Ig Cyclorrhapha. 



Length 3,2—3,5 mm. 



This species is very characteristic and does not vary; it cannot 

 be confounded with any of the two other Danish species. 



L. tristis is much less common in Denmark than the other two, 

 but where it occurs it may be numerous; it was not known as Danish 

 until 1908; at Fure Sø and Faxe Ladeplads; on Langeland at Lohals, 

 and in Jutland in Vejle Nørreskov and at Hald near Viborg (the 

 author). My dates are ^^/e — '^k\ at Lohals I once took it in very 

 great numbers on a shaded, humid road in a wood, where it sat on 

 the ground; at Fure Sø I have taken it swarming low over the water 

 surface together with species of Hilara, and both sexes swarmed. 



Geographical distribution: — Europe down into Italy; towards the 

 north to southern Sweden. 



CYCLORRHAPHA. 



ASCHIZA. 



SYRPHOIDEA. 



Syrphidae. 



Head generally more or less semiglobular, short or somewhat 

 longer; it is as a rule a little broader than high, as broad as, or 

 generally a little broader than thorax; behind it is somewhat ex- 

 cavated, or it may be flat. The eyes are generally touching in the 

 male for a shorter or longer distance; sometimes they only meet in 

 a point, or they are not touching, only more or less approximated, 

 but always nearer to each other than in the female, in which sex they 

 are well separated. Vertex somewhat prominent, bearing three ocelli; 

 in the males with touching eyes it is triangular or more or less 

 elongated, sometimes long and narrow; in the females and in the 

 males with separated eyes the vertex and frons are evenly widening 

 downwards, in some cases the horders are almost or quite parallel, 

 and often in the male the upper part has parallel horders, and below 

 the rniddle a more rapidly widening begins. The vertex is more or 

 less hairy, but there are no individualised bristles (though in the 

 bristle-bearing species of Chilosia there may be some bristly hairs). 

 Frons generally more or less prominent, sometimes slightly or not at 



