BY FREDERICK A. A. SKUSE. 829 



hexagonal, longer than wide ; the great cross-vein situated at or 

 beyond the middle of its length ; fifth, sixth and seventh longitu- 

 dinal veins gently arcuated ; the last short, scarcely reaching to 

 one-tbird the length of the wing. 



345. Rhabdomastix Osten-Sackeni, sp.n. (PI. xxii., fig. 15). 



^.— Length of antennae 0*250 inch ... 6*34 millimetres. 



Expanse of wings 0-180 x 0-040 ... 4-56x1-01 



Size of body 0-145x0-020 ... 3-66x0-50 



Front dull brown ; rostrum brownish or ochreous-brown ; palpi 

 and antennae brown, the latter nearly twice the length of the body. 

 Thorax dull brown, the scutellum sometimes more ochreous-brown. 

 Halteres long and slender, brownish. Abdomen brown, clothed 

 with short brownish hairs ; forceps brownish-ochreous. Legs 

 brown or ochreous-brown, with a light sericeous reflection in a 

 certain light ; the tarsi white. Wings pellucid, almost hyaline, 

 glabrous, granulate on account of being covered with microscopic 

 dots which represent rudimentary pubescence ; margaritaceous 

 reflections ; veins greyish-brown. Auxiliary vein reaching costa 

 at a point not quite half the distance from origin of second longi- 

 tudinal vein to inner end of second sub-marginal cell ; preefurca 

 almost imperceptibly bent at its origin, almost straight, nearly 

 equal in length to the remainder of the second longitudinal ; the 

 third longitudinal and following veins at apex of wing all gently 

 arcuated posteriorly. 



Hah. — Berowra, N.S.W. Three specimens in August (Masters 

 and Skuse). 



Obs. — I have named this species in honour of Baron Osten- 

 Sacken, who has so greatly advanced Dipterology ; especially by 

 his unsurpassed knowledge of, and excellent publications, onTipu- 

 lidse. 



