Genus Basilarchia 



Fig. 17, as to obviate the necessity for a lengthy verbal de- 

 scription. 



Chrysalis. — What has been said of the caterpillar is also true 

 of the chrysalis (see Plate IV). 



The larva feeds upon the willow, cherry, apple, linden {Tilia), 

 huckleberry, currant, and other allied shrubs and trees. The 

 butterfly is somewhat variable, and a number of varietal formi 

 have been described. It ranges generally over the United States 

 and southern Canada as far as the Rocky Mountain ranges in 

 the West, and is even said to occur at high elevations in Mexico. 



(2) Basilarchia arthemis, Drury, Plate XXll, Fig. 4, 6 , form 

 lamina, Fabricius; Fig. 5, 5 , form proserpina, Edwards, Plate 111, 

 Fig. 26, larva; Plate IV, Figs. 14, 2}, chrysalis (\\\Q^i\v\dtd Purple). 



Bititerfly. — Easily distinguished in the form lamina from asty- 

 anax, which in other respects it somewhat closely resembles, by 

 the broad white bands crossing both the fore wings and the hind 

 wings, and followed on the secondaries by a submarginal row of 

 red spots shading inwardly into blue. In the form proserpina 

 there is a tendency on the part of the white bands to become ob- 

 solete, and in some specimens they do entirely disappear. The 

 likeness to astyanax in such cases is striking, and the main point 

 by which the forms may then be discriminated is the persistence 

 of the red spots on the upper side of the secondaries; but even 

 these frequently are obsolete. Expanse, 2.50 inches. 



Egg. — The egg is grayish-green, with " kite-shaped" cells. 



Caterpillar. — Greenish- or olive-brown, blotched with white 

 in its mature form, which is well represented in Plate 111. It 

 feeds upon the willow, the hawthorn {Crataegus), and probably 

 other plants. 



Chrysalis. — The figure in Plate IV is sufficiently exact to ob- 

 viate the necessity for further description. 



This beautiful insect ranges through northern New England 

 and New York, Quebec, Ontario, and the watershed of the 

 Great Lakes, spreading southward at suitable elevations into 

 Pennsylvania. 1 have taken it about Cresson, Pennsylvania, at an 

 elevation of tv/enty-five hundred feet above sea-level. It is not 

 uncommon about Meadville, Pennsylvania. The species appears 

 to be, like all the others of the genus, somewhat unstable and 

 plastic, or else hybridization is very frequent in this genus. 

 Probably all the species have arisen from a common stock. 



184 



