THE MOSQUITOES OF THE SOUTHEASTERN STATES OG 
fourth instar, the ring is incomplete, so far as observed, in the third 
instar. With other species of Aedes the plate is reduced to a small 
dorsal saddle in the third and earlier instars. 
1. Kighth abdominal segment with an elongate air tube (figs. 10, B, and 20) ; 
abdomen without palmate hairs__ tre bana a 
Air tube lacking (spiracles sessile); some abdominal segments with 
dorsal palmate hairs (figs. 10, A, and 22, B)_ gS Anopheles 19 
2. Air tube of normal shape, cylindrical or fusiform___________ Shit, 3 
Mouth brushes 
/ 
\ 
\ 
\ 
\Y 
~ 
) 
CS ee Antennal hair tut? 
== -==-— —Antenna 
€-—-—----- /vreantennal hair 
Vi 
----Lower head hair 
Ygper head hair 
[epee ae | 
C—O een! 
0.5 mm. 
FIGURE 21.—Head of larva of Aedes vexrans. 
4. Head hairs normal, sJender, frequently multiple; head wider than long, 
spinelike (fig. 25, 4). [Eighth abdomina! segment with a lateral plate 
having a row of teeth on its posterior margin; air tube with one pair 
of ventral brushes; anal segment ringed by plate. ]_-----__ Uranotaenia 20 
bd. Air tube with several paired ventral hair tufts or single hairs, a row ot 
hairs beyond pecten, or a pair of tufts at base (Culex, Culiseta)_______ 23 
Air tube with a single pair of ventral hair tufts, more or less centrally 
placed (sometimes very small or obsolete in Psorophora; a second very 
small pair near apex in Deinocerites). [Antennae in most of the species 
of uniform shape, the hair tuft placed near middle.| (Psorophora, 
VAC SHED CLIOCCT ULES) eect oe ears nee le ee rte a A ee 6 
6. Anal segment not completely ringed by plate, or, if ringed, tufts form- 
ing ventral brush posterior to plate (fig. 24, A and B); air tube not 
-] 
midventral line by tufts of ventral brush (fig. 23, 4); mouth brushes 
formed of stout prehensile hairs (subgenus Psorophora), or air tube 
large and swollen centrally (except in P. discolor), with few pecten 
spines. [Comb of few scales in a single row. ]_----------~ Psorophora 34 
