3. OXYCERA 95 



yards square that is not surprising. The very limited variations occur in 

 the amount of pale markings on the frons of the female, the pale band 

 behind the eyes of the female, the extreme tip of the scutellum in the 

 female, and to a small extent the amount of pale coloring on the legs. 

 All these variations tend towards 0. pygmcea, but the more I study the 

 specimens the more I believe them to be distinct, because of the larger 

 and stouter build, the longer larger antennre which have the basal joint 

 of the thicker style more dilated, and the less silvery inflated lower 

 part of the back of the head, besides the darker coloring and thoracal 

 pubescence. 



0. nigripes has occurred on only July 20 and 21, 1886, in some 

 abundance on a small grassy glade by the side of the small river which 

 flows down Ben More of Assynt, about a mile from Inchnadamph in 

 Sutherland. In the same very limited spot Orimarga virgo also occurred, 

 and both species could be caught by sweeping. 



Synom/my. — There should be no synonymy for a new species, but I cannot help 

 believing that some of the records of 0. ■pyyvum nuist refer to this species, especially 

 when authors have been limited in their material like (for example) Jaennicke in his 

 remarks in Berl. Ent. Zeitschr., 1866, p. 226, and it is possible that similar specimens 

 caused J. C. Dale to propose the name 0. ajfinia for what was subsequently con- 

 sidered a variety of O.pygvuta ; while Loew in Berl. Ent. Zeitschr., i., p. 32 mentions 

 that the female of 0. pygvuta is very variable in the extent of the yellow marking 

 of the head. 0. nigrijies may be only a large stout dark mountain form of 0. 

 pygimna, but I am disposed to consider it a distinct species. Although the name 

 0. nuiripes appeared in my List of British Diptera, 1888, it has remained until now 

 a mere catalogue name, as no previous description has been given, and why there- 

 fore it appears as a good species in Kertesz's Katalog with 0. pardalina Walk, (nee 

 Meig.) as a synonym is strange, especially as I consider that Walker's 0. pardaliTm 

 is only a bad description of Meigen's 0. pardalina. 



4. O. formosa Meigen. Cubital vein not forked. Thorax brilliantly 

 shining; scutellum and legs entirely yellow. 



A small species easily known by its brilliantly shining 

 thorax and completely pale legs. 



S. Face and frons forming a small black equilateral triangle; jowls almost 

 absent, but the lower part of the back of the head moderately inflated and 

 bearing moderately long greyish white pubescence ; vertex raised and forming 

 a triangle apparently only rather longer than broad as any prolongation 

 forward is very narrow and inconspicuous, bearing tiny pubescence above the 

 ocelli ; proboscis in life conspicuously whitish yellow. Eyes touching for 

 about two-thirds the distance between the occiput and the antennae, practi- 

 cally bare ; facets^ on the upper two-thirds conspicuously larger than those on 

 the lower third and the contrast rather abrupt ; in life the eyes are ricli 

 brownish red with green reflections, and with a narrow almost equal deep 

 purple band all across at the top of the small facets, Antennt^i not long, 

 all black or with the two basal joints sometimes brown ; arista almost as long 

 as the annulated thii-d joint and with a tiny white apical hair. 



Thorax brilliantly shining black, i)racLically impunctate and almost bare 

 as the pubescence is reduced to some minute si)arse pale hairs which do not 

 extend to the broad middle front part of the disc ; a large yellow spot on each 

 side extends from the humeri above the dorso-])leural suture to the transverse 

 thoracic suture, while the humeral knob and a line all along the upper margin 

 of the mesopleurae are also yellow, and this line is irregularly but obviously 

 continued under the wiiigs to the end of the pleuraj just below the base of 

 the halteres, and there is an obvious yellow spot on the top part of the sterno- 

 pleurse ; postalar calli conspicuously yellow, and the yellow colour extends a 



