38 BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



9. Effects subsequent to exit of male. 



The exit of the male does not necessarily premise death to the host, 

 as has been shown in a previous paragraph. There are, however, 

 external conditions which take advantage of the cavity left by the male 

 and cause death. Brues (1903) believes that a drying of the viscera 

 is incident to the escape of the male because of the admission of air 

 through the often broken pupal envelope. Perkins (1905) asserts that 

 the leafhoppers generally die within a few hours or days after the 

 exit of the male parasite and attributes this to drying and the access 

 of light. He holds that insects parasitized by males are weaker 

 than those containing females, so they are probably even more sus- 

 ceptible on this account. 



An after effect recorded only by Perkins is that of fungus attack, 

 regarding which he says: 



Again in the case of leaf-hoppers, at least at certain seasons, no sooner does the male 

 parasite emerge than a fungous disease at once starts its attack in the opening thus 

 made, the results of which are absolutely deadly. Sometimes, but much more rarely, 

 one will find the fungus has developed at the point of protrusion of the female parasites. 

 This fungus disease seems to be a constant concomitant of stylopid attack on leaf- 

 hoppers, both in America, Australia, and Fiji. 



The records under Polistes annularis indicate a strong possibility 

 that some wasps from which a male parasite has escaped can success- 

 fully pass through hibernation. 



3. EFFECTS OF VARIOUS HOST CONDITIONS UPON THE PARASITES. 



This section is somewhat difficult of treatment, as but few instances 

 can be found upon which to base the discussion. 



1. The parasites are dependent upon light in effecting their freedom. 

 Saunders (1850) writes: 



So long as the Hylaei remained in the dark the parasites, deprived of those external 

 influences which under ordinary circumstances would serve to stimulate their dor- 

 mant energies, made no attempt to abandon their pupa tenements; as an incentive 

 to which light appears to be absolutely essential in order that their perceptions may 

 be awakened to an intuitive consciousness of the bees having quitted their cells. 



2. The death of the host does not occasion the death of a male 

 parasite in the pupa stage. Saunders (1852) found an Hylechthrus 

 alive five days after the death of the bee. Regarding this record a 

 manuscript note by him in the author's personal copy reads: 



Produced in 1851 from a dead Hylseus on placing merely in the window, under the 

 influence of a strong light, but without additional warmth from the sun. 



Mr. Dury hatched a male OpMhalmochlus duryi from Priononyx 

 atrata on August 19, at Cincinnati, Ohio, three days after the death 

 of the host. 



