TACHINID PARASITES OF THE GIPSY MOTH. 235 



The specimens reared, to the number of several hundred, with 

 several hundred of the Japanese Crossocosmia, were colonized 

 together, and under favorable circumstances, as indicated by the 

 recovery of Blepharipa from the immediate vicinity as the result of 

 coincidental colonization. Should the two species be in very truth 

 the same, they will probably hybridize, and enough have been 

 liberated to make one good colony. Should they refuse to inter- 

 mingle, there is not a sufficient number to make what past experience 

 has indicated as a "satisfactory" colony of either. 



UNIMPORTANT TACHINID PARASITES OF THE GIPSY MOTH. 



There are not as many unimportant dipterous as there are unim- 

 portant hymenopterous parasites of the gipsy moth in Europe, and 

 there are other reasons why they need not be considered at so much 

 length. One of them, Pales pavida Meig., which is occasionally 

 present in shipments of gipsy-moth caterpillars, is much more com- 

 monly received as a parasite of the brown-tail moth, and Dexodes 

 nigripes Fall., which is very rarely associated with the gipsy moth, 

 is a very common parasite of the other host. Both of these species 

 will be discussed later, and something will be said of their life and 

 habits and of what has been done toward securing their establish- 

 ment in America. 



Of the remaining tachinids which have been reared from imported 

 material from Europe, none has been positively associated with the 

 gipsy moth itself. There is always the chance that one or two cater- 

 pillars of some other species may have been accidentally included 

 amongst those of the gipsy moth, and while the number of such has 

 always been very small, the chance that a strange parasite should be 

 reared from them rather than from the gipsy-moth caterpillars is 

 large. 



To date at least 98 per cent of the tachinid puparia which have 

 been received from Japan as parasitic upon the gipsy moth have been 

 either of Tachina or Crossocosmia. The remaining 1 or 2 per cent 

 have been of various species, among which was one that resembled 

 Pales pavida and another has been described as "Compsilura-like." 

 There have been so few of these strange forms as to make impossible 

 a definite statement as to their host relations. It seems rather 

 curious that against the 8 European tachinids, all of which are of at 

 least local importance as parasites of the gipsy moth, Japan should 

 be able to produce only two. It may be that the tachinid fauna of 

 Japan is much less extensive than that of Europe or of America. 

 It may also be that a more thorough survey of the Japanese situation 

 will reveal the presence of species which have not been received 

 hitherto on account of the inadequacy of the methods of collection 



