744 



AN INTRODUCTION TO ENTOMOLOGY 



This species was formerly supposed to be the Papilio ajax of 

 Linnseus, and the specific name ajax has been commonly applied to 

 it in this country. 



Subfamily PARNASSIIN^ 



The Parnassians 



The Parnassians are butterflies of medium size in which the ground 

 color of the wings is white shaded with black, and marked with round 



red or yellow spots margined 

 with black. 



In structure the parnassi- 

 ans are closely allied to the 

 swallow-tails; but in their 

 general appearance they show 

 little resemblance to them, 

 differing in the ground color 

 of the wings, and in lacking 

 the tail-like prolongation of 

 the hind wings in all of our 



species. 



In the venation of the 

 wings (Fig. 951) they differ 

 from the swallow-tails in that 

 radius of the fore wings is only 

 four-branched and the first 

 anal vein is wanting. They 

 agree with the swallow-tails 

 and differ from all other butter- 

 flies in that the cubitus of the 

 fore wings is apparently four- 

 branched. 



The larvae possess osme- 

 teria similar to those of the larvae of swallow-tails. When about to 

 pupate the larva either draws a leaf or leaves about its body by a few 

 threads or it merely hides under some object on the ground. The pupa 

 is cylindrical and rounded, not angulate like those of swallow-tails. 



Only four species have been found in North America; they all 

 belong to the genus Parnassius. Of the four species, two are Alaskan ; 

 the others occur in the mountains of the Pacific States, in Wyoming, 

 and in the Rocky Mountains. Of each of the two latter there are 

 several named varieties. 



Fig. 951. — Wings of Parnassius. 



Family PIERIDiE 



The Pierids 



These butterflies are usually of medium size, but some of them 

 are small; they are nearly always white, yellow, or orange, and are 



