1863.] 
115 
Var. b. Having all the abdominal segments yellowish, except the 
anus, which is black. 
Var. c. Having the whole of the thorax black, except the anterior 
portion above, and a few hairs on the scutelliim which are yellowish. 
Var. d. Having the whole of the thorax yellowish, except a slight 
admixture of blackish between the wings. 
Female. Not seen. 
Twenty-two specimens examined. Mass., Conn., N. Y., N. J., Penn., 
Del., Md., Ill. (Coll. E. Norton, and Ent. Soc. Phila.) 
Although Eabricius described this species as having the thorax en¬ 
tirely yellow, it will be seen above that it varies from almost all yellow 
to almost all black. The most common variety, however, has a black 
band between the wings. The yellowish color of this species, as is 
generally the case with most of the bees, often fades to a dirty white; 
the color when fresh is doubtless a bright lemon-yellow. 
It may be possible that B. nidulans of Fab., is only a variety of this 
species, as some of the specimens before me have the anus tinged with 
fulvous. 
This species resembles Boinhus fervidus very much in coloration, 
and may possibly be parasitic on that species. 
In concluding this paper I would state that I have done the best I 
could in separating the species of this group, and it may be that I have 
made too many new species, but when we consider the great difficulty 
experienced by authors in bringing about a correct division of the Euro¬ 
pean species, it will perhaps be a sufficient excuse for any such errors 
that I have made in this paper. 
I desire, here, to express my thanks to Mr. Edward Norton, Dr. Thos. 
B. Wilson, and the Smithsonian Institution, for the loan of specimens, 
and for much valuable assistance. 
