AMERICAN DIPTERA. 283 



along the edges; hind legs of the male frequently armed at the 

 knees or trochanters; fore metatarsi of the males sometimes en- 

 larged. Wings generally narrow, with the front and hind margin 

 more or less parallel, the discal cell always present, emitting three 

 simple veins to the wing margin ; third vein always furcate; anal 

 cell shorter than the second basal, both bounded by a vein nearly 

 parallel with the hind margin of the wing; anal angle prominent, 

 but rarely projecting. 



Several attempts have already been made to divide this complex 

 genus into groups of species. Dr. Loew in a series of papers in the 

 Berliner Entomologischer Zeitschrift, vol. xi-xiii, has grouped the 

 European species about a few typical forms, and the same may be 

 done with more or less completeness in the case of the American 

 species. The genus Enoplempis, erected by M. Bigot* for those 

 species of Empis, the males of which have armed hind knees, fell in 

 Mr. Coquillett's Revision. His reasons for the abandonment of the 

 genus were that it was established on characters found in the male 

 sex only, and that the females were indistinguishable from typical 

 Empis. Although this may not be a sufficient reason for the disso- 

 lution of a genus ; for example, witness those dolichopodid genera 

 founded on male characters alone, such as Polymedon, which are 

 considered valid, yet Enoplempis is not here reinstated with generic 

 value, as it merges with other Empis through the species nodipes on 

 the one side and teres on the other. 



The subgenus Lamprempis^ deserves a better fate, for as yet, it 

 is very exclusive and probably will always remain so. Its distinc- 

 tive character, a color difference, it is true, is yet so deep seated 

 that it can be regarded as morphological. Intergrades between the 

 yellows and blacks of Empis are common, but an intergrade be- 

 tween the metallic blue of this group and the ordinary color of 

 Empis would be difficult to conceive of, and hence, especially as the 

 species all present a similar facies which is quite different from that 

 of the rest of the group, we feel justified in raising Lamprempis to 

 the rank of a genus. 



Empimorpha, iovmdQd by Mr. Coquillett on Empis barbata Loew, 

 has been allowed to remain as a distinct genus, although its rela- 

 tionships with the group Aldrichii of Empis are quite evident. 



* Bull. Soc. Ent. France, 1880, p. 47. 



t Wheeler et Melander, Biol. Cent. Am., Nov., 1901, p. 366. 



TKANS. AM. ENT. SOC, XXVIII. AUGUST, 1902. 



