^^^'1 ZOOGENESIS ^''^^ 



like our beaked butterfly. Most butterflies feed on 

 several or many closely related plants. 



It often happens that a butterfly in its feeding habits 

 shows an abrupt departure from its nearest relatives. 

 Thus in that restricted group of swallowtails which 

 includes our common black or parsnip swallowtail 

 and the common yellow swallowtail of Europe all of 

 the species except three feed on umbelliferous plants. 

 One in eastern Asia feeds on plants of the rue family. 

 Another in Sardinia feeds on garden rue. The third, 

 in the Rocky Mountain region, feeds on Artemisia — a 

 composite plant. All three live with another species 

 of the same group which feeds on umbelliferous plants, 

 and the last two are very closely related to the forms 

 with which they live. 



In the group of butterflies that includes the hair- 

 streaks, blues and coppers there is very great diversity 

 in food and feeding habits, with a corresponding 

 diversity in the caterpillars, though not in the eggs 

 or adults. In this group many of the species are 

 carnivorous, feeding on ants, aphids or other insects, 

 or are at first plant feeders becoming carnivorous in 

 the later stages. Some feed on lichens or on algas, or 

 bore into fruits. Nearly all are cannibals. 



In some butterflies sexual development is very slow 

 and full maturity is not reached until some time after 

 emergence from the pupa. In those butterflies that 

 pass the winter as adults the eggs do not mature till 

 spring, that is, until the butterflies have been in the 

 adult stage for about six months. In the summer 

 brood of the same butterflies, however, maturity 



