156 Oithorrhapha brachycera. 



rowed at the apex (in the American genera Metatrichia and Pseuda- 

 trichia the first posterior cell closed); the anal cell closed at some 

 distance from the margin; the first basal cell longer than the second. 

 Alula developed. Squamula alaris present, squamula thoracalis not 

 developed; frenulum distinct. In rest the wings lie parallel over the 

 abdomen, 



The larvæ quite resemble those of Thereva, the body likevise 

 apparently consisting of twenty segments; they are amphipneustic. 

 The pupa is free, and it also resembles a Thereva pupa. 



The Scenopinids are in appearance very curious, small flies; the 

 common S. fenestralis is found in houses on windows, other species 

 occur in the open on flowers. 



Of the family only one genus with 14 species occurs in the 

 palæarctic region; in North America three genera with 12 species 

 occur; two species are common to both regions. 



No case of parasitic Hymenoptera on Scenopinids is known to me. 



Scenopinids earlier recorded from Denmark : — Bri^inniche, 1763 

 (Pontopp. Danske Atl.) records Musca fenestralis. Muller has no 

 Scenopinus nor has Fabricius any species directly recorded from Den- 

 mark. Zetterstedt in 1842 (Dipt. Scand. I) records S. fenestralis and 

 in the following volumes no other species, thus one species has been 

 known hitherto. In the present work two species are enumerated. 



Scenopinus Latr. 



Species of rather small size, very slightly hairy, and of black or 

 blackish colour, in the male generally with white incisures between 

 some of the abdominal segments. Head as broad as thorax and 

 broader than high, arched in front, slightly excavated behind. Eyes 

 either touching in the male, well separated in the female, or separated 

 in both sexes and with only a slight difference in the breadth of the 

 frons according to the sex; the eye-facets in the male are in the first 

 case larger above than below with a distinct dividing line, in the 

 second case they are of equal size. Antennæ inserted near to each 

 other, below the middle. Jowls not descending below the eyes, very 

 small, forming only a narrow rim. Antennæ three-jointed, the first 

 two joints small, the third large. Epistoma very short and retreating. 

 There is no oral cone; clypeus somewhat horseshoe-shaped, stretching 

 horizontally from the epistoma to the labrum. Proboscis short; labrum 

 triangular, truncate, short. as long as the basal part of labium ; the 

 maxillæ have a pointed lacinia vvhich is slightly longer than the labium, 

 and one-jointed, slightly club-shaped palpi which are somewhat long, 



