IV CAMPONOTIDES SLAVE-MAKING ANTS 151 



but are pointed and curved ; they are therefore used after the 

 manner of poignards, and when the ant attacks a foe it seizes 

 the head between the points of these curved mandibles, and driv- 

 ing them with great force into the brain instantly paralyses the 

 victim. 



Mandibles of this shape are evidently unfitted for the purposes 

 of general work, they can neither cut, crush, nor saw, and it is 

 not impossible that in their peculiar shape is to be found the 

 origin of the peculiar life of Polyergus : we find similar mandi- 

 bles reappearing amongst the aberrant Dorylides, and attaining a 

 jnaximum of development in the ferocious Ecito7i ; they also 

 occur, or something like them, in a few aberrant Myrmicides ; 

 and in the male sex of many other ants, which sex exercises no 

 industrial arts, this sort of mandible is present. 



The ants that Polyergus usually attacks in order to procure slaves 

 are Formica fusca and F.fusca, race auricularia ; after it has routed 

 a colony of one of tliese species, P. rnfescens pillages the nest and 

 carries off pupae and some of the larger larvae to its own abode. 

 When the captives thus deported assume the imago state, they 

 are said to commence working just as if they were in their own 

 houses among their brothers and sisters, and they tend their 

 captors as ftiithfully as if these were their own relatives : possibly 

 they do not recognise that they are in unnatural conditions, and 

 may be quite as happy as if they had never been enslaved. The 

 servitors are by no means deficient in courage, and if the place 

 of their enforced abode should be attacked by other ant-enemies 

 they defend it bravely. The fact that P. rufescens does not feed 

 its larvae has been considered evidence of moral degeneration, 

 but it is quite possible that the Insect may be unable to do so 

 on account of some deficiency in the mouth -parts, or other 

 similar cause. The larvae of ants are fed by nutriment regurgi- 

 tated from the crop of a worker (or female), and applied to the 

 excessively minute mouth of the helpless grul) : for so delicate 

 a process to be successfully accomplished, it is evident that a 

 highly elaborated and specialised arrangement of the mouth- 

 parts must exist, and it is by no means improbable that the 

 capacity of feeding its young in true ant-fashion is absent in 

 Polyergus for purely mechanical reasons. 



M'Cook states that the North American ant, Polyergus lucidus, 

 which some entomologists consider to be merely a variety of 



