338 



PERCY SLADEN TRUST EXPEDITION 



Notonaulax, Becker. 



Notonaulax Becker, Mitt. Zool. Mus. Berlin, ii., p. 153. 



45. Notonaulax trisulcata, n. sp. 



$, ?. Head. Frons brownish black with a brown antennal margin ; quite dull 

 except for a somewhat shining arched line from the ocelli to the eye-margins and an 

 abbreviated pointed mid-line down the small frontal triangle from the ocelli. Face, jowls 

 and palpi yellowish brown; mouth margin and tongue shining black. Eyes pubescent. 

 Antennse with the second joint concolorous with the margin of the frons, the third joint 

 much blackened, arista black and slightly pubescent. 



Thorax. Dorsum shining blackish brown, finely haired, slightly dusted, with three 

 deep sulci ; the central sulcus is punctate in one uniform row, the side sulci are more 

 widely punctate, the basal part having two rows of punctures side by side ; these side 

 sulci increase in breadth from about the level of the cross suture. Pleura same colour as 

 dorsum. Scutellum triangular, slightly flattened, same colour as the thorax, with black hairs : 



Fig. 23. Notonaulax trisulcata, n. sp., whig. 



Fig. '2i. Oscinis dissimilicornis, n. sp., wing. 



a deep cross groove demarcates it from the rest of the thorax ; there are about three 

 short stout marginal bristles on each side, which gradually decrease in size towards the 

 base, and a crossed terminal pah. 



Wings (Fig. 23) with dark brown veins. 



Halters yellow. 



Legs yellow with slightly infuscate hind femora ; the hind tibiae have on the upper 

 side a peculiar dusty "brand" on the middle line like that mentioned in H.femorata; 

 it is situated on about the middle third. 



Abdomen, either concolorous with the thorax or somewhat lighter at the base ; it is 

 clothed with fairly long hairs. 



Size. 2\ mm. 



Localities. Seychelles. Silhouette: high forest, 2000ft., VIII. — IX. 1908; Mare 

 aux Cochons and forest above, IX. 1908. Mahe" : from near Morne Blanc, about 800 ft., 

 X.— XI 1908 ; high forest of Morne Blanc and Pilot, X.— XL 1908 ; Morne Seychelles, 

 over 1500 ft., 4. II. 1909; Mare aux Cochons district, 1500— 2000 ft., I. — II. 1909; 

 Cascade Estate, about 1000 ft., 1909. 



