WHEELER— THE PARASITIC ACULEATA. 19 



petitor the Ccropales larva turns again to the spider and devours it com- 

 pletely except for a few unassimilable remnants. Then the larva weaves a 

 network of pale brown threads among which on the following day it spins a 

 pale brown cocoon. In one case which I observed the feeding period of the 

 larva extended over a period of 12 days." 



It will be seen that the general ovttlines of the behavior of the 

 solitary parasitic bees and wasps are strikingly similar. Among the 

 wasps we can recognize two types, that of Nysson, Stisus unicinctus 

 and Psammochares pectinipes and that of C^ro/'o/^.y, whereas in bees 

 only a single type, bearing a great resemblance to that of Ccropales, 

 is known. It is probable, nevertheless, as I have indicated above, 

 that the Nysson type may be represented among the bees by SpJic- 

 codcs. The two types are shown in the accompanying diagrams in 

 which the main activities of the parasite and its host are repre- 

 sented in parallel series. 



Nysson. 



Nyssoji Mating Finding Host Nest 



Goryfes Mating Nidification, Provisioning, Oviposition. 



Destroying Host Egg Ovipositing Larva Appropriating Prey. 



Ccropales. 



Ccropales Mating Finding Host and Prey, Ovipositing. 



Psammochares Mating Provisioning, Nidification 



Larva feeding. . . .Killing Host Larva. . . .Appropriating Prey. 



Oviposition Larva feeding 



Stelis. 



Stelis Flower visiting Mating Finding Host Nest, Ovipositing. 



Alcidamia Flower visiting Mating Nidification, Provisioning 



Larva feeding Killing Host Larva Appropriating Food. 



Ovipositing. . . .Larva feeding 



In all the cases the parasite takes possession of the food-supply 

 (prey or bee-bread) by eliminating the egg or young larva to which 

 it belongs as a result of the activities of the host, but this elimina- 

 tion may be effected in two ways, either by the adult or by the larval 

 parasite. In the Nysson type the mother appropriates the prey and 

 bequeaths it to her offspring, in the Ceropales-Stelis type the larval 



