390 PERCY SLADEN TRUST EXPEDITION 
fig. 38) :—the face is almost entirely occupied by a large broad knob or snout extending 
from the frons to the mouth-margin: this knob separates the antennee widely at the 
base. Side view (Plate 20, fig. 39):—sub-quadrate in form with a projecting frons on 
the edge of which the antennz are inserted. Jowls deep, the irregularly oval eyes 
projecting backwards over the head. Mouth-margin projecting, so that the face is 
concave in profile. Antennze with spine and hairs on second joimt, third jomt oval with 
a strongly pectinate arista bearing upper and lower rays, and a few short rays of the 
inner row. Vibrissa on side of snout with a row of long bristles above mouth-margin. 
Palpi flattened, paddle-shaped. 
Thorax. Fairly normal in shape: as far as the rather damaged state of the speci- 
mens permits, there can be made out the following bristles:—a hind pair of d. ¢., and 
another forward pair just behind the cross-sutural line: just across the suture are two 
more small bristles on the same d.c. line: acrostichals in two rather sparse rows. Two h., 
presut. just above them., n. p.; alar bristles not to be seen clearly, two long st. jo Wine 
scutellum has long terminal bristles crossed about two-thirds down, and long side bristles: 
the scutellum is evidently swollen. The wings are peculiar, Fig. 33: there is a very well- 

Fig. 33. Dettopsomyia formosa, n. sp. x 50. 
marked Milichid-like nick in the costa with two spines (such as in D. fracticosta, &c.), 
the end is pointed, the costa to fourth, all the veins much undulated, the second bends 
sharply up to the costa half-way between first and third. 
The abdomen and legs show no specially noteworthy characters. The whole 
insect (except the abdomen) is diversely and beautifully variegated. 
Type. The following species. 
47. Dettopsomyia formosa, n. sp. (Fig. 33 and Plate 20, figs. 36, 37, 38, 39). 
Head. Vertex; broad eye-margins shiny greyish-white, swollen behind ; bordering 
the eye-margin inside is a black line joining the black vertex behind, broader than the 
margin in front, narrower behind, in front each of these lines is divided into a short fork 
by two silvery-orange spots over the lunule ; the central area of frons orange-silvery with 
an elongate oval ocellar area which is black : it may also be described by saying that the 
frons is all black between the eye-margins except for an elongated horseshoe-shaped area 
from the antennze to the vertex, which 1s orange-silvery, as well as the above two orange 
spots. The facial knob is dark brown on top half, with a silver-orange dorsal spot, 
