J 4:2 DIPTERA OF NORTH AMERICA. [PART II. 



scarcely perceptible short pubescence. The lower part of the 

 occiput only with the usual fringe of cilia. Scutellum without 

 hair. Coxae and feet comparatively bare, the latter with very 

 few bristles ; the first joint of the hind tarsi without bristles. 

 Wings not very broad, somewhat narrowed towards the basis ; the 

 last segment of the fourth longitudinal vein little inflected ; hypo- 

 pygium small, rounded, rather imbedded, its outer appendages 

 more filiform than lamelliform ; the inner appendages small. 



The next related genera are Rhaphium and Porphyrops. The 

 characters of the 'genus Rhaphiuni have already been described. 

 The species of Xiphandrium differ from the species of Porphyrops 

 by their smaller size, more slender form, less hair, especially on 

 the lower part of the occiput and on the coxae ; the third joint of 

 the antennae of the males is more elongated, more distinctly hairy, 

 particularly on the whole lower side ; the arista is beset with a 

 comparatively short but easily perceptible pubescence ; the wings 

 are less broad and towards their basis still narrower. It cannot 

 be mistaken for the genera Systenus, Synarthrus and Smiliotus, 

 as they differ from Xiphandrium and Rhapjhium bj the same 

 distinctive marks. 



The name (from |i>oj, sword, and av^p, man) has been given to 

 this genus on account of the sword-shaped antennae of the male. 



Out of Europe, no species of Xiphandrium are as yet known. 

 I have a female from North America, which probably belongs to 

 this genus. As it has lost its antennae, its systematical location 

 could not be ascertained. 



Gen. XX. PORPHYROPS. 



The genus Porphyrops comprises species of at least middle 

 size, rather stout shape and very hairy. The first joint of the 

 antennae has no hairs on the upper side ; the second is transverse ; 

 the third is moderately elongated in the male and shorter in the 

 female ; the hairs upon it are very short and the whole under side 

 (with the exception of a few species) is entirely bare. Arista 

 altogether apical with an almost imperceptible and very short 

 pubescence. The under side of the occiput more or less densely 

 fringed. Scutellum without hairs. Coxae and feet with rather 

 much hair and bristles. First joint of the hind tarsi without 

 bristles. Wings comparatively broad, towards the basis only a 



