Trixa. 417 



sexes ocellar and inner vertical bristles, in female a number of orbitals. 

 Behind postocular bristles black hairs. Frontal bristles reaching just 

 below insertion of antennæ, an upper oiitwards directed bristle in 

 female. Cheeks bare. Vibrissal ridges not sharp, converging below 

 and thus epistoma of oval sliape; vibrissæ fine, pluriserial, ascending 

 to the end of antennæ; no large vibrissa on the angle. Eyes bare. 

 Epistoma slightly retreating, st'rongly carinate; oral aperture rather 

 small. Proboscis quite short and clypeus small, horse-shoe-shaped. 

 Palpi clavate in male, in female shorter and bulbous. Antennæ in- 

 serted much below middle of the eye, short, not reaching half way 

 to end of epistoma, third joint about as long as second; arista with 

 second joint short. Thorax a lit tie rectangular; four postsutural 

 dorsocentrals and only the posterior pair of præ- and postsutural 

 acrostichals; no præsutural intraalar bristle and only two postsutural. 

 Scutellum with four or five marginal bristles on each side, the apical 

 diverging. Three sternopleural bristles discernible among somewhat 

 strong hairs. Pteropleura with a bundle of somewhat long hairs above. 

 Abdomen somewhat short, ovate; excavation on second segment 

 not reaching hind margin; there are discai and marginal bristles, 

 also on second segment; fifth segment with bristles all over. Legs 

 long, especially tarsi long, with long joints; claws and pulvilli some- 

 what strong in both sexes, most in male. Wings with first posterior 

 cell open, ending near apex of wing; discai angle obtuse, with a 

 short veinlet; no costal spine. 



The biology is not known, but some species f. inst. alpina are 

 recorded to be larviparous and depositing on dung, and they are 

 supposed to be parasitic on coprophagous Scarabæid larvæ; Brauer 

 found oestroidea depositing larvæ under grass. Meade records the 

 latter as bred from Cheimatobia boreata, but the statement seems 

 doubtful. 



Of the genus 5 European species are recorded, one occurring 

 in Denmark. 



1. T. alpina Meig. 



1824. Meig. Syst. Besclir. IV, 223, 1. — 1862. Schin. F. A. I, 446. — 

 1889. B. B. Denkschr. Akad. Wiss. Wien, LVI, 108, Tab. VI, Fig. 109. — 

 1896. Pand. Rev. Entom. XV, 94, 1. — 1907. Kat. palåarkt. Dipt. III, 438. 



— 1924. Stein, Arch. f. Naturgesch. 90, 6, 179. — T. coerulescens Meig. 1824. 

 1. c. IV, 224, 2, Tab. XL, Fig. 16. — T. fermginea Meig. 1824. 1. c. IV, 224, 4. 



— T.lapponica Zett. 1838. Ins. Lapp. 629, 1. — T.limhata Zett. 1838. 1. c. 

 630, 3 et 1844. Dipt. Scand. III, 1200, 1. — 1862. Schin. F. A. I, 447, nota. 



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