300 Orthorrhapha brachycera. 



wards, and their apices are free^; thorax has, as usual, some short 

 bristles above; at the front edge of thorax there are two, long spiracular 

 tubes. Abdomen has seven pairs of small spiracles; the abdominal 

 segments have each, except the first, a girdle of small, flat, brown 

 spines above; the apex of adomen is bilobate. Laboulbéne notes that 

 the pupa rested in a cocoon, from which it worked half way out at the 

 time for the final development, and at the escape of the imago the 

 pupal skin remains sticking in the cocoon. Tlie cocoon was on the 

 inside clothed with a thin film. 



The species of Systenus have, I think, exclusively been found on 

 the ulcerative sap of trees as Fagus, Betula, Ulmus and Aesculus, and 

 the larvæ live in this sap and in the decaying wood, and here the 

 pupæ are also found. It is remarkable that the species have most 

 often been bred, and that all the known five species have been bred, 

 and one of thera, leucurus, is only known from bred specimens. 



Of the genus 5 species are known from the palæarctic region; 

 2 have hitherto been found in Denmark. 



Table of Species. 

 As there is every reason to believe that all five European species 

 occur in Denmark, since they have all been found in England, I shall 

 give a table over them all, chiefly after Verrall (1. c, 251); the two 

 species hitherto found in Denmark will easily be determined after 

 the table. 



1. Gubital and discai veins strongly approximated before 



the tip 2. 



— Gubital and discai veins almost parallel 3. 



2. Wings with a dark spot at the apex (only the male known) . . Scholtzii. 



— Wings with the apex uncoloured 1 . adpropinquans. 



3. Antennæ entirely black 4. 



— Antennæ with the basal joint conspicuously pale yellow. . tener. 



4. Third joint of the antennæ in the male conical and 

 broad, arista shorter than the third joint; hypopygium 

 small, with a long, black peduncle, outer lamellæ long, 

 forked, dirtily whitish; middle tibiæ in both sexes with 

 only two bristles at the base, hind femora with a blackish 



ring near the apex ^ hipartitus. 



^ The feniale of S. hipartius is not described, but according to Loew's remarks 

 under S.leucurus 1. c. it seems then to have been known to him; he gives the 

 distinctive character of the bristles on the middle tibiæ. and further he says 

 that the female of leucuru s has a longer third antennal joint, and a black arista: 

 it would thus seem, that hipartitus has another colour of the arista, but in 

 the description of bij)artitiis he says nothing of the colour of the arista. 



