THEODORE H. FRISON 307 



SYSTEMATIC AND BIOLOGICAL NOTES ON BUMBLEBEES 

 (BREMIDAE; HYMENOPTERAj 



BY THEODORE H. FRISON 

 Urbana, Illinois 



The present paper is the result of a study of a series of l)uml)le- 

 bees in the collection of the author from Arizona, several speci- 

 mens in the collections of the United States National JVIuseum 

 and the Biological Survey, and the entire collection of North 

 American bumblebees of the Academy of Natural Sciences of 

 Philadelphia and the American Entomological Society. To 

 Mr. E. T. Cresson, Jr., Dr. Henry Skinner and Mr. J. A. G. 

 Rehn, I owe my sincere thanks for their many courtesies and the 

 privilege of studying in detail the types and collection of some 

 twenty-eight hundred bumblebees belonging to the American 

 Entomological Society. I am also under obligations to Mr. S. A. 

 Rohwer for the loan of and notes on several specimens belonging 

 to the United States National Museum, and to Mr. Henry L. 

 Viereck for the loan of specimens from the collection of the 

 Biological Survey. 



For the sake of convenience and because of the nature of the 

 subject matter itself, I have deemed it advisable to divide this 

 article into five parts. 



A. Descriptions and Notes on Bumblebees from Arizona 



Prior to 1913 only seven species of Bremus and no species of 

 Psithyrus were known from Arizona. Recently in Entomological 

 News,^ I recorded five species and one subspecies of Bremus. and 

 one species of Psithyrus which were additions to the list of this 

 state. This increased the number of Bremidae known to occur 

 in Arizona from seven to thirteen species. When this article 

 was sent to press, I had some other bumblebees from the same 

 state, which I hesitated to report upon at that time because of 

 doubt as to their specific status. Further study has shown these 

 specimens to represent two new varieties of Bremus kirbyellus 



1 XXXII, pp. 144-148, (1921). 



TKANS. A.M. ENT. SOC, XLVIII. 



