Diptera 77 c 
Key to Genera — Con. 
19. Cheek much less taan half as high as eye; palpi with very long apical bristle 
Cordylura Fallen, pt. 
Cheek about half as high as eye ; palpi without a long apical bristle 20 
20. Mid femur with a long stout bristle art middle on anterior sm-face. .Ceialinostoma Meade. 
Mid femur without such bristle Sactophnga Fallen, pt . 
20a. Third antennal joint rounded at apex; arista almost bare; fore tibiae with short 
bristles, the inner surface with minute black setulse Microprosopa Becker. 
Third antemial joint angulate or pointed on upper side at apex 21 
21. Area between dorso-centrals cephalad of suture with more than two series of setulje. . 
Spathiophora Rondani. 
Area between dorso-centrals cephalad of suture with only two series of setulse 
Trichopalpus Rondani, pt. 
(Opsiomyia Coquillett) 
22. Fore tibiae with ventral surfaces armed with short stout spines on their entire length; 
male with a large bifid chitinous plate on each side of apical exposed sternite. . . . 
Allomyia, n. gen. 
Fore tibiae without short stout ventral spines; apical abdominal sternite not as above. 23 
23. Apical half of first wing-vein bristly; sixth vein not extending to margin 
Dasypleuron, n. gen. 
Apical half of first wing-vein bare; sixth vein extending to margin 24 
24. Wings with a number of dark spots, those between third and fourth veins usually 
enclosing rudimentary veinlets Ernoneura Becker . 
Wings clear, sometimes with the cross-veins clouded, but never with small dark spots 
enclosing veinlets as above Scatophaga Fallen, pt. 
The genotype of Bucephalina, gen. nov., is Cordylura viegacephala Loew, 
a species originally described from the District of Columliia, which I have seen 
from Illinois, and from Plummer's island, Maryland. 
Gonatherus Rondani. 
I refer one species to this genus. It agrees with the general description 
of the genotype very well except that the female genital segments are not com- 
pressed. Nothing has been known up to this time of the immature stages of 
this genus. 
Gonatherus atricornis, n. sp. 
PuPARiuM.- — Terra-cotta, almost opaque; apices of posterior spiracles 
glossy black. 
Cephalic and thoracic segments missing. Surface rather closely covered 
with slight, linear, discontinuous, transverse ridges. No protuberances on base 
of dorsum of abdomen; each segment with a broad transverse band of very 
minute locomotor spinules on dorsum and venter; apical segment irregularly 
rugose on surface, viewed from behind with eight distinct marginal and sub- 
marginal protuberances, as follows: a large one slightly below transverse line 
of spiracles, a smaller one below it on margin and another, still smaller, sub- 
marginal one slightly ventrad of the lower one, and a large marginal one laterad 
of anus; spiracles elevated, their height equal to their apical diameter, separated 
by about three times the width of their diameter, the openings three in number, 
the upper and lower ones directed straight dorso-ventrad, the outer directed 
straight laterad, on inner side of disc there is a rounded depression. 
Length, 5 mm. 
Imago. Female. — Black, densely grey pruinose, only the abdomen and 
legs slightly shining. Head yellowish testaceous, densely whitish pruinose, 
upper part of occiput and greater portion of frons fuscous, anterior portion 
of interfrontalia slightly reddish; antennae deep black; proboscis glossy black; 
palpi whitish yellow, fuscous at apices. Dorsum of thorax with two poorly 
defined, narrow vittse on anterior half between the acrostichals and dorso- 
centrals. Legs black; apices of femora below, and all of tibiae reddish, tarsi 
fuscous. Wings clear, veins dark brown. Calyptrse white. Halteres brown. 
