HABITS OF ANTS. 361 
The ichneumon-flies (Fig. 358) are very numerous in spe- 
cies and individuals ; by their ovipositor, often very long, 
they pierce the bodies of caterpillars, inserting several or 
many eggs into them; the larve develop feeding only on 
the fatty tissues of their host, but this usually causes the 
death of the caterpillar before its transformation. Certain 
minute species, with veinless wings (Fig. 359, Platygaster), 
of the canker-worm eggs, are egg-parasites, ovipositing in 
the eggs of butterflies, dragon-flies, etc. 
Fig. 357,—Gall-fly of oak. 
if 
Fig, 358,—An Ichneumon-fly. 
Fig, 355. —Horn- j w& 
tail : larvaof Tre- f 
mexcolumba. Nat. \ 
size. A 
co 
Fig, 356.—Pear Slug, 
patural 6170 ean Fig. 359.—Egg parasite of Canker. 
larged ; 2, the fly. worm. Highly magnified. 
The family of ants is remarkable for the differentiation 
of the species and the consequent complexity of the colony, 
the division of labor and the reasoning powers manifested 
by the workers and soldiers, which, with the males and 
females, constitute the ant-colony. 
Certain ants enslave other species; have herds of cattle, 
the aphides ; build complicated nests or formicaries (Fig. 
361), tunnel broad rivers, lay up seeds for use in the winter- 
