134 
ZOOLOGY: L. 0. HOWARD 
Proc. N. a. S. 
On the other hand, such secondary and supplementary hosts have in a 
number of cases existed there, and as a result the establishment of the im- 
ported species was not only rendered more certain but the species has 
acted in a most beneficial way by destroying other pests, some of them 
in fact being native to the country into which the imported parasite was 
brought. 
It is this side line in such importations upon which I wish to dwell for a 
moment in this paper. 
Parasite introduction has never been attempted in any part of the world 
on so large a scale as it has been in this country since 1905 in the effort 
to secure the European and Japanese parasites and natural enemies of 
the gipsy moth and the European enemies of the brown-tail moth. In 
this work, although more than thirty species have been imported, not more 
than seven or eight have become established. Lack of secondary hosts 
may have been the cause of the failure of many of them, or there may have 
been other causes. An attempt is being made at the present time to deter- 
mine these causes, and for the first time since the world war experts from the 
Bureau of Entomology are now in Europe and Japan studying the native 
parasites of the gips}^ moth and endeavoring to send over new supplies 
of those species which previously failed of establishment and at the same 
time to secure additional species which we had not found before the war. 
But the value of the comparatively few species that have actually become 
a part of the insect fauna of the United States as the result of the earlier 
introductions has been very considerably enhanced from the fact that 
some of them have taken readily to other imported or native caterpillars 
which destroy American trees and crops. The following table indicates 
the present situation with regard to four of these species. 
Hymenopterous Parasites 
HOST FOR WHICH IMPOR- 
TED 
NAME OF PARASITE 
AMERICAN SPECIES AT- 
TACKED 
COMMENT ON ABUN- 
DANCE 
Euproclis chrysor- 
A panteles lacteicolor 
Datana ministra 
Rare 
rhoea L. 
Vier. 
Drury 
A panteles lacteicolor 
Hyphantria textor 
Rare 
Vier. 
Harris 
A panteles lacteicolor 
Apatela hasta 
Rare 
Vier. 
Guenee 
A panteles lacteicolor 
Schizura unicornis 
Only in the labora- 
Vier. 
S. & A. 
tory, but here 
readily attacked 
EuprocHs chrysor- 
Meteorus versicolor 
Hemerocampa leu- 
Rare 
rhoea L. 
Wesm. 
co stigma S. & A. 
Meteorus versicolor 
Hyphantria textor 
Rare 
Wesm. 
Harris 
Porthetria dispar 
A panteles melanos- 
Hemerocampa leu- 
Apparently abun- 
celus 
Ratz. 
co stigma 
S. & A. 
dant 
