200 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
List of secondary parasites reared from American cocoons of Apanteles in the order of relative 
abundance. 
[In this list the number of individuals of Apanteles killed, not the gross number of the secondaries reared, 
is given. In case of tie, the species which was relatively the more important in the particular lot or lots 
from which it was reared is given preference.] 
Hypopteromalus 1, 276 
Dibrachys 583 
Asecodes 
Hemi teles No. 60 
Hemiteles No. 61 
Hemiteles No. 75 
Pezomachus 
Eulophid 
Hemiteles No. 62 
161 
2 58 
52 
2 49 
64 
71 
18 
Pezomachus No. 65. 
Pteromalid No. 68 . 
Hemiteles No. 63... 
Pteromalid No. 70.. 
Eupelmus 
Hemiteles No. 66... 
Anastatus 
15 
6 
5 
2 
2 
2 
1 
Total 2.288 
Local conditions as affecting the control of this parasite through hyperparasites 
were well represented in 1909 by a comparison between the relative abundance of sec- 
ondary parasites in cocoons from two colonies, the " Reading-Wilmington," and the 
"West Manchester, " which were planted at about the same time. In both repro- 
duction was abundant, and a large number of cocoons was collected from each. Only 
those which were left in the field until all of the Apanteles which remained healthy 
had issued are counted in the following: 
Reading-Wilming- 
West Manchester 
ton colony. 
colony. 
Cocoons. 
Per cent. 
Cocoons. 
Per cent. 
Apanteles 
70 
8 
543 
Ki2 
66. 5 
Hyperparasites 
624 
68 
20 
Predators 
8 
1 
22 
2.5 
Unhatched Oct. 20 
218 
23 
89 
11 
Total 
920 
816 
The West Manchester colony was located in rather dense forest, with a swamp 
partly overgrown with brush and partly with thick forest on one side. The trees 
were large, and cocoon masses were frequently far beyond reach. Only those which 
could be reached from the ground were collected. There were more cocoons in this 
colony than in the other, but they were not quite so easily collected. It is of course 
possible that the larger number of cocoons explains in part the smaller percentage of 
hyperparasitism. 
The increase in hyperparasitism in the cocoons of the second generation over the 
first can only be demonstrated in the case of the West Manchester colony, which was 
the only one where there was a second generation in sufficient abundance to permit 
of adequate field collections. In this it is or appears to be very striking, when 
the fact is taken into consideration that a considerable number of parasites hibernated 
in the cocoons of the second, while none were found in those of the first which failed 
to hatch after the 1st of September. 
i Many Asecodes remaining unhatched within the cocoons will doubtless attempt to hibernate. 
' l Hemiteles NO. (10 and Hemiteles \'o. 75 may possibly be one and the same species. It is possible, too, 
that further study will cause a change in the relative position of the two species. 
