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 larvaB 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. 355. Horn- 

 tail : larva of Tre- 

 mexcolumba. Nat. 

 size. 



Pig. 357. Gall-fly of oak. 



Fig. 358. An Ichneumon-fly. 



Pig. 356. Pear Slug, 

 natural size, gnawing 

 leaves, a, larva en- 

 larged ; &, the fly. 



parasite of Canker, 

 ighly 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- 



