Syritta. 527 



Vertex much elongated ; frons very small, not prominent, without hairs. 

 Antennæ inserted in the middle of the head, the second joint without 

 bristles; arista short, bare. Epistoma keel-shaped, very slightly hollowed 

 from the antennæ to the mouth edge, which latter is the more pro- 

 duced part; the epistoma is not descending, it is vvhite pruinose, the 

 lower side parts bare, yellow; it has only slight hairs at the sides 

 below. Jowls very narrow, not descending. Oral cone and proboscis 

 rather long. Clypeus with the basal part small. Mouth parts other- 

 wise of usual construction, but they are much longer than in Xylota 

 and for the rest also else differing from the mouth parts in this genus. 

 Labrum long, semitubular, the median process cleft, with emergences, 

 the upper lateral process thin and pointed, the lower lateral process broad, 

 with a broad end and as usual with the lower corner rounded, the 

 upper drawn a little out; hypopharynx long, slightly shorter than 

 labrum, parallel-sided, attenuated at the end but the apex itself rounded; 

 maxillæ likewise long but shorter than hypopharynx, of usual shape 

 and structure, rounded at the end ; the palpus a little shorter than 

 the lacinia, thread-like, microscopically haired, with some short bristles 

 and one long at the apex; labium with the basal part longer than 

 the not large, oval labella. Thorax rectangular, the anterior side 

 margin yellowish pruinose. Scutellum black, without marginal fringe 

 below. No thoracai or scutellar bristles, only a few very short, bristly 

 hairs at the apex of scutellum. Metapleura with short, dense hairs, 

 a little longer towards the hind margin. Abdomen narrow and elongate 

 with parallel sides, rather flat; in the male there are four not trans- 

 formed segments, the first not quite small, the others about equal in 

 length ; the first segment has the hind corners rounded off and the 

 second is produced much forwards at the basal corners; the first 

 ventral segments are somewhat narrow so that there is a broad side 

 membrane; the fourth ventral segment is shorter than the dorsal, 

 roundly incised at the hind margin. Genitalia large, the outer lamellæ 

 elongated triangular, the terminal appendages styliform, a little curved. 

 In the female there are five visible abdominal segments but the fifth 

 is very small, pointed, often almost hidden; the rest are hidden, the 

 last terminates with two small lamellæ ; the fourth ventral segment is 

 about as long as the dorsal. Legs with the hind femora very strongly 

 thickened, with small spines below and serrated on the apical part; 

 the hind tibiæ distinctly curved, hind metatarsi a little thickened; the 

 legs are very short-haired, there are longer hairs only behind the 

 middle femora, and below the hind femora there are a few long 

 bristles. Glaws and pulvilli moderately developed; empodium spine- 

 shaped, hairy. Wings with the cubital vein curved a little down above 



