108 Tachinidae. 



on second segment, so that a laterally deeply incised middle line is 

 formad. 



Length 6—7,5 mm. 



G. rotundatum is somewhat rare in Denmark ; Dyrehaven, Tisvilde, 

 Rørvig; on Funen at Odense and in Jutland at Sønderborg, Hørup- 

 hav, Sandager, Funder near Silkeborg and Rebbild; the dates are 

 19/g — 28^^_ j^ occurs on various flowers. The species is known as 

 parasitic on Palomena prasina^ Chlorochra juniperina^ Piezodorus 

 literatus and Rhaphigaster nehulosa. Nielsen has (Vidensk. Medd. fra 

 Dansk Nat. Foren, 67, 1916, 18) treated its biology; he found the 

 eggs on Chlorochroa^ in September; the eggs are laid in various piaces 

 on the host; the larva hibernates in second stage and bores out in 

 next spring; only one yearly generation. The host survives the boring 

 out of the parasite. 



Geographical distribution: — Europe and in Turcomania; to- 

 wards the north to middle Sweden, and in Finland. 



8. Cystogastep Latr. 



Smallish species, very similar to G. rotundatum. The genus is 

 also very nearly related to Gymnosoma, and in most characters 

 conform with it. The differences are: Frons above a little narrower 

 and about equal in both sexes. Orbits bare in both sexes. Vibrissal 

 ridges broad and flat, the vibrissæ a little ascending and not smaller 

 upwards, the lower above lower margin of epistoma. Antennæ short, 

 only reaching to the middle of epistoma, third joint slightly longer 

 than second; arista short-pubescent, second joint slightly elongated. 

 Femora without spinules below, otherwise legs as in Gymnosoma 

 without bristles, no ventral bristle either on middle tibiæ in both 

 sexes; claws and pulvilli in male only slightly elongated, nearly 

 equal in both sexes. Wings with first posterior cell longer petiolate, 

 ending at apex of wing; posterior cross-vein near middle between 

 medial cross-vein and angle. 



The species is known as parasite on Aelia acwmma/a-imagines; 

 it belongs to Pantel's group 1. 



Of the genus only one species is known, also occurring in 

 Denmark. 



1 The author states that he did not breed the fly, but that he had taken 

 it earlier in the year in the same locality, and that the larva behaved 

 quite in the manner known for the Gymnosoma. 



