88 EXPLANATION OF THE PRESENT STATE OF 



of Tetramorium,, and in some manner contrive to assas- 

 sinate their queen. I have shown that a nest of ants 

 may continue, even in captivity, for five years, without 

 a queen. If, therefore, the female of Anergates could 

 by violence or poison destroy the queen of the Tetra- 

 TnoriumSy we should in the following year have a com- 

 munity composed of the two Anergates, their young, 

 and workers of Tetramorium, in the manner described 

 by Van Hagens and Forel. This would naturally not 

 have suggested itself to them, because if the life of 

 an ant had, as was formerly supposed, been confined, 

 to a single season, it would of course have been out of 

 the question ; but as we now know that the life of ants 

 is so much more prolonged than had been supposed, it 

 is at least not an impossibility. 



It is conceivable that the Tetrartioriums may have 

 gradually become harder and stronger ; the marauding 

 expeditions would then be less fruitful and more dan- 

 gerous, and might become less and less frequent. If, 

 then, we suppose that the females found it possible 

 to establish themselves in nests of Tetramoriuvi, the 

 present state of things would almost inevitably be, by 

 degrees, established. Thus we may explain the re- 

 markable condition of Strongylognathus, armed with 

 weapons which it is too weak to use, and endowed with 

 instincts which it cannot exercise. 



At any rate, these four genera offer us every grada- 

 tion from lawless violence to contemptible parasitism. 

 Formica sangidnea, which may be assumed to have 



