118 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
There is very little published information at hand bearing upon 
this subject, and that which is available is general rather than defi- 
nite in its tenor. Anyone who for the first time encounters a tree 
covered with caterpillars of the gipsy moth dead and dying through 
the effects of the ‘‘wilt”’ disease is very apt to think that at last 
the gipsy moth has met its Waterloo, and disillusionment has only 
come in the present work as the result of several years’ consecutive 
observations in the same or similar localities. In lke manner the 
observations of foreign entomologists, or of American entomologists 
traveling abroad, as to the actual effectiveness of the parasites in 
accomplishing the control of the moth have to be taken with a grain 
of conservatism. Parasitism by a species as conspicuous as Apan- 
teles fulvipes to the extent of 50 per cent would undoubtedly create 
a most favorable impression and the more conspicuous parasitized 
caterpillars would easily appear to outnumber the healthy. This 
amount of parasitism would certainly be inefficient in America unless 
it were supplemented by a much larger amount of parasitism by 
other species. 
On this account it has been necessary to depend very largely upon 
the study of the parasite material imported from abroad as a source 
for information of this sort. From the beginning accurate notes 
have been kept of the many thousands of boxes of eggs, caterpillars, 
and pupe of the gipsy moth and brown-tail moth, in which are 
recorded the locality from which each lot came, its condition on 
receipt, and the number and variety of parasites reared in‘ each 
instance. The records are necessarily based in most instances upon 
such information as may be gained through a study of the condition 
of the material on receipt and the parasites reared, but in a few 
careful dissection work has been carried on to determine the true 
conditions, and thus to check up the results of the rearing work. 
It has been found that the amount of dependence which can be 
placed upon the rearing records is relatively small, and that noth- 
ing more than a general idea of conditions actually prevailing can be 
gleaned from them. Nearly always some of the caterpillars or pupe 
are dead or dying upon receipt as a result of the ordeal through which 
they have passed. On the average, taking the gipsy-moth material 
from all localities, not more than 25 per cent has arrived in good 
condition (when the shipment of eggs is excepted). The brown- 
tail moth material has averaged very much better, and probably 75 
per cent has been in good condition on receipt. ~ 
It has been found that sometimes a larger percentage of parasites 
than of caterpillars or pupe died en route, while at other times these 
conditions are entirely reversed, and since dissections can not be 
made in every instance, it has been necessary to consider the para- 
sitism indicated by the notes upon two different bases, i. e., that of 
