166 
Psyche 
[December 
THE NESTING HABITS OF BOMBUS MEDIUS 
CRESSON, THE MEXICAN BUMBLEBEE. 
By Phil Rau, 
Kirkwood, Missouri. 
Specimens of this bumblebee were collected at flowers at 
Cordoba and Jalapa in the State of Vera Cruz. At Tama- 
zunchale, S. L. P., four nests were found among the dense 
growth of weeds in an abandoned banana field ; these were 
pointed out to me by Mr. Olivarez, the manager of the El 
Sol Tourist Courts. Two of these nests were dug up on the 
night of July 7, 1940. Since Dr. T. H. Frison of the Illinois 
Natural History Survey (who kindly identified the bumble- 
bees for me) writes that nothing is known of the life history 
of this species, the data of these two nests are herewith pre- 
sented. 
Both colonies were in slight cavities in the ground which 
evidently had been rodents nests, containing masses of fine 
roots, bits of narrow stems evenly cut, parts of leaves, and 
excrement of mice. There were no special galleries leading 
into the nests, but the comb was brought to view by brushing 
away the surface material to a depth of an inch and a quarter 
to an inch and three quarters. 
When disturbed, the bees let out a steady, musical hum 
which, while not as loud as that of our Missouri B. ameri- 
canorum, could be heard from a distance of ten to twelve 
feet. Their sting, while quite painful, is not so severe or 
lasting as that of its American relative. The workers of B. 
medius are smaller than those of B. americanorum, but the 
queens are almost equal in size. 
An examination of the two nests, designated as A and B, 
revealed the following data. Nest A had one old queen, with 
wings badly frayed, and nest B had two queens, an old one 
with the tips of the wings badly damaged, and a young one 
with perfect wings and portions of the pubescence of a 
lighter, cleaner yellow. There were no males in either nest. 
