Culicidce, or Mosquitoes 
99 
female. The most characteristic feature is that the margins of the 
wings and, in most cases, the wing veins possess a fringe of scale-like 
hairs. These may also cover in part, or entirely, the head, thorax, 
abdomen and legs. The females, only, suck blood. 
On account of the importance of the group in this country and the 
desirability of the student being able to determine material in various 
stages, we show in the accompanying figures the characters most 
used in classification. 
The larvae (fig. 73) are elongate, 
with the head and thorax sharply 
distinct. The larval antennae are 
prominent, consisting of a single 
cylindrical and sometimes curved 
segment. The outer third is often 
narrower and bears at its base a 
fan-shaped tuft of hairs, the ar¬ 
rangement and abundance of which 
is of systematic importance. About 
the mouth are the so-called rotary 
mouth brushes, dense masses of 
long hairs borne by the labrum 
and having the function of sweep¬ 
ing food into the mouth. The 
, , , fatral brush $.(5 
form and arrangement or thoracic, <,/ dm 
abdominal, and anal tufts of hair anal .../fgplf 
vary in different species and present ‘ J ' IL /// DonaJ. tufa 
characteristics of value. On either / 7 I 
side of the eighth abdominal seg- 73 - Ct ^ucture showing details of external 
ment is a patch of scales varying 
greatly in arrangement and number and of much value in separating 
species. Respiration is by means of tracheae which open at the apex 
of the so-called anal siphon, when it is present. In addition, there 
are also one or two pairs of tracheal gills which vary much in appear¬ 
ance in different species. On the ventral side of the anal siphon is a 
double row of flattened, toothed spines whose number and shape are 
likewise of some value in separating species. They constitute the 
comb or pecten. 
The pupa (fig. 139,b) unlike that of most insects, is active, though it 
takes no food. The head and thorax are not distinctly separated, but 
the slender flexible abdomen in sharply marked off. The antennae, 
dnk.il rial 
tuft-, 
1 \ Pltuth brush • 
dnknna 
