1921.] 239 



mouth-edge, very sliort antennae and arista, is very distinctive. 

 Thorax grey, brownisli on the disc — the darkening varying according 

 to the point of view, but usually showing indications of three stripes 

 down the lines of bristles. Abdomen viewed right from behind 

 grey with most of the first segment darkened, two narrowly 

 separated quadrate (longer than wide) dark patches on second 

 segment and two very much smaller, narrower, and more widely 

 separated dark patches on third segment. In some lights tliis 

 coloration may be reversed, the abdomen appearing dark with the 

 dark patches mentioned above greyish or light brownish. Ilypo- 

 pygium beiieatJi (on the part which bears the anal opening) with 

 two tufts of hairs directed downwards and somewhat towards 

 each other. Legs black, dusted greyish, with the extreme knee- 

 joints reddish. Hind femora with an anteroventral row of bristles, 

 short and tino on basal third, becoming much longer towards tip; 

 posteroventrally with 2-3 distinct long bristly hairs on basal half. 

 Front tibiae with 1-2 bristles behind near middle; middle tibiae 

 with about 3 bristles behind on middle third ; hind tibiae with 3-4 

 anteroventral bristles on apical half and two anterodorsal on middle 

 third. Claws and pulvilli short. "Wings almost clear. Squamae 

 whitish. Ilalteres yellow. 



2 . Greyer than the male. Frons more than ^ the width of head. 

 Interfrontalia produced about % the distance from front ocellus to 

 front of frons. Thorax grey with three narrow more or less distinct 

 brown .efripes down the lines of bristles. Abdomen grey except 

 for similar, though smaller, and less quadrate, light brown patches, 

 on second and third segments ; these patches appearing the same 

 from all points of view. Chaetotaxy of legs very much as in male 

 (including long posteroventral hairs on hind femora about base), but 

 there is often a small bristle in front of middle tibiae and a small 

 posterodorsal bristle near middle of hind tibiae. 



Length 6-7 mm. 



This species cannot be confounded with any other in Britain. It 

 is a sea-coast species which has occurred to Mr. Verrall at Aber- 

 lady (Haddington), Dyffryn (Merioneth) ,and Fawley (Hants), to 

 Col. Yerbury at Fiudhoru (Elgin) and Studland (Dorset), and to 

 Miss W. E. Breuchley and myself at Blakeney Point (Norfolk). It 

 may be found during June, July, and August. Mr. H. W. Andrews 

 has taken.it at Porthcawl (Glamorgan) and in Ireland. 



Subgenus Gymnodia. 



Only one British species .... 18. humilis Zett. 



{si-jjtemnotata Auct. nee Zett.). 



c? . Easily distinguished by the exceedingly narrow, and largely 

 bare, frons. In profile the eyes occupy almost the whole of the 

 head leaving the narrow jowls visible, but the very convex frons is 

 only just visible and the very narrow facial orbits almost completely 

 hidden. Arista microscopically pubescent. Thorax distinctly 

 brownish, dull, and practically without stripes. Acrostichals 



