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No. 417.] NESTS OF AMERICAN ANTS. 719 
Owing to the absence of wings in the males, mating takes 
place within the nests. This can be easily observed both in 
the natural and in the artificial nests. The couples may be 
killed without separating, by immersion in warm alcohol. 
The nuptial flight of the females was observed by von Hagens 
(67) on the 12th of August in the Rhine province. Some of 
the queens may perhaps fly to other nests and there be ferti- 
lized, and although there is usually only one fertile queen to 
a colony, it is possible that there may occasionally be several 
originating from different nests. If this were not the case we 
should have the condition to which Forel has called attention 
(74, p. 343), viz., that all mating must necessarily take place 
between brothers and sisters of the same colony. 
The missing workers of Anergates atratulus are replaced in 
the mixed colonies by the workers of Tetramorium cespitum. 
Whatever progeny is found in these colonies belongs exclu- 
sively to the Anergates. The Anergates of both sexes are 
nourished with food regurgitated from the mouths of their 
Tetramorium auxiliaries. They appear to be incapable of 
obtaining their food in any other manner. 
Adlerz (86, p. 231) and Wasmann (91, p. 136) have ascer- 
tained that the Tetramorium auxiliaries of the Anergates pay 
relatively little attention to the young queens, while, on the 
other hand, they very frequently carry the males about and 
lick them long and assiduously. During this operation the 
males assume a characteristic motionless attitude. The two 
authors compare the attention thus bestowed on the male 
Anergates by the Tetramorium auxiliaries to that bestowed 
on myrmecophilous beetles that secrete certain substances of 
Which the ants appear to be fond; e.g., the attention bestowed 
on Claviger testaceus by Lasius flavus. 
Adlerz and Wasmann have made experiments with a view to 
determining the method whereby a new mixed colony is formed, 
t.e., by the association of the female Anergates with the Tetra- 
morium workers. Adlerz (86) in Sweden placed several unfer- 
tilized Anergates queens in a strange nest of Tetramorium. 
They moved about among the Tetramorium as if unperceived. 
He obtained nearly the same results on placing unfertilized 
