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 tins 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, Perilam- 

 pus cuprinus, and Ohalcis fisJcei; 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 



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