100 DIPTERA OF AUSTRALIA 



posterior cell petiolate. Front broad, slightly gibbose anteriorly. 

 E/Ostrum very short, arched in front, with a short obtuse nasus. 

 Antennce 7-jointecl (1 in both sexes), shorter' than the head. Palpi 

 with the last joint short. Genitalia in both sexes inconspicuous. 



Rostrum not half the length of the head ; nasus obtuse, hairy ; 

 palpi short, the last joint about the length of the third or 

 shorter (PI. vi., fig 38). Antennae somewhat shorter than 

 the head ; 7-jointed (1 in ^) ; first joint of scapus stout, cylin- 

 drical, more than ^ length of entire antennae, second somewhat 

 narrower, elongate, cyathiform ; fii'st flagellar joint as long as, 

 but somewhat narrower than, second joint of scapus (rather 

 longer and narrower in S. imperatoria), obovate ; remaining 

 joints linear (PI. vi., fig. 37). Front broad, a little gibbose 

 anteriorly above the antennae. Thorax large and gibbose, con- 

 siderably larger in ^ than in the ,^ ; suture distinct ; abdomen less 

 than twice the length of the thorax, robust, clavate, the second 

 segment truncate-conical ; thii'd to fifth segments wide, short ; 

 the rest short, diminishing in width ; genitalia in both sexes 

 inconspicuous, diflicult to study in dried specimens. Legs long 

 and slender ; in the ^ the tarsi more than twice the length of the 

 tibipe, in ^ less than twice their length ; tibife armed with a pair 

 of short spurs ; ungues strong, hooked ; erapodia distinct. Wings 

 large, divai'icate, shorter and nari'ower in the ^ than in the 9 j 

 anal angle most distinct in the Q, not so prominent in the ^. 

 Auxiliary vein reaching the first longitudinal in S. ducalis before, 

 in S. impteratoria opposite, inner end of first posterior cell, con- 

 nected at the tip to costa by a cross-vein ; the ultimate section of 

 the anterior branch of the second longitudinal appearing as a 

 continuation of the first longitudinal ; second posterior cell petio- 

 late ; discal cell oblong, pentangular, in punctiform contact with 

 fifth postei'ior cell, or connected to it by a very short vein, about 

 the middle of its length. 



408. Semnotes ducalis, Westwood. (PI. v., fig. 14.) 



S. ducalis, Westw., Trans. Ent. Soc. Lond. p. 502, pi. in. fig. 

 2a, 1876. 



