52 SYRPHID F, 
cox entirely pale yellow; front tarsi with the basal joint showing 
at the base a very conspicuous but short black stripe. Wings 
hyaline, with a faint yellowish tinge; subcostal cell very long, pale 
yellowish, but there is no distinct stigma; veins black, yellowish 
towards the base, the first being yellow throughout its whole 
length; third vein strongly bent backwards at the end, and _ there- 
fore ending be yond the tip of the wing, the submarginal cell being 
greatly dilated at the apex. 
Type d,a single specimen from Ruwe, Lualaba R., Belgian 
Congo, e/rca 11°S., 26° E., ii. 1906 (Dr. A. Yale Massey). 
A single badly-preserved male from Durban seems to belong to 
this or to a very closely allied species ; it has no black spot on the 
breast, and the hind borders of the abdominal segments are very 
narrow and linear 
46. Rhingia semicerulea, Arsten (1893). 
Distinguished by the zneous, partly czeruleous, thorax, and by 
the yellow, black-banded abdomen, the band on the second segment 
not being dilated at the sides. 
The determination is doubtful, because the specimens are not 
well preserved; the subcostal cell is distinetly yellowish, the legs 
are infuseated, the thorax, sides, and pleure are partly dark 
yellowish, the frons of the female is shining blue, but the antennal 
tubercle is yellow in front and black behind. 
A couple from Blantyre, Nyasaland Protectorate, 5.11. 1910 
(Dr. J. #. S. Old), the male with the proboscis accidentally pro- 
truding, measuring ‘9 mm. in length, while normally the probos scis 
is not longer than the snout: an immature female specimen from 
Zomba, Nyasaland (Dr. H. S. Stennus). The species was origin- 
ally described from Sierra Leone. 
47, Rhingia pellucens, sp. n 
é 9. Length of body 9 to 10 mm. 
Allied to the preceding, but distinguished by its smaller size and 
differently coloured thorax and abdomen. 
Head of the male almost entirely occupied by the eyes, which 
are united along a very long line, as long as 25 times the black 
vertical triangle, and have the upper facets very large and redder 
in colour than the others; eyes of the female with equal facets, 
parted by a broad frons which is blue, very glittering, with short 
dark hair, without any tomentum and with Phe ertecoal tuberele 
dark reddish yellow ; face and snout in both sexes and the bare 
frontal triangle in the male reddish yellow; peristoma yellow ; 
antenne orange-coloured, the third joint a little longer than broad, 
with a long es yellow arista, which is brown tomes the tip. 
Thorax shining blue or wneous in the middle, clothed with erect 
pale hairs in the male and with very short ones, inserted on small 
punctures, in the temals ; sites of thores broadly, and pleuree more 
