8 BULLETIN 766, U. S. DEPARTMENT OF AGRICULTURE. 
proved that the parasite had become established from the colonies 
of 1906 and 1907. It was in 1909 that assistants from the laboratory, 
in scouting for larve of Calosoma sycophanta L., found numbers of 
Compsilura puparia in the field. Since the first substantial recov- 
ery in 1909 the parasite has been recovered from 303 towns in New 
England. These towns are scattered throughout the entire gipsy- 
moth area, with very few outside. (See map, Pl. II.) An interest- 
ing recovery of Compsilura was made in 1915, from the Island of 
Nantucket, Mass., 25 miles from the mainland, where the nearest 
colony of the parasite is located. 
Compsilura is scattered over so wide a territory that it is usually 
possible to collect it in almost any part of New England within the 
gipsy-moth area. This is especially so where the gipsy moth is 
abundant in a locality not far distant from where Compsilura has 
been colonized any length of time. The general method is to make 
trial collections of 100 fourth-stage larve and maintain them in 
feeding trays.t These trays are small and rectangular, the bottoms 
being covered with thin cloth and a narrow band of tanglefoot ap- 
plied near the top to prevent the escape of larve. If this trial 
collection shows a parasitism of 8 to 10 per cent, the location is con- 
sidered a good field for bulk collections to secure parasite material 
for colonization. In a few instances where both trial and bulk col- 
lections showed a very high percentage of parasitism the first year, 
it has not been considered necessary to make trial collections from a 
given locality the following year. This is not always relied upon, 
however, as Compsilura may be present in a locality in fairly large 
numbers one year, while the following year collections from the 
same locality will give a low percentage of parasitism. This is par- 
ticularly true of places where the brown-tail moth is scarce and 
which may have a good infestation of gipsy moths. Compsilura 
seems to be more prevalent where there is a rather heavy infestation 
of both brown-tail moths and gipsy moths. ; 
All of the collections are sent by mail or brought into the labora- 
tory in wooden boxes 33 by 51 by 94 inches. These boxes have a 
hole in one end through which the larvee are put as they are col- 
lected, about 350 to 400 larve in each box; this hole is then covered 
by a piece of tin or zinc, which is secured by four tacks. Fresh 
food is placed in the boxes as the larvee are collected; this keeps 
them separated in transit. As soon as these boxes are received at 
the laboratory they are opened, the location recorded and filed under 
a number, and the larve counted and placed in a feeding tray, the 
size of which is governed by the number from a single locality. 
1These trays have been described in Department of Agriculture Bull. No. 250, July, 
1915. 
