202 
PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
relations by physiological rather than by physical limitations, and 
the difference is as great as that which separates the true predator 
from the true parasite. 
Did time permit-, and were this the proper place, a lengthy digres- 
sion might be made, in which several of the parasites typical of both 
groups, and which have been somewhat carefully studied at the 
laboratory, could be compared, the better to give strength to the 
statement just made. A little later attention will again be called to 
the matter. 
At this time it is merely desired to define the modified stand which 
it has been necessary to take upon the question of hyperparasites. 
It is no longer possible, on account of the absence of their secondaries, 
to expect a much if any greater degree of efficiency from the imported 
parasites in America than the same species possess abroad. Since 
the foreign hyperparasites of the gipsy moth are generally the coun- 
terpart of the American species, which will become hyperparasitic 
upon the gipsy moth just so soon as there are any primary parasites, 
their introduction could not possibly do more than result in the 
existence in America of a somewhat greater variety of hyperparasites, 
which as a group would play exactly the same role as the lesser variety 
now existent here. Consequently the only secondary parasites which 
we have to fear are those which have no counterparts in America. 
That such exist is beyond question; that they are in the minority 
is equally true. The only species which have been recognized as 
possibly or probably falling into that group are the hyperparasites 
reared from the gipsy-moth eggs from Japan, the Melittobia parasite 
of tachinids; the eulophid parasite of Pteromalus egregius, Perilarn- 
pus cuprinus, and Ohalcis fiskei; and, most unfortunately, two primary 
parasites already introduced, which are also secondary, Pteromalus 
egregius and Monodontomerus sereus. The two last mentioned are 
probably both beneficial rather than noxious in the final analysis, 
but nevertheless both are peculiarly adapted to act as secondary 
parasites of the brown-tail moth better than as secondary parasites 
of any other primary host. 
It is not intended to ignore the secondary parasites in the future 
any more than in the past, but the same fears which have been 
expressed concerning their introduction are no longer felt in the 
same manner, and the benefits which were formerly expected to 
accrue through their exclusion are not so great as hoped. 
TACHINID PARASITES OF THE GIPSY MOTH. 
In proportion as one after another of the previously mentioned 
hymenopterous parasites of the gipsy moth have been eliminated 
from the lists as of no more than incidental or technical interest, and 
as the prospects for successfully introducing the one species which 
