LAMB—DIPTERA: HETERONEURIDA, ORTALIDA, TRYPETID A, SEPSIDA, ETC. 367 
Thorax. Quite smooth shining black clothed with fine black bristly hairs. 
Cheetotaxy normal, except that a small pair of d. c. bristles are visible in front of the 
usual last pair, and the tiny prescutellars are more visible. Scutellum somewhat brassy, 
its surface minutely granulate; the usual four bristles, 
terminal crossed. Wings, as Fig. 46, milky-white with 
pure white veins: the costa black bristled to just beyond 
the second vein, then slightly thickened to the fourth. 
Halters with long yellowish-white heads and _ slightly 
suffused stalks. The legs are black except the end of 
front coxze, front and middle trochanter, and the middle Fig. 46. Madiza albipennis, 
and last tarsi which are paler orange coloured except at eye 
the distal ends of each jomt. The hind femora are distinctly flattened: middle tibize 
with terminal spine. 

Abdomen. Shining black, last segment a little longer than others, all clothed with 
small moderately sparse black hairs: the long fleshy ovipositor is nearly half as long as 
the abdomen. 
Size, about 2°1 mm. without ovipositor ; wing, 12 mm. 
Locality. Seychelles. Mahé: Cascade Estate, at or above 800 feet. 
Rurcnorssa Loew, Wien. Ent. Monatschr., vi. (1862), p. 174. 
64. Rhicnoessa ferruginea, n. sp. (Fig. 47 and Plate 21, fig. 60). 
Head, distinctly concave behind in top view. Top view :—frons orange, slightly 
shining: ocellar triangle grey ; eye-margins and two fine frontal stripes more yellow, one 
outstanding lower f. 0. bent out, two upper f. 0. bent out and last somewhat back ; tiny 
bristles between the f. 0., and an inner row of small bristles from level of middle f. 0. to 
forehead. I. v. and o. v. on the back of the somewhat swollen vertex, finer convergent 
p- v. well down on back of head; two ocellar inserted nearer front than side ocellus, two 
small bristles between the hind ocelli, also between them and a few other bristles on the 
ocellar area; the yellow frontal lines bristled from the level of front of the ocellar triangle 
to lunule ; three pairs of these bristles are very much larger than others, and form three 
well-marked macrocheetal crossed pairs: a similar pair overhang the forehead. Front 
view :—the antennal bases touch, so that the yellow depression below lunule forms but a 
single shallow triangular depression, in which is a pair of small bristles; the yellow lip is 
arched and the clypeus very visible. Side view (Plate 21, fig. 60) :—antennee orange ; 
2nd joint bristled above, one being very long; 3rd a little darkened, disc-shaped ; arista 
with lower joint stout, orange, second less stout, black pubescent flagellum. Strong con- 
vergent true vibrissa on upper angle of mouth, followed by two large supplementary 
vibrissee and a few stoutish mouth bristles. Hind jowls bristly all over, especially long 
below mouth. Post-orb. row regular from middle of eye upwards, a few strong bristles 
behind v. b. Palpi orange, somewhat flattened laterally, slender and black haired : 
tongue orange. 
