92 PROCEEDINGS OF THE ACADEMY OF [1896. 



wholly dark. (In phymakc the tubercles are more or less pallid.) 

 Tegulse hyaline. Wings milky hyaline, nervures and stigma al- 

 most colorless, the latter yellowish. (In its pallid wings it resem- 

 bles semicrocea.) Stigma large ; marginal cell short, substigmatal 

 portion longest, 2d submarginal narrowed about one-half to mar- 

 ginal ; 3d discoidal distinct. 



Legs black, knees pallid, anterior tibise in front, anterior tarsi 

 and an obscure stripe on middle tibire, yellow. Tip of abdomen 

 rounded or subtruncate, not emarginate. (It is emarginate in fal- 

 lax.) 



Hub. — Las Cruces, N. M., on Bigelovia wrightii, Sept. 23, 1895, 

 in some numbers with P. phymatce. Its superficial resemblance to 

 phymatce is such that when catching the specimens I thought I had 

 only one species, but a careful examination shows striking differ- 

 ences in the head, thorax and wings. The $ was not found. 



54. Perdita semicrocea Ckll., Proc. Phila. Acad., 1895, p. 13. $. (Hab., Las 

 Cruces, N. M.). 



In 1895 this species has been taken commonly at Las Cruces ; on 

 Bigelovia ^vrightii, Sept. 2d and Sept. 12th ; on Solidago canadensis, 

 Sept. 3d ; on Giitierrezia sarothrce var microcephala, Sept. 25th. The 

 original specimen was taken in October. P. semicrocea is less 

 strictly limited to one flower than most of the genus, being taken 

 rather freely on all the plants mentioned — perhaps most freely on the 

 Solidago. The ^ differs in having the face below the level of the 

 antennae entirely yellowish-white, except the clypeal dots. The 

 pale color does not extend further upward, but is slightly notched 

 on each side of the antennse, the outer margin of the notch being a 

 little higher than the termination of the pale color on the orbital 

 margin. The cheeks are unarmed. The narrow tip of the abdo- 

 men is very narrowly truncate, not em*arginate. The anterior and 

 middle legs are yellow, except a dark patch on the femora behind. 



66. Perdita luteola Ckll., Ent. News, 1894, p. 328. S- (Hab., Las Cruces, N. M.). 



Very abundant on Bigelovia wrightii, Sept. 2d, etc. On Sept. 23d, 

 I caught several on Gutierrezia sarothroe var. microcephala. I have 

 found them on no other flowers, except that once I saw one in the 

 net after sweeping over Pedis papposa. 



The 9 differs in having a black line in place of a black spot be- 

 fore the eyes, being really the groove usually seen in that situation, 

 wholly black ; a similar black line placed longitudinally on each 

 side of the anterior half of the second segment of the abdomen ; and 



