1916.] NATURAL SCIENCES OF PHILADELPHIA. 513 
18. Male hypopygium with the dorsal pleural appendage armed 
with a chitinized hook 19 
Male hypopygium with the dorsal pleural appendage without a 
hook, although ^vith two powerful bristles at the tip 20 
19. Male hypopygium with the dorsal appendage two lobed, the 
caudal arm a powerful chitinized spine; ventral arm with a 
sharp, chitinized, feebly curved spine. (Eastern United 
States.) suhcinerea Osten Sacken. 
Male hypopygium with the dorsal appendage irregular, not two 
lobed, the outer face near the apex with a strong, curved, 
chitinized hook. (Extra-limital; Guatemala.) 
cequalis Alexander. 
20. Male hypopygium with the ventral appendage prominent, 
directed caudad, narrowed at the base, the apex a slight 
chitinized tooth directed proximad. (Western United States.) 
virgnta Doane. 
Male hypopygium not as described 21 
21. Male hypopygium with the ventral appendage a double,, dark- 
colored lobe, the inner arm stout-cylindrical; the outer arm 
slender, curved, bearing at the tip two divergent hairs; penis- 
guard subtended by two divergent chitinized arms that are 
acute at their tips. (Extra-limital; Guatemala.) 
unicolor Alexander. 
Male hypopygium with the ventral appendage pale, not 
chitinized; penis-guard long and pale, the apex bifid by a 
deep U-shaped notch; the divergent subtending arms are 
slender, the ventral margin with a few sharp, appressed teeth. 
(Extra-limital; Mexico.) mer^ca/ia Alexander. 
Subgenus LEIPONEURA Skuse. 
The Cinerea Group. 
Gonomyia (Leiponeura) alexanderi Johnson. 
EUipiera alexanderi Johnson; Psyche, vol. 19, p. 3, fig. 6 (1912). 
This handsome little fly is locally common. Its known distribu- 
tion over the eastern United States is as follows: 
New York, Fulton County, Sport Island, Sacandaga River, June 
11, 1914, to August 24, 1910 (Alexander), the type-locality; Herkimer 
County, Indian Castle, June 13, 1915 (Alexander). 
North Carolina, Buncombe County, Black Mountains, June 13, 
1912 (Beutenmuller). 
A female specimen from Piano, Collin County, Texas, in August 
(E. S. Tucker), probably belongs here, but may possibly represent 
G. helophila Alexander. This is also the species mentioned by 
Osten Sacken in the Monographs, part 4, p. 179, without locality. 
The wing is shown on Plate XXVI, fig. 17. 
