NEW NORTH AMERICAN BEES OF THE GENUS ANDRENA, 



By Henry L. Viereck and T. D. A. Cockerell. 1 



The genus Andrena is richly represented in Europe, Asia, northern 

 Africa, and North America, the species differing greatly in size and 

 appearance and having diverse flower- visiting habits. Although 

 very many species have been described, it is evident that many more 

 remain to be discovered. The present paper makes known a series, 

 chiefly from the Rocky Mountain Region. 



-a 1 . Species with only two submarginal cells. 

 a 2 . Female with yellow face-marks ; stigma small. 



ANDRENA VERBESINAE, new species. 



Cotulla, Texas. May 12, 1906, (F. C. Pratt), on Verbesina ence- 

 lioides. 



Female. — Length, 11 mm. Robust. Black; all the tarsi and the 

 anterior and middle tibiae ferruginous. A mark occupying most of 

 clypeus, its lower end trilobed, and very large semicircular lateral 

 marks light yellow. Facial quadrangle a very little broader than 

 long. Process of labrum slightly emarginate. Clypeus shining, 

 well punctured, flattened in middle, with a smooth band; facial 

 fovese seen from above light ochreous, occupying a little more than 

 half distance between eye and antenna, 2 below rapidly narrowing, 



1 A number of years ago Mr. Viereck began a revision of the genus Andrena as found in North America, 

 and at different times published part of his results, chiefly in the form of tables. The tables for the sepa- 

 ration of the groups and species are nearly completed, but the completion of the whole work is unavoidably 

 delayed. It has therefore seemed advisable to publish descriptions of a number of new species, principally 

 from the Rocky Mountains. These species were all recognized as new and given names by Mr. Viereck, 

 and in working over them I have used Mr. Viereck's tables, giving the characters separating them from 

 species previously described as well as from numerous species not yet published. It has been impossible 

 to credit specifically the matter derived from Mr. Viereck's manuscript, but it will be understood that while 

 I am alone responsible for the form of the present paper, it is based upon Mr. Viereck's work and is in every 

 sense a product of our joint labors. All the species which Mr. Viereck regarded as distinct are separately 

 described, although several appear to me to be varietal forms only and are here given as such. Mr. Viereck, 

 on going over the manuscript, writes that he will provisionally accept my opinions on these matters, being 

 at present unable to reinvestigate the questions involved. It is hoped that the account given is sufficiently 

 full to enable students to determine all the forms, whether regarded as varieties or distinct species. The 

 "key" referred to in this paper is that in Mr. Viereck's manuscript. The comments within brackets are 

 mine alone.— T. D. A. Cockerell. 



2 This refers, strictly speaking, to the distance between eye and vertical line running through outer edge 

 of antennal socket; hence not necessarily to the breadth of the fovea at transverse level of antenna. 



Proceedings U. S. National Museum, Vol. 48— No. 2064. 

 59758°— Proc.N.M.vo1.48— 14 1 1 



