362 AMERICAN HYMENOPTERA. 



and shining ; pleura usually entirely covered with yellow to bases of legs ; 

 sides of median segment sometimes with black, sometimes with yellow 

 pile. 



Abdomen. — Dorsum with segments one and two entirely covered 

 with yellow pile ; segment three entirely black ; segment four either 

 black on basal half or entirely concolorous with segments five and six, 

 these being covered with yellowish-ferruginous pile of greatly varying 

 shade. Venter very thinly clothed with pile, the predominating color 

 often being light yellowish, especially toward the apex. Hypopygium 

 without a median carina. 



Wings. — Light, only slightly stained with brown. Fore wings dark- 

 est on median and submedian cells, on anterior portion of radial cell 

 and beyond the end of the radial cell. 



Legs. — Coxae, trochanters and femora quite variable, sometimes 

 bearing only dark pile, sometimes with a considerable amount of light 

 or yellow hair. Fore and middle tibise usually bearing very little light 

 pile; corbicular fringes quite strongly ferruginous, but usually with 

 more or less black hairs intermixed. Posterior metatarsi bearing only 

 short spines and pubescence, except for a basal posterior fringe of 

 rather short hairs and a few hairs of about the same length on the 

 basal portion of their outer sides. 



Worker. — Much like the queen, but often with an admixture of black 

 hairs with the yellow on the occiput ; lower parts of pleura often dark 

 brown or black ; metapleura often with black hair only ; sides of me- 

 dian segment with only black hair ; coxae, trochanters, femora and 

 fore and middle tibiae black ; corbicular fringes often black. Wings 

 lighter, as a rule, than those of queen. Clypeus sparsely punctate or 

 entirely smooth. 



Male. Head. — Somewhat rounded triangular in outline. Face with 

 a very conspicuous patch of yellow pile between and below the bases 

 of the antennae; this patch, as a rule, not nearly reaching the inner 

 margin of the eye on either side. Occiput usually bearing pure yellow 

 pile ; pile above bases of antennae usually yellow and black mixed, the 

 latter being greatly predominant ; ventro-lateral portions of head usu- 

 ally with a considerable amount of light yellow pile. Labrum slightly 

 concave transversely ; malar space longer than its width at the apex, 

 about one-fourth as long as the eye ; clypeus mostly covered by pile ; 

 fiagellum of antenna nearly three times as long as scape, rather sud- 

 denly thickened at base ; third and fifth antennal segments subequal 

 in length, fourth shorter than either. 



Thorax. — Coloration of pile much as in queen. 



Abdomen. — Coloration of pile much as in queen and worker, but the 

 fourth as well as the third dorsal segment often entirely black ; venter 

 usually with very little, if any, dark hair. 



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

 much like those of B. mixtus (figs. 108 and 109). 



