114 DIPTERA OF AUSTRALIA, 



06s.— Distinguished by the absence of yellow stripe on the 

 pleurfe, the uniformly coloured collare, structure of antennae, 

 sessile second posterior cell, &c. 



2. Antennce usually short, sometimes very long, normally 13- 



jointed, sometimes more, in both sexes. 



a. Genitalia protruding in both sexes. 



* Antennce serrate. 



Genus 13. Ischxotoma, gen. no v. 



First longitudinal vein incurved into the anterior branch of 

 second longitudinal near the base ; prasfurca short, but longer 

 than great cross-vein ; ultimate section of second longitudinal vem 

 arcuate, as in Holorusia ; second posterior cell petiolate. Eyes 

 rather large. Front moderately broad, with a distinct tubercle 

 anteriorly, above the base of antennae. Rostrum more or less the 

 length of the head, with a distinct, pointed nasus. Antennae short, 

 serrate, the length of head and rostrum taken together; 13-jointed ; 

 first joint of scapus and first flagellar joint long. Genitalia of $ 

 short, not incrassate, of rather simple structure ; 9 ovipositor 

 with rather short valves. 



Rostrum very minutely pubescent, as long as the head in /. 

 serricornis and /. par, shorter in /. ruhriventris ; the nasus very 

 prominent. Palpi long, the first three joints progressively increas- 

 ing in length, the fourth flagelliform. Collare slightly prolonged 

 into a short neck. Antennae with the first flagellar joint long, 

 cylindrical ; the following eight or nine progressively diminishing 

 in length and more or less distinctly produced beneath, very dis- 

 tinctly in /. serricornis and /. par (PI. vi., fig. 46); last two ternunal 

 joints small ; the joints only microscopically pubescent. Eyes ovate, 

 almost contiguous beneath (not so close in /. ruhriventris). Front 

 with a fulvous tubercle anteriorly. Thorax elongate-ovate, convex ; 

 transverse suture distinct ; scutellum small ; metanotum convex. 

 Abdomen long, slender, cylindrical, glabrous, or with only a very 

 minute pubescence ; $ forceps short, not wider than the preceding 



