OF WASHINGTON. 201 
line, a careful watch was kept to detect, if possible, the breeding of the in- 
quiline. But all the bees that emerged were either workers, queens, or 
drones. No Apathus was developed. It was noticed, however, that the 
workers and queens differed somewhat from others collected in the field, 
and a reconsideration of the characters of the two forms showed that the 
colony in captivity was not B. fervidus, but B. borealis a species previ- 
ously overlooked by the writer, but well described (the female only, how- 
ever), and distinguished by Kirby.*. All the 9 ? and 9 of these 
two species in the collection were accordingly easily separated, but among 
the rP cf only one form could be found that with precisely the coloration 
of B. borealis, and identical with those bred from the captive colony of 
that species. Not a $ specimen was found that showed any probability 
of belonging to B. fervidus. 
Meanwhile two bumble-bees had been captured in copulation by Mr. 
O. E. Pearce.f These were examined, and proved to be a 9 Bombus fer- 
vidus and a < Apathus elatus ! 
An examination of the structural characters of A. elatus with a view to- 
ward finding therein the warrant for placing the species in Apathus in- 
stead of Bombus was next made. The males of Apathus are said to differ 
from those of Bombus by having the outer side of the tibia of the poste- 
rior leg rounded and covered with hair, and by having no corbicula. 
Bombus has a flat naked tibia and a corbicula. Apathus elatus has, it is 
found, a corbicula, rudimentary it is true, and the hairs on the outer sur- 
face of the tibia are shorter and scantier than in any other species of 
Apathus. So far as these structures are concerned, therefore, A. elatus, 
while apparently clearly an Apathus, is really intermediate between the 
two genera. 
Next, several colonies of genuine B. fervidus were taken, in the autumn 
of 1886. at the season of producing males, and in every case the so-called 
A. elatus emerged from the nymph'-cells in abundance, and no other form. 
A female A. elatus has never been described. 
The writer, therefore, considers Apathus elatus to be the male of Bom- 
bus fervidus, the evidence being summed up as follows : The female of 
Apathus elatus is unknown. The male of Bombus fervidus is unknown. 
The coloring of the two is alike. The structural characters of A. elatus do 
not unequivocally keep it out of Bombus. A. elatus has been bred in colo- 
nies of B. fervidus, and in the colonies of no other species. No male bee, 
*In B. fervidus the hairs of the head are entirely black, and those of the 
pleura yellow. In B. borealis the hairs of the head, on the vertex and on 
the face cephalad of the antennae, and sometimes caudad of the antennae, 
are partly yellow, and those of the pleura black. The yellow hairs of B. 
borealis on all parts of the body have a tawny shade, quite different from 
the lemon-yellow of B. fervidus. 
fA similar case has been recorded by Mr. Benjamin D. Walsh (Proc. 
Ent. Soc. Phil., iii, 247, foot-note [1864] ). 
