290 STUDIES IN AUSTRALIAN MKroPTERA, i., 



well be mistaken for a hypopliarynx, but dissection soon reveals 

 their true nature. Labium (Fig. 8) with well-developed sub- 

 mentum (sm) and mentum (m), no palpi. The distal end of the 

 labium is produced into a very distinct proboscis, the two halves 

 of which are only partially fused; their distal portions form a 

 large bifid labellum (lb) carrying short hairs and bristles set in 

 conspicuous chitinous pits with raised rims. The proboscis is 

 probably formed by the two paraglossee. 



Thorax: prothorax rather small. Pterothorax large and 

 strongly built, the mesothorax larger than the metathorax. Legs 

 long and slender, the coxsb immense, the femora long and fairly 

 broad, the tibise long and slender, with a pair of short spurs at 

 the distal end; tarsi five-jointed, slender, the first joint very 

 long, claws and empodium small. 



Wings in repose held over the back of the abdomen in the 

 form of a steep roof or tent (much as in HemerohiidcB). Winy- 

 Tiiemhrane covered all over with an immense number of minute 

 hairs or microtricJiia., larger bristle-like hairs or macrotrichia are 

 present along all the veins, and also form a dense short fringe 

 all round the wing, but are absent from the wing-membrane itself, 

 except on the pterostigma, where they encroach slightly inwards 

 from the border. Venation (Text-fig. 1) open, regular, fore- and 

 hindwings subequal, the distal portions closely similar, but the 

 basal venations showing considerable dift'erences. Sc shortened. 

 A distinct but weakly chitinised pterostigma present between 

 the distal end of Rj and the wing-border. R2+3 unbranched, 

 and hence first apical fork absent in both wings {(if'. Diptera 

 Brachycera). Discoidal {dc) and median {mc) cells present, 

 closed. Second (Af^), third (Afg), and fourth (Af4) apical forks 

 present. Thyridium {t) at about middle of wing. Cubital fork 

 (cuf) near base; from it Cu^ arches up to fuse w4th the main 

 stem of M for some distance; this stem is continued in a direct 

 line by Cuj as a strong convex vein, while M arches away 

 from it anteriorly, branching into two at t. In hindwing, Cuo 

 fuses with lA soon after leaving cuf. Couplirig apparatus 0/ 

 wings (Plate xvii., tig. 10) consisting of a very distinct /re?m^Mm 

 (yr) in hindwing, formed of a small jugal process carrying two 



