3 
except in Wyeomyia and Trichoprosopon. The thoracic scales 
vary in the different groups ; they are present on all parts save 
the me ta thorax (except Trichoprosopon), and may be neither 
flat, narrow, and curved or spindle-shaped The abdomen 
joins the thorax closely, the first segment generally being more 
or less nude, but showing one or two patches of scales and 
numerous long hairs ; the segments number nine, and may 
(Culex, Megarhinus) or may not (some Anopheles) be covered 
with broad or other scales, more or less hairy, especially in the 
£ ; male genitalia consists of a pair of large basal joints covered 
with scales and a thin nude terminal joint or clasper to each, 
which may be two-jointed ; in the female the two anal lobes 
end in round, bristly, or scaly spatulate extremities. Wings 
with the veins covered and edged with scales of various forms, 
the membranous surfaces sometimes being hairy ; the scales 
may be spread uniformly (Culex pipiens, etc.) or in groups, thus 
giving a spotted appearance to the wings (C. annulatus), 
etc.) or the wings may be coloured on the membrane (Mucidus 
mucidus, etc.) 
There is always a border-fringe of scales, which vary in 
form and arrangement ; the costa is usually dark, and may be 
spotted (Anopheles) ; the auxiliary or sub-costal vein joins the 
costa considerably before the apex of the wing, the first longi- 
tudinal near the apex ; the second and fourth longitudinals 
are both forked, the forks forming the first sub-marginal 
and second posterior cells respectively ; these cells may be either 
long and thin (Culex, etc.), or very short (Megarhinus) ; the 
third longitudinal vein is simple, and is united to the second 
and fourth by the supernumerary and mid-cross veins respectively; 
the fifth long vein gives off an anterior branch at about half 
its length, forming a large anal cell, the anterior branch being 
