6 Bulletin American Museum of Natural History, [Vol. XXIII, 



by regurgitation as if they were workers. They usually submit to these 

 effusive attentions passively, but at times they may be seen to struggle and 

 disengage themselves from the embraces of their hosts. When fully mature 

 both sexes of the Orasema become highly phototropic and endeavor to escape 

 from the dark nest to the open air and sunshine. The ants, however, 

 redouble their attentions and carry them back to the dark chambers. Al- 

 though usually aided by the workers in hatching from their pupae, the 

 Orasemae themselves often remove the pupal envelopes from their antenna by 

 rubbing them with their fore legs, and, though fed by the ants, they some- 

 times visit and partake of the sugar in artificial nests. They spend much 

 of their time in lying on their sides among the ant larvae and pupae. While 

 the workers thus appear to be infatuated with their beautifully sculptured 

 and brilliantly colored parasites, the latter are not sufficiently hypocritical 

 to feign any interest in their hosts. They are, in fact, interested only in 

 the ant brood and, as I shall show, only in a certain portion of the brood. 



As several successive broods of Orasema pupae appeared and hatched in 

 my artificial nests, I was sure that the larval stages must also be present. 

 These stages, it would seem, should be readily detected, but for a long time 

 I was completely misled in my search for them, and even after I had found 

 them, I was deceived by their appearance. This arose partly through cer- 

 tain prepossessions based on analogy with what I had read about other Chal- 

 cidids, and partly through the confusion produced by the high degree of 

 polymorphism in the Pheidole. As nearly all Chalcidid larvae are internal 

 parasites in other larvtie, I was under the impression that the Orascmce also 

 start their life cycle within the larvae of their hosts, and certain peculiarities 

 in the Orasema larvae merely tended to strengthen this prepossession. The 

 great number of larval and pupal forms of the ant added to my confusion, 

 especially as some of their larvte differed in shape according to their feeding. 

 Thus for a time I regarded certain small, spherical, sexual larvae, fed with 

 regurgitated liquids, as the young larvae of Orasema. It was not till after I 

 had left Texas and had nothing but preserved and stained material at my 

 disposal that I succeeded in gaining a clear idea of the early larval stages of 

 the parasite. 



I have not seen the eggs of O. v.iridis after oviposition, but only the very 

 young larvae. Dissection of the female shows that, as we should expect in a 

 parasite, the eggs are extremely numerous and minute. The mother insect, 

 when she comes to oviposit, exercises a very careful selection among the ant 

 brood. In the first place she has nothing to do with the instabilis larvae but 

 directs her attention to the pupae. In the second place she selects, as a rule, 

 only the pupae of the soldiers, males, and females. The small worker pupae 

 would not furnish sufficient food for her larvae. In the third place she selects 



