128 DIPTERA OF AUSTRALIA, 



Hutton). In the 9 of M. costalis and M. Hehnsi, and in both 

 sexes of the remaining four species now described, the antennae 

 are short, about the length of, or a little longer than the head and 

 thorax taken together ; the first joint of the scapus obconical, not 

 unusually long or thick ; second joint small, short, cyathifoi'm ; 

 flagellar joints diminishing in length and thickness, beset with 

 minute hairs ; the first four or five joints elliptical, or sub- 

 cylindrical attenuate at the base ; the remaining six or seven 

 joints more or less linear, sometimes the last one (or even two) 

 minute (evidently subject to modification). Front broad, with a 

 tubercle or gibbosity anteriorly, which is more distinct in the ^ 

 than in the ^ ; in the ^ of J/, costalis the tubercle is very large 

 and hairy (PI. vi.. fig. 48) ; whilst in both sexes of i/. humilis it 

 is reduced to a scarcely perceptible gibbosity. Thorax elongate- 

 ovate, gibbose (densely haired in the ^ of M. costalis) ; meta- 

 notum convex; transverse suture distinct. Abdomen short, not 

 more than about twice the length of the thorax ; in ^ cylindrical ; 

 in 2 more stout ; the genitalia in both sexes inconsi)icaous, 

 narrow, only a little protruding (PL vi., fig. 50, ^ genitalia of 

 if. costalis) ; two very small valvules ai'e visible in the 

 terminal segment of the 9. Legs long and slender; fore tibite 

 with a single small spur, the intermediate and hind tibise each 

 with a pair ; tarsi considerably (especially the hind pair) longer 

 than the tibiae ; ungues small ; empodia present. Wings lanceo- 

 late ; anal angle usually inconspicuous, tolerably distinct in the ^ 

 of M. costalis. Auxiliary vein terminating in first longitudinal 

 vein at inner end of stigma ; the inner end of stigma thickened 

 (figured as a vein by Westwood and Jsennicke) ; first longitudinal 

 vein joining antei'ior branch of second longitudinal vein near the 

 base ; the latter branch not very obliquely situated ; rhomboid 

 cell small ; prsefurca usually longer than great cross-vein, in dii-ect 

 line with remainder of the second longitudinal ; inner end of 

 second submarginal and first posterior cells obliquely in line ; 

 second posterior cell petiolate ; discal cell elongate, pentangular, 

 usually in punctiform contact (at about 1 of its length) with fifth 

 posterior cell ; seventh longitudinal vein usually short and running 

 close to the margin, the most distant from it in M. costalis. 



