330 PERCY SLADEN TRUST EXPEDITION 
? Head. Eyes bare. Top view :—frons slightly narrowing in front, about half width 
of head at back, dull black from the vertex forward, brown-orange from the forehead back- 
wards, the colours merging in two indistinct boundary lines from ocellar area to outer edges 
of lunular boundary. Eye-margins broad and shining black from front f. 0. to vertex and 
back of head. Front f. 0. sub-parallel and forwardly bent, hind f. o. divergent and back- 
wardly bent, inserted rather close together ; a row of fine bristles extends from latter to 
forehead, the first, between the two f. 0., being the longest. Convergent i. v., divergent 
0. v., p. v. crossed at tip, oc. inserted between basal and front ocelli, long and divergent. 
Post-oc. rows evident. Front view :—antennz touching basally ; a well-marked snout 
or keel extending from the base of the antennz to two-thirds down face, widening to 
the end which has a rounded margin : face black, with sparse pale orange pollen, the 
snout much more orange, clypeus prominent. Side view (Plate 19, fig. 16) :—antennze 
darkened orange, 2nd joint with a large basal bristle and a smaller bristle in front ; 
3rd joint silky, arista orange with darker rays, the top row with 5 progressively 
smaller rays; bottom row with one ray between 3 and 4 on top; one end ray, a few 
fine rays of the inner row. There is a stout vibrissa close to the eye-margin followed 
by a row of smaller ones on the darkened jowl; hind jowls orange with 2 or 3 bristles; 
palpi clubbed, flattened, black, with a few short bristles: tongue more orange. 

Fig. 17. Drosophila fracticosta, n. sp. x 20. 
Thorax. Dorsum, scutellum, and pleura above a line from. the wing base to 
below the humeral calli and the metanotum, all intensely black; the dorsum very 
shining, other parts duller, humeri slightly orange in tone, duller ; scutellum minutely 
granulate: lower pleura and sternum entirely pale yellowish-white. Only the last ~ 
pair of d. c., two h., n. p., three bristles over wing base, one large and one small 
st. p.; the dorsum all covered with fine bristles; the acrostichals form about eight 
rows between d. c., but are entirely the same in character as the rest of the small 
bristles. The scutellum is rounded in outline and swollen in profile; the terminal 
bristles just cross at tip, small side bristles inserted somewhat nearer the terminal 
bristles than to the base. 
Wings, Fig. 17, yellow with yellow veins: the costal slit is very marked, and 
ends in a black callosity provided with spines, and turned over so as to lie roughly 
perpendicular to the plane of the wings. Costa to 4th vein. Halters with black knobs 
and pale stalks. Legs entirely whitish-yellow: the front femoral rows weak, one 
spine at end of middle tibia. 
