1 4 4 THE NA TURK- S TUD Y RE VIE IV [ 3 : s -may, . 9 o 7 



the queen of the Tetramoriums, we should in the following year 

 have a community composed of the two Anergates (the king 

 and queen), their young, and workers of Tetramorium, in the 

 manner described by Van Hagens and Forel." 



But in view of the structual weakness of the supposed murder- 

 ess, this too would seem impossible. We must, therefore, once 

 more resort to the adoption-idea as an explanation of the origin 

 of these colonies. Conceive for a moment that an Anergates 

 queen had succeeded in making her way into an old and queenless 

 colony of Tetramorium. As has been experimentally verified, 

 she would most probably be adopted. Once established, she 

 would lav her eggs, which in time would give rise to several males 

 and females that would live on with their queen-mother as long as 

 their Tetramorium slaves survived. On the death of the latter, 

 however, one of the winged females of the new generation 

 might succeed in locating and infecting some new colony and 

 thus repeat the process. Surely no more degraded condition 

 can be conceived. 



We have now described the slave-making habit among ants 

 from the simplest to the most complex conditions. At the be- 

 ginning was the occasionally temporary slavery in which the 

 F. sanguinea indulged and to which no ill effects could be traced. 

 In the Amazons later a striking adaptation toward slave-making 

 was observed, every individual in the colony with the exception 

 of the sexual forms being a soldier or a robber. Most of the 

 constructive instincts, including even the ability to feed them- 

 selves, are sacrificed in the race for sharpened jaws. Finally, 

 there are observed those cases where the habit reaches its 

 highest point and becomes sheer parasitism. In Strongylogna- 

 thus and Anergates the slave-makers, not the slaves, are reduced 

 in structure and entirely dependent, producing a type as far from 

 the self maintaining, active and ingenious ant of ordinary ob- 

 servation as can be imagined. 



Let us see what series of circumstances may have led to the 

 formation of this habit. In the first place, it is clear that in this, 

 as in many other biological phenomena, there are several origin- 

 ally distinct factors combined to produce the complex condition. 

 We must, therefore, look for suggestions to the simplest cases 

 where these factors may be found dissociated. In this way we 

 learn to distinguish two elements; first, the founding of the 



