THE PIERIDS 



Caterpillar. — Length, about one inch. In shape it is 

 cylindrical ; its color is velvety green with a yellowish stripe 

 down the back and on each side. 



Food-plants. — Cabbage and other Cruciferre. 



If butterflies were in the habit of forming pro- 

 tective associations, some thirty years ago we 

 would have heard of cabbage leaf petitions signed 

 by various native Americans who were being sup- 

 planted by foreigners "plentiful and cheap." 

 America had white cabbage butterflies of her own 

 with most interesting and intricate histories ; they 

 were conservative in habits and did not appear in 

 vulgar hordes, but took their toll quietly from all 

 our cruciferous plants of the garden and espe- 

 cially from the cabbage. In i860 the European 

 cabbage butterfly was introduced at Quebec, and 

 in 1868 it gained footing in New York. From 

 these points has spread this importunate foreigner 

 and, by appearing earlier in the season and having 

 more broods a year, it has starved and driven out 

 of American gardens the native cabbage butter- 

 flies ; these have fled before the invader to the 

 wilderness and there lead a precarious existence 

 on wild Cruciferae. Scarcely a quarter of a cen- 

 tury had elapsed after this emigrant came to our 

 shores before it had captured America from the 

 Atlantic to the Pacific and from the Gulf of 



79 



