Oestrus. 83 



above, dark below. Antennæ yellowish brown, arista dark. Thorax 

 brownish before the suture, black and somewhat shining behind; 

 it is clothed with dense, all reddish pile, or with a narrow trans- 

 verse band of black pile behind the suture. Scutellum with black or 

 brown pile. Abdomen somewhat short, black, somewhat shining, 

 with greyish yellow pile on basal segments, black on third and more 

 or less of fourth segment, and reddish at apex; all the pile long. 

 Legs with femora black, paler at apex, tibiæ and tarsi brown or 

 brownish yellow. The hairs on femora black or brownish to yellow, 

 on tibiæ yellow. Claws and pulvilli long. Wings a little greyish tinged ; 

 veins yellow; posterior cross-vein placed a little before or just below 

 medial cross-vein. Squamulæ white, the lower with a long white 

 fringe. Halteres yellow. 



Female. Frons broader than the eye. Pile on abdomen other- 

 wise coloured than in male, pale greyish yellow at base, black on 

 third segment and whitish on last segments; sixth segment cylindrical, 

 seventh a little longer than broad, with a pair of strong triangular 

 lamellæ at end. Claws and pulvilli as in male. 



Length 12 — 13 mm. 



G. nasalis is perhaps a little less common in Denmark than 

 the others; as imago it is only rarely seen; we have some specimens 

 from Farsø and from Gjerlev near Randers, besides larvæ. 



Geographical distribution: — All Europe and in North America. 



II. Oestrinae. 



2. Oestrus Linn. 



Medium sized species with a somewhat inflated head and ab- 

 domen of a peculiar black and whitish marbled aspect. Head almost 

 not broader than thorax, semiglobular, concave behind, higher 

 than long. Frons and face somewhat swoln, much raised above the 

 level of the eyes; frons in male a little broader than the eye, widening 

 downwards, in female much broader, with parallel margins; orbits 

 broad. The anterior outline of the head evenly convex. Jowls about 

 as broad as the eye is high, in female broader. No bristles present 

 and occiput without real postocular bristles. Cheeks rather broad, 

 with few fine hairs. Vibrissal ridges surrounding the antennæ, con- 

 verging below them, running parallel for a distance and then diverging 

 towards the lower margin; the median part of epistoma thus narrow 



6* 



