518 Cc. H. RICHARDSON 
Food. The natural food of Spalangia muscidarum was not 
ascertained. In the laboratory, however, it was observed to 
feed rather sparingly upon banana peel and sweetened water, 
showing a preference for the former. 
Copulation. The male is sexually the more active. When he 
comes in contact with the female, he vibrates his wings rapidly, 
usually running around her once or twice before coitus. By some 
means not discovered but probably an olfactory sense, the female 
appears to detect the presence of the male when he is within 
close proximity. Upon his approach, she stops and drawing the 
antennae closely together, remains motionless and at the same 
time throws down the sternite which shields the genital opening. 
Coitus lasts but a few seconds after which the male clings firmly 
to the female with his forelegs and rubs the sides of her abdomen 
with his middle and hind legs. At the same time the female 
rubs her abdomen with her hind legs. 
Oviposition. My observations show that S. muscidarum is 
exclusively a pupal parasite. The egg was invariably found upon 
the dorsum or sides of the host’s abdomen within the puparium. 
Never more than one egg or a single larva was found on the same 
host. When ready to oviposit, the female, feeling her way with 
her antennae, crawls over the fly puparium. A suitable place 
having been found, she thrusts her ovipositor through the pupa- 
rium either inter- or intrasegmentally and deposits an egg in 
from seven to eleven minutes. The parasite may occupy a 
nearly middle position on the puparium or one farther toward 
the posterior end. That a miscalculation may sometimes occur 
is evident from the fact that one female was observed to ovi- 
posit near the anterior end of a puparium. In such eases, it is 
highly probable that the active planidium larva could easily 
reach the abdomen. 
Kclosion. 'The imago issues through an irregularly round hole 
made with its mandibles at or near the anterior (head) end of 
the house fly puparium. The insect is active almost immediately 
upon emerging. 
Length of life of the imago in captivity. The imago when con- 
fined within a glass test tube in the insectary and fed daily upon 
