The Bees of the Genus Nomada 
Found in Colorado, 
With a Table to Separate All the Species 
of the Rocky Mountains. 
BY T. D. A. COCKERELL. 
When I undertook to work up the species of Nomada con¬ 
tained in the collection of the Colorado Agricultural College, I 
supposed that I should find a few new ones, but that the great 
majority would be well-known forms long ago discovered by Morri¬ 
son, Ridings, and others. I find that the collection contains 29 
species and varieties, and of these no less that 15 are new. Two 
others represent undescribed sexes of- species previously known. 
This result serves to indicate the richness of the Agricultural Col¬ 
lege collection in rare and new forms, and the great value of the 
material gathered together by Professor Gillette and his associates. 
I have included in the table of species all those known to occur in 
Montana, Wyoming, Colorado and New Mexico. Some synonyms 
and doubtful records have been omitted. Our knowledge of the 
more northern species, from Wyoming and Montana, is exceeding¬ 
ly incomplete, but it is perhaps not without significance that the 
few species known from these states all range eastward. The spe¬ 
cies of Colorado, on the other hand, appear to represent a largely 
endemic fauna, though some eastern elements appear, particularly 
in the north. It is possible to separate the species into three 
groups, those which belong to the Rocky Mountain fauna proper, 
