8 
A Monograph of Culicidae. 
* 
SCALES. 
After examining some thousands of specimens of Culicidae 
sent to the Museum, to myself, and in private collections em¬ 
bracing all the genera, 1 am convinced that the scale structure 
is one of the most important characters for both generic and 
specific distinction and characters which cover a greater number 
of species than any other, such as the formation of the ungues 
or paljh, which vary materially in closely related species ; these 
latter characters are of specific value, but I am convinced they 
can go no further, hence several of Arribalzaga’s genera have 
been here dispensed with ; even Ochlerotatus, which I retained 
for some time, has had to be given up because a very closely 
related species, which, if the genus was retained, would have to 
be excluded from the company of undoubted relations. 
The genus Culex has previously contained all those Culicidae 
in which the palpi in the £ are long and in the 9 short; such 
are the number of Culicidae having this character in common 
that I searched for some other character by which the unwieldy 
genus could be subdivided : palpi, ungues, and halteres w r ere alike 
examined, but nothing definite could be obtained from them nor 
from the £ genitalia. Strange to say, the halteres, which one 
would expect to show great variation owing to their being degene¬ 
rating organs, are subject to little structural variation in this 
family of Dipt era. 
On the other hand, the structural peculiarity of the scales is 
very persistent in certain groups, for instance, in Megarhinus, 
Aedes , Mucidus, Arc. In certain closely related species the arrange¬ 
ment of those on the head and wings alone enables the species 
to be separated. Scales form structural characters, and thus are 
of generic and specific value, and-as such I have used them 
in this work. A short account of the various forms found is 
thus essential. 
(1.) Scales Oil the head. —On the head of a typical Culex , 
such as C. pipiens, L., will be found three forms of scales ; on 
the occiput are rather narrow curved ones, which stand more or 
less from the surface and which lie in no definite order; these 
(Fig. 8, 5) are spoken of in the text as “ narroiv curved scales 
and are usually golden, brown, or creamy colour. As far as I 
