4 [June, 



but it is often more or less grey at the base. Again, there is often a narrow longi- 

 tudinal black stripe on the dorsum of the first and second abdominal segments, as 

 well as a black line on the posterior edges of the segments, while in other specimens 

 the abdomen is entirely unmarked. These and some other minor distinctions are by 

 no means constant, and I can find no essential differences of structure ; therefore I 

 believe the R. populi and R. variegata of Meigen are only varieties of R. scutellaris 

 of Fallen. 



H. dubia, sp. n. 



Oblongo-ovato cinerea ; fronte vix prominente ; ore non producto ; ocidi in mare 

 subcontigui ; seta breviter plumata ; thorace lineis quatuor distinctis nigris ; abdo- 

 mine vitta dorsali macnlisque indeterminatis nigro-fuscis ; vena transversali interna 

 pone medium cellulce discoidalis posita. Long. 3| ad 4 tin. 



Head : forehead very slightly prominent ; eyes of male long-haired and sub- 

 contiguous, separated by a narrow black line, which is bordered by a silvery-white 

 margin ; face silvery-white, with black reflexions ; epistome slightly projecting ; an- 

 tennae narrow, third joint about twice the length of second ; arista short-haired. 



Thorax light ash-grey, with four longitudinal very distinct black stripes nearly 

 equal in width, but varying somewhat in breadth in different specimens ; the outer 

 pair interrupted at the suture ; scutellum covered with ash-grey tomentum, of which 

 it is sometimes partially denuded so as to leave a black spot at the base or in the 

 centre ; four setae are placed longitudinally on each side behind the suture in the 

 space between the middle and lateral stripes. 



Abdomen grey, with a longitudinal black stripe extending on the dorsum over 

 the first two or three segments ; sides marked or tessellated with black patches, 

 which assume the form of irregularly shaped spots on the bases of the segments, 

 when viewed in some directions ; third segment without seta? on the disc. 



Wings slightly tinged with yellow at the bases and along the veins; internal 

 transverse vein placed a little behind the centre of the discoidal cell, and almost 

 exactly opposite the end of the auxilliary vein ; external transverse vein slightly 

 oblique and a little sinuous. 



Calyptra nearly white. Halteres yellow. Legs black ; posterior tibia? without 

 any long hairs on their anterior or inner surfaces, and with only a few setae on their 

 outer sides. 



This species is not common. I have three British specimens, one of which I 

 captured near lake Windermere, and another near Wakefield ; I also received one 

 from Mr. Kowarz, of Franzensbad, taken in Hungary. I first named it R. Ivgubris, 

 Meig., but, on receiving a typical specimen of that species from the continent, I at 

 once saw that they were quite distinct. It more closely corresponds to the de- 

 scription of R. consobrina, Zett., and is perhaps the same, but Zetterstedt's account 

 is so short and incomplete, that his species cannot be identified with certainty without 

 the examination of the specimens in his collection, so I have thought it better to 

 describe it as new. 



It may be distinguished from R. iugubris of Meigen (R. morio,Zett.), of which 

 I have not seen a British specimen, by the mouth being much less prominent and 

 less hairy ; by the thorax being more grey and more distinctly striped ; by the dorsal 

 abdominal stripe being narrow and nearly even, while in Ivgubris it is dilated on 



