THE DIODONTL 105 



any rate it must be confessed that <the parasite has not prevent- 

 ed americanits from becoming a flourishing species. 



Although as a rule, Diodontus worked for the coming gener- 

 ation, the captured aphis sometimes served not as food for the 

 young but as a dainty morsel for herself. In these cases there 

 was no malaxation, the aphis being held in any position while it 

 was sucked dry of all its juices and then thrown away. This 

 may be a further development of the habit described by Belt of 

 stroking the frog-hoppers to get the drop of honey which they 

 can yield without harm to themselves. It has little in common 

 with the method of Philanthus apivorus, which, according to 

 Fabre, squeezes the honey from its bee because if left, it would 

 prove fatal to the young larva. It is rather like that of Ody- 

 nerus nidulator which takes nothing from the caterpillars 

 which are destined to feed the young, never storing up those 

 from which it has sucked the juices. 



Cerceris ornata offers us still another habit. The neck of 

 Halitftus, its prey, is brutally compressed, the skin being broken 

 so that the juices of the body exude, and these juices are licked 

 off by the wasp.* The object of the malaxation, however, seems 

 to be to produce lethargy for the benefit of the wasp larva, since 

 the bee is afterward stored up. The taste that the wasp gets of 

 bee-juice is rather an accident than anything else. How is it 

 that thei honey is not fatal to the young of Cerceris, as it is to 

 that of Philanthusl 



As has been said, the excavation of the nest of Diodontus is 

 a difficult matter, but in six cases we succeeded in finding the 

 pocket with its contents. In these nests the number of aphides 

 varied from five to forty, the provisioning being only just begun 

 in some cases while in others it had been completed, and the 

 nest closed up. 



With a single exception the aphides in these nests were dead. 

 They were usually green when first taken out but turned yellow 



*Etude sur 1' Instinct du Cerceris ornata, Archives de Zoologie Ex- 

 perimentale et Generate, Deuxi&ine Serie, Tome V., 1887, p. 27. 



