116 PERCY SLADEN TRUST EXPEDITION 



frontal row placed beneath the outer but not so near the eye margin, upper pair of supra- 

 antennal bristles much wider apai-t than the but little smaller lower pair. 



Thorax greyish-black, scutellum with only two distinct bristles, pleurae brownish- 

 black, mesopleura with one long stout bristle and a number of minute ones. 



Abdomen dull black, hypopygium greyish with a long curved bristle on each side 

 near the base and a long yellow anal organ. 



Legs yellow, hind legs somewhat brownish, front tarsi long, cilia to hind tibiae 

 indistinct. 



Wings quite clear, much as in innocens but costal ciliation shorter, thin veins very 

 faint. Halteres blackish. 



Length about I mm. 



Locality. Mahd : Cascade Estate, about 800 — 1500 feet. One male. 



Note. One male specimen, gummed to card, from the same locality, like invenusta has 

 dark halteres and bristly mesopleura though I cannot trace the long stout bristle, but is 

 not much more than half the size of that species, has a narrower frons, wings not so clear, 

 thin veins moi'e distinct, slightly longer costa, subcostal vein not ending quite so near the 

 fork and is probably a distinct species. 



18. Aphiochceta media, n. sp. 



$. Frons greyish-black, about as wide as long, bristles normal though the outer 

 bristle of lower frontal row is placed somewhat above the inner, uppei' pair of supra- 

 antennal bristles wider apart tlian the smaller lower pair, antennae small, yellowish, 

 obscured above, palpi yellow. 



Thorax bx'ownish-yellow, with only two scutellar bristles, pleurae yellow, mesopleura 

 bare. 



Abdomen dull black with very narrow whitish -yellow hind margins to all segments, 

 and the basal and discal portion of ail segments more or less brownish-red, hypopygium 

 small and greyish, anal organ stout and yellow. 



Legs yellow with hind knees obscured, front tarsi slender, hind femora with a few not 

 very long hairs beneath at base, cilia to hind tibiae inconspicuous. 



Wings with a yellow tinge, venation much as in innocens. Halteres yellow. 



Length about '7 b mm. 



Locality. Mahe : Cascade Estate, about 800 — 1500 feet. Two males. 



Note. Two specimens. No. 1 from Mahd, Cascade Estate, about 800 feet and over, 

 and No. 2, also from Mahe, Cascade Estate, though having pale halteres and bare pleurae 

 differ from media in their darker colour, and rather longer costa and from each other in 

 that No. 1 has a dull abdomen, somewhat stout front tarsi, longer costa with longer and 

 more scanty ciliation and subcostal vein ending only slightly more than half-way between 

 humeral cross-vein and end of costa ; while No. 2 has somewhat shining abdomen, and 

 subcostal vein ending much nearer to end of costa than to humeral cross-vein. 



19. Aphiochceta latinervis, n. sp. (Plate 5, fig. H). 



$. Frons greyish-black, longer than wide, inner bristles of lower frontal row placed 



