

 in a night. The moth, worm and egg are shown 

 in Fig. 1 6. The worms are marked, when partially 

 grown, by distinct white lines along the sides; and, 

 unlike the cabbage worms, they have legs only at 

 the ends of their bodies, so that they travel by "loop- 

 ing" and not by crawling. In their life history they 

 are quite similar to the cabbage worms, but appear 

 earlier in the season and continue longer, with the 

 same overlapping of broods which prevents easy 



?c= 



Fig. i6 — Looper — a, Larva ; i, Chrysalis ; c, Moth. 



destruction. In addition they have other peculiari- 

 ties which increase the difficulty of combating them. 

 They feed upon such a range of plants that poisoned 

 trap-crops are of little benefit ; and they work largely 

 upon the under side of the leaves, where they may 

 remain unnoticed until much damage has been done, 

 and where only very thorough application of reme- 

 dies will affect them. They are also active in 

 movements, and discriminating in taste, so that they 



