Diptera 77 c 



Key to Genbha — 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 at middle on anterior surface. . Cei atinostonm Meade. 

 Mid femur without such bristle Sactophaga Fallen, pt . 



20a. Third antennal joint rounded at apex; arista almost bare; fore tibiae with short 



bristles, the inner surface with minute black setulae Microprosopa Becker. 



Third antennal joint angulate or pointed on upper side at apex 21 



21. Area between dorso-centrals cephalad of suture with more than two series of setulae. . 



Spathiophora Rondani. 



Area between dorso-centrals cephalad of suture with only two series of setulae 



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 fia:st 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 megacephala Loew, 

 a species originally described from the District of Columbia, which I have seen 

 from Illinois, and from Plummer's islandp 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 ther« 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. Calyptrae white. Halteres brown. 



