40 Bulletin American Museum of Natural History. [Vol. XXIII, 



first sight the second cpnclusion seems not to be justifiable. For how is 

 it to be reconciled with the occurrence of as many as 20% of pseudogynes 

 in a single nest ? We must not, however, lose sight of the fact that the usual 

 percentage of pseudogynes does not surpass that of the winged females, 

 which may occur in a colony of Formica sanguinea or rufa, and that it cer- 

 tainly does not surpass the maximum which, according to my observations, 

 may reach 5% in many sanguinea colonies. Now the pseudogynes do not 

 leave the nest but remain in it, whereas the normal females escape at the 

 time of the nuptial flight; hence it is only necessary that the conversion of 

 larvae into pseudogynes should be repeated for several generations and 

 several years, to raise the number of these individuals to 20%." Wasmann 

 also states that it is nearly always the same Formica colonies that are found 

 to contain Lomechusa and Atemeles year after year. These considerations, 

 however, fail to throw any light on the above described colony of F. incerta 

 with its enormous number of pseudogynes associated with winged females 

 and so small a number of workers. For if A"", cava hibernates with C. novx- 

 boracensis it does not seem probable that it would return year after year to 

 the same incerta nest, when there are hundreds of nests of this ant in the 

 immediate neighborhood. Then, too, incerta colonies, unlike those of 

 sanguinea, rnja, and ]usca are very small, rarely comprising more than 

 about 500 individuals, and could not even survive to raise X. cava year after 

 year if the larvae of this beetle are as destructive to the brood as the larvae 

 of Lomechusa and Atemeles. But this wholesale destruction would seem 

 to be necessary, according to Wasmann's view, to bring about the conver- 

 sion of female larvae into pseudogynes. Moreover, if the pseudogynes are 

 as short-lived as Wasmann supposes, how can they accumulate to any great 

 extent in a single colony? And finally, how can a colony of incerta of the 

 size of the one above described produce as many as 213 females in a single 

 season ? These considerations lend probability to the view that Wasmann's 

 theory may require some emendation when we come to have a fuller knowl- 

 edge of the habits of Xenodusa. 



F. incerta and rubicunda are not the only North American ants that are 

 able to produce pseudogynes. In going over my collection I find that I have 

 mounted a number of these anomalous individuals with the normal workers 

 from nests of the following ants: 



1. F. rufa integra Nyl. 



(a) A single pseudogyne taken several years ago by Mr. J. Angus at 

 West Farms, now a part of New York City. 



(b) A couple of callow pseudogynes collected July 8, at West Chester, 

 Pennsylvania, by Mr. J. C. Bradley. 



