GENUS OF SHORT-BEAKED GNATS. 191 
rounded. The antennez arise close together at the anterior end, 
each on a small prominence. They are slender and somewhat 
depressed, each bearing at the tip three stout and rather lengthy 
chetz. Pressed backwards in their natural attitude of repose their 
tips lie opposite the ocelli, which are dark, very minute, and circular 
in outline. They are situated on the dorsal surface near the lateral 
margin. There are no compound eyes. Fine sensory hairs are 
arranged as follows on the dorsal surface of the head: one on each 
side a short distance behind the base of each antenna, one just outside 
each eye, and a row of about five parallel to the lateral margin, a short 
distance in front ofeach eye. There is an S-shaped row of short, stout, 
simple chetz on each side of the head, commencing on the dorsal 
surface a short distance behind the eye and curving down on to the 
ventral surface. Immediately posterior to the bases of the antenne, 
on the middle line of the ventral surface, there is a bunch of slender 
pectinate chetz which probably can be extended forwards, but in 
my specimens is folded backwards. The mandibles bear at the 
anterior end of their inner margin two stout rather blunt teeth, the 
outermost of which is the smaller of the two. Below these and on 
a different level six other teeth form an uninterrupted series, the 
first being the largest, the sixth the smallest, and the others subequal. 
Below the teeth there is a little T-shaped projection. The maxilla 
is rather slender and deeply notched on its free margin. The whole 
appendage is covered with minute chitinous projections. Two large 
cheetz are borne above the notch (the uppermost béaring a short 
subsidiary tooth on its upper margin) and two below it, the latter 
pair being very unequal in size. The lower lip is rather narrow, 
and the teeth on its anterior margin are slender, the central tooth 
being larger than any of the others, which are arranged approximately 
large and small alternately. There is a semi-circular row of stout 
simple bristles at the base of each maxilla, and at each side of the 
lower lip there are three sensory hairs, one situated near the end of 
the lip, the other twe arising together some little distance posteriorly. 
All the segments of the thorax are distinct and transverse. As 
seen from above, they have an irregularly hexagonal outline, and are 
produced to a point at each side, both the anterior and the posterior 
margins being sinuous, or (in the case of the posterior margin of the 
third segment) distinctly excavated in the middle. Each joint bears 
on the lateral point a bunch of long simple bristles. 
The first segment of the abdomen, which consists of nine true 
segments, is broader than any of those of the thorax and more 
markedly produced at the sides, but otherwise resembles them. 
The succeeding joints are narrower and less distinctly hexagonal in 
dorsal profile. With the exception of the ninth, they bear a bunch 
of simple bristles at either side. The siphons are stout, of moderate 
length, and closely welded. together ; apparently they lie almost 
in the same line as the abdomen. They are provided round their 
