86 DIPTERA OP NORTH AMERICA. [PART II. 



brown upon the apical half. Arista with a comparatively long 

 and striking pubescence. Front covered with a snow-white dust. 

 Cilia of the inferior orbit black. Thorax and scutellum metallic 

 violet ; no hairs are perceptible upon the surface of the latter. 

 Abdomen metallic dark green. Coxoa and feet yellowish ; middle 

 coxae upon the outside with a grayish streak. Tarsi from the tip 

 of the first joint gradually blackened. The usual row of bristles 

 on the upper side of the fore tibiae is extant and complete ; the 

 single bristles, however, comparatively short. Cilia of the tegulce 

 black. Wings tinged with grayish-brown, a little more brown 

 towards the anterior margin ; the third and fourth longitudinal 

 veins very slightly converging towards the end. 

 Hob. Middle States. (Osten-Sacken.) 



9. Cr. silTjdilatatus LOEW. . Viridis, antennis nigris, coxis n?gri- 

 cantibus, anticarum apice pedibusque flavis, maris tarsorum anticorum 

 articulo ultimo depresso, subdilatato. 



Green ; antennae black ; coxse blackish ; tip of the fore coxse and the feet 

 yellow; the last joint of the fore tarsi of the flattened and a little 

 enlarged. Long. corp. 0.13. Long. al. 0.13. 



SYN. Gymnopternus subdilatatus LOEW, Neue Beitr. VIII, 31, 8. 



Metallic green, rather bright. Face covered with a whitish 

 dust. Antennae entirely black ; third joint short, rather rounded ; 

 arista with a scarcely perceptible, extremely short pubescence. 

 The cilia of the inferior orbit seem to be black ; upon the scutel- 

 lum, besides the usual two bristles, a few small hardly perceptible 

 hairs are inserted. The rather large lamellae of the hypopygium 

 are more kidney-shaped than crescent-shaped, upon their lower 

 side brownish-yellow, upon the upper part brownish-black, closely 

 fringed with black bristle-like hairs ; the interior appendages are 

 simple. The fore coxas blackened as far as the middle, middle 

 and hind coxae almost as far as the tip. Feet yellowish, a little 

 more slender than in the allied species. The hairs on the hind 

 femora are also blackish upon their under side, and more distinct 

 than in the related species. The usual row of bristles on the 

 upper side of the fore tibiae is extant, but the single bristles are 

 very short. Fore tarsi from the tip of the first joint strongly 

 iufuscated, towards the tip black, very slender, but hardly longer 

 than the tibiae. Their first joint is as long as the two following 

 taken together ; the last joint is flattened and a little enlarged, 



