456 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol, 2 



jmpa was found within the cocoon of Spilocryptus, upon the larva of 

 which it had fed, and in the remaining fifteen it was apparently a 

 secondary upon Ophion. It may have been truly what it seemed, that 

 is hyperparasitic, or it may have been that its occurrence in this role 

 was purely accidental, and that in oviposition the female selected the 

 cocoons irrespective of the character of their contents. Most 

 frequently the Ophion larva was overcome before it had completed 

 its cocoon, but in several instances the Theronia escaped, or attempted 

 to escape through the perfectly formed cocoon. The preponderance 

 of the instances in which Theronia appeared to be secondary is quite 

 what would be expected, owing to the longer period during which 

 Ophion would be open to attack. It is believed that after the 

 promethea has pupated, and the pupa is hardened, that it is immune, 

 and that oviposition can only be successful when the prepupal cater- 

 pillar or perfectly fresh pupa is selected. Ophion, on the contrary, 

 since it hibernates as a larva, is open to attack at any time during the 

 fall. 



Only two of the pupae of cecropia, and none of the other hosts were 

 attacked by Diglochis, and in both instances, while the number of 

 larvEe of the parasite was sufficient to kill the host, there were not 

 enough nearly to consume it. As a consequence the larvaB and pupfe, 

 surrounded by the unconsumed and decomposing matter, nearly all 

 died. A very few adults which were reared oviposited with great 

 freedom upon the pupse of promethea to which they were given ac- 

 cess. It is certain that they would attack this host as well as cecropia 

 in the open, were it not for the protection afforded by the cocoons. 



Inter-Relations of the Primary Parasites 



A considerable amount of evidence has accumulated during the 

 past three summers at the laboratory which tends strongly to support 

 the contention that the prescience of the female parasite is insuf- 

 ficient to enable her to distinguish between parasatized and unpara- 

 sitized hosts for her progeny. If this be a fact, the result must be 

 that an individual host is frequently attacked by two different species 

 of parasites, or as has been presupposed in the instance of the 147 

 Tachnia maggots already mentioned, by the same species more than 

 once. Instances of double parasitism are, in fact, of frequent occur- 

 rence, and a study of the results in specific instances are often very 

 interesting. Several rather novel examples were encountered in the 

 present study. 



The apparent secondary parasitism of Ophion by Theronia is 



