108 S. A. ROHWER. 



Male. — The male differs from the female in having the clypeus 

 deeply, narrowly notched, the antennae serrate beneath, the posterior 

 face with indications of lateral ridges, and the tegulae are sometimes 

 white. The tibiae sometimes have a black spot within. 



Habitat.- — Florissant, Colorado, June 19 to July 7 (T. D. A. 

 Cockerell and S. A. Rohwer). Caught while flying over sandy 

 soil, and on the foliage of Ribes vallicola and Salix brachycarpa. 



Close to rugosus Fox, but may be separated by the U-shaped 

 emargination of the clypeus (not V-shaped as in rugosus) , and 

 the teeth at the side of the clypeus in the female. It was 

 found in company with rugosus which I have both sexes 

 from Florissant. 



NITELIOPSIS Saunders. 



Up to the present time no male of the genus Niteliopsis 

 Saunders has been known. My collecting in 1908 brought to 

 light males representing nine species, eight of which were new. 

 The male of another species inermis Cresson has been taken 

 by Rev. G. Birkmann, and sent to me for study. In this paper 

 eight new species are described, and a table to separate the 

 species of this genus in boreal North America is given. 



In the sense used in this paper the genus Niteliopsis includes 

 all those species having three cubital cells, the second of which 

 is petiolate; the mandibles not incised on the outer margin; 

 the eyes converging slightly towards the vertex; the middle 

 tibiae with one apical spur, and the female without or with a 

 poorly developed pygidial area. The relative length of the 

 median and submedian cells, or the position of the first 

 recurrent nervure is not of generic importance in this group. 



TABLE OF SPECIES. 



Females 1 . 



Males 9. 



1. Abdomen red 2. 



Abdomen black 5. 



2. All the tibiae with a white stripe exteriorly 3. 



All the tibiae black 4. 



3. Pronotum black; median and submedian cells equal. (Califor- 



nia.) striatipes Ashm. 



Pronotum with two white lines; median and submedian cells not 

 equal, submedian longer. (Colorado.) vierecki Roh. 



