APANTELES MELANOSCELUS GIPSY-MOTH PARASITE. 19 
These larvae are placed in trays and fed until the parasite maggots 
issue. The maggots, upon issuing, spin their cocoons, usually attached 
to the caterpillar or to the object on which the host was resting at 
time of issuance. Each day the gipsy -moth larvae are fed, the trays 
cleaned out, and all of the parasite cocoons removed. The cocoons 
are put up in lots of 500 and kept in a refrigerator until they are 
placed in the field. They are colonized as soon after removal from the 
trays as possible, usually on the following day. Occasionally it has 
been necessary to keep the cocoons in the ice chest five or six days, 
and this has been done without any apparent injury to the parasite. 
The second method of securing material for colonization may be 
divided into two parts, namely, the fall work which consists of 
gathering and caring for the hibernating cocoons, and the actual 
breeding work which is carried on in the spring. There is a great 
mortality of wintering A. melanoscelus, largely due to secondary 
parasitism, and a large number of cocoons must be gathered in order 
to have a few adults of Apanteles in the spring to start the breeding 
work. The cocoons are collected as soon as possible after they have 
been found, in an endeavor to get them before the secondaries or 
ants do. 
From 10,000 to 20,000 cocoons are collected during July from 
places where the parasite is abundant. Some of the secondaries 
present at this time hibernate within the cocoon, but there are many 
which have one or more generations during the early fall. 
For a number of years these cocoons were isolated in gelatin 
capsules as soon as they arrived at the laboratory. This prevented the 
issuing secondaries from doing any further damage, but it was 
found that the spring issuance of A. rnelanoscelus from apparently 
good cocoons was exceedingly small. This was due partly to sec- 
ondaries which hibernate within the cocoons, partly to injury while 
handling, and considerably to the drying of the maggots of A. 
meloMOScelus in the cocoons. The last two years the cocoons have not 
been isolated, with the result that a better spring issuance has been 
obtained. Instead of isolating the cocoons they were separated into 
lots of 100 each and placed in glass tubes 1 by 4 inches, which were 
plugged with cotton batting. These tubes were then placed on a 
background of white in a warm bright place where they could be 
watched and the secondaries were removed as fast as they issued. 
Most of the secondaries issuing in the summer leave the cocoons with- 
in two weeks after collection, although a few continue to issue for 
two weeks longer. After the secondaries have stopped issuing the 
cocoons are picked over and the empty ones and those showing ex- 
ternal injury are discarded. Many of the cocoons which contain 
hibernating secondaries at this time can be distinguished by a slight 
discolored spot on the cocoon; such cocoons also are destroyed. The 
