NORTH AMERICAN SPECIES OF TWO- WINGED FLIES BE- 

 LONGING TO THE TRIBE MILTOGRAMMINI 



By Harry W. Allen 



0/ the Mississippi Agricultural Experiment Station 



INTRODUCTION 



An attempt lias been made in this paper to define the Hmits of a 

 small group of Muscoid flies which have long been associated, some- 

 what incorrectly, by most American workers in Diptera with the 

 family Tachinidae, and to render the species of the group thus defined 

 readily determinable. 



In the American literature of the past 30 years, with the exception 

 of Townsend's, the genera which are discussed in this paper have 

 been rather widely scattered among genera of Tachinidae with which 

 they are but distantly related. Owing to the difficulty of obtaining 

 a clear conception from the existing literature, of the limits of the 

 group, and of the genera contained, it has been found advisable to 

 define and redescribe quite fully. A special effort has been made in 

 the generic descriptions to disregard characters v/hich fall within the 

 range of specific variation, and to make the limits of the genera, which 

 fortunately are more readily distinguished than in the great central 

 mass of either the Sarcophagidae or Tachinidae, broad enough to 

 include not only the kno\vn species, but others as yet unloiown, of 

 which there must still be many. In the genera to which new species 

 have been added, the old species not adequately defined have been 

 quite fully redescribed. 



It has been found necessary to change the generally accepted 

 nomenclature and the synonomy to a considerable extent, from two 

 causes; first the failure of earlier v/orkers, doubtless handicapped by 

 the lack of properly determined European material, to recognize the 

 identity of certain American forms with previously described Euro- 

 pean species, and secondl}^, the inclusion in one genus, namely 

 Hilarella, of several heterogenous Nearctic elements each of which is 

 very evidently entitled to generic rank. While Coquillett's concep- 

 tion of the genera of this group has been adhered to in most cases, 

 the author has recognized some of Townsend's genera not hitherto 

 generally accepted. 



No. 2610.— Proceedings U. S. National Museum. Vol. 68. Art. 9 



54292— 26t 1 1 



