94 THE HOUSE FLY— DISEASE CARRIER 



to ovipositing in confinement ; they are, however, seem- 

 ingly not as prolific or as generally parasitic as Nasonia. 



The writers did not obtain certain data concerning 

 the entire seasonal history of this parasite, but they 

 think that it confines itself principally to the puparium 

 stage of the house fly, hibernating in the puparium as 

 a larva and pupating itself and emerging early in the 

 spring as an ^dult four-winged parasite. The first 

 specimens found by them emerged the first week in 

 September, and from that time on until frost it was 

 comparatively abundant. It was reared from puparia 

 collected on September 23d and again from some col- 

 lected on October 21st, emerging from these Novem- 

 ber 6th. Hibernation probably commenced about Oc- 

 tober 2 1 St. 



Examination of the house fly pupae, after the para- 

 sites have emerged, indicates that the larva of the para- 

 site feeds externally on the pupa of the fly, sucking its 

 juices. The attachment is to any portion of the body 

 of the pupa. Opening a puparium from which the 

 adult parasite had emerged revealed the blackened and 

 shrunken remains of the fly pupa lying in its natural 

 position along the floor of the pupal shell. 



The meconium, or excrement passed by the para- 

 site larva when about to change to pupa, is distinctive 

 — dark in color and round-angled, looking like a small, 

 solid, black, round bit, resembling somewhat a coarse 

 grain of powder but not as irregular or angular. It 

 dififers from the meconium of the other parasites of the 

 house fly studied by the authors mentioned. The adult 



