416 AMERICAN HYMENOPTERA. 



This species has a very close ally in B. nevadensis, but I 

 know of no other very closely related species in the Western 

 Hemisphere. A discussion of the more striking differences 

 separating the two species follows my description of neva- 

 densis. 



Bombus (Bonibias) nevadensis Cress. 

 Bombus nevadensis Cresson, Trans. Am. Ent. Soc, V, 1874, p. 102, 

 9 6^. 

 " " Cresson, Rep. Geogr. and Geol. Explor. and Surv. 



100th Merid., 1875, V, p. 728, n. 130, 9 cf ; T. 

 34, fig. 5. 

 improbus Cresson, Proc. Ac. Nat. Sci.Phila., 1878, p. 186, cf. 

 nevadensis Cresson, Trans. Amer. Ent. Soc, VII, 1879, p. 



230. (Catal.). 

 improbus Cresson, Trans. Amer. Ent. Soc, VII, 1879, p. 230. 

 (Catal.). 

 Cresson, Syn. Hym. No. Amer., 1887, p. 308. 

 nevadensis Cre?i?,o-Q., Syn. Hym. No. Amer., 1887, p. 308. 



" Ant. Handlirsch, Ann. Naturh. Hofmus. Wien., 



Ill, 1888, p. 245, 9 S . 

 improbus Dalla Torre, Cat. Hym., X, 1896, pp. 526, 538. 

 nevadensis Cockerell, Bull. Sci. Lab. Den. Univ., XI, 1898, p 

 71. 

 " race cressoni Ckll., Annals and Magazine of Nat 



Hist., Ser. 7, IV, Nov., 1899, p. 388. 

 improbus Cockerell and Porter, Ann. and Magaz. Nat. Hist. 



Ser. 7, IV, 1899, p. 389. 

 nevadensis Cockerell, Entomologist, XXXII, June, 1899, p 

 156. 

 Fowler, Rep't Cal. Agr'l Exp. Sta., 1902, Part II 



p. 317. 

 Ashmead, Proc. Wash. Ac. Sci., IV, 1902, p. 124 

 Titus, Can. Ent., XXXIV, 1902, pp. 37 and 40 



9 8 6^. 

 Viereck, Trans. Amer. Ent. Soc, XXIX, 1903, p 



44. 

 Viereck, Can. Ent., XXXVI, April, 1904, p. 98. 

 Ashmead, Hym. of Alaska, 1904, p. 130. 

 Cockerell, Trans. Amer. Ent. Soc, XXXII, Nov., 



1906, p. 313. 

 Cockerell, Bull. Amer. Mus. Nat. Hist., XXII, 



Article XXV, Dec. 17, 1906, p. 453, n. 117. 

 Cockerell, Univ. Color. Studies, IV, 1907, p. 258, 

 9 c?. 



