1923] Observations on the So-called Bumblebee Trumpeter 151 
While this restless activity was in progress on the south side 
of the building, not a single bee, as a rule, was engaged in “trump- 
eting” in the two colonies which were kept on the north side, 
although one of the latter — also belonging to Bremus impatiens — 
consisted of more than 450 workers. The exposure to the hot 
midday sun evidently did not agree with the bees, for the colonies 
on the south side of the building did not thrive nearly so well as 
those on the north side, and during the following summer all of 
m}^ bumblebee colonies were therefore kept in shady situations. 
While “trumpeting” in a bumblebee colony is most pro- 
nounced when the nest is exposed to the rays of the sun on a hot 
day, it may, as is indicated by the observations of Goedart (1685), 
de Pluche (1764), Hoffer (1882-83), Bengtsson (1903), and Bach- 
mann (1915, 1916), also take place in the morning and evening, 
in fact, as Wagner (1907) has pointed out, at any time of the day. 
Thus, for example, I have occasionally found one or two workers 
fanning at various hours during the night, even if the temperature 
outside was less than 70°. In this case, as has been suggested by 
von Buttel-Reepen (1903), fanning no doubt has to do with the 
expulsion of moisture or disagreeable odors from the nest. 
Neither is it true, as Hoffer (1882-83), von Buttel-Reepen 
(1903), and Sladen (1912) assume, that “trumpeting” is resorted 
to only by species which have subterranean nests. Wagner 
(1907) found that Bremus muscorum, a European species which 
usually nests on the surface of the ground, resorts to fanning 
when the temperature of the nest gets too high, and this, as will 
be seen later, is also true of Bremus fervidus in this country. 
As already stated, Hoffer (1882-83) believed that small 
Bremus colonies have no “trumpeter.” Wagner (1907) and 
Lindhard (1912), on the other hand, claim that small colonies 
also resort to fanning. In order to determine which one of these 
claims is correct, the following experiment was performed. At 
2 P. M., on June 3, 1922, I exposed the next-box of a small 
colony (1 queen and 2 workers) of Bremus impatiens to the rays 
of the sun. Three minutes later, one of the workers crawled to 
the top of the nest and began to fan, and within another minute, 
the remaining worker and the queen appeared and assisted in 
this activity. 
