382 ZOOLOGY 



rotten tree, or are built up of clay. The ants live upon both 

 animal and vegetable substances, and are very fond of sweet 

 things. Some of them keep Aphides, and by gently stroking them 

 with their antennae they induce them to secrete some of their 

 honey-dew, which the ants greedily lick up. Certain species 

 of beetles are also always found living with ants, though the 

 relationship between them and their hosts is not understood. 



Certain species, as Polyergus rufescens, and in some countries 

 Formica sanguinea, make slaves of other and smaller species. 

 The slaves are carried off either as ova or pupae, and are reared 

 by the masters, who become so dependent upon their slaves 

 that if these be removed the colonies of P. rufescens perish. 



The leaf- cutting ant Oecodoma cuts small circular pieces 

 out of leaves, which are carried home often by another indi- 



1 



Fig. 215. — Leaf-cutting and foraging ants. 

 1. Oecodoma cephal-us. 2. Eoiton d/repanophora. 3. Bciton erratica. 



vidual, and it is believed that a fungus is grown upon these 

 leaves, which the ants eat. The nests of this genus are very 

 large, and are built of clay. The leaf-cutting ant does very 

 considerable damage to vegetation, and it is difficult to keep 

 them away from any spot. They have been known to tunnel 

 under a river to reach a wood. 



Group 2. Vespiaeiae (Wasps). 



Wasps have slender, almost naked bodies, of a usually 

 yellow and black colour ; the antennae are usually elbowed ; 

 the wings are long and narrow, and longitudinally folded when 

 the insect is at rest. 



There are three families : the Vespidae, or social wasps, and 

 two families of solitary wasps — the EuMENiDAE.and Masaridae. 



Family Vespidae. — Social wasps, whose colonies contain 



