48 
PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
which are known' to check its ravages over there. The insect was undoubtedly brought 
over by Trouvelot without any of its natural checks. In my judgment it would be 
well worth trying to import its parasites from abroad. The advantage would be this: 
If you failed to exterminate it by spraying, its parasites, seeking for this particular 
host, would be more apt to find the overlooked or escaped specimens than man would. 
No action was taken upon this suggestion, and the State author- 
ities, believing that such an attempt would be useless owing to the 
fact that their effort for some years was consistently devoted to the 
aim of absolute extermination of the gipsy moth, perhaps wisely 
saved the expense of a mission abroad for this purpose. Then, also, 
there was some hope that the native parasites, particularly the ich- 
neumon flies and the native species of Apanteles, as well as tachina 
flies and some of the carabid beetles, might gradually accommodate 
themselves to the imported pest and prove prominent factors in the 
fight against it. 
This last faint hope, however, was not justified. In the course of 
the careful work done by the State during the next seven or eight 
years, the better part of which is summarized in the admirable Report 
on the Gipsy Moth, by Forbush and Fernald, published in 1896, sev- 
eral native parasites and predatory insects were observed to attack 
the gipsy moth in its different stages, but at no time was the per- 
centage of parasitism sufficiently great to have any value as a factor 
in the suppression of the pest. At no time was there a greater per- 
centage of parasitism by native parasites than 10, whereas the con- 
dition in Europe is such that the percentage reaches frequently well 
above 80. It may be worth mentioning that parasitism by native 
species has never exceeded 5 per cent in any collections made since the 
present laboratory was established. It is nearer 2 per cent on the 
average. 
In discussions among the Washington entomologists it was repeat- 
edly pointed out by E. A. Schwarz and by B. E. Fernow (at that time 
Chief of the Division of Forestry of the United States Department of 
Agriculture) that one of the most important of European enemies of 
the gipsy moth, and the nun moth as well, is one of the tree-climbing 
ground beetles known as Calosoma sycophanta L. There exist a num- 
ber of species of this same genus Calosoma in the United States, but 
none of them has the tree-climbing habit developed to the same ex- 
tent as have Calosoma sycophanta of Europe and its relative Calosoma 
inquisitor L. Prof. Fernald, writing to the famous German authority 
on forest insects, Dr. Bernard Altum, early in 1895, asked his opinion 
as i o 1 he advisability of importing these tree-inhabiting ground beetles, 
but received the reply that such an importation would not give good 
results. Prof. Altum considered the services of the hymenopterous- 
parasites of the old genus Microgaster as of much more importance. 
In l he report just cited Fernald disposed of the question of import- 
ing parasites in the following words: 
