250 NOTES ON AUSTRALIAN TABANIDAE, ii., 



joints clothed with short black hairs; third joint globose in profile, compressed 

 laterally. Palpi long and slender, clothed with numerous short black bristles. 

 Genae with long black hairs. Thorax : Dorsum of thorax with traces of golden 

 dusting, anterior two-thirds clothed with black hairs, posterior third and scutel- 

 lum with white hairs. Legs densely clothed with black hairs, knees pale. Wings: 

 Vein E. 4 without appendix but markedly geniculate. Abdomen long and narrow, 

 densely clothed with black hairs, excepting apes of segments one to six which 

 are white. 



Dimensions: ?. Total leng-th, 11 mm.; wing, 10.5; width of head, 3.80; 

 width of frons, 0.40. 



Type unique; in coll. Australian Institute of Tropical Medicine, Towns- 

 viUe, N.Q. 



Hab. — N. Queensland: Gordonvale, December (A. P. Dodd). 



This species appears to be most closely related to Silvius cUstinctus Taylor 

 (Bathui-st Island, Northern Territory) from which it is distinguished, int<er alia, 

 by the form of callus, presence of silvery pubescence on thorax and seutellum, 

 more sinuous vein R. 4, and much narrower white bands on abdomen. 



A male from Moa Island probably belong's to the same species, but as both 

 antennae are broken the identity is not certain. 



Silvius trtpherus Taylor. 



Silvius trypherus, Taylor, Proc. Linn. Soc. N.S. Wales, xl., part 4, 1915, p. 

 811. — Silvius elongatulus, Taylor, loc. cit., p. 812. — Silvius elongaitulus var. per- 

 simdUs, Taylor, op. cit., sliv., part 1, 1919, p. 43. 



We have had under examination a series of S. elongatulus Taylor, and of 

 S. elongatulus yar. persimdlis Taylor from Batchelor and Stapleton and also the 

 unique type of S. trypherus Taylor from Boorooloola. Included in the series 

 are specimens from Stapleton which were placed by Taylor in two series A and 

 B, no name being however attached. A. agrees with var. persimilis in that the 

 base of the abdomen is lighter in colour, while B. agrees with S. elongatulus. In 

 both cases there is, however, some difference in the shape of the callus. Examin- 

 ation of the series of elongatulus shows that the callus is variable in shape as is 

 also the amount of light colouration of the base of the abdomen. 



The type of jS*. trypherus Taylor has also been compared with the series and, 

 while at first sight the species a^jpears to differ from S. elongatulus in that the 

 callus seems broader and less prominent, examples occur in the series of S. 

 elongatulus in which the callus is exactly as in S. trypherus. One specimen has 

 the callus of S. trypherus and the abdomen of S. elongatulus var. persimilis. 



It seems evident therefore that these three names apply to only the one species 

 which is, however, variable in the exact shape of the callus and in the abdominal 

 colouration. 



The name trypherus has priority of one page over elongatulus. 

 Silvius lueidus Walker. 



Walker, List Dipt., 1, 1848, p. 140; Ricardo, Ann. Mag. Nat. Hist., (7), 

 v., 1900, p. 121 and (8), xvi., 1915, p. 260; Ferguson and Henry, Proc. Linn. 

 Soc. N.S. Wales, xliv., 4, 1919, p. 838.-6'. hackeri, Taylor, Proc. Linn. Soe. N.S. 

 Wales, xliv., 1, 1919, p. 45. 



The type of S. hackeri Taylor in the Queensland Museum has been examined 

 and compared with a specimen of 8. luridus Walk, from Kendall. The determina- 

 tion of the Kendall series was originally made by comparison of a specimen 

 with Walker's type. 



