1896.] NATURAL SCIENCES OF PHILADELPHIA. 69 



it from Fort Collins, Colorado, where it was collected in August ; 

 this is the most uorlhern locality known for it. The most southern 

 locality is Alma, Socorro Co., N. M., where it was found by Mr. 

 Alfred Holt. I have myself collected it as follows : 



(1). Albuquerque, June oOth and Aug. 16, 1895. (2). Lamy, N. 

 M., July 2d and July 13th. (3). Santa Fe, N. M., July 5th to 

 Aug. 3d. (4). Watrous, N. M., July 13th. (5). Las Vegas, N. 

 M., July. (6). lia Junta, Colo., July. 



Everywhere it is found in great abundance on flowers of Cleome 

 serrulata, and on nothing else ; whereas the closely allied P. bakerce 

 is found on Solidago. On July 12th, at Santa Fe, I saw them settle 

 on the stamens of the Cleovie, climb to the top, and collect the pollen. 

 At Watrous I saw one inserting its tongue in the base of the flower, 

 running down the inner surface of the petals. 



In the $ s the face-markings are very constant, but frequently the 

 light bands of the abdomen will be interrupted on segments 3 and 4. 

 The 9 s vary much in the clypeal marks, from no marks on the 

 clypeus but the usual pair of dots, to two black bars or even an 

 almost wholly black clypeus. These variations do not seem to have 

 any reference to the environment. 



Mr. Fox has examined for me all Cresson's type specimens of 

 zehrata ( 9 ) and reports that they have the supraclypeal spot 

 notched above, except one, which has it divided in two. This last 

 was the one Cresson actually had in hand when describing, as may 

 be seen from his description. The clypeus in four specimens is bi- 

 spotted with black, in one entirely yellow. 



A species very like P. zehrata, found on Solidago in Colorado. 

 24. Perdita bakerae n. sp. or race. Figs. 11, 12, (head and cf genitalia). 



$ . — Like the $ of P. zehrata, but seems to average smaller, the 

 pale bands of the abdomen are small and interrupted, at least on 

 the third and fourth segments, and the supraclypeal mark is nearly 

 twice as broad as long. Sometimes the abdominal bands are entire, 

 but the supraclypeal mark still affords a distinguishing character. 



9 . — Seems to diflTer only from 9 zehrata in its broader supra- 

 clypeal mark, notched in the middle. 



Hah.—¥on Collins, Colorado, 12 $, 3 9, sent by Mr. C. F. 

 Baker. They were collected as follows: (1). On Solidago canad- 

 ensis, Aug. 8, 1895, both sexes. (2). On Solidago canadensis, Aug. 

 15, 1895, a $ . (3). On sticky flower-buds of Helianthiis annutis, 

 Aug. 20, 1895, two ^s. 



