8(j Syrphidae. 



hind metatarsi a little incrassated. Legs haired in the usual way, on 

 front feniora the hairs generally black, on posterior femora whitish, 

 but black at the tip; sometimes also paler on front femora; tibiæ 

 rnainly dark-haired, with short hairs, only a more conspieuous frlnge 

 above the hind tibiæ; the tarsi and ventral apical parts of tibiæ as 

 usual with short, adpressed, yellow pubescence, on the tarsi it may 

 be partly darker. Wings clear; stigma yellow to brownish black. 

 Squamulæ white to somewhat smoky. Balteres whitish to dirty yel- 

 lowish. 



Female. Antennæ larger and longer than in the male, the third 

 joint larger, and perhaps slightly longer than broad. Frons slightly 

 punctate, side dust spots small and not well defmed; frons black- 

 haired above the antennæ and in front of the ocelli, but yellow-haired 

 in the middle. Epistoma with white or greyish white hairs. Occiput 

 broad above and shining, all pale-haired. Eyes much shorter-haired 

 than in the male, the hairs brownish. Thorax with somewhat short, 

 quite pale pubescence. Abdomen with the spots generally larger than 

 in the male, rounded inwards but pointed outwards and thus trans- 

 versely pear-shaped ; they seem always to be present; the abdomen 

 is clothed with short sometimes quite white hairs, but generally the 

 hairs at the incisures black. Both thorax and especially abdomen 

 more coarsely punctate than in the male. Femora shorter-haired than 

 in the male, and all pale-haired and likewise tibiæ ; hind femora more 

 thickened than in the male. 



Length 6 — 8,5 mm, the latter size rarely reached. 



This species is I think most nearly related to P. noctiluca, but it 

 may generally be distinguished by the smaller size and clear wings 

 . which latter character I believe to be of some value; the colour is 

 often distinctly bluish, and the abdominal spots smaller; abdomen, 

 though coarsely punctate, is in both sexes more shining; the legs are 

 absolutely blacker, and finally the antennæ in both sexes shorter. — 

 I have foilowed the synonymi given in the Kat. palåarkt. Dipt., but I 

 have my doubts. Thus it seems that geniculata with its white-haired 

 face and clouded wings is more like signata than himaculata. Zetter- 

 stedt had received geniculata from Stæger; in Stæger's coUection there 

 are a male and two females; the male I consider as signata, the 

 feraales on the other hånd as noctiluca. Malm (1. c.) considered Zetter- 

 stedt's geniculata as lugubris, but he laid no stress at all on the ab- 

 dominal spots, a character which I think may be used to some 

 degree. Whether Verrall's himaculata is the present species I dåre not 

 say as he describes the wings as distinctly clouded; otherwise the 

 description is agreeing; on page 104 he declares that Meigen's type 



