3) BULLETIN 1487, U. S. DEPARTMENT OF AGRICULTURE 
LIFE CYCLE OF APANTELES MELANOSCELUS 
Before proceeding to a discussion of hyperparasitism as affecting 
Apanteles melanoscelus it will be well to review the important points 
in the life cycle of this Apanteles. Following is a concise summary 
of the more important features of the life history of that species. 
A more detailed account will be found in a bulletin by Crossman (3). 
Apanteles melanoscelus is essentially an internal solitary parasite of 
the larvae of the gipsy moth, Porthetria dispar L., although it is some- 
times also obtained from the white-marked tussock moth, Hemero- 
campa leucostigma S. & A. It passes through two cenerations upon 
the gipsy moth, which itself is single-brooded. Adults of the parasite 
first appear in May, directly after the hatching of the gipsy-moth 
eges, and attack the first-stage larvae. The parasitic larvae com- 
plete their development in 18 to 20 days, and emerge from the second 
and third stage P. dispar caterpillars to form their cocoons. About 
seven or eight days later adults emerge, and, after mating, the 
females attack third-stage larvae of the host species to begin the 
second generation. From 16 to 20 days afterward, or early in July, 
the cocoons of this generation of the parasite begin to appear. This 
is the hibernating form. The mature parasitic larvae remain dor- 
mant in these cocoons until the following spring, when they transform 
to pupae preparatory to becoming adults. Thus, while the cocoons 
of the first generation are exposed to the attacks of hyperparasites 
for only a very short period, those of the second generation can be 
attacked from July until cold weather, when activity of the hyper- 
parasites ceases. These cocoons, furthermore, are largely in exposed 
situations, on the under side of branches, under loose bark, and in 
similar places, and so are easily reached by the secondaries. 
METHODS EMPLOYED 
The field work in connection with these studies consisted of obtain- 
ing monthly collections of Apanteles melanoscelus cocoons from June 
to October, inclusive, over a three-year period, from three different 
localities. Between 200 and 300 cocoons constituted a collection, 
except in a few instances when it was impossible to obtain so many 
within a reasonable time. The three localities selected, Pembroke, 
Mass., Boylston, Mass., and Rye, N. H., were approximately 50 miles 
apart. One collection of first- -generation cocoons and four collections 
of second-generation cocoons were obtained from each point during 
each of the three years. ‘These cocoons were isolated and held at 
the laboratory, at Melrose Highlands, Mass., under outdoor tempera- 
tures, for the issuance of Apanteles and its parasites. To supple- 
ment the records from these collections, data were obtained covering 
many thousands of cocoons collected in July of each year in localities 
where Apanteles was particularly abundant. These collections have 
been made annually for some time in connection with the propaga- 
tion and artificial distribution of A. melanoscelus, as discussed by 
Crossman (3). From all this material it has been possible to obtain 
a reasonably clear understanding of the relative importance of the 
various species of hyperparasites that attack A. melanoscelus. 
All the species that appeared to be of any importance as enemies 
of this Apanteles have been studied more or less in the laboratory. 
