S2 EXPEDITIONS OF POLYEEGUS. 



their nest. The Rufescent ants now ascended the 

 hillock, collected in crowds on the summit, and took 

 possession of the principal avenues, leaving some of 

 their companions to work an opening in the side of the 

 ant-hill with their teeth. Success crowned their enter- 

 prise, and by the newly-made breach the remainder of 

 the army entered. Their sojourn was, however, of 

 short duration, for in three or four minutes they 

 returned by the same apertures which gave them 

 entrance, each bearing off in its mouth a larva or a 

 pupa.' 



The expeditions generally start in the afternoon, 

 and are from 100 to 2,000 strong. 



Polyergua rufescens present a striking lesson of 

 the degrading tendency of slavery, for these ants have 

 become entirely dependent on their slaves. Even 

 their bodily structure has undergone a change: the 

 mandibles have lost their teeth, and have become mere 

 nippers, deadly weapons indeed, but useless except in 

 war. They have lost the greater part of their instincts : 

 their art, that is, the power of building ; their domestic 

 habits, for they show no care for their own young, all 

 this being done by the slaves ; their industry they 

 take no part in providing the daily supplies ; if the 

 colony changes the situation of its nest, the masters 

 are all carried by the slaves on their backs to the new 

 one ; nay, they have even lost the habit of feeding. 

 Huber placed thirty of them with some larvae and pupae 

 and a supply of honey in a box. * At first,' he says, 



