17 
Adult Characters of Culicidae . 
The thorax is chiefly composed of the mid-division, the meso- 
thorax, which is large and convex ; the prothorax is reduced to a 
pair of lobes—the prothoracic lobes—on each side of the meso- 
thorax, between the head and the mesothorax. 
The scutellum is very distinct, and may be composed of a 
median and lateral lobes, with a posterior border of bristles, or 
of a single lobe. The metanotum is well developed in all save 
Megarhinus and Toxorhi,nchite where it is more or less hidden 
under the scutellum ; it bears neither scales nor bristles, except 
in Wreomyia and Trichoprcsopon . The thoracic scales vary in 
the different groups ; they are present on all parts save the 
metathorax (except Trichoprcsopon), and may be either 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 , Mega¬ 
rhinus) 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, <fec.) or in groups, thus giving a spotted 
appearance to the wings (C. annulatus , &c.), or the wings may 
be coloured on the membrane ( Muciclus 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 longitudinal 
near the apex ; the second and fourth longitudinals are both 
forked, the forks forming the first sub-marginal (Fig. 13, d) and 
second posterior cells (g) respectively ; these cells may be either 
long and thin ( Culex , ifec.) or very short ( Megarhinus) ; the third 
long vein is simple, and is united to the second and fourth by 
the supernumerary- and mid-cross veins (y and z) respectively; 
the fifth long vein gives off an anterior branch at about half its 
length, forming a large anal cell (k), the anterior branch being 
united to the fourth long vein by the posterior cross-vein (p) ; 
the sixth long vein is simple and sinuous; the second and third 
long veins may be prolonged into the first basal cell, which is 
VOL. i. c 
