BY R. J. TILLYARD. 553 



scuta and scutellse yellow, surrounded by black. Underside 

 greenish-yellow. Legs black; coxse and undersides of profemora 

 yellowish. 



A b d o m e n. — 1-2 swollen, 3-7 narrow, 8-10 broad and clubbed. 

 Colour : 1 black above, with a large triangular yellowish mark; 

 sides 3Tellowish : 2 with a suboval dorsal yellowish mark, some- 

 what contracted in the middle; sides yellowish; genital appen- 

 dages large, black; spurs rounded : 3-6 black, with a transverse 

 basal yellowish band; 7, basal third yellowish, rest black, the 

 yellow marking enlarged above and extending along the dorsal 

 ridge to a sharp point at anal end of segment : 8 black; on each 

 side, low down, a basal yellowish spot : 9-10 black. 



Appendage s. — Superior 1 mm., wide apart, parallel, 

 subcylindrical, fairly thick, ending outwards in a small spike; 

 bright yellow, bases black. Underneath is a curved blunt 

 hooked tubercle. Inferior very short, one-third as long as 

 superior, bifurcate, the two parts wide apart; blunt, curved 

 upwards in a hook, so as to meet superior near bases; black, 

 separated by a brownish tubercle on 10. 



5. A similar but slightly larger insect; total length 47 mm.; 

 wings often tinged with pale brownish. Differs from $ as 

 follows : — Abdomeri much thicker, subcylindrical, not clubbed; 

 no spurs on 2; 10 short, swollen below appendages into a rough 

 blackish tubercle. 



Appendages. — 0.8mm., conical, slightly separated and 

 inclined towards one another, tips with a sharp spike on the 

 outer margin, blunt inwards, touched with black. Colour 

 yellow. 



Hab. — Kuranda, N.Q.; January; local. 



Unlike the two preceding species, this one is never found 

 along the banks of the main river, but is confined to a few densely 

 wooded mountain creeks in its vicinity. It is extremely local, 

 but abundant when it occurs. It has a fast zig-zag flight, and 

 is fond of sitting on leaves of trees or grass stems. It takes 

 alarm very easily, but is not difiicult to capture. 



