GERTRUDE RICARDO. DIPTEREN II. 405 



is only slightly darker on the posterior margins of segments 2 — 5, this description agrées 

 exactly with two females in Prof. DE Meijere's Coll., which may be regarded as a subspecies, 

 Silvius dimidiatus subsp. femoralis. 



The true S. dimidiatus is a handsome species easily recognised by the black posterior 

 band of thorax, the anterior half being yellowish, covered with yellow or grey hairs, and by 

 the yellow abdomen with black bands on the posterior segments. Legs blackish brown. OSTEN 

 SACKEN remarks it is not a true Silvius the antennae having a différent shape, and the eyes 

 showing a trace of a broad crossband, while known species of Silvius hâve greenish eyes dotted 

 with black. 



Silvius dimidiatus subsp. femoralis subsp. n. 

 Type from Regen Island. 



Agrées in ail respects with S. dimidiatus, with the exception of the colour of legs and 

 of abdomen. The femora are yellowish red, the tibiae obscurely yellowish brown, the tarsi the 

 same. Abdomen yellowish red, from the third segment onwards irregularly marked with reddish, 

 no black bands distinct. Length 13 mm. 



2. Silvius vittatus n. sp. 



Type (female) and others from Bivak Island, from Regen Island, and from Lorentz River. 

 A brownish species with a broad yellow tomentose stripe on the abdomen, the thorax 

 is also covered with tomentum of nearly the same shade. Length 1 1 mm. 



Face covered with pale greyish tomentum and a few whitish hairs in the middle. Palpi 

 reddish yellow, the second joint long, flat, ending in a fine point. Proboscis almost twice as 

 long as the palpi. Beard white. Antennae reddish yellow, black at base, the first joint small, 

 the second one cupshaped only half its length, the third broad on its basai part which is as 

 long as the first two joints together, the annulated apex narrow. Forehead broad, slightly 

 narrower anteriorly, a little darker in colour than the face, with a reddish brown narrow 

 callus almost reaching the ocelli. Eyes appear to hâve one or more greenish crossbands, as 

 in Silvius dimidiatus. Tliorax covered with greyish yellow tomentum, (in denuded spécimens 

 it is greyish) and with some scanty yellowish pubescence, chiefly appearing at sides and poste- 

 riorly; breast covered with grey tomentum, with grey pubescence. Scutellum same as thorax. 

 Abdomen a dark chestnut brown, the médian stripe composed of large semi-triangular spots 

 which are fully a third of the width of abdomen, forming a united stripe, those on the last 

 two segments are smaller and grey in colour, thèse spots are covered with yellowish tomentum 

 and with short yellow pubescence, which is very noticeable in denuded spécimens; underside 

 yellowish, covered with grey tomentum. Legs yellowish, the tibiae and tarsi rather darker, 

 the pubescence on coxae and femore yellow, elsewhere blackish. Wings clear, the stigma 

 yellowish brown, fore border very slightly tinged with yellow. 



3. Silvius de meijerei n. sp. 



Type and other females from Rivierkamp (Dr. Lorentz) and Digul River (Dr. Koch). 

 A brown species the base of abdomen and segmentations paler. Antennae red. Forehead 

 yellowish with a large oblong frontal callus. Length 1 1 '/ 2 nim. 



