FAMILY BRACONIDAE. 



SUBFAMlIiT MICROGASTERINAE. 

 BY C. V. RILET. 



It is difficult to properly consider the Microgasters affecting the larvae 

 of New England Rhopalocera without a careful revision of the whole 

 group ; but, at Mr. Howard's request, I have prepared the following notes 

 which may not be without interest. 



In the "Notes on North American Microgasters" (Trans. Acad. Sc. St. 

 Louis, Vol. iv, No. 2, April, 1881) I have shown that the species are 

 more variable than had been up to that time supposed, and that even in 

 the manner of forming their cocoons, as well as in the character of tiie 

 cocoons, there may be considerable variation in the same species. A 

 large amount of additional material obtained since the publication of that 

 paper, and in most cases connected with the host, has served to complicate 

 the whole question of species, so that their delimitation becomes at times 

 almost impossible. In short, a careful study of this group, as of most 

 other groups well and fully represented, confirms the idea of the non- 

 existence of species as such in nature, and renders it almost as easy to 

 make a continuous series as to make well marked divisions. On the pres- 

 ent occasion, however, it is not necessary to enter into a consideration of 

 this general subject of species, except in so far as to warn the reader that 

 the species here treated of are characterized as such more for convenience 

 than anything else ; that if I have avoided a strong disposition to lump 

 and combine forms hitherto considered good species, it is purely to assist 

 in recognizing the alliances ; and that the average characters of assemblages 

 rather than individual characters have been utilized. 



In the terminology of parts there is need of greater precision than 

 American authors, including myself, have hitherto employed ; but I have 

 often used scutellum for the prominent triangular piece, strictly the meso- 

 scutellum ; and postscutellum when including the more critically differ- 

 entiated mesopostscutellum, metapraescutum and metascutum, as the 

 characteristic fovea usually extends across this last. Metascutellum is used 

 for the larger piece, which I have heretofore called the metanotum. In 

 the genus Apanteles I have begun with glomeratus, making the description 

 of this species most full, for obvious reasons and for purposes of compari- 

 son. 



The group is a difficult one on account of the monotony of the coloring 



