Clytiomyia. 103 



and an intraalar bristle present. Scutellum with two bristles on each 

 side, Abdomen yellow with a narrow base, a middle stripe and the 

 apical part, including fifth and most of fourth segment, black; it is 

 yellowish pruinose except second segment, and thus the hinder part 

 of the middle stripe and the apical part appear yellowish. Abdomen 

 is black-haired with marginal bristles, on second segment a pair, on 

 the others a row. Fifth sternite short, bow-shaped. Legs black; claws 

 and pulvilli a little elongated. Wings brown fumigated; veins blackish 

 brown; first posterior cell narrowly open or just closed, ending at 

 apex of wing; angle on discai vein obtuse. Squamulæ deep yellow. 

 Halteres yellow. 



Female. Similar; frons a little broader with the frontal stripe 

 broader; orbits less pruinose and strongly haired. Abdomen much 

 darker than in male as there is only a yellow side spot at the base, 

 but the dark part as in the male yellow pruinose. 



Length 4,7 — 6 mm. 



C. pellucens is somewhat common in Denmark; Ordrup Mose, 

 Ermelund, Dyrehaven, at Fure Sø, Ryget Skov, Ruderhegn, Ege- 

 bæks Vang, Humlebæk, Grib Skov, Lave Skov at Helsingør, Tisvilde, 

 Jægerspris, Alindelille, and at Vordingborg; on Lolland in Lysemose 

 and Kældskov; in Jutland at Sønderborg; on Bornholm (Stein). 

 The dates are ^5 — ^Vs- It occurs on flowers, especially Achillea and 

 umbellifers, and it is in some years rather frequent. The develop- 

 ment is hitherto unknown. 



Geographical distribution: — Europe, towards the north to 

 middle Sweden, and in Finland. 



6. Xysta Meig. 



Species of medium size, blackish with greyish or brownish prui- 

 nosity. Head broader than thorax, nearly flat behind and slightly 

 puffed out below. Frons quite narrow in both sexes, narrowest in 

 female, with the orbits nearly or quite touching, a little protruding. 

 Jowls broad but rather horizontal. In male none, in female small ocellar 

 and inner vertical bristles. No orbital bristles. Behind postocular 

 bristles black hairs above. Frontal bristles reaching to the insertion 

 of antennæ, all crossing in both sexes. Cheeks bare. Vibrissal ridges 

 short, and thus the angle with the large vibrissa high above the 

 lower margin of epistoma; the vibrissæ somewhat ascending. Eyes 

 in female with the facets in upper part distinctly larger than below, 



