182 
Psyche 
[August 
Workers of Brernus affinis, bimaculatus, impatiens, and vagans. 
Result: Same as in experiment l. 3 
Experiment 6. Introduced: Worker from another fervidus 
colony. 
Result : Attacked with legs and mandibles. No attempt 
at daubing. 4 
Experiments 7, 8 and 9. Introduced (separately): Worker 
honeybee ( Apis mellifica ), male of Brernus impatiens , and male of 
Polistes pallipes Lepeletier. 
Result : All stung to death and thrown out of the nest. No 
attempts at daubing. 
Experiments 10, 11, 12, IS and 14- Introduced (separately): 
Blue bottle fly ( Calliphora vomitoria), drone fly ( Eristalis tenax), 
dragon fly ( Sympetrum rubicundulum) , small cricket ( Nemobius 
sp.), and gypsy moth ( Porthetria dispar). 
Result : Same as in experiments 7, 8, and 9. 
Experiment 15. Introduced: Katydid ( Conucephalus sp.). 
Result: Stung to death, but also daubed. 
Experiments 16, 17, and 18. Introduced (separately): 
Earth worm ( Lumbricus sp.), young frog ( Rana sp.), and mouse 
(Mus 7nusculus). 
Result: All stung to death. No attempts at daubing. 
From these experiments it will be seen that the workers of 
a Brernus fervidus colony, at least when dealing with insects, 
vary their method of attack with the nature of the intruder. 
If stingless, or comparatively weak (e. g., the honeybee), the 
intruder is seized immediately and stung to death, while daubing 
is invariably resorted to if the intruder possesses superior fighting 
abilitv. What enables Brernus fervidus to make these distinctions, 
it is difficult to say. In this connection it must be stated that 
3 ln connection with experiment 4 it may be stated that a worker of Brernus impatiens, 
an exceedingly pugnacious species, sometimes attacks a fervidus worker, and may then be 
stung to death by one or more workers of the latter species, though other members of the 
colony, even during the struggle, continue to daub the intruder. 
^Similar results obtain if two fervidus colonies are combined. During the course of the 
summer, the writer made four such combinations (one colony in each case being queenless), 
but never noticed any daubing. 
