156 Journal New York Entomological Society. [Vol. xvi. 



mountains. Neither form seems to be plentiful in this region though 

 they cannot be said to be rare. Amorpha californica, on which the 

 larvae feed, grows quite plentifully in Mission Valley. 



13. Eurymus caesonia Stoll (61). 



One fair specimen was taken in Devil's Canon, near Jacumba, 

 during July, 1906, by Mr. Geo. Field. So far as I am aware, this is 

 the only specimen ever taken this side of the desert. It should occur 

 along the Colorado River in what is now Imperial County. 



14. Eurymus eurytheme Boisduval (65). 



15. Eurymus ariadne Edwards (65a). 



16. Eurymus keewaydin Edwards (65 syn.). 



These species are quite confusing to the amateur and I am not at 

 all clear in my own mind about them. The form eurytheme occurs 

 only late in the season, ariadne occurs only early in the season, and 

 keewaydin may be found from early spring to late in the fall. During 

 1906 I captured and spread some 150 or more specimens of these spe- 

 cies and on close study found that they intergraded so closely that it 

 was practically impossible to say where one form ended and the next 

 began. Of ariadne I had but three specimens of which I was certain ; 

 of eurytheme , less than twenty, while all the rest were either keewaydin 

 or intergrades. The latter were taken as early as March ro, and as late 

 as November 10. In 1907 I took one keewaydin on February 9. 

 Wright's "West Coast Butterflies" has been my guide in separating 

 these species, and I am inclined to think with him that keewaydin is the 

 stem of the species and that eurytheme and ariadne are but varieties. 

 Albinistic females in both eurytheme and keewaydin were very com- 

 mon during 1906, but I have not seen so many this year. 



17. Eurymus harfordi Hy. Edwards (67). 



One of the commonest butterflies to be seen in the mountains 

 of this region is harfordi. In July, 1906, we saw it in thousands 

 flying among the brush on the hillsides, along the river banks, on the 

 mesa, in fact, it seemed to be everywhere. It is a difficult insect to 

 catch. It is swift in flight, seems to be very powerful on the wing 

 and is seldom seen at rest. We were able to get but few, though at 

 times the individuals were so plentiful that we took them from the 

 wagon while traveling. 



18. Pyrisita mexicana Boisduval (8i). 



So far as I know but two specimens of this species have been 



