832 DIPTERA OF AUSTRALIA, 



pi. XVII., fig. 1; O.-Sacken, Berl. Ent. Zeits. XXVL, p. 89, 1882; 

 Studies, II., p. 203, 1887; Trentepohlia, Bergroth, Ent. Tidsk. 

 1888, p. 136, fig. 3 (wing). 



Two sub-marginal cells; the first very short ; second in immediate 

 contact with the discal cell, consequently the small cross-vein is 

 wanting ; marginal cross-vein situated before the inner end of the 

 first sub-marginal cell ; discal cell open or closed ; three or four 

 posterior cells ; anal cell closed ; auxiliary vein reaching costa 

 usually a very short distance before the tip of the first longitudinal 

 vein. Antennae 16-jointed. Tibiae without spurs ; tarsi without 

 empodia. 



I do not know sufficient about the species having only three 

 posterior cells to criticise the above synonymy, but accept them as 

 congeneric with those possessing four, on the authority of Dr. 

 Bergroth. Baron Osten-Sacken has more than once suggested the 

 relationship of Lirnnobia Trentepohli, Wied., and Cylindrotoma 

 alhitarsis, Dolesch., with Westwood's Mongoma, but the descrip- 

 tions appear too incomplete to satisfactorily decide. In the above 

 diagnosis I have combined the principal characters of the two 

 sections. 



In the species now described the tips of the auxiliary and first 

 longitudinal veins join the costa at rather widely separate points 

 (which also seems to be the case with T. exornata^ Bergr.), thus 

 differing from T. fragillima, Westw., and T. tenera and ^penm^es, 

 O.-Sack., in which they terminate close together. (PI. xxiv., fig. 

 59, forceps). 



Two specimens in the Macleay collection, from Fiji Islands, are 

 possibly distinct from T. australasice, but at any rate belong to a 

 closely allied species. The auxiliary and first longitudinal veins 

 are separated as in the Australian example; the prsefurca is rather 

 more than twice the length of the distance between the origin of 

 the third longitudinal vein and the inner end of the discal cell ; 



