LAMB—DIPTERA: HETERONEURIDA, ORTALIDA, TRYPETIDA, SEPSIDA, ETC. 327 
on hind and mid tibie, front femora with a few longer fine bristles beneath and 
outside. 
Abdomen. The ground colour is yellow, the second segment is bristly only on 
its upper angles and margins and is silvery; third pale yellow, rather silvery, with 
long marginal and a few scattered discal bristles ; fourth with three large black marks, 
the side ones extending right over the edges and from front to back, the middle 
also extending from front to back, hence the orange-yellow ground only shows as two 
rather irregular dark orange lines; the three black bars are nearly equal in width: 
the fifth segment has also three marks, the middle extending right across, the side 
ones sometimes only reaching over the side margins and not front and back: sixth 
segment with a small dark central spot. These last three segments have long scattered 
dorsal and longer marginal bristles. 
@ The female differs in its colour scheme as follows. The thorax is more or 
less silvery in side view on tip, but always quite visibly so on the sides of the thorax, 
and on the upper part of the pleura. The dorsum is brownish orange, darkish, with 
two dim darkenings forming side stripes along the d. c. lines, and darkened again 
before scutellum. The latter is darkened except at the tip which is white. 

Fig. 14. Drosophila sericea, n. sp. x 25. 
The abdomen has its second segment creamy with large dark triangular spots 
occupying the sides and most of the lower margins, but well separated distally on the 
centre line. The next two segments have the orange ground much covered with black 
somewhat shining colour forming two large side and one large middle mark, both 
extending from margin to margin: these segments could also be collectively described 
as being shining black with two orange stripes separating three broader black ones. 
The fifth segment has three spots like the male, as has the sixth segment, the last has 
two large side spots with a narrow line between. 
A certain amount of variation occurs, the blackening being variable in extent in 
both sexes. 
Size, 25 mm. ; wing, 24 mm. 
Localities. Seychelles. Silhouette: forest near Mont Pot-d-eau, ca. 1500 feet, 
VIII. 1908 ; Mare aux Cochons, IX. 1908. Mahé: Cascade Estate, ca. 800 feet and 
over, 1908—9; Morne Seychellois, over 1500 feet, II. 1909; high forest of Morne 
