900 ° 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.] 
Ely popteromalus=-2css se". 2542 - i, 276. | Pezomachus (No. Gore-.-+-.--2-2-5- 15 
Dalbrachiys (32s sees ete eee Dos: | geteromalicwNon G8ieese eee cee as se 6 
NISC COG Came ce eee ao eer ee PGds|Eemiteles NonGs assess. ere ee 5 
HemitelessNoyG0s-c-243. 6428. bo. 2-584 PteromalidiNoms/Ons-2 ee aaa 2 
iEHeratelessNo.Gl-eo5- =. a2. eae 52 | apelimiistes.2 22 sean oe wees 2 
FMemitelesyNo: (OD; 9.2sc.ssck es eee 249: lenntelessNO-.60242- 45 eee 2 
Revzomaehise nests Aan fe he ats 64 |) Amastals®.22.2- cen eee eeeee eee 1 
HOMO eee ce et ee ene 71 oan 
Beis INO 2022 220 eee eee 18 MI occa aeeessoezesiscsos- oe 
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. 
PAD ETILC TOS Aye gait eats rere re cee pe ewe cee ir aie ee oe ee rte ree 70 8 543 66.5 
HT METMALASULES Seem Semis erate ee eee oe tee oe ree eee ee 624 68 162 20 
Te CA TOLS ep a prt So eA oe re ec ee a eS Cr eens My 8 1 22 DY. 
Wins tehedkO ct a0 Ssscm chet ee ene oe ee ese ea eee ers 218 23 89 11 
ATS Gem Se arerer atts oper es ore epee Ea OR a eee chan O20 ts ee SIGsio ss se ge 
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 lst of September. 
1 Many Asecodes remaining unhatched within the cocoons will doubtless attempt to hibernate. 
2 Hemiteles No. 60 and Hemiteles No. 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. 
