334 Orthorrhapha brachycera. 



part of the discai vein very slightly curved, and slightly converging 

 towards the cubital vein, it is considerably shorter than the first part 

 of the vein; the last part of the postical vein shorter than the cross- 

 vein; this latter somewhat oblique and its lower inner angle rect- 

 angular. Squamulæ yellow, with a pale yellow fringe, the margin very 

 slightly darkened. Halteres yellow. 



The female I do not know. 



Length fully 3 mm. 



This species resembles jaculus, but is easily distinguished by the 

 epistoma, which is shining below the ridge, and by the relative length 

 of the two parts of the discai vein, and the oblique cross-vein causing 

 the lower inner angle to be rectangular. 



M.petro'philus is very rare in Denmark, we have only one specimen, 

 a male, taken many years ago, probably in the vicinity of Copen- 

 hagen. It is recorded to occur on rocks and stones on dry beaches. 



Geographical distribution: — Europe dow^n into Italy; its northern 

 limit is in Denmark, and it occurs in England. 



32. Scellus Loew. 



Species of medium or somewhat large size, and of dark metallic 

 colour. This genus agrees in most essential respects with the 

 following, Hydrophorus. Head a little broader than thorax; it is higher 

 than broad, narrowed downwards, slightly arched behind. Vertex a 

 little excavated, the oceliar tubercle prominent. Frons somewhat 

 broad, decreasing in breadth towards the antennæ. There are oceliar 

 and postvertical bristles, but the vertical bristles are only represented 

 by a very small hair; on the oceliar tubercle are a pair of likewise 

 very small hairs. Eyes large, somewhat oval but narrowed below; 

 the hind margin is curved very slightly forwards; in the living speci- 

 mens (of notatus) they are reddish with a green, transverse band at 

 the height of the antennæ; they are densely short-hairy. The facets 

 are in the male enlarged on the front side towards the epistoma. The 

 eyes are well separated in both sexes, a little more in the female 

 than in the male. Jowls very narrow or almost absent. The posto- 

 cular bristles form a single row, only present on the upper half of 

 the occiput, the whole lower half densely covered with somewhat long 

 hairs. Antennæ placed near to each other, high above the middle; 

 they are a little elongated, about as long as the head or longer; the 

 first joint somewhat elongated, linear, the second short and simple, 

 the third generally short, as long as, or a httle longer than broad; in 

 a few cases it is (in non Danish species) more elongated; it may be 



