TRICHOCERA. 231 



Thorax of a purer gray than any of the preceding 

 species ; the two brown stripes are very faintly 

 marked on the front part of the mesonotum only ; 

 wings clearer hyaline than in the preceding 

 species ; venation as in the preceding species ; 

 stigma very faintly iufuscated ; halteres with a 

 brown knob ; long, corp. about 0.2 . . brumalis Filch 1 



The small materials in my possession do not allow me to 

 attempt the description of the apparently new species. At the 

 same time, the existing descriptions are too incomplete or too in- 

 correct to admit of a positive identification. The description of 

 T. himacula Walker, for instance, is such as to render it very 

 doubtful whether the species given above under that name is 

 really Walker's species ; the character, " abdomen with alternate 

 tawny and brown rings," is not visible in my specimens. 



A large number of specimens and a comparison with the 

 European species will be necessary to those who will attempt the 

 description of the North American species. 



