Oo” 
It becomes apparent that the species of so-called Poneride or Po- 
nerine of which the habits are known belong to five different natural 
groups which are likely to be recognized at some future time as dis- 
tinct families; at least the differences of habit and social organiza- 
tion are as great or greater than those of many families or orders 
among the higher plants and animals. It is becoming more and more 
appreciated that such characteristics afford as good or better indica- 
tions of evolutionary history than do mere differences of structure 
and proportions. Indeed, the evolutionary significance of a structural 
character can not be determined until the biology of the plant or ani- 
mal is known—that is, its mode of existence and place in the economy 
of nature. 
There may be said to be two methods of classification, correspond- 
ing to the two states of knowledge regarding a group of animals or 
plants. Under what may be called the analytical system, classifica- 
tion is based primarily on a logical analysis of formal characters, the 
various groups, such as orders, families, genera, and species being 
reached from the top downward by repeated subdivision. The con- 
crete or synthetic method reverses this procedure. Coherent groups 
of normally interbreeding individuals are recognized as constituting 
species; closely allied species are grouped into genera, and genera into 
families. 
Owing to their vast numbers and diversity, the classification of 
insects is still largely in the analytical stage, so that recognition of 
the kelep as representing a distinct family would not be consistent 
with the current classification. Nevertheless, it may be fully expected 
that in due time the insect groups will be treated in better accord with 
the methods by which the mammals, birds, and other higher animals 
are classified. 
The five groups referred to above may be typified by the gener: 
Stigmatomma, Odontomachus, Ponera, Pachycondyla, and Ecta- 
tomma. The first and second groups have already been recognized 
as families or subfamilies because of structural peculiarities of the 
adult insects, the Amblyponine (including Stigmatomma) having 
no deep constriction behind the node or first abdominal segment. 
The Odontomachide are characterized by their remarkable mandi- 
bles, which are inserted close together near the middle of the head 
instead of at the anterior corners, as in all the related groups. The 
true Poneride, as represented by the typical genus Ponera, show the 
most backward stage of social organization and have very small 
colonies. The larvae are provided, according to Professor Wheeler, 
with four pairs of peculiar adhesive dorsal tubercles, supposed to 
have the function of holding them in position against the sides of the 
nest chamber. In Pachycondyla and Leptogenys the larvee are, like 
