ANTS AND THEIR GUESTS WASMANN, 461 



auxiliary species, is absent. Hence, the main question in the expla- 

 nation of slavery is not: Wliy docs this species of ant in question cap- 

 ture strange pupae as prey? but: Why does it rear auxiliaries from 

 them? This second question remains also unsolved if one (with 

 Emery and Viehmeyer) attempts to derive dulosis directly out of a 

 "primitive predatory female state," for which, moreover, any sup- 

 porting facts are wanting ; for, as Emery has himself first shown (1909) , 

 the present-day parasitic and dulotic ants are to be phylogenetically 

 derived from their present-day auxiliary ants; there, however, we 

 find nowhere such prunitive predaceous females, but indeed manifold 

 conditions of dependence in the foundation of colonies b}^ one species 

 upon those of another species. Let it be, moreover, expressly remarked 

 that the hypothesis of the origin of dulosis in Formica can not be 

 simply extended to the other dulotic genera of ants; for example, 

 among the myrmicines. Other reciprocal relations, also, than those 

 of facultative social parasitism, may there have led to the origin of 

 slave making (Harpagoxenus-Leptothorax). In any case, the origin 

 of slavery can not be explained through the accidental survival of 

 captured ant pupae within a strange nest (Ch. Darwin). 



Probably starting from a sanguinea-\ike state, and linked phylo- 

 genetically with the development of dulosis within the genus For- 

 mica, the genus Polyergus represents the culmination of the slave- 

 making instinct within the subfamily of Camponotini. If we com- 

 pare the mandibular structure of the European amazon ant (Polyer- 

 gus rufescens) with that of our Formica sanguinea (fig. 7), a remark- 

 able difference is shown. Formica sanguinea (lig. 7a) has normal 

 triangidar mandibles with a toothed inner margin C'Kaurand"); 

 Polyergus, on the contrary (fig. 7h) has narrow, sharply pointed 

 sickle-mandibles. In these nior]ihological distinctions the difl^erence 

 in the dulotic instinct of the two is also expressed: Formica sanguinea 

 is at a more primitive stage of the development of that instinct; and 

 it is even developed to a different extent in the different North 

 American races of this species, as Wheeler has particularly shown. 

 F. sanguinea keeps comparatively few slaves, can even dispense with 

 them entirely, and is not dependent upon them. The amazon ant, on 

 the contrary', in its European and in its North American races, stands 

 at the apex of dulosis, exists only by the capture of slaves and in 

 that connection develops the most brilliant warrior talent that we 

 know in the entire animal kingdom. Its mandibles are modified to 

 be solely weapons for killing and are unsuited for domestic occupa- 

 tions; furthermore it has even lost the instinct of feeding by itself and 

 must be fed out of the mouths of its slaves. The excessive develop- 

 ment of dulosis is here already connected with distinct character- 

 istics of parasitic degeneration. Its mandibular structure gives ex- 

 pression to both sides, the light and the shadow of its organic and 



