No. 417.] NESTS OF AMERICAN ANTS. 709 
Sometimes when they desire to leave the nest, the Tomognathus 
are detained by the auxiliaries in much the same manner as 
Polyergus. 
The males of Tomognathus do not mate with the females of 
the same nest, but do so readily with the virgin queens of other 
nests. The larva are so similar to those of the Leptothorax 
that Adlerz was unable to distinguish them. They are nour- 
ished with both liquid and solid food.  Adlerz's description of 
the manner in which the larve are fed with pieces of flies 
tallies exactly with my observations on the primitive method 
of feeding adopted by the Ponerinz and the Myrmicinz of the 
genera Stenamma (Aphzenogaster) and Pheidole (00 and '00^). 
Strongylognathus. —'The species of Strongylognathus have 
perfectly edentulous, falcate mandibles, and more or less pro- 
jecting postero-lateral corners to the head. Four species of 
the genus are known to occur in Europe: S. huberi Forel, 
S. testaceus Schenk, S. christophi Emery, and S. cecilie Forel. 
The habits only of the first two have been observed (Forel, 
74 and '00*; Wasmann, '91) and these present interesting 
differences. Both species form mixed nests with Tetramorium 
cespitum: S. huberi in southern Europe and northern Africa, 
and S. ¢estaceus in southern and central Europe. 
S. huberi seems like a diminutive and feeble caricature of 
Polyergus. Forel (74) found by experiment that it would rob 
the larvae and pupz of Tetramorium and fight with the rightful 
owners after the manner of Polyergus. But it is not known 
whether S. Zuberi under natural conditions really provides its 
nests with auxiliaries by carrying on regular marauding expedi- 
tions. Forel, in a more recent paper on this species ('00%, 
P- 275), expresses the opinion that it may not make sorties but 
keep up the mixed colony by alliance with the Tetramoriums 
Instead. The workers of Strongylognathus are able to exca- 
vate, but they are fed by the Tetramorium workers. The 
latter are present in considerable numbers in the mixed nests, 
but up to the present time fertile queens of Tetramorium have 
not been found with them, though from what is known of 
S. testaceus one or more of these queens may perhaps be 
Present in some cases. 
