12 ON THE ORIGIN AND [CHAP. 



the egg, it finds ready a sufficient store of whole- 

 some food. 



Other wasps are social, and, like the bees and ants, 

 dwell together in communities. They live for one 

 season, dying in autumn, except some of the females, 

 which hibernate, awake in the spring, and form new 

 colonies. These, however, do not, under ordinary 

 circumstances, live through a second winter. One 

 specimen which I kept tame through last spring and 

 summer, lived until the end of February, but then 

 died. The larvae of wasps (Plate II., Fig. 9) are fat, 

 fleshy, legless grubs. When full-grown they spin for 

 themselves a silken covering, within which they turn 

 into chrysalides. The oval bodies which are so nu- 

 merous in ants' nests, and which are generally called 

 ants' eggs, are really not eggs but cocoons. Ants are 

 very fond of the honey-dew which is formed by the 

 Aphides, and have been seen to tap the Aphides with 

 their antennae, as if to induce them to emit some 

 of the sweet secretion. There is a species of Aphis 

 which lives on the roots of grass, and some ants 

 collect these into their nests, keeping them, in fact, 

 just as we do cows. One species of red ant does 

 no work for itself, but makes slaves of a black kind, 

 which then do everything for their masters. 



Ants also keep a variety of beetles and other insects 

 in their nests. That they have some reason for this 

 seems clear, because they readily attack any un- 

 welcome intruder ; but what that reason is, we do not 

 yet know. If these insects are to be regarded as the 

 domestic animals of the ants, then we must admit that 

 the ants possess more domestic animals than we do. 



