DIMORPHIC QUEENS IN AN AMERICAN ANT. 157 



/9-form would represent the queen of some inquiline or symbiotic 

 species. Although this explanation is readily suggested by the 

 well-known cases of dulosis and xenobiosis in ants, we are, never- 

 theless, bound to reject it for the following reasons : Though 

 the ^-females were taken in several nests and, in one case, were 

 seen to celebrate their nuptial flight at the very same time as the 

 a-females, no males or workers which could represent any species 

 except latipcs were to be found in the nests. The same argument 

 would hold mutatis mutandis, were we to consider the ,9-form as 

 the only true female of latipes. The workers and males of all 

 the known North American Lasii have been accounted for, and 

 there is still a female form left over, so that there is no species 

 known that could be enslaved by, or live as an inquiline with, L. 

 latipes. \Ye should have to suppose that the inquiline species 

 was represented by females only, and this is most improbable. 

 Finally, the deep coloration above noted as occurring in the 

 /9-females of nest No. 5 would indicate that both the - and 

 /9-females belong to the same species. We believe, therefore, that 

 this hypothesis may be safely rejected. 



2. It may be suggested that the ^-female is the normal female 

 of latipcs, whereas the /9-females are diseased forms --individuals 

 afflicted with some strange emmet elephantiasis or acromegaly ! 

 But even apart from the very frequent occurrence and uniform 

 development of the ^-females, dissection shows that such a view 

 cannot be seriously entertained. Their internal structure is in no 

 respect abnormal. The fat body is well developed and the 

 ovaries are in the same stage and have the same normal structure 

 as the ovaries of the ^-females. If anything, the /9-females are 

 more vigorous, somewhat larger and supplied with more fatty 

 tissue (even in the distal lobes of the large fore femora !) than the 

 a-females. In a word, the ^-females are somewhat above normal, 

 while the a-females, so far as we are able to judge, are quite 

 normal. Hence this hypothesis, also, may be safely rejected. 



3. The dimorphism may be regarded as the result of hybridism 

 between /,. claviger and L. latipcs. This view is supported by 

 the following considerations : 



(a) Both species occur in the very same localities, and latipes 

 is much rarer than claviger. Hence the queens of the latter may 



