NO. 2181. NEW TERTIARY INSECTS— COCKERELL. 375 



BIBIO GDBNETENSIS. new ap«dM. 



Plate 31, fig. 4. 



Wing about 5 mm. long, clear hyaline, stigmatic region pale brown- 

 ish, venation normal for the genus. Tlie following measurements 

 are in microns: Upper apical side of first basal cell, 145; lower apical 

 side (on first posterior) of first basal, 640; second basal on first pos- 

 terior cell, 960; second basal on fourth posterior, 1,040. 



Oligocene: Gurnet Bay (Brodie). British Museum, I. 8641. The 

 apical sides of the first basal cell (the upper short, the lower, or cross- 

 vein, long) are like those of the Florissant fossil B. atavus Cockerell. 

 Meunier lists no species of Bihio from Baltic amber. 



BEBIO OLIGOCENUS, new species. 



Plate 31, fig. 5. 



Wing about 8 mm. long, fuliginous; the whole costal region very 

 dark. Venation normal for the genus. Stem of vein, 2-3 before dis- 

 cal cross-vein 896 microns long, and discal cross-vein only 256 microns. 

 Lower end of discal cross-vein 1,440 microns apicad of level of basal 

 corner of fourth posterior cell. 



Ohgocene: Gurnet Bay (Brodie). British Museum, I. 8650. 

 Eeadily distinguished by the dark wings and the venation as de- 

 scribed. 



PLECU WmCHESTERI, new species (Bibionidae). 



Wing about 7.3 mm. long and 3 broad, dilute fuliginous; third vein 

 rather strongly arched; anterior cross-vein shorter than distance 

 from it to fork of fourth vein. A broad-winged species of normal 

 type. The following measurements are in microns: Third vein from 

 origin (separation from first) to anterior cross-vein, 1,520; third vein 

 from anterior cross-vein to fork, 1,330; length of upper branch of 

 third vein (second vein), 960; third vein from fork to end (lower 

 branch) 2,240; length of anterior cross-vein, 240 ; anterior cross-vein 

 to fork of fourth, 400; fourth posterior cell on wing-margin, 1,490. 

 The second posterior cell on upper side is sHghtly over 3 mm. long. 



Oil shales (Eocene), banks of Hay Gulch (S. E. quarter of section 

 36, township 1 N., Range 96 W), Colorado, September 9, 1914 (D. E. 

 Winchester), United States Geological Survey. This is very possi- 

 bly the female of P. woodruffi Cockerell, but if so, this can not be 

 proved, and as the locahty is different, I give it a distinctive name. 

 The wing is colored exactly like that of P. fulvicollis Fabricius, from 

 Los Banos, Philippine Islands (Baker). 



Type.—C&t. No. 62535, U.S.N.M. 



