134 M. W. R. de V. GRAHAM 



the ventral edge of the eyes ; scape just reaching the median ocellus, its length slightly greater 

 than the transverse diameter of an eye ; combined length of pedicellus and flagellum 0-85 times 

 the breadth of the head ; pedicellus nearly twice as long as broad, nearly equal to the anelli 

 plus the first funicular segment ; funicle proximally not stouter than the pedicellus but thicken- 

 ing distad, with segments one to three slightly elongate, four quadrate, five and six slightly 

 transverse ; clava 1-75 times as long as broad, slightly broader than the funicle, its length 

 about equal to two and a half of the preceding funicular segments ; flagellum with very short, 

 mostly subadpressed hairs, so that it has an unsually smooth appearance ; sensilla in one 

 row on each segment, sparsely distributed on the proximal segments of the funicle, numerous 

 on the distal segments and clava. 



Pronotum (Text-fig. 98) : collar with its lateral angles slightly toothed, its anterior edge 

 slightly ridged with just a trace of three teeth. Mesoscutum nearly twice as broad as long, 

 finely reticulate. Scutellum as broad as long, slightly convex, sculptured as the mesoscutum ; 

 the frenum, which is marked off by a very fine line, slightly more coarsely. Propodeum about 

 three quarters the length of the scutellum ; its median area with sculpture like that of the 

 scutellum, but that of the nucha rather finer ; median carina vaguely indicated in the middle 

 by some stronger sculpture ; spiracles rather small, oval, separated by nearly their own length 

 from the metanotum ; callus alutaceous. Metapleuron finely though strongly reticulate ; 

 mesepimeron rather less strongly. Fore wing (Text-fig. 94) relatively short (about 21 times as 

 long as broad), relatively sparsely haired ; lower surface of costal cell with a single row of hairs, 

 partly double in the distal quarter, its upper surface bare ; basal vein bare or with a single 

 hair ; basal cell bare, both it and the speculum open below ; on the upper surface of the wing 

 the speculum large and extended as a bare strip below the proximal half of the marginal vein, 

 whilst there is also a nearly bare triangular area between the postmarginal and stigmal veins ; 

 disc of wing beyond the speculum relatively sparsely haired ; marginal vein about 2-2 times 

 the length of the stigmal vein and 1 -4 times the length of the postmarginal vein. Legs not very 

 slender ; spur of mid tibia about half as long as the first tarsal segment. 



Gastral petiole about 1 -3 times as long as the propodeum and reaching well beyond the tips 

 of the hind coxae, nearly three times as long as broad, finely reticulate, its sides converging very 

 slightly posteriorly ; there are two hairs on each side. Gaster ovate, shorter and narrower 

 than the thorax, about 1 -8 times as long as broad ; basal tergite occupying more than one third 

 the total length, its hind margin truncate medially ; following tergite slightly longer than broad, 

 about 1-3 times as long as the basal tergite ; remaining tergites retracted. 



o*. Differs from the $ as follows : 



Antennal scape testaceous ; flagellum testaceous, only slightly darker dorsally. Scape 

 (Text-fig. 109) not reaching the median ocellus, its length distinctly less than the transverse 

 diameter of an eye ; combined length of pedicellus and flagellum about 1-25 times the breadth 

 of the head ; flagellum practically cylindrical, the first funicular segment a little stouter than 

 the others, distinctly stouter than the pedicellus, its segments subequal in length and i-6 to 

 2 times as long as broad ; clava about three times as long as broad, its length about equal to 

 that of the two preceding funicular segments together ; flagellum with short, whitish, sub- 

 adpressed hairs ; sensilla very numerous, in three rows on each segment. Scutellum slightly 

 more convex and slightly elongate. Fore wing rather less sparsely haired, there being a few 

 hairs between the base of the postmarginal vein and the stigmal vein ; the basal vein has 

 nought to two hairs. Gastral petiole with three to four hairs on each side. Gaster very much 

 shorter and narrower than the thorax ; fifth and following abdominal tergites more or less 

 retracted. 



The characters which distinguish glabrata from the other described European 

 species of the genus are given in the accompanying keys to males and females. 



Holotype^. Sweden : Halland, Enslov, 27.vi.1952, reared from galls of Melan- 

 agromyza simplicoides Hendel, (Dipt., Agromyzidae) on Populus tremula L. {Hugo 



