ANTS. 



and each ant so sequestered touch all the others with its antenna during 

 tlie three- enduing da\>, these ants will live amicably together there- 

 after, although thev he of different colonies, varieties, species, genera 

 or subfamilies." Such experiments are of the greatest interest a> 

 showing the importance of the philoprogenitive instincts and the uni- 

 formity of their development in the workers of the most diverse species 

 of Formicid.-e. and adequately account for the presence of slaves in the 

 mixed o>lonic>. hut they cannot be said to throw any light on the other 

 essential peculiarities of slavery, namely, the raiding habit and its con- 

 centration on particular species. These peculiarities, as we shall see, 

 must he referred to a different source. 



Like the temporary parasites, with the possible exception of O.ry- 

 </vnc, the slave-making ants are confined to the north temperate zone 

 and extend far up into boreal and alpine regions. Indeed, it is not 

 improbable that the development of the slave-making habit is connected 

 in some way with the long winters, short summers and small amount 

 of food in the subarctic belt. All the known slave-makers are members 

 of four genera: Formica (the species of the sanguined group), Poly- 

 crgus, Strongylognathus and Harfago.renus, the first two comprising 

 Camponotine, the last two Myrmicine ants. The habits of Harpo- 

 (/o.rcnns are imperfectly known, but the other genera form an inter- 

 esting series, in which Formica sanguined represents the slave-making 

 habit in process of development. Polycrgus its most specialized and 

 Strongylognathus its involutionary or degenerate development. F. san- 

 i/itinca and Polycrgus have been studied by many observers. As 

 Huber's and Forel's brilliant accounts of these ants have been exten- 

 sively quoted in many accessible works, it will not be necessary to repeat 

 them here. I shall therefore confine myself to a brief enumeration of 

 the known slave-makers and to some observations of my own on the 

 American forms. This will be the more advisable, since there are few 

 published observations on our sanguined and almost none on the expe- 

 ditions of our Polycrgus. 



i. The European Sanguinea. The typical form of this, the san- 

 guinary, or blood-red slave-maker, which is easily distinguished by the 

 median notch in the anterior border of its clypeus, is common through- 

 out temperate Europe and probably also in northern Asia (Fig. 267"). 

 In Japan, the easternmost portion of its range, it has developed at least 

 one variety, fusciceps. In Europe it lives under stones, in logs and 

 stumps, or about the roots of plants and often accumulates considerable 

 vegetable debris about its nest entrances. Those who have studied its 

 habits are unanimous in regarding it as one of the most gifted and 

 versatile of ants. It is certainly one of the most belligerent, and, at 



