250 



AN ECONOMIC ENTOMOLOGY. 



common eastern species, extending westward to the Rocky 

 Mountains, is C. philodice, whose larva feeds upon clover. It is 

 a green caterpillar somewhat similar to the " cabbage- worm," 

 but although it may be quite abundant, rarely does injury enough 

 to be noticed. As a rule, the larva is rather difficult to find, even 

 where the butterflies are abundant, and practically no measures 

 need be taken against it. 



In the sub-family PapilioiiincB we have in our country only the 

 typical genus Papilio, containing species abundant enough to 

 become of economic importance. The most common of these is 



Fig. 268. 



Papilio asterias, male. 



P. asterias, a black " swallow-tail," expanding between two and 

 three inches, the hind wings tailed and excavated on the inner 

 margin, so that the abdomen is free, not enfolded in a groove. 

 The male is somewhat smaller than the female, and has a diag- 

 onal row of yellow spots crossing the fore-wings outwardly and 

 the hind wings nearly across the centre. Near the outer margin 

 of both wings there is a row of yellow, lunate spots, and at the 

 inner angle of the hind wings is a peculiar, eye-like spot, just at 

 the margin. The female has the inner row of yellow spots very 

 much reduced, sometimes altogether wanting, but on the hind 

 wings the space between the faint series of yellow spots and the 

 outer lunules is beautifully powdered with metallic blue scales. 

 These butterflies lay their eggs on carrots, parsley, and other 

 plants of the same natural family, and from them hatqh bright 



