Apr. 1, 1925 
Two Imported Egg Parasites of the Gipsy Moth 
651 
near the felt and also near the cotton 
at the base of the cage; some were 
present in the folded food cloth, and a 
few were under the gipsy-moth egg 
masses. On January 3, 1916, all of the 
gipsy-moth eggs were removed. During 
the week of January 3 to 10 the ther¬ 
mograph in the yard recorded as low as 
6° F. and on several days below 10°. 
On January 10 the Schedius were ob¬ 
served crowded together in little groups 
on the walls of the cage near the felt, 
and a few were in the folds of the food 
cloth. A few which were brought into 
the laboratory began to move within 
15 minutes. During the week of Janu¬ 
ary 9 to 16 the temperature fell to 3° F. 
On January 17 a few Schedius were 
brought into the laboratory; one of 
these moved in 10 minutes after being 
in the warm room and several became 
quite active within 45 minutes. Many 
which had dropped from the walls of 
the cage were dead, apparently killed 
by the cold. The reviving Schedius 
were in all cases females. There was a 
small amount of snow on the ground at 
this time but the Schedius in the cage 
were probably not so well protected 
from cold as they would have been if 
they had been covered with snow. 
The temperature in the yard was 
below zero on February 14 to 16, and 
on the 14th the thermograph registered 
— 10° F. The ground and cage were 
covered with over a foot of light snow. 
The cage was examined on February 
16 and many dead Schedius were 
found on the floor. A few Schedius in 
the food cloth revived after being 
exposed for a short time in the labo¬ 
ratory. On March 8 several living 
Schedius were noted after the tray had 
been brought into the laboratory for a 
short time. On March 27, a warm 
spring day, several Schedius were seen 
to move in the cage. Again on April 
11, a warm sunny day, several Schedius 
were seen moving about in the cage. 
A few nonparasitized gipsy-moth eggs 
were placed in the tray on this date 
with a small quantity of food (one-half 
honey and one-half water). On May 
8 these eggs were removed, and on 
May 22 adult Schedius began issuing 
from them. On April 24 several 
Schedius were seen active in the cage. 
On May 2 over 20 adults were running 
about the cage, and three gipsy-moth 
egg clusters were placed in the tray. 
Most of the Schedius were ovipositing 
in the eggs which had been put in the 
tray on April 11. After a short time 
one female oviposited several times in 
a new egg cluster. On May 13 the 
second lot of gipsy-moth eggs which 
were placed in the tray began to hatch. 
The Schedius were very active and ovi¬ 
posited freely. On May 20 all but six 
of the hibernated Schedius were dead. 
The weather had been cool and rainy 
for several days. On May 27 only two 
Schedius were alive. On this date two 
of the three egg clusters which were put 
into the tray on May 2 were removed. 
On June 25 two Schedius issued from 
the two egg clusters removed. One 
hibernated Schedius was alive on June 
2, and one female Schedius was still 
alive on June 24. When the tray was 
next observed a generation of Schedius 
had begun to issue from the single egg 
cluster which remained in the cage, so 
that it was impossible to know how 
long after June 24 the hibernating 
female had livhd. The mortality of 
Schedius late in the fall is enormous 
and only a very few strong females in 
especially favorable hibernating quar¬ 
ters survive. It is probable that the 
females which hibernate successfully 
are fertilized in the fall but do not ovi¬ 
posit, for the first individuals found 
early in the spring are always large 
females with greatly extended abdo¬ 
mens. Both sexes are present in the 
progeny developed from these hiber¬ 
nating females. It is probable that 
certain individuals enter hibernating 
quarters at various times during the 
fall and thus lessen the chance of 
extermination should a sudden drop in 
temperature late in the fall kill all of 
the active individuals. 
NUMBER OF GENERATIONS 
The records obtained from hiber¬ 
nating experiments carried on at the 
laboratory have been substantiated by 
field observations. Schedius which 
have hibernated successfully become 
active on the first warm days of April 
and are occasionally observed ovi¬ 
positing during the latter part of this 
month in the overwintering gipsy-moth 
eggs. They are scarce at this early 
date and it is probable that the first few 
seen in April have hibernated in pro¬ 
tected spots which were warmed by the 
early spring sun. Only rarely do 
Schedius issue from eggs collected 
before the middle of April, and the 
majority do not leave their winter 
quarters until the last week of this 
month. These adults, which are al¬ 
ways females (at least no males have 
been found in the spring until there 
has been ample time for a spring gener¬ 
ation to develop), live three to five 
weeks, so that the oviposition period 
is prolonged over several weeks. Six 
weeks are 'required for the first spring 
generation to develop on the overwin- 
