146 



DOLICHOPID.E. 



with three distinct joints besides the slender ones which compose 

 the arista, the second joint usually the shortest of these three, and 

 most closely attached to the third, intromitting a slender tubular 

 process into an oblique sinus in the base of the third joint, which 

 is rather thick in this part, but elsewhere compressed, without any 

 trace of division, bearing a two-jointed arista, usually on its upper 

 edge, sometimes at its extremity, the arista in the latter case being 

 sometimes contracted to a style. The thorax is convex, the suture 

 of the mesonotum before the wings merely traced in its commence- 

 ment at each side. The bristles are chiefly disposed in longitudinal 

 lines : the scntellum has commonly two unequal bristles at each 

 side, and the disc rather flat and naked. The wings of them- 

 selves afford very definite characters of the family, although at 

 first sight like some of the Muscida. The costal vein terminates 

 where the prsebraclrial meets it : the subcostal is short, rarely ap- 

 proaching the middle of the anterior margin ; the mediastinal is 

 very faint and lies close to the subcostal ; the radial springs from 

 this almost close to the humeral transverse vein, and the cubital 

 vein, which is simple, parts from it almost immediately, its origin 

 forming a thickened dot, close to which a very short and oblique 

 transverse vein connects it with the prasbrachial ; the pradrackial 

 areolet, which is thus bounded, is close to the root of the wing, 

 and very minute. So also is the anal areolet (" angular area," 

 Mn.), which is scarcely circumscribed behind, the anal vein being 

 here very faint, and in its outer course appearing rather as if a 

 continuation from the subanal, which returns back from the po- 

 brachial in a strong curve. The pobrachial areolet is merely indi- 

 cated in position as very minute, but is not separated from the 

 ducal ; which is oblong, closed, at about the half length of the 

 wing, or nearer to the posterior margin, by an unbranched trans- 

 verse vein ; only two veins proceeding from it to the margin, as 

 continuations of. the prsebrachial and pobrachial veins, the former 

 of which sometimes approaches the cubital thenceforth in a curve, 

 or is bent abruptly, or even branched (g. Psilopus] . No axillary 

 lobe, the sinus straight; the axillary alulae are small, deflected, 

 fringed with long hairs, the colour of which sometimes affords 

 subsidiary specific characters; the scutellar alulas are obsolete. 

 The abdomen is composed of jive segments above, the inflected 

 sides of which nearly conceal the ventral plates, and are marked 

 with a row of small polished foveolse. Besides the silvery white 

 tomentum so conspicuous in some (e. g. Argyra), the abdomen is 

 usually clothed with pubescence pale especially on the sides, and 





