AET. 13. DESCRIPTIONS OF FOSSIL INSECTS COCKERELL. 7 



CYTTAROMYIA RECLUSA. new species. 



Plate 2, fig. 1. 



Male. — ^Length 13.5 mm,; wings 12 mm.; slender; vertex brown, 

 but orbits pale; thorax brown without evident markings; halters 

 about 2 mm. long, very slender, with large abrupt knobs; abdomen 

 pale brown, very slender basally, broader toward the apex, where the 

 segments show pale bands, anterior to which, laterally, are large 

 pale areas; there are also rather indistinct pallid discal marks in 

 pairs. The pale bands and lateral patches are similarly indicated in 

 Scudder's C. oligoccna from Florissant. Wings pale brownish with- 

 out conspicuous marlrings, but the end of the marginal cell and the 

 veins bounding the discal cell apically are somewhat clouded, the 

 apical clouding of the marginal cell being as in Gylindrotoma. The 

 discal cell is elongate, being about 1,840 microns long and 640 microns 

 wide at the broadest (subapical) part, whereby the species is readily 

 separated from C. fenestrata Scudder, which is also a considerably 

 .smaller insect. The venation is almost as in G. oligoceria^ but the dis- 

 cal cell is distinctly longer and more slender; the wings of C. oligo- 

 cena are only 9.6 long. The marginal cell is distinctly longer than 

 the width of the wing; its first section (to separation of third vein) 

 is about 2,480 microns, the second section 1,810 microns. The third 

 posterior cell is distinctly shorter than the discal, and thus in Scud- 

 der's key the species runs to C. cancellata Scudder, a species with 

 wings 9 mm. long, from Florissant. The basal part of the marginal 

 cell is proportionately shorter in cancellata. 



Horizon and locality. — Green River Eocene, Roan Mountains, 

 Colorado, collected by John Byram at Station 5, at end of spur west 

 of that on which the Ute trail passes, opposite the head of Salt Wash, 



Holotyjjc.—C^t. No, 69178, U,S.N.M. 



Family SYRPHIDAE. 



SYRPHUS EOCENICUS, new species. 



Plate 2, fig. 2. 



Robust, 12 mm. long; abdomen 7 mm. long and 4,5 mm, wide; head 

 and thorax black, the scutellum not pallid as in modern Syrphics, 

 but appearing a shade lighter than the abdominal bands; abdomen 

 with very well-defined markings, the three broad light bands all in- 

 terrupted by a narrow median band, somewhat broader, but still 

 very narrow, on first segment; the light bands reach the extreme 

 margins, and are of approximately equal width, the first however 

 conspicuously wider mesally than the others, the upper edge of the 

 second dark band presenting a double curve on each side; the other 

 dark bands also have a double curve on each side, but not sufficiently 



20183— 2.5— Proc.N.M.vol.64 IG 



