38 BULLETIN UNIVERSITY OF MONTANA. 



Butterfly — Wings above rather pale greenish yellow, outer borders 

 black; border of female is broader than in male, and contains a sub- 

 marginal row of yellow dots; discal spot in the male is elliptical; an- 

 tennae, costa and fringes roseate; a submarginal row of dots on the under 

 side, the last three on the fore wings black, the remainder brown with 

 pink scales. Dimorphic females occur with wings nearly or quite white, 

 and also a black form. Expanse 1.75, 2.25 inches, 38-57 mm. 



Early Stages— The food plant is clover. The eggs are pale yellow, 

 changing after being laid to crimson. The caterpillar is slender, green, 

 striped longitudinally with paler green. The chrysalis is pale green. 



Distribution — The species ranges from New England to Florida and 

 westward into the Rocky Mountains. The collection at the University 

 of Montana contains specimens from Missoula, Fish Creek, McDonald 

 Lake in the Mission Mountains, Do Lo Hot Spings, Flathead Lake, Madi- 

 son Valley, National Park and Mount Lo Lo. 



Remarks — It is one of our common butterflies. It shows many varia- 

 tions in size, coloration and markings. We have despaired of separating 

 the males of philodice, eurytheme and alexandra, so much are they alike, 

 and so much do they vary. It would at first seem as though philodice 

 should not be found west of the range, but specimens from Flathead 

 Lake are indistinguishable from those in the eastern end of the state; 

 and if the labels of Montana specimens were exchanged with those col- 

 lected by Wiley and the writer from Iowa, Michigan, Illinois, and Mis- 

 souri the difference could not be told. The large series (about 100) of 

 insects of this species in the University collection shows that the species 

 in markings and coloration apparently merges into Eurytheme, and it 

 has often occurred to us that they may possibly overlap. 



THE EURYTHEME SULPHUR. 

 Eurymus eurytheme, Boisduval. Plate IV. 



Butterfly— Expanse of wings 2 to 2.35 inches, 50-90 mm. Closely re- 

 sembling philodice in size, shape and markings, but color orange, of 

 varying shades, instead of yellow. Male usually orange-yellow, shading 

 to sulphur yellow on the costa of both wings and on inner margin of hind 

 wings, base and inner margin sprinkled with black scales; outer border 

 black, broadest at apex; anterior veins yellow where they cross the 

 black; width of border about one-fourth the length of wing; discal spot 

 black on fore wings, orange on hind wings, usually with two spots in 

 the latter; both wings have roseate reflection; under side yellow, 

 middle of fore wings tinged with orange; on both wings a sub-terminal 

 row of dots, the three posterior of fore wings black, the remainder 

 brownish, also two dots on costa near apex; discal spots repeated, the 

 anterior black, with a few light scales, posterior gemmate, silvery, an- 

 nulate with roseate brown or ferruginous; a dash on the costa of the 

 hind wings near the apex, and a rosy spot at the base. 



Female of same general color; border contains a row of yellow spots, 

 the third from the posterior and on fore wings sub-obsolute; border of 

 hind wings wider than in male, and with rudiments of yellow spots; 

 under side similar to that of male. 



