844 



THE BUTTERFLIES OF NEW ENGLAND. 



Described from 29 3 , in 9 . 



Secondary sexual peculiarities. For the male stitjraa, see the description of the 

 fore winss. The scales (46; 24) found in the stiarma are much longer and slenderer 

 than in the other species, Ijeing about six titnes longer than broad, nearly equal, with 

 slightly rounded quadrangular ends. 



Geographical variation. The form I. a. irioides, found on the Pacific Coast and 

 looked on by many as a distinct species, diHers but slightly though with apparently 

 constancy from the eastern type. It is slightly the larger, never has the median stripe 

 of the under surface of the hind wings bordered with white, and lacks generally the 

 depth of tint upon the basal half of the under surface of the Mud wings found in 

 the eastern type; while the male has a slightly smaller discal stigma and the female 

 nearly the whole upper surface of the wings distinctly suffused with dull ferruginous. 



Caterpillar. Last stage. "Carmine red, covered with very short hair, each seg- 

 ment involute above, with deep double foveae" (H. Edwards). Length, 12.7 mm. 

 (Nevada specimens). 



Chrysalis. "Pitchy brown, covered with very short bristly hair; ... wing-cases 

 paler." Length, 10 mm. (H.Edwards). The chrysalis differs strikingly from I. nlphon 

 in the absence of piceous blotches covering nearly the whole ground. In place of 

 these are a few small, circular, blackish fuscous spots sparsely scattered over the body, 

 on the abdomen accompanied on each side by two rows of slightly larger and more 

 distinct spots, an infralateral central row and a laterostigmatal post-central row, 

 each with one spot to a segment. The tracery of raised lines is obscurely fuscous, 

 more delicate than in I. niphon. The hairs are black and rather more sparsely dis- 

 tributed than in I. niphou, and the spiracles inconspicuous from being concolorons 

 with the surroundings. (Nevada specimen.) 



Distribution (23:5). The distribution of this insect seems to l)e 

 somewhat peculiar, as our map makes clear. Apparently reaching its 

 maximum of development in New England, it occurs also in the Canadian 

 fauna even as far as Cumberland House on the Saskatchewan, nearly in the 

 centre of the continent, and has been described from California as a dis- 

 tinct species of the Pacific coast ; it has also been found in Arizona 

 (P>lwards), Utah (Palmer) and even in Colorado. Notwithstanding its 

 occurrence in California and Colorado, it has not otherwise been reported 

 in the United States west of New York (Albany, Lintner), but it follows 

 the Appalachian chain to West Virginia. A specimen in the Yale Col- 

 lege museum. No. 17G2, is credited to the District of Columbia (Dodge). 

 North of our boundary it occurs as far east as Halifax, N. S. "not uncom- 

 mon" (Jones) and has been taken at Quebec (Bowles), Bergerville 

 (Fyles), Montreal (Caulfield), and even at London, Out. (Saunders) ; 

 the western type occurs on the Saskatchewan as stated and at Vancouver 

 Island (Fletcher). 



In New England it is widely distributed and will probably be found in 

 al)iiiidance over all tiie wilder portion. The northernmost point from 



