Bithia. 529 



1. P. geniculatus Zett. 



1844. Zett. Dipt. Scand. III, 1039, 30 et 1859. XIII, 6081, 30 {Tachina). 

 — 1893. B. B. Denkschr. Akad. Wiss. Wien, LX, 139. — 1907. Kat. palåarkt. 

 Dipt. III, 415. — 1924. Stein, Arch. f. Naturgesch. 90, 6, 165. 



Of this species I know only the female. Frons much broader 

 than the eye, very protriiding. Head greyish silvery; frontal stripe 

 brown. Ocellar bristles parallel. Orbits with fine black hairs; jowls 

 hairy only below, Occipiit grey, with black hairs, and pale hairs 

 below, Antennæ black, third joint somewhat broad; arista thickened 

 in fully basal half. Palpi yellow. Thorax greyish or yellowish grey, 

 with four darker grey stripes as in Demoticus; sciitellum reddish 

 just at apex. Thorax black-haired. Abdomen all yellowish grey 

 pruinose, with large yellowish red side spots; it is black-haired; 

 second segment with a pair of marginal bristles, third with a pair of 

 discai and marginal and fourth with a pair of discai and a row of 

 marginal bristles. Legs black, apical part of femora, and tibiæ reddish. 

 Wings slightly yellowish tinged; veins yellow; discai angle rounded. 

 Squamulæ whitish with a yellow margin. Halteres yellow. 



Length 8 mm. 



P. geniculatus is very rare in Denmark, I know only one specimen, 

 a female, taken at Vedbæk many years ago (Stæger). 



Geographical distribution: — Northern and middle Europe 

 dow^n into Germany; towards the north to southern Sw^eden, and in 

 Finland. 



129. BitKia R. D. 



Species of medium size, greyish or yellowish pruinose, with red 

 spots on sides of abdomen. The genus is nearly related to Demoticus^ 

 and in many characters conform with it. Head a little broader than 

 thorax, convex behind and somewhat puffed out below, slightly 

 higher than long. Frons rather broad, broadest in female, rather 

 protruding. Jowls one third of the height of the eye or more. In both 

 sexes outwards directed ocellar and inner and outer vertical, in female 

 further two orbital bristles, the upper directed outwards. Distinct 

 postocellar and occipital bristles. Behind postocular bristles black 

 hairs. Frontal bristles not reaching end of second antennal joint, 

 all Crossing in both sexes. Cheeks bare, Vibrissæ not ascending. Eyes 

 bare. Epistoma slightly retreating, somewhat reflected and protruding 

 below. Proboscis rather long and slender; palpi thread-like, in female 



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