312 NOTES ON BUMBLEBEES 



this species collected by Mr. E. J. Oslar at San Miguel and Clear 

 Creek, Colorado. In the collection of the American Entomo- 

 logical Society are queens of this species which are from Colorado, 

 and it is likely that these are the specimens on which Cresson's 

 record of 1879 is based. In view of the records just given, the 

 occurrence of a variety of sylvicola in Arizona is not remarkable, 

 and the species probably occurs in most of the high mountain 

 ranges of the western United States. 



Bremus pleuralis Nylander 



This species is represented from Arizona by one queen, col- 

 lected by Mr. E. J. Oslar, in the Patagonia Mountains, Arizona, 

 on July 11, 1919. 



I have carefully compared this specimen with queens and 

 workers of 'pleuralis in the United States National Museum and 

 the American Entomological Society, collected by T. Kincaid 

 on the Harriman Alaskan Expedition of 1899. In coloration, 

 except for the triangular patch of black hairs extending down- 

 wards on the basal dorsal portion of abdominal segments one 

 and two, and the more yellow scutellum and mesopleura, it re- 

 minds one of kirbyeUus var. arizotiensis. Structural differences, 

 such as the carinate hypopygium, length of the malar space, and 

 strictly tridentate type of mandibles, readily serve to distinguish 

 pleuralis from kirbyeUus var. arizonensis. Cockerell's record of 

 pleiiralis from the northern peninsula of Michigan in 1916 is 

 certainly wrong. His statement that the specimen he question- 

 ably determined as pleuralis cannot be a melanic variety of 

 B. consimilis {= vagans], because of ''the malar space being 

 too short, "likewise prohibits it from heingpleuralis. In pleuralis 

 the malar space is comparatively almost as long as that of 

 vagans. Cockerell says also that the general coloration of the 

 specimen is like that of vagans, whereas pleuralis usually has a 

 triangular patch of black pile on the dorsal middle portion of 

 abdominal segments one and two, a condition not encountered 

 in vagans. I have studied a large series of bumblebees from 

 various parts of Michigan, and am inclined to believe that the 

 pleuralis listed by ('ockerell from that state is a worker of the 

 variable and oftentimes puzzling buml)lebee so well named 

 perplexus by Cresson. The melanic coiKhtion r(»ferred to, the 

 "general coloration" of vagans and (he "abdomen entirely 



