FAMILIES OF HETEROGYNA. 93 



less minierous, possessing wings and are produced only for the pr()])a- 

 gation of their species. * * * These insects have attracted the 

 attention of the observers of Nature fi'oni the earliest time ; and 

 their untiring exertions for the welfare of the community, their de- 

 votion to the young and their carefulness in the collection and storing 

 up of various materials, have led to their being regarded as examples 

 of surprising instinctive foresight." (Westwood). 



While considerable has been published concerning the habits of 

 certain of our species, the scientific study of these most interesting 

 creatures has been sadly neglected, owing doubtless to the want of a 

 knowledge of generic characters, which have nowhere, until now, 

 been tabulated in the English language ; these tables, however, in 

 consequence of the neglect of the study and the ignorance existing 

 concerning our species, must necessarily be very incom])lete. The 

 collection of the American Entomological Society, so rich in most of 

 the other series, is exceedingly meagre in this, and it is notorious that 

 in the many collections sent in, from time to time, for determination, 

 very few ants are represented and then only the most common, which 

 may be partly accounted for by the fact that as a majority of the 

 species are subterranean in their habits and of small size, they are 

 apt to escape the notice of collectors. 



The series is characterized by the petiole of the abdomen having 

 one or more scales, or nodes, and the societies consisting of three 

 sexes, males, females and workers. It is divisable into five families, 

 in the following manner: 



Table of Families. 



Petiole with a single joint. 



Abdomen proper (not inchuling petiole) not constricted between segments 1 

 and 2. 

 Insertion of the mandibles distant. 



Clypeus always distinct and often very large; frontal crest more or less 

 long, not snrrounding the insertion of the anteniuK ; i)etiole almost 



always surraonnted by an erect scale FORMICID^. 



Clyjieus very small or even indistinct; frontal crest very short, snrround- 

 ing the insertion of the antenna; in front; petiole depres.sed, uodi- 

 form ; % large, with the abdomen long and cylindrical: 9 :i"tJ 5 

 not j)0sitively known, the former probably larviforin.DORYLID.ffi. 

 In.scrtion of the mandibles contiguous or nearly so ( ^ 9 )• 



ODONTOMACHID^. 



Abdomen proiier constricted between segments 1 and 2. PONERID^. 



Petiole composed of two joints MYRMICID^. 



