310 Orthorrhapha brachycera. • 



fresh parts, they are thiis phytophagous ; in winter they go dowii 

 into the root, and in next spring they go again up into the growing 

 stalk. When the larva is ready for pupation, it forms a cavity and 

 eats a transverse canal out towards the surface, so that here a 

 round hole is formed, only covered by the dermis of the stalii. The 

 pupa rests in the cavity, and when time for escape comes, it works 

 out through the weak covering of the hole, and here the pupa-skin 

 remains sticking in the hole, while the imago escapes. 



There is no doubt that the species bred by Lubben is T.smaragdinus. 

 and its larva thus evidently lives in the stalks of Phragniites ; but the 

 occurrence of a peripneustic larva in the family of the Dolichopodidae 

 or upon the whole in the Orthorrhapha brachycera is so astonishing 

 that I cannot but think, that there may be some mistake, either with 

 regard to the larva, or with regard to the description of the tracheal 

 system. 



The female, according to Lubben, deposits the eggs in the stalks 

 of Phragmites by aid of the strong ovipositor; as T. hellus has a 

 similar ovipositor, it no doubt lives as larva in a similar way. As 

 said, the larva hibernates in the Phragmites in about half-grown 

 condition, and the further development and transformation to pupa 

 and imago follow in next spring or summer. 



The known species of Thrypticus are found on meadows, and in 

 fens and at streamlets with reeds. 



Of the genus two species are known from the palæarctic region, 

 but according to Verrall (Ent. Month. Mag. XVI, 1905, 83) and Loew 

 (1. c.) one or two more may exist, yet undescribed. One species has 

 been found in Denmark. 



1. T. bellus Loew. 



1869. Loew, Beschr. eur. Dipt. I, 303, 181. — 1903. Kat, palåarkt. 

 Dipt. II, 326. 



Male. Vertex and frons metallic green. Epistoma somewhat nar- 

 row, metallic green, a little pruinose on the lower half. Palpi dark, 

 Occiput greenish; postocular bristles yellowish. Ocellar and vertical 

 bristles blackish or brownish, somewhat yellowish shining. Antennæ 

 short, black, third joint roundish; arista apical. Thorax green or 

 bluish green, slightly brownish pruinose, shining; all bristles yellow. 

 Pleura green, slightly brownish pruinose, especially downwards. Ab- 

 domen green or slightly bluish green; it is clothed with short, yellow 

 hairs, and has very short hindmarginal bristles, slightly longer on the 

 first segment. Venter greenish. Hypopygium green, the ventral lobes 



