APANTELES MELANOSCELUS GIPSY-MOTH PARASITE. 7 
the first gipsy-moth larva was introduced. She worked actively 
every time she was allowed to do so each day to and including June 2. 
On the morning of June 3 she was found dead in the tube. A dissec- 
tion showed that her ovaries still contained about 150 mature eggs 
and about 200 eggs in different stages of development. 
From this and other records, together with notes made from dis- 
sections of mature females of A. melanoscelus, it seems safe to as- 
sume that under natural conditions each female is capable of de- 
positing in the vicinity of 1,000 eggs. 
Egg. 
The egg at time of deposition averages 0.55 mm. in length and 0.1 
mm. in width. It (PL I, B) is deposited singly in the body cavity 
just beneath the skin of the host. It is transparent, with the cephalic 
end rounded, the caudal end, which is slightly narrowed, bearing a 
short stock. The chorion appears to be entirely without ornamenta- 
tion. Development within the egg is rapid and the embryo begins 
to show form after 15 to 20 hours (PL I, C). By this time the egg 
has widened a little and is slightly shorter than when first deposited. 
Many eggs have hatched 48 hours after deposition. Just before 
hatching, the fully developed embryo is plainly seen, often in the po- 
sition illustrated in Plate I, D. At this time the egg measures 0.7 
mm. in length and is greatly swollen around the area which incloses 
the head. On one occasion an egg, which was ready to hatch, burst 
while under observation and the larva floated out as illustrated in 
Plate I, E, after which the eggshell shriveled up considerably. 
The length of the egg stage is from 48 to 72 hours, depending on 
the temperature. If the weather is warm, the majority of the eggs 
hatch in about two days. 
Larva. 
FIRST-STAGE LARVA. 
The following measurements are the average for newly-hatched 
larva? : Total length, 0.7 mm. ; width of head, 0.2 mm. ; width of body, 
0.1 mm. ; length of caudal horn, 0.1 mm. 
The freshly-hatched larva (PL I, F) is found free in the body 
cavity. Directly after hatching it may be found in almost any part 
of the cavity, depending on the point of deposition of the egg. After 
a few hours it works its way to the dorsal part of the posterior third 
of the host and usually remains in that area until about ready to issue 
as a third-stage maggot. 
The larva is transparent and extremely delicate, with a large head 
which is twice the width of the body. The head is composed of a 
single segment. The labium, labrum, and maxillae are present. The 
