PARASITISM OF BROWN-TAIL MOTH IN AMERICA. 143 
tion to the number of pupe collected than would be the case had 
these collections been made irrespective of the localities where the 
species was so recently colonized. 
Parasitism by Theronia is somewhat less on the average than in 
some other years when similar studies have been made. At times 
it has amounted to as much as 2 per cent. 
Sarcophagids are not considered as parasites, but rather as scav- 
engers. Their true status is yet to be determined, however. 
Compsilura concinnata is not commonly secured from the pupe, 
and in one instance in which more than an insignificant number of 
this species was recovered the collection consisted of caterpillars, 
which had prepared for, but not undergone, pupation. 
No Monodontomerus were reared from any of the collections of 
pupe included in Table IV, nor has the species ever been recovered 
from counted lots of pupz collected in the open. It was found in 
1910, as in 1909, by the examination of unhatched pupez after the 
most of those remaining healthy had produced the moths, and issued 
in unsatisfactory numbers from collections of pupz made at the same 
time. These were not counted at the time of collection, and on that 
account were not included in the table. 
PARASITISM OF THE BROWN-TAIL MOTH IN AMERICA. 
The brown-tail moth in America is subjected to a considerably 
higher percentage of native parasitism than is the gipsy moth, but at 
the same time, as will appear in the summarized results of the rearing 
work in 1910, the aggregate is scarcely sufficient to be considered as 
consequential. 
The following species have been reared, and doubtless the list will 
receive additions in the near future. 
TRICHOGRAMMA PRETIOSA RILEY. 
A very considerable percentage of the egg masses collected in the 
open is parasitized by this species, but because of the inability of 
the parasite to attack any but the more exposed eggs in a mass, the 
actual percentage of parasitism is insignificant. 
LIMNERIUM CLISIOCAMP® WEED. 
In 1907 a single specimen of this common parasite of the tent 
caterpillar was reared from a brown-tail caterpillar collected in 
Exeter, N. H. One or two other rather doubtful records have been 
made since. It is unquestionably not an important parasite of the 
brown-tail moth. 
