130 ANTS. 



from the same nests. It is. therefore, largely a matter of convenience 

 that the soldier or worker is selected as the paradigm of the species and 

 takes precedence of the other forms in systematic descriptions. It is 

 dhvious that the female, as presenting more numerous and complete 

 characters, would occupy this position, were it not that this caste is, as 

 a rule, less easily obtainable. Except for the same reason, the male 

 would also occupy a more important place in generic and specific 

 diagnosis, since this sex is very stable and often presents important 

 characters, especially in the structure of the genitalia. It is probable, 

 therefore, that at some future time, when large numbers of male and 



FIG. 74. Worker of Myrniicaria brunnca of India. (Bingham.) 



female specimens have accumulated in our collections and have been 

 carefully studied, the present classification of the Formicidge will un- 

 dergo considerable alteration. I'ntil this time arrives, however, it will 

 be prudent to move slowly in establishing new genera. Mayr, Forel and 

 Emery have all shown admirable conservatism and a laudable absence 

 of the " mihi-itch " in dealing with this aspect of the subject. 



Another difficulty arises from the great variability of ants, both 

 among members of the same colony and hence among the progeny of a 

 single or a very few mothers, and among colonies of the same species 

 in different stations or localities. In the former case we have what 

 are known as " nest varieties," in the latter " local or geographical 

 varieties." The danger of basing species on mere nest varieties is 

 often considerable and can be overcome only by studying large series 

 of specimens collected from the same colony. Probably many of the 

 ' species " of exotic ants included in our faunistic lists are nothing 

 more than nest varieties. The local varieties are of peculiar interest. 

 Like other animals, certain species of ants may be very stable though 

 widely distributed, others highly variable though very restricted in their 

 range. Some widely distributed species may be stable in some por- 

 tions of their range and highly variable in others. And finally, some 

 widely distributed species seem to be decidedly variable wherever 



