148 DIPTERA OF NORTH AMERICA. [PART IV. 



been introduced by Meigen as early as 1803 (Illiger''s Magazin, 

 Vol. YI). In the first volume of his principal work (Systemat. 

 Beschr. etc. Yol. I, p. 108) he mentions among the characters 

 of the genus that "the wings are pubescent along the veins 

 only." It must not be overlooked, however, that at the time of 

 the publication of this volume he had not seen any of the species 

 with the wings hairy on the whole surface. When he obtained 

 such a species (E. varia, Yol. YI, p. 237) he included it in the 

 same genus. Since Meigen, Erioptera has been understood by 

 later authors (Macquart, Zetterstedt, Staeger, and "Walker) in the 

 same sense, that is, as including the species with the wings 

 pubescent on the whole surface, as well as those pubescent along 

 the veins only. 



In 1833 Mr. Curtis (British Entomol. 444) proposed the adop- 

 tion of the genus Molophilus for a species which he described as 

 Molophilus brevipennis, but which later English entomologists 

 unanimously considered as synonymous with E. atra Meig.' 

 The characters upon which this genus was established (modified 

 shape of abdomen and thorax, small size of the wings, and large 

 size of the male forceps) do not warrant its retention in the sense 

 of the author, but the name Molophilus may be well retained for 

 the subgenus to which E. atra belongs. 



In 1848 Mr. Rossi (System. Verz. etc. p. 12) proposed the 

 generic name of Cheilotrichia for the European species having a 

 discal cell (E. imhuta and E. cinerascens) , however without 

 nearer defining this new genus. 



In 1860 Mr. Kolenati (Wien. Entom. Monatschr. Yol. lY) 

 adopted the genus Rhypholophus for a new species, discovered 

 by him in Austria. This name has been retained in the present 

 volume, but in a more extended sense. 



' The synonymy of M. brevipennis with E. atra M., admitted by all 

 English authors (compare Westwood, Walker, etc.), is probably based 

 upon a comparison of original specimens. If we hold on to Mr. Curtis's 

 description only, this synonymy may appear doubtful. He (^Brit. Entom. 

 557) mentions both E. atra and E, viurina among the species found in 

 England, although in the same article he speaks of M. brevipennis as a 

 distinct species. In the description of this species he says that the wings 

 are "straw-colored" at the basis ; from the fact that the author, having 

 both sexes before him, does not notice the difference in the length of their 

 wings, one would infer that they are short in both, and this is not the case 

 with E. atra, etc. 



