212 zyg^nidjE and bombycid^ 



cept that the costal streak is much more clearly defined, has a pale 

 yellow tinge and reaches the outer edge of the submarginal band. 

 The basal spot is also larger and approaches the inner margin more 

 nearly than above. 



Expanse of wings, 1.08 inches ; length of body, o. 58 inch. 



Habitat. — Canada, Nova Scotia, (Kirby). Hudson's Bay, (Walker). 

 California, (Grote). Oregon, (Walsingham). 



With the ? I am acquainted only through the medium of Kirby 's 

 figure, which, judging from the body, evidently belongs to this sex. 

 It differs chiefly in the shorter length of the body. There seems to 

 be considerable confusion or else variation in the colors of this species. 

 Kirby 's figure* shows the markings to be yellow, while his description 

 gives them as white. It is just possible that the yellow tint is the 

 effect of age on an inferior kind of white color, which not unfrequently 

 undergoes this change, to the disgust of the artist. Grote, however, 

 (Bull. Buffalo Soc. Nat. Hist. Vol. i, p. 31,) states that a specimen 

 from Owen's Lake, Nevada, (this lake is in Inyo County, California,) 

 shows a sulphur tinge on all the wings, but most decidedly in the pri- 

 maries, while in my specimen from Oregon, the markings are all white 

 except the basal spot on the primaries. 



The general pattern of ornamentation in A. maccullochii, A. ridingsii^ 

 A. lorquinii ■AX\.di A. Similis is so similar that it is not very easy to draw 

 the difference in words. The most available character is the outer spot 

 on the primaries. In Ridingsii the inner margin of this spot is very 

 irregular in its outline; in Lorquinii\hQ spot is nearly linear, attenu- 

 ated at both ends ; in Maccullochii it is wider, the sides parallel, and 

 sharply truncated at each end, in this respect resembling Ridingsii ; 

 while in Similis it is broadly oval. These peculiarities will readily 

 separate the species. 



Of all the species with which we are yet acquainted, the present has 

 the widest geographical range. Its home appears to be in northern 

 latitudes, and on the high mountain ranges to the southward where 

 altitude takes the place of latitude. 



*For this figure I am indebted to the kindness of W, Saunders, Esq. 



