APANTELES MELANOSCELUS GIPSY-MOTH PARASITE. 23 
SECONDARY PARASITISM. 
Cocoons of the first generation are not seriously attacked by sec- 
ondary insects. Small collections of cocoons of this generation are 
made each year over a considerable area and rarely are they para- 
sitized over 10 per cent ; more often not more than 2 or 3 per cent are 
killed by secondaries. 
Unfortunately it is a different story with the hibernating brood, 
for approximately 75 per cent are killed annually by native secondary 
insects and ants. This seriously handicaps the increase of A. melan- 
oscelus. Among the insects which have been reared from the hibernat- 
ing cocoons are at least three Ichneumonidae, and members of the 
Pteromalidae, Elasmidae, Eurytomidae, Entedonticlae, and Eupel- 
miclae. In this complex there are secondary, tertiary, and possibly 
quaternary and quinquenary insects. An investigation of the life 
histories and host relationships of these insects has received consid- 
erable attention at the laboratory, but has not been completed. Some 
of these insects have several generations during the early fall and 
then hibernate within the cocoons of A. melanoscelus. 
THE VALUE OF A. MELANOSCELUS AS A GIPSY MOTH PARASITE. 
The problem of obtaining the actual percentage of parasitism of 
the gipsy moth by A. melanoscelus or by any of the other introduced 
parasites, except the egg parasites, is a difficult and complicated mat- 
ter involving many factors. Eecords at the Gipsy Moth Laboratory 
show that larvae picked promiscuously from tree trunks and foliage 
to-day may give 30 per cent parasitism, while to-morrow the same 
number of larvae, collected by the same individual, in the same man- 
ner, and in the same locality, may not even show the presence of the 
parasite. 
For a number of years collections of gipsy-moth larvae have been 
made daily through the entire larval period at Melrose and Stone- 
ham, in an attempt to learn the true status of the parasites in that 
section. Each collection contained 100 larvae all of the same stage. 
The collections of each stage were continued as long as that particular 
stage could be found, and collections of the next stage were started 
as soon as 100 larvae of the next stage could be found. As there is 
quite an overlapping of stages, there were very often two collections 
on the same date at the same place. All of the collections were kept 
separate and the larvae were fed in trays until all of the parasites 
had issued. The trays were examined each day and any parasites 
which issued were removed and recorded. Individual collections, con- 
taining 100 caterpillars each, gave from nothing to as high as 40 
per cent parasitism of second-stage gipsy-moth larvae for the spring 
