114 
Psyche 
[December 
The material for this key has been modified from the works 
of many authors, notably Smith (1903), Headlee (1921), 
Dyar (1922, 1928), Dyar and Shannon (1924), Matheson 
(1925, 1929), Bradley (1936), Edwards (1932), Johannsen 
(1903, 1923, 1934), Marshall (1938) and King, Bradley and 
McNeel (1939). 
Mosquitoes are small two-winged insects belonging to the 
order Diptera, family Culicidae. The Culicidae are separated 
from all other Diptera by a characteristic wing venation 
which is outlined by Edwards (1932) as follows: Subcosta 
(Sc) long and reaching costa; radius 4-branched, R 2+3 
forked, R 4+5 simple, no cross vein connecting R 1 and R 2 ; 
media two branched ; cross veins r-m and m-cu both present ; 
cubitus forked ; anal vein long and reaching wing margin ; 
axillary vein absent or very faint (Fig. 5) . There is no other 
single character which separates the family from other Dip- 
tera. Other common family characters are (1) the small or 
rudimentary first antennal segment and the more or less en- 
larged second segment, ( 2 ) the completely divided pronotum, 
the posterior divisions of which appear to form part of the 
pleurae. These characters, however, are not distinctive since 
they are shared by one or more families of Diptera. 
The larvae of the Culicidae are distinguished from all other 
dipterous larvae by the presence of a complete head capsule 
and of only one pair of functional spiracles situated dorsally 
on the eighth abdominal segment opening free to the surface 
(Fig. 19) or into an air tube or by the presence of a com- 
plete head capsule and air sacs in the thorax and seventh 
abdominal segment (Fig. 17) (Chaohorus ) . 
Key to Subfamilies of Culicidae 
Adults 
1. Antennal flagellum 14 segmented ; vein Sc ending above 
or before base of Rs (Fig. 5). Mouthparts short, 
wings without scales : Dixinx 
Antennal flagellum 13 segmented ; vein Sc ending much 
beyond base of Rs. Wings with scales at least on 
fringe 2 
2 . Mouthparts short, palpi incurved; scales almost con- 
fined to wing fringe : Chaoborinx 
Mouthparts modified to form a long proboscis, palpi not 
incurved ; wing veins and legs scaly : Culicinx 
