TRUE GUESTS, EL'TO- AND ENTOPARAS1TES. 



409 



to the presence of Loin cell lisa larvae, and caused her to be adopted by 

 a new set of unusually, healthy workers from an uninfested colony. 

 Under the changed conditions her eggs developed into larvae that gave 

 rise to perfectly normal workers. 



As a rule the pseudogynes make their appearance in sanguinca 

 colonies only after these have been infested with Lomechusa for several 

 consecutive years and are therefore in an exhausted or moribund con- 

 dition. I was impressed with this fact during the summer of 1907, 

 while examining a large 

 number of mostly slave- 

 less sanguinca colonies in 

 two separate localities in 

 the Upper Engadin. 

 Nearly all of these colo- 

 nies contained abundant 

 Lomechusa larvae, but 

 many were, nevertheless, 

 very populous and flour- 

 ishing and contained no 

 pseudogynes. These 

 were found only in a few 

 very weak colonies which 

 in some cases contained al- 

 most no normal workers. 

 Such -colonies, which 

 were nearly all situated 

 in lower and damper 

 ground, represented, in 

 all probability, the wrecks 

 of once opulent communities that had succumbed to the inevitable 

 annual scourge of Lomechusa. 



This being the effect on the colonies that harbor the Lomechusa, 

 one naturally inquires, why the habit of rearing these parasites has not 

 long since led to the extinction of sanguined? This question has been 

 at least partially answered by Wasmann. He finds that the ants treat 

 the beetle larvae like their own, even when the former are ready to 

 pupate, and therefore embed them in the soil. And this is what the 

 Lomechusa require, but they must not be unearthed again after pupa- 

 tion, like the ant brood, or they perish. The ants, however, are utterly 

 ignorant of these different developmental requirements and therefore 

 unearth as many of the Lomechusa pupae as they can find. Thus death, 

 in the guise of what might be called a regulatory nemesis, overtake 



FIG. 245. Parasitic mites. ( Berlese.) A. 

 Echinoincgistns wlieeleri (dorsal view), from 

 Lasins apliidicola; B, same, ventral view; C. 

 Cillibano hirticoma (dorsal view) from Eciton 

 schmitti ; D, ventral view. 



