External Structure of a Mosquito (Scales'). 11 
scales, no curved narrow ones being present, but differ from 
Megarhinus in that they have upright forked ones as well ; this 
head ornamentation is persistent and very striking, and I have 
taken it as a character by which .certain members of the old 
genus Gulex can be isolated from that genus and grouped 
together in the new genus Stegomyia (Fig. 9, A). The cephalic 
scale structure does not require a high magnifying power to 
discern, it may be even made out by means of a strong Cod- 
dington lens, although microscopic examination is essential for 
every species for its proper identification and description. By 
this and other characters a number of closely related Culices , of 
which C. fasciatus , Fabricius can be taken as the type, are 
grouped together. 
(2.) Scales On the thorax. —The thoracic scales are in five 
distinct forms :— 
(a) narrow hair-like curved scales (Fig. 8, 4). 
((3) narrow curved scales (Fig. 8, 5). 
(y) spindle-shaped scales (Fig. 8, 6). 
(S) flat scales (Fig. 8, 1). 
(e) long twisted scales (Fig. 8, 10). 
The first (a) are very thin and always curved, and often form 
a dense felting over the mesothorax ; in colour they are mainly 
brown, golden-brown, reddish-brown, golden or yellowish, and 
they usually lie all in one direction. 
The narrow curved scales (/3 ) may occur all over the meso¬ 
thorax and scutellum, or they may be noticed at the sides of the 
mesonotum and in front of the scutellum where the hair-like 
scales predominate. 
The spindle-shaped scales (y) lie more or less closely applied 
to the surface, irregularly scattered about, and are usually bronzy 
or white in colour and never form a complete thoracic covering. 
A small, rather short variety occurs in the genus Megarhinus; 
they are most typically exhibited in Culex vigilax, Skusp. 
Flat scales resemble those of the head, and often occur 
as a covering to the scutellum ( Stegomyia ) (Fig. 9, A and D) 
and over the roots of the wings and prothoracic lobes ( Mega¬ 
rhinus) ; they may be long or short, the long ones being found on 
the scutellum, the smaller on the sides of the mesothorax. 
The long twisted scales are peculiar to the genus Mueidus; 
they have long stalks, more or less bent, and widely expanded 
