Neoascia. 373 



than thorax; it is flat behind, the excavation above much smaller. 

 Eyes separated in both sexes, a little more in the female than in the 

 male. Antennæ more or less elongated, sometimes rather short, the 

 third joint from a little longer than broad to twice or more than 

 twice as long as broad, but it is narrower than in Sphegina; arista 

 considerably shorter, and apparently bare. Epistoma less hollowed 

 below the antennæ, more evenly but fully so much protruding; it is 

 grey pruinose, a little haired below. Jowls small and narrow. The 

 mouth parts mainly as in Sphegina, but the oral cone and proboscis 

 relatively longer, and also the palpi slightly longer; the shape of the 

 apex of labrum is different, the median process is much shorter than 

 the others, cleft in the usual way and not as in Sphegina; the upper 

 lateral process is long, thin and pointed, the lower of the usual broad 

 shape ; the basal part of labrum is more chitinised and dark, Scutellum 

 without apical bristles. There is . no such process bearing the hind 

 coxæ as in Sphegina, but the pleura of metathorax stretch in behind 

 the hind coxæ and are almost or quite meeting in the middle below ; 

 upwards they divide triangularly and the upper pointed corners stretch 

 in under the balteres as in Sphegina, but they are here directed out- 

 wards so that there is a protruding apex at each side at the base of 

 abdomen. Abdomen is narrow and clavate, but less than in Sphegina; 

 it is otherwise shaped in the same way, and there are likewise four 

 not transformed segments in the male, the sternites of which are, 

 however, of usual shape, not small as in Sphegina, and there are thus 

 no such membranous spaces as in this genus. The genitalia are 

 relatively smaller, the apical appendages of the ninth segment short, 

 with various processes and some spines. In the female there are five 

 normal abdominal segments. Legs as in Sphegina, hind femora like- 

 wise thickened and clavate, and hind metatarsi a little thickened. 

 Hind femora likewise with rows of bristles below, but besides with 

 long hairs above, and middle femora with a row of long hairs below, 

 and also the hairs below the front femora not quite short ; hind tibiæ 

 with a short, dense fringe below in the apical half. Wings somewhat 

 elongate; the medial cross-vein longer before the middle of the discai 

 cell than in Sphegina; subcostal vein somewhat short; radial vein a 

 little undulated ; the marginal cross-veins both perpendicular, and their 

 lower angles rectangular or the angle at the upper cross-vein a little 

 rounded, but less than in Sphegina; vena spuria very weak, only 

 visible to the medial cross-vein; no anal fold. Alula almost wanting. 

 Squamulæ narrow, the alar squamula with short, simple hairs, the 

 thoracai squamula with long, partly simple, partly slightly branched 

 hairs. Plumuia rudimentary. 



