282 AMERICAN HYMENOPTERA. 



middle ; chitinous thickening on its anterior margin very 

 heavy, especially so on the median projection ; middle por- 

 tion of this spatha usually with two parallel chitinous thick- 

 enings running almost anteriorly and posteriorly and usually 

 with a line of hairs running up the middle line between them 

 for a short distance ; as a rule, without fenestrae. Claspers 

 (figs. 61 and 68) long and rather thick and powerful in appear- 

 ance ; branches very broad at base, but narrowing rapidly to 

 a sharply rounded, almost pointed, apex (as seen from above); 

 volsellae broad and heavy, narrowest toward apex, with 

 broadly rounded and recurved apical projections, with very 

 coarsely and irregularly serrate margins ; squamae large and 

 prominent, with outer lobe vestigial, usually extending in- 

 ward considerably past the inner margin of the volsellse, irre- 

 gularly quadrate, with inner posterior part pointed or nearly 

 so ; sagittae with extremely irregular heads, consisting of a 

 basal part with a prominent tridentate projection, this being 

 connected, by means of a narrow elevated ridge, running 

 along the shaft, with the very irregularly quadrangular api- 

 cal portion, which has a very prominent anteriorly directed 

 tooth on its outer end ; shafts of sagittae wide and flaring ; 

 uncus usually with a prominent recurved portion. 



Bombus (Bombiis) borealis Kirby. 

 Bombus borealis W. Kirby, Fauna Bor.-Amer., IV, 1837, p. 272, n. 

 378. 



Cresson, Proc. Ent. Soc. Phila., II, 1863, p. 93, n. 9. 



Cresson, Proc. Ent. Soc. Phila., Ill, 1864, p. 41, n. 6, 



" fervidus Putnam, Proc. Essex Instit., IV, 1864, p. 99 (pars.). 

 " " Packard, Proc. Essex Instit., IV, 1864, p. 110 (pars.). 



" borealis Bethune (Reprint, Kirby's Faun. Bor.-Amer.), Can. 



Ent., X, 1878, p. 117. 

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



(Catal.). 

 " fervidus Radoszkowski, Bull. Soc. Natural. Moscow, LIX, 



1884, p. 77 ; T. 2, F. 25. 

 borealis Cresson, Syn. Hym. No. Amer., 1887, p. 307, 1887 



(Catal.). 

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



1888, p. 237 (pars.); T. 10, F. 5. 



