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A STUDY OF COMPSILURA CONCINNATA. ah 
placed in trays with 25 third and fourth stage gipsy-moth larve 
which had been reared under screen from hatching. Attempted 
larviposition was noted, but in no case were Compsilura larvee se- 
cured and none were found upon dissecting the hosts. This same 
false larviposition was noted with larve of Bombyx mori. The 
piercer punctured the integument of the host, for each time an 
attack was made the caterpillar bled at the point of attack. A 
number of the Compsilura used were dissected, but none showed 
uterine eggs or developing maggots in the uterus. In several of 
these females the posterior uterus had become lengthened as is the 
case after fertilization. 
COPULATION. 
When union was successfully accomplished, copulation lasted 
from 26 minutes to 1 hour and 50 minutes, and while a number of 
records were secured, the foregoing represents the extremes. At- 
tempted coition was noted at times which occupied several seconds, 
but in cases of such short duration these attempts were unsuccessful. 
The results of observations on copulation seem to be more or less 
contradictory. In some cases Compsilura were confined in glass 
jars, screen cages, or glass-covered trays for several days, and did 
not copulate; whereas in one case a male, which was 16 days old and 
had been mated previously, copulated for 1 hour and 50 minutes 
with a female which was only 24 hours old. Another pair that 
were only 18 hours old copulated for 14 hours. In cases where 
copulation occurred soon after emergence from puparia the tem- 
perature and humidity were quite high. It was observed also that 
the flies will copulate more readily if the male is from 2 to 4 days 
older than the female. 
LARVIPOSITION. 
Compsilura will attempt larviposition in confinement when only 
one day old and before copulation takes place. It is physically im- 
possible that this attempted larviposition can be effective, as Comp- 
silura is viviparous and young larve have not had sufficient time to 
develop within the mother in that length of time. 
The method of larviposition is as follows: The female approaches 
_ the host, stopping within about an inch of it and, after surveying the 
victim carefully, strikes quickly. The host makes a quick movement 
of the entire body and the Compsilura flies off, only to return imme- 
diately until she is finally satisfied. If larviposition is successful at 
the first attempt, the parasite seems satisfied for a few moments. 
Records were secured of Compsilura attacking one gipsy-moth larva 
as Many as seven or more times in rapid succession, the whole occur- 
ring within 14 minutes. Larviposition will be attempted shortly 
