WHAT I SAW IN AN ANTS NEST. 339 



given to speculate on the origin and acquirement of the 

 practices of human existence. Pierre Huber, son of the 

 famous entomologist, was the first to describe the slave- 

 making instinct in a species (Polyergus rufescens) noted for 

 its predaceous instincts, and subsequent observations have 

 shown that other species participate in these habits. Poly- 

 ergus is thoroughly dependent on its slaves. Without these 

 bondsmen it is difficult to see how the ants could exist. 

 Huber tells us that the workers of this species perform no 

 work save that of capturing slaves. Use and wont, and the 

 habit of depending entirely on their servitors, have produced 

 such changes in the structure of these ants, that they are 

 unable to help themselves. The jaws of these ants are not 

 adapted for work ; they are carried by their slaves from an 

 old nest to a new one ; and, more extraordinary still, they 

 require to be fed by their slaves, even with plenty of food 

 close at hand. Out of thirty of these ants placed by Huber 

 in a box, with some of their larvae and pupae, and a store of 

 honey, fifteen died in less than two days of hunger, and of 

 sheer inability to help themselves. When, however, one 

 of their slaves was introduced, the willing servitor " estab- 

 lished order, formed a chamber in the earth, gathered to- 

 gether the larvae, extricated several young ants that were 

 ready to quit the condition of pupae, and preserved the life 

 of the remaining Amazons." It must be noted, that there 

 are very varying degrees in the dependence of the ant- 

 masters on their slaves. In the recognition of this graduated 

 scale of relationship and dependence, indeed, will be found 

 the clue to the acquirement of this instinct. The horse-ant 

 (Formica rufa] will carry off the larvae and pupae of other 

 ants for food, and it sometimes happens that some of these 

 captives, spared by their cannibal neighbours, will grow up 

 in the nest of their captors. A well-known ant, the Formica 

 sanguinca, found in the South of England, is, however, a 

 true slave-making species, but exhibits no such utter depend- 

 ence on its servitors as does Polyergus. The slave-making 

 habit is not only typically developed in the Sanguineas, but 



