20, a large number of males and a single female were taken on the 

 banks of the Yellowstone River, among the sage brush ; of these, 

 most of the specimens taken on the 18th were pretty fresh; but some 

 males were somewhat or considerably rubbed ; of those taken on the 

 20th, only one specimen was fair, the others being very badly rubbed; 

 some of these were very small, one measuring but thirty-seven milli- 

 metres in alar expanse. 



16. Colias Eurytheme Boisd. This species was taken only 

 at Heart River Crossing, near timber in the river bottom, June 26, 

 Three pretty good males and two good females were captured, be-- 

 sides three females, rather badly worn. 



17. Synchloe Protodice (Boisd.-LeC.) Scudd. Two fe- 

 males only were taken, both fresh ; one at Heart River Crossing, June 

 26 ; the other on the Yellowstone, July 18. 



18. Amaryssus Polyxenes (Fabr.) Scudd. A single fe- 

 male, badly torn and worn, was taken at Heart River Crossing, 

 June 26. 



19. Amaryssus Zolioaon (Boisd.). A single male, fresh in 

 color, but a little torn, was taken on the Yellowstone, July 18. 



URBICOL.^, 



20. Epargyreus Tityrus (Fabr.) Scudd. A single female, 

 torn (perhaps in capture) but pretty fresh, was taken at Heart River 

 Crossing, June ,26. 



21. Thorybes Pylades Scudd. A single fresh male was taken 

 at Heart River Crossing, June 26. 



22. Erynnis Persius Scudd. A single, rather rubbed male, 

 apparently belonging to this species, though differing somewhat from 

 eastern examples in the abdominal appendages, was taken on the 

 Yellowstone, July 18. 



23. Erynnis Lucilius (Lintn.) Scudd. A single male, not 

 very fresh, was taken with the preceding species. It does not differ 

 from the eastern type, even in the abdominal appendages. 



24. Hesperia tessellata Scudd. Three fresh males were 

 taken at Heart River Crossing, June 26; but three worn specimens, 

 a mile and two females, their fringes all gone, were taken at the 

 crossing of the Big Muddy, only two days later, 



25. Oarisma Hylax (Edw.). Three pretty fresh males were 

 taken at Heart River Crossing, June 26, 



