168 



Syrphidae. 



beneath, the short hairs here all yellow, or a couple of black at the 

 apex. Wings soraetimes darker than in the male. 



Length 8—9,5 mm. 



This species is similar to chloris, but, however, distinguished with- 

 out difficulty; chloris is a larger and, especially in the male, less 

 broad species; it has both eyes and body longer-haired, thorax more 

 finely punctate, epistoma of another shape, all tibiæ with distinct, 

 black rings, the arista yellow at base, and fmally it has no thoracai 

 or scutellar bristles, while fraterna has always at all events distinct 

 postalar bristles; in the female chloris has a larger and brighter third 

 antennal joint. — According to Zetterstedt the name dimidiata was 

 due to Stæger. 



C. fraterna is rare in Denmark; Ordrup Mose (Stæger), Geel Skov, 

 Nøddebo (the author) ; on Lolland at Nysted and in Kældskov (L. Jør- 

 gensen), and in Jutland at Allerup in Vendsyssel (Esben Petersen); 

 in all only eight specimens. My dates are only ^^k — ^/e. 



Geographical distribution: — All Europe down into Italy; towards 

 the north to middle Sweden (after Wahlgren, Zetterstedt only records 

 it from Denmark, but according to Becker (1. c. 247) a female of 

 Zetterstedt's flavicornis was fraterna): recently it is also recorded from 

 Finland. 



20. C. Bergenstammi Beck. 



1894. Beck. Nov. Aet. Leop. Carol. Akad. LXII, 462, 102, Fig. 55. — 

 1901. Verr. Brit. FL VIII, 250,21, fig. 228. ~ 1907. Kat. palaarkt. Dipt. 

 111, 23. 



Male. Eyes with somewhat long, yel- 

 lowish brown hairs, disappearing at the 

 lower end. Frons a little pruinose, with a 

 shallow longitudinal groove not reaching 

 the top. Vertex yellow-haired, just in front 

 with some black hairs; frons with mixed 

 black and yellow hairs. Epistoma slightly 

 pruinose, shining, most pruinose below the 

 antennæ; it is hollowed below the antennæ, 

 the central knob not large, somewhat pro- 

 minent: between the knob and the mouth 

 edge the epistoma a little hollowed, the 

 lower part somewhat protruding and des- 

 cending. Eye-margins of medium breadth, 

 a little pruinose, with short, yellow hairs. Occiput grey pruinose, this 

 colour stopping below the eye; the hairs yellow, or below more 



Fig. 84. Head of 

 C. Bergenstammi d". 



