236 
PARASITES OF GIPSY AXD BROWX-TAIL MOTHS. 
and shipment . It is rather expected that the latter may be the true 
explanation and that the apparent scarcity of tachinids in the para- 
site fauna of the gipsy moth in Japan may not prove to be real. 
PARASITES OF THE GIPSY-MOTH PUPiE. 
THE GENUS THERONIA. 
The discussion of the pupal parasites of the gipsy moth ma}' well 
begin with mention of the most generally distributed of all — Theronia. 
The genus has already been the subject of brief comment in the 
account of the American parasites, and something was said of the 
habits of Theronia fulvescens in its relation to this host in America, 
and of its unimportance. The form which by courtesy is thus specif- 
ically designated is very imperfectly differentiated from T. atalantx 
Poda, which prevails throughout Europe in relatively about the same 
abundance in relation to the gipsy moth. It is readily distinguished 
from the American form by its habitat and to a less satisfactory 
extent by color. 
In Japan occurs still another, indistinguishable biologically (so far 
as its biology is known) or morphologically, but differing in color from 
either the American, from which it is most distinct, or from the Euro- 
pean. It has been described as Theronia japonica Ashm. 
The role played by these so-called species in the countries to which 
they are severally native is nearly identical and at the same time 
unimportant, when economically considered. The likelihood that 
either the European or the Japanese would become relatively more 
effective in America than the American itself seems so very remote 
as to make unworthy of consideration any serious attempts to intro- 
duce and colonize either. Quite a good many of the European have 
been liberated in America from time to time, but in a purely inci- 
dental way. More will probably be received in the future and 
similarly liberated. 
It was in the winter of 1907-8 that the late Mr. Douglas demons, 
of the laboratory, found a large number of the females of T. fulvescens 
congregated beneath old burlap bands in a tract of woodland in which 
the gipsy moth was actively being fought. Some of these females 
were dissected some days later and found to be without fully devel- 
oped eggs, and on the basis of these inadequately conducted dissec- 
tions it is supposed that, as in Monodontomerus, the males die in the 
fall, leaving the females to hibernate. It would, in other words, 
mean that the species is single-brooded. 
The subject ought to have been still further investigated, but the 
unimportance of the species from an economic standpoint has robbed 
it of interest other than thai which has attached to the remarkable 
and suggestive vagaries which it has exhibited in its host relations. 
