6 PKOCEEDINGS OF THE NATIONAL MUSEUM. vol. 64, 



of the media. It therefore seems hardly necessary to propose a new 

 generic name for the fossil. 



Acnemia is known to occur fossil in Europe; A. holsiusi Meunier 

 in Baltic amber, and A. simplex Cockerell in the Oligocene of the Isle 

 of Wight. 



Family BIBIONIDAE. 



PLECIA RHODOPTERINA, new species. 



Plate 2, fig. 6. 



Female. — Length 4.4 mm., robust, with small head and stout legs, 

 the short antennae with joints considerably broader than long; wings 

 5 mm. long and slightly over 2 broad, ferruginous (as in P. fuVuicollis 

 Fabricius) ; section of radial sector between anterior cross- vein and 

 the fork distinctly but not greatly shorter than upper branch of fork ; 

 section of media between cross-vein and fork distinctly but not nmch 

 shorter than fork; lower branch of cubitus strongly curved down- 

 ward apically. 



Horizon and locality. — Green Eiver Eocene; head of East Alkali 

 Gulch, about 8 miles south of De Beque, Colorado. (John P. By ram, 

 1922.) 



Holotype.—Cdit. No. 69177, U.S.N.M. 



Much smaller than any of the four species previously recorded 

 from the Green River shales and having rather the aspect of a Myce- 

 tophilid. 



Family TIPULIDAE. 



Genus CYTTAROMYIA Scudder. 



This genus of Cylindrotominae was founded by Scudder for a 

 species {G. fenestrata Scudder) fossil in the Green River Eocene of 

 Fossil Canyon, Utah. Subsequently he described four additional 

 species from the Miocene of Florissant, and remarked that he was 

 acquainted with still other species from* the ^Vhite River basin 

 (Green River Eocene). The genus is not so aberrant as Scudder be- 

 lieved, being in effect a Cylindrotoma with an additional cross-vein 

 between R4+5 and the anterior branch of the media, making a 

 closed cell above the discal. Alexander regards the Cylindrotominae 

 as a decadent group, not nearly so well developed to-day as in Ter- 

 tiary times. In his phylogenetic tree, he places the subfamily as an 

 offshoot near the base of the stem, not leading to any further de- 

 velopments. The larvae are quite exceptional among Tipulidae in 

 feeding on the leaves of plants. Cylindrotoma has six species of the 

 North Temperate Zone, three being American. 



