1922 ] Unique Method of Defense of Bremus fervidus Fabricius 183 
bumblebees never molest certain intruders, e. g. the larva3 of 
Brachycoma, even though the latter are very deadly to their 
brood. 
At first there was some doubt as to the nature of the liquid 
which Bremus fervidus uses in connection with this interesting 
behavior, but the writer finally decided that it is honey. This 
conclusion is based on the following facts: (1) the liquid has a 
sweet taste; (2) a young Psithyrus ashtoni queen which was 
being daubed (experiment 1), lapped up a drop of liquid which 
accidentally adhered to some cotton; and (3) the fervidus 
workers themselves lapped up the liquid from the wings of a 
katydid (expirement 15) after the latter had been stung to death. 
This habit of daubing certain intruders with honey recalls 
an interesting habit of the honejTee. According to Phillips 
(1921, p. 117), it sometimes happens that lizards or small 
snakes get into a hive. The honeybee workers seal up such 
intruders in propolis, a sticky substance which they obtain from 
trees and other sources. Because of the different nature of the 
substances used, it seems rather improbable that the habit of the 
honeybee and the habit of Bremus fervidus are related, yet it 
would be interesting to know whether there is any similarity in 
behavior while the substances are being applied. 
It would also be interesting to ascertain whether any other 
species than Bremus fervidus resort to honey daubing. The writer 
found no trace of such a habit in his affinis, bimaculcitus, impatiens, 
and vagans colonies. Nor is such a habit mentioned by Goedart 
(1700), Reaumur (1742), Huber (1802), Putnam (1865), Hoffer 
(1882-83), Ivristof (1883), Coville (1890), Harter (1890), Beng- 
tsson (1903), Lie-Petterson (1906), Wagner (1907), Gundermann 
(1908), Sladen (1912), Armbruster (1914), Bachman (1916), 
and Frison (1917, 1918), all of whom have paid more or less 
attention to the behavior of bumblebee colonies. However when 
we consider that Putnam (1865), who had colonies of Bremus 
fervidus under observation, did not notice this habit, it may well 
be that it was overlooked in other species. 
According to the classifications of Franklin (1912-13) and 
Sladen (1912), one based on structure and the other on habit, 
