1898.] NATURAL SCIENCES OF PHILADELPHIA. 51 



1. H. bardus Cr., known by the clear wings and fuscous nervures. 



2. H. politics Sm., from Mexico, with the face broader above, 

 wings strongly yellowish. 



3. H. forbesii Rob., having the clypeus less produced. 1 have 

 examined a great number of coriaceus from Wash., and various 

 specimens from New Mexico and Illinois, considered to be forbesii ; 

 also an Illinois coriaceus from Mr. Robertson. The result of this 

 study is that I believe all belong to one somewhat variable species. 

 The characters given by Robertson to separate the females seem not 

 to be constant, but I have not been able to compare the males. It 

 is to be remarked, however, that Robertson's description of the 

 metathoracic enclosure of forbesii, " bearing irregular radiating 

 ruga?, which reach the posterior margin," will hardly apply to what 

 I have (Tr. Am. Ent. Soc, 1897, p. 163) regarded as that species, 

 so it may be that the real forbesii is a valid species near -pacificus, 

 which I have not seen. In that case it will be separated from paci- 

 ficus by the continuous abdominal bands, which are whitish instead 

 of ochraceous. 



The following table separates some males which are more or less 

 similar to pacificus : 



A. Clypeus wholly dark sisymbrii. 



B. Clypeus partly yellow. 



a. Legs all dark, size small angustior. 



b. Legs partly yellow. 



i. Hind tibia? black except ends, enclosure of metathorax 



plicate pacificus. 



ii. Hind tibia? yellow with only a suffused dark patch. 



a. Size large, rlagellum all dark, enclosure of metathorax 

 irregularly wrinkled lerouxii. 



b. Size smaller, flagellum ferruginous beneath. 



1. Size larger, head and thorax black .... ligatus. 



2. Size smaller, head and thorax greenish . . fasciatus. 



Colletes pascoensis n. sp. 



$ . — Length 10 mm. or slightly over, black, with dull white 

 pubescence having only a faint yellow or ochreous tinge. Face and 

 thorax densely covered with long hair, cheeks with black hair, vertex 

 shining but well punctured ; clypeus shining, with large close sub- 

 lanceolate punctures ; distance between eye and base of mandible 

 short, the space twice as broad as long; mandibles dark; antenna? 

 wholly dark, reaching to tegula? ; mesothorax and scutellum shin- 



