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Psyche 
[December 
of the nest were true sister queens, sharing in the activi- 
ties alike, and so far as I could see no individual assumed 
the haughty role of queen. 
At this point it will be well to digress from the nest- 
building habits of this species and discuss the facts of 
pleometrosis and its origin. 
In a very interesting paper by Dr. J. Bequaert, entitled 
“Vestigial Pleometrosis in the North American Polistes 
pallipes ,” 4 the term “pleometrosis” (which Wasmann intro- 
duced for ants) is used to signify the founding of a new 
colony by two or more fecundated females. Bequaert 
says that when pleometrosis occurs “among strictly mono- 
gynous wasps as with Polistes , it is well worthy of care- 
ful investigation, since it evidently is then one of those 
vestigial instincts whose study is of great value for a 
proper understanding of animal behavior.” 
Pleometrosis occurs here about St. Louis abundantly in 
P. annularis, occasionally in P. rubiginosis and but rarely 
in P. pallipes. This seems to be contrary to the findings 
for P. pallipes about New York . 5 
After viewing the occurrence of this habit in our Polistes, 
I am inclined to believe that pleometrosis in our northern 
species of Polistes had its origin in the “swarming” habit 
of tropical Polistes. In a paper now in course of publi- 
cation on Polistes canadensis and Polistes versicolor of 
Barro Colorado Island in Panama, I show that when the 
colony grows too large or a catastrophe occurs to the nests, 
4 Bull. Brooklyn Entom. Soc. 18: 73-79, 1923. 
5 During a period of ten years, I have seen, among a thousand or 
more nests of P. pallipes examined, only six nests with two queens, 
and only one nest with three queens. I have always been on the 
lookout for the nests in the spring before the workers emerged, so 
that I could mark the queens with paint and find if one was truly a 
specialized egg-laying queen, and the other sank into the insignificant 
role of worker. In every case where this was tried, the queens 
deserted the nests soon after the ordeal of being marked, and the 
problem remains unsolved. Had I waited until larvae were in the cells 
they might have been more faithful to their tasks; one must, however, 
mark the queens in pallipes before the young emerge, since it is not 
possible to distinguish workers from queens by either size or color. 
In course of two years I have been able to examine only about twenty- 
five nests of P. variatus in early spring, but I have never found more 
than one queen founding a nest. 
