10 STRUCTURE OF ANTS. 
least seven years old, and seem still quite strong and 
well. I have also some workers which I have had in 
my nests since 1875. 
The body of an ant consists of three parts: the 
head, thorax, and abdomen. 
The head bears the principal organs of sense, and 
contains the brain, as the anterior portion of the 
nervous system may fairly be called. 
The thorax, supporting the legs, and when they are 
present, the wings, contains the principal muscles of 
locomotion. 
The abdomen contains the stomach and intestines, 
the organs of reproduction, the sting, &c. 
Returning to the head: the antenne consist of a 
short spherical basal piece, a long shaft, known as the 
scape, and a flagellum of from six to seventeen (gene- 
rally, however, from ten. to thirteen) short segments, 
the apical ones sometimes forming a sort of club. The 
number of segments is generally different in the males 
and females. 
The eyes are of two kinds. Large compound eyes, one 
on each side of the head ; and ocelli, or so-called simple 
eyes. The compound eyes consist of many facets. The 
number differs greatly in different species, and in the 
different sexes, the males generally having the greatest 
number. Thus, in Formica pratensis there are, 
according to Forel, in the males about 1,200 in each 
eye, in the fertile females between 800 and 900, in the 
workers about 600. Where the workers vary in size 
