264 



THE STUDY OF INSECTS 



distinct species. Without taking into account the more minute difference^ 

 these forms can be separated as follows. 



(1) The early-spring form, Tphiclides marcellus marcellus. — This is 

 the f«»rni figured here. It expands from c| to 2^ inches; and the tails of 

 the hind wings are about f of an inch in length and tipped with white. 



(2) The late-spring form, Iphiclldes marcellus telamonides. — This 

 form is a little larger than the early spring form and has tails nearly one- 

 third longer; these tails are bordered with white on each side of the distal 

 half or two-thirds of their length. 



(3) The summer form, Iphiclldes marcellus lecontei.- — -The summer 

 form is still larger expanding from 3I to 3^ inches, and has tails nearly 

 two thirds longer than the early spring form. 



The life history of this species has been carefully worked out by Mr. 

 W. H. Edwards. He has shown that there are several generations each 

 year, and that the winter is passed in the chrysalis state. But the early- 

 spring form and the late-spring form are not successive broods; these are 

 both composed of individuals that have wintered as chrysalids, those that 

 emerge early developing into marcellus marcellus, and those that emerge 

 later developing into marcellus telamonides. All of the butterflies pro- 

 duced from eggs of the same season, and there are several successive 

 broods, are of the summer form, marcellus lecontei. 



The larva feeds upon papaw 

 (Asimina). This insect is found 

 through out the eastern half of the 

 United States except in the extreme 

 north. 



The pamassians. — They 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 pamassians 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 prolongations of the hind 

 wings in all of our species. 



In the venation of the wings 

 (Fig. 460) they differ from the swal- 

 low-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 butterflies in that 

 the cubitus of the fore wings is apparently four-branched. 



The larva? possess osmeteria 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. 



FlG. 460. — Wings of Parnassius. 



