640 
THE STUD Y OF INSECTS. 
Family FORMICID.fi (For-mic'i-dse). 
The Typical Ants . 
The ants of this family can be recognized by the follow. 
ing characteristics: the pe¬ 
duncle of the abdomen con¬ 
sists of a single segment; 
there is no constriction be¬ 
tween the second and third 
abdominal segments (Fig. 
765); and the queens and 
workers have no sting. The pupae are sometimes contained 
in a cocoon and are sometimes naked. The following are 
some of our more common species: 
The Carpenter-ant, Camponotus pennsylvanicus (Cam-pa- 
no'tus penn-syl-va'ni-cus).—This is one of the largest of our 
common ants. Its entire body is black. It builds its nests 
in the timbers of buildings, in logs, and in the trunks of 
trees. Frequently they build in the dead interior of a liv¬ 
ing tree, excavating a complicated series of chambers. The 
way in which new colonies of this ant are founded is de¬ 
scribed on page 635. 
The Mound-building Ant, Formica exsectoides (For'mi-ca 
ex-sec-toi'des).—This species is the builder of our largest ant¬ 
hills; these are often five or six feet across, and sometimes 
more than twice that in diameter. The head and thorax of 
this ant are rust-red, while the legs and abdomen are black-* 
ish brown. This species has been supposed to be the same 
as the European Wood-ant, Formica rufa , and is referred to 
in many books under that name. 
The Slavemaker-ant, Formica difficilis (F. dif-fic'i-lis).— 
One of our common slave-making ants is this species. It 
very closely resembles the preceding in size and in color; 
in fact it is difficult to distinguish the two apart without the 
use of a microscope. The Slavemaker-ant usually makes 
its nest almost entirely underground. We often find these 
