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 adult 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 21 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 
differs from the meconium of the other parasites of the 
house fly studied by the authors mentioned. The adult 
