314 Transactions. 



margin (which projects as a short snout in bilineata) ; posterior femora 

 thickened and with an inferior triangular tooth near apex (in bilineata there 

 is no triangular tooth, but a pronounced bristly swelling). 



T. bilineata White. (Plate XLIX, fig. 3.) 



Milesia bilineata White, Voy. " Erebus " and " Terror " (?) ; Walker, 

 Cat. Dipt. Brit. Mus., p. 566 (1849) ; Hutton, Cat. Dipt. N.Z. 

 p. 43 (1881) ; Trans. N.Z. Inst., vol. 33, p. 40 (1901). 



A large elongate blackish fly with a pair of stripes on the dorsum of 

 the thorax. 



$. Eyes bare, moderately dichoptic ; ocellar triangle elongate, blackish- 

 brown with blackish-brown hairs ; ocelli situated well forward ; vertex 

 and upper part of front dullish black ; lunular area and lower part of 

 front shiny black, the latter region brownish centrally ; across the front 

 and separating the black into two areas is a tawny band as shown in 

 fig. 51. The front anteriorly is cone-shaped and prominent ; in profile it 

 descends steeply to the prominence, which is more or less horizontal, thus 

 forming an angle with the more oblique upper part (fig. 52). Vertex and 

 upper black area of front clothed with black hairs ; the tawny band with 

 yellow hairs. Antennae inserted close together at about middle line of head ; 

 black and comparatively large ; 1st joint short and bristly, 2nd triangular, 

 bristly and with a long inferior bristle, the anterior margin forming three 

 blunt processes for the reception of the 3rd joint, which is orbicular, and 

 greyish-pruinose ; arista black and long, bare distally but minutely pubes- 

 cent proximally. Face vertical though somewhat receding and projecting 

 abruptly to form a short snout at oral margin (fig. 52) ; lower margin of 



Fig. 4. — Tropidia bilineata : wing. 



head almost horizontal but descending slightly at anterior oral margin ; 

 face with a shiny black median stripe and black areas along oral margin, 

 otherwise tawny with brownish reflections and clothed with short delicate 

 pale hairs ; arrangement of colour-pattern shown in fig. 52 ; cheeks tawny 

 and bearded with white hairs ; an indistinct crescentic blackish reflection 

 at lower corner of eye ; a tawny spot on oral margin below cheeks ; 

 proboscis and palpi blackish-brown, the labella large and deeply bi-lobed ; 

 occiput greyish or whitish yellow with blackish reflections ; somewhat 

 swollen and hairy below, but slightly concave and bare above. 



Thorax rectangular ; dorsum with 3 black longitudinal stripes, the median 

 one forked ; except for black areas the dorsum is tawny, with greyish 

 reflections ; colour-pattern shown in fig. 54 ; alar regions clothed with 

 long golden hairs, dorsum clothed with short brownish hairs ; scutellum 

 shiny blackish-brown and clothed with long brown hairs. In front of 

 the mesopleurae the sides of the thorax are hollowed apparently for the 

 reception of the anterior femora ; pleurae for the most part black, golden- 

 pruinose, the sternopleurae with a golden pubescent area above ; the 



