ALIEN ASSOCIATES AND AFFINITIES 



(Camponotus) in several species and varieties are often 

 the hosts of X. cava. 



All the beetles of this group, the Lornechusa group of 

 Staphylinids, are true ant-guests. They are treated by 

 their hosts, both as adults and larvae, quite as their own 

 fellows, being fed, cleansed, and carried about. Indeed, 

 it is said that in case of real or fancied danger, the beetle 

 larvae and pupae have precedence of their own young 

 in the ants' attention. 



This is all the more remarkable because, according to 

 Father Wasmann (S. J.), a devoted and distinguished 

 observer, and perhaps our highest authority on myr- 

 mecophilous insects, these adopted citizens repay the 

 host's care by ravenous assaults upon their own brood, 

 devouring numbers of eggs and larvae. The effects of 

 this, in weakening the commune, are apt to be serious. 

 It works toward deterioration, as Wasmann show^s, in 

 another way. This brood - parisitism appears to orig- 

 inate a curious form of abortive individuals inter- 

 mediate between the female and the worker, known as 

 pseudogynes. They are cowardly and indolent. They 

 decline to dig and nurse, and trot about the nest aim- 

 lessly. Thus, in sharp contrast with the valiant and 

 active workers, they hold a sort of "frustrate existence." 



How comes this about? Wasmann believes, and 

 seems to prove, that it is caused by the diminished care 

 and diet due to the queen larvae for their full develop- 

 ment a case of restricted growth through defective 

 nourishment. A brood of beetles (Lomechusa) begin 

 life with a brood of worker-ants. The beetle larvae, as 

 they appear, are not only generously fed by the ants, 

 but begin to feed upon their eggs and larvae ; and as they 

 are extremely voracious and grow rapidly, they devour 



16 231 



