192 
Journal of Agricultural Research 
Vol. XIV, No. S 
still in colonies, near the winter web. But as they become larger they 
crawl to various parts of the tree or even to different trees nearby, feeding 
ravenously; they attain their growth about the middle of June, and are 
then inches in length. Pupation takes place within loosely spun 
cocoons fastened in leaves that have been drawn together from the sides, 
in crevices of the bark, in stone walls, and in other protected places. 
The moths, issuing after about three weeks, mate, and the females begin 
depositing their eggs. There is only one generation a year. 
IMPORTATION OF THE PARASITES 
In the winter of 1905-6, following the first visit by Dr. L. O. Howard, 
Chief of the Bureau of Entomology, to Europe for the purpose of arranging 
for the sending to New England of parasites of the gipsy and brown-tail 
moths, large numbers of the winter webs of the latter species were 
received at the parasite laboratory, then located at North Saugus, Mass. 
These webs were placed in special cages, one of which is shown in Plate 
19, A. The cage consisted of a large wooden box, capable of holding 
about 1,000 webs of the brown-tail-moth caterpillars, and having a 
number of glass tubes projecting from the upper half of one side. Any 
parasites issuing from the webs would be attracted into the tubes by the 
light ’ 
Very early in the spring many individuals of Pteromalus egregius 
Foerster, a chalcidoid external parasite of the wintering brown-tail 
moth larvae, and also many specimens of Monodontomerus aereus Walker, 
another chalcidoid, that frequently hibernates as an adult in the brown- 
tail web, entered the tubes. Shortly the brown-tail-moth caterpillars in 
the cages became active and made their way into the glass tubes; as 
these became filled, the caterpillars were removed and destroyed, since the 
probability of their harboring internal parasites seemed slight. However, 
Mr. E. S. G. Titus, at that time in charge of the work, fed a few of the 
caterpillars for a time, as an experiment, and secured from them repre¬ 
sentatives of two parasitic species, both braconids, one of the genus 
Apanteles and the other belonging to the genus Meteorus. It is these 
two species with which this paper deals. 
REARING AND COLONIZATION OF THE TWO PARASITES 
As a result of the discovery by Mr. Titus, the caterpillars from the 
webs received during succeeding winters were not destroyed upon issuing 
in the spring, as had been done previously, but were fed for several weeks, 
so that any internal parasites might be reared. For rearing methods 
and types of cages used, see Howard and Fiske (i). 1 This was continued 
until 1911*, when importations ceased, with the result that some 40,000 
cocoons of Apanteles lacteicolor and about 1,600 of Meteorus versicolor 
Reference is made by number (italic) to '* Literature cited,” p. 205 . 
