Baccha. 363 



horse-shoe-shaped, the basal part rather arched, somewhat prominent, 

 the side prolongations very delicate. Proboscis short. Labrum some- 

 what strong, high at the base; it is of the usual shape, the median 

 process cleft and divided into fine emergenees, the upper lateral pro- 

 cess very thin and delicate, pointed and also a little branched, the 

 lower process broad and rounded at the apex; below, along the side 

 margin labrum has the usual row of small warts or papillæ; maxillæ 

 short, knife-shaped, palpi short, slightly longer than the lacinia, a little 

 clubbed ; towards the apex they have some bristles and they are beset 

 with fine hairs; the lacinia has, as usual, very fine, microscopical hairs, 

 arranged somewhat in rows: hypopharynx as long as labrum, a little 

 attenuated but with the apex rounded. Labium with the basal part 

 a little shorter than the broad labella, not strongly chitinised, of yellow 

 colour. Thorax slightly rectangular, somewhat arched ; scutellum æneous, 

 without fringe below the margin. No bristles present. Pleura without 

 yellow markings, at most somewhat vaguely pale; metapleura with 

 very short hairs: in contrast to the foregoing genera there is a distinct, 

 chitinised metasternum behind the hind coxæ (or this part is formed 

 of the metathoracal pleura). Abdomen elongated and narrow, a little 

 widened behind and thus somewhat clavate; it is about four times 

 as long as thorax; first segment short, broad at the base, narrowed 

 behind, short conical; second and third segments long and narrow, 

 of about equal length, fourth shorter, widening backwards, and fifth 

 much shorter, about one third of the length of the fourth and the 

 broadest of all ; the first ventral segment about quadratic and a little 

 arched; in the female the abdomen is more clubbed than in the male, 

 but pointed again towards the apex and the broadest part lying more 

 forwards as the third segment is widening backwards and shorter, 

 the fourth the broadest, the rest decreasing in breadth. In the male 

 there are five not transformed segments; the genitalia are of usual 

 shape, relatively large; in the female there are five segments of 

 length about as in the male, but the small sixth to eighth segments 

 are generally also distinctly seen, and at the apex are a pair of small 

 lamellæ. Legs slender and long, especially the hind legs; hind tibiæ 

 with the usual incurvation near apex on the posterior side; hind 

 metatarsi somewhat thickened. The legs are very inconspicuously 

 haired, and the hairs all short except a row of long hairs on the 

 postero-ventral side of middle femora. Glaws and pulvilli normally 

 developed, not large; empodium small, very short, bristle-shaped and 

 hairy. Wings somewhat elongate; medial cross-vein well before the 

 middle of the discai cell; the cubital vein terminates below the apex 

 of the wing; vena spuria well developed; axillary lobe slightly pro- 



