dublin] SLAVE- MAKING HABITS OF ANTS 141 



shown by many observers that if left for as short a period as 

 two or three days without the aid of their slaves they would 

 starve to death, even if surrounded with an abundance of 

 food. Replace the black ants and the scene changes immedi- 

 ately; the Amazons take new courage and are soon fed with 

 the regurgitated food which the slaves are only too eager to offer 

 them. 



We may now clearly seethe degrading effect of the slave-making 

 habit. Unlike the formicas, both the American and European 

 types of Polyergus are thoroughly dependent upon their slaves. 

 Every aspect of the domestic affairs of the Amazons is dull and 

 lifeless. Apart in one chamber of the nest are generalby located 

 the fertile male and females, the others clustering everv where 

 within the slave-dug galleries, idle and listless. In truth, the 

 so-called slaves are within the nest the real masters. Thev 

 determine the character of the nest, plan and conduct migrations, 

 carrying the Amazons from place to place, the latter subject to 

 no impulse of their own. An originally fine group of animals 

 is, thus, reduced to a mere band of soldiers and robbers other- 

 wise absolutely unable to care for themselves. The true worker- 

 caste has been replaced by soldiers and all those creative 

 instincts which make the life of the ant-species so strikingly 

 self sustaining seem here to be sacrificed to the mere develop- 

 ment of the mandibles as powerful weapons of offence. In 

 America, this once widely distributed species is on the road to 

 extinction. This is certainly a big price to pay. It is the 

 fighting and larvae-robbing instinct which natural selection has 

 developed. In this alone now lies the secret of their preser- 

 vation, for there has been developed a fighting organization 

 with which very few other species can compare. 



The next stage in this story of degeneration is that presented 

 by a species widely spread over the continent of Europe and 

 known as Strongylognathus testaceus. This is a light-red ant 

 of considerable size and is found associated with a well organized 

 and active little form, Tetramorium caespitum. Like the 

 Amazons, these slave-makers possess ridgeless, sabre-like 

 mandibles which they try to use in much the same way. But 

 altogether they are really nothing more than the merest cari- 

 catures of those powerful fighters. In the first place, the very 

 mandibles upon which the soldiers of the latter so effectively 



