Social Insects. 35 



other species, or eveji against colonies of their own, while with 

 many species there is a form of neuter known as the soldier which 

 seems to be developed for no other purpose than to defend the 

 colony or make war upon some other colony. The soldiers are 

 characterized by an enormous and abnormal enlargement of the 

 head, jaws and mouth-parts. In these wars the greatest pugiui- 

 city and courage are exhibited, the contest lasting sometimes for 

 days, and the weaker party ultimately succumbing from sheer 

 exhaustion and decimation. 



There is a gradation in the warlike spirit in different species 

 and genera. Thus in Myrmecina and Tetramorium the ants do 

 not fight, but roll up and feign death. Lubbock shows that in 

 Formica cxsccta, an active but delicate species, the individuals 

 advance in serried masses, and that when fighting with larger 

 species, like Formica 'pratcnsis, several in unison, attack' an iiuli- 

 vidual of the latter, some of them jumping onto the back of the 

 foe and sawing off the head from behind. The species of Lazius, 

 he says, will suffer themselves to be cut to pieces rather than let 

 go when they have once seized an enemy, while Polycrf/u^ nifcs- 

 cciix, the notorious slave-making ant of the Amazons, seizes the 

 head of her enemy by closing the jaws, so as to pierce the brain, 

 thus paralyzing the nervous system ; so that a comparatively 

 small force of Polyergus will fearlessly attack much larger armies 

 of the small species and suffer scarcely any loss themselves. 



Hlave-makijstg. — Nor must T pass without brief mention of an- 

 other fact which has been well observed among ants, namely, 

 that some of the species repeatedly raid the colonies of weaker 

 ants and make slaves of them. In most cases it is a large pale 

 ant which enslaves a small black ant, and this is done either by 

 capturing fully developed workers or more often by carrying 

 home from the weaker colony larvse and pupa? and allowing these 

 to develop in the formicaries of their masters. 



It is most interesting to note, also, that the slave-making habit 

 among ants produces the same demoralizing results for the slave- 

 maker that it does among men. The habit is degrading. Thus, 

 as Lubbock points out, Polyergus nifescciis has become entirely 

 dependent on its slaves. It has lost the power of building, as 

 also most of its domestic habits. Its impotence away from its 

 slaves has gone so far that even the habit of feeding has been lost, 

 and it will starve in the midst of plenty rather than feed itself. 



