Apr. 1, 1925 
Two Imported Egg Parasites of the Gipsy Moth 
661 
water solution on blotting paper was 
put in the tray and 150 adult Ana- 
status which had issued from hiberna¬ 
tion at about this time were introduced. 
The female Anastatus began to ovi¬ 
posit immediately. The gipsy-moth 
eggs were examined on August 9 and 
many Anastatus pupae were seen. 
From August 10 to 20, 172 male and 28 
female Anastatus issued. A few days 
later 18 more adults appeared; the sex 
was not noted. An examination of the 
eggs showed that 50.3 per cent of them 
had been parasitized by Anastatus, 
and of this 50.3 per cent, 17 per cent 
had issued and 33.3 per cent were typ¬ 
ical hibernating Anastatus larvae. The 
hibernating larvae were kept through 
the winter, and the following summer 
75.9 per cent of them issued. 
The adult Anastatus from this experi¬ 
ment, together with others which issued 
during the fall from field-collected gipsy- 
moth eggs, were used in reproduction 
experiments. These females of the fall 
generation were observed to mate and 
to oviposit. The eggs in which they 
deposited were saved through the win¬ 
ter and adult Anastatus issued from 
many of them in the following sum¬ 
mer. 
LONGEVITY EXPERIMENTS 
In laboratory trays adult Anastatus 
are short-lived as compared with the 
adults of Schedius. They usually do 
not live much more than 10 days to 2 
weeks. Occasionally adults have lived 
in confinement for 3 weeks. 
Cold storage experiments have shown 
that the Anastatus larvae can live over 
a long period. Gipsy-moth eggs con¬ 
taining Anastatus hibernating larvae 
were collected in the spring and placed 
in cold storage at a temperature of 
about 30° F. There they were kept 
until a year from the following July, 
when they were brought to the lab¬ 
oratory. In August both sexes of 
adults issued, the Anastatus larvae 
having lived two years within the host 
egg. These females oviposited suc¬ 
cessfully in new gipsy-moth eggs, and 
the following summer their progeny 
issued. 
REPRODUCTION ON GIPSY-MOTH EGGS 
Normally, Anastatus oviposits in 
fresh gipsy-moth eggs and its larva 
develops quickly, consuming the entire 
egg contents before the gipsy-moth 
embryo develops. Occasionally it is 
found ovipositing in the field in gipsy- 
moth eggs which have developed. 
Laboratory reproduction experiments 
have been successful, using gipsy-moth 
eggs in which the embryo was fully 
developed. A generation of Anastatus 
has also been developed on dead gipsy- 
moth eggs which had been placed in 
cold storage before the gipsy-moth 
embryo had developed. 
REPRODUCTION ON EGGS OTHER THAN 
THOSE OF THE GIPSY MOTH 
Anastatus females attack the eggs 
of the gipsy-moth more freely than they 
do the eggs of other insects to which 
they have been given access in labora¬ 
tory cages. Females have been con¬ 
fined in cages with various lepidop- 
terous eggs, but oviposition, with re¬ 
production, has not been observed in 
these experiments except on the eggs 
of Hemileuca oliviae and Hemerocampa 
leucostigma. 
REPRODUCTION ON APANTELES MELA- 
NOSCELUS RATZ. 
During the years 1921, 1922, and 
1923 over 87,000 cocoons of Apanteles 
melanoscelus were collected from the 
field in New England for reproduction 
and rearing. It was necessary to isolate 
each of these cocoons because of the 
enormous amount of hyperparasitism. 
From this great mass of material four 
adults of Anastatus bifasciatus have 
been reared. 
WINTER MORTALITY OF ANASTATUS 
During a severe winter in New 
England there is a large mortality of 
unprotected gipsy-moth eggs and of 
hibernating Anastatus. This fact was 
very evident in the large collections of 
gipsy-moth eggs which were made dur¬ 
ing the winter of 1917-18 to obtain 
Anastatus for colonization. 
During this winter about 79 per cent 
of the Anastatus in the eggs under 
observation were killed. This figure 
was obtained from 52,800,000 gipsy- 
moth eggs, which contained 8,349,000 
Anastatus larvae. Most of these eggs 
were collected at Peabody, Mass. The 
lowest temperatures for the winter 
recorded at the gipsy moth laboratory 
were observed on December 30, 1917, 
and February 2, 1918, when the read¬ 
ings were —14° and —15° F., respec¬ 
tively. 
The collections of gipsy-moth eggs 
made south of Boston during the winter 
showed a much lower mortality of 
Anastatus, and in some areas there was 
practically no winter killing. 
To determine the winter mortality 
of Anastatus, collections of gipsy-moth 
eggs were made during the spring of 
1922 and 1923 from points scattered 
over the area where it was well 
established. The collections showed 
