1922 ] Notes on Nesting Habits of North American Bumblebees 191 
largest colony was taken on September 1, 1922. It contained 
the old queen, 19 young queens, 27 males, and over 175 workers. 
Not long ago, Bequaert (1920) described a new variety of 
Bremus affinis which he called novce-anglice. This variety oc- 
curred in 2 of the 8 nests mentioned above. The first of these 
was taken July 11, 1922. It contained (1) the old queen, 1 
young queen, and 43 workers of Bremus affinis ; (2) 12 workers of 
Bremus affinis var. novce-anglice; and (3) 1 worker of Bremus 
terricola Kirby. The second nest was taken August 4, 1922. 
In it were found (1) 23 workers of Bremus affinis; (2) 9 workers 
of Bremus affinis var. novce-anglice; and (3) 1 worker of Bremus 
terricola. The contents of these two nests, and the character 
of the bees reared from the second, suggest that Bremus affinis 
var. novce-anglice Bequaert is a hybrid between Bremus affinis 
and Bremus terricola, a question which will be discussed in an- 
other paper. 
Two other of the 8 Bremus affinis nests were victimized 
by Psithyrus ashtoni Cresson. One of these, on August 9, 1921, 
contained (1) the old queen and about 100 workers of Bremus 
affinis; and (2) the old queen, 3 young queens, and 6 males of 
Psithyrus ashtoni. A detailed account of the subsequent history 
of this affinis-ashtoni colony has appeared in another paper 
(1922). The second -colony parasitized by Psithyrus ashtoni 
was taken on July 26, 1922. It contained (1) the old queen and 
about 20 workers of Bremus affinis; and (2) the old queen (dead), 
2 young queens, and 2 males of Psithyrus ashtoni. During the 
following weeks several more young Psithyrus queens and males 
were obtained from this colony. 
Bremus affinis frequently stores a considerable quantity of 
pollen in long, waxen cells, which Hoffer (1882/83, II. pp. 85, 86) 
called pollen cylinders. I noticed a number of these pollen 
cylinders in 2 of the 8 Bremus affinis colonies. Both of these 
colonies were rather large, each one having over 150 workers. 
In one of these two nests most of the pollen cylinders were from 
5 to 6 cm. long, and the total pollen contained in them weighed 
about 2 ounces. 
