336 AMERICAN HYMENOPTERA. 



Abdomen. — Dorsum : segment one covered with pure yellow pile ; 

 segments two and three covered with deep ferruginous-red pile ; seg- 

 ment four sometimes entirely black and sometimes entirely yellow, but 

 usually mostly black and with more or less yellow pile either on the 

 sides or along the apical margin or both ; segment five usually entirely 

 black, but very often with a touch of yellow pile on the sides and some- 

 times with pile of the same color along the apical margin ; segment 

 six black, with rusty tip. Venter, except apical segment, usually 

 clothed for most part with light pile. Hypopygium without median 

 carina. 



Wings. — Rather strongly stained with brown, but not dark ; the fore 

 wings lightest across the middle portion. 



Legs. — Coxse sometimes entirely dark, but usually with some light 

 hair ; trochanters always with more or less light pile, especially the 

 hind pair, the fore pair sometimes with very little ; fore and middle 

 femora sometimes entirely dark, but usually with more or less light 

 pile on the lower sides of their basal portions ; hind femora always 

 with a large amount of yellow hair on the lower sides of their basal 

 halves; fore tibiae always dark ; middle tibiae usually entirely dark, 

 but sometimes with more or less ferruginous hair near the tips on the 

 outer sides; corbicular fringes very often entirely black, but usually 

 more or less strongly ferruginous with black hairs admixed. 



Worker. — Much like the queen, but with wings slightly lighter and 

 corbicular fringes usually entirely black. 



Male. Head. — Face and occiput bearing yellow pile without a very 

 strong admixture of black hairs ; ventro-lateral sides of head with a 

 considerable amount of light pile. Malar space distinctly longer than 

 its width at apex, about one-fourth as long as the eye ; clypeus covered 

 up with pile ; flagellum of antennae about two and two-thirds times 

 as long as the scape ; third antennal segment shorter than fifth, the 

 fourth shorter than the third. 



Thorax. — Coloration much as in females ; yellow on anterior part 

 of dorsum usually more pronounced, thus making a black interalar 

 band more definite ; pleura and sides of median segment densely 

 covered with light yellow pile. 



Abdomen. — Coloration much as in females. Fourth dorsal segment 

 sometimes entirely black, but usually mostly covered with yellow pile 

 with only a small amount of black hair intermixed ; fifth segment 

 sometimes entirely black and sometimes entirely yellow, but usually 

 mostly black with a touch of yellow near each side margin or along 

 the apical margin ; sixth and seventh segments entirely black. Venter 

 clothed mostly with yellow pile. 



Genitalia. — Outer spatha much like that of B. vagans (fig. 131), 

 but with posterior border usually more irregular. Inner spatha like 

 that of B.perplexus (fig. 145), but with only a very small fenestra. 

 Claspers andsagittae resembling those of B . fernaldi (figs. 74 and 110) 



