66 MISC. PUBLICATION 336, U. S. DEPT. OF AGRICULTURE 
blood or ova.) As shown in the generic key, Aedes and Psorophora 
are distinguished also from the other mosquitoes, except Mansonia 
titullans, by the presence of postspiracular bristles. The Psorophora 
are distinguished from Aedes by having spiracular bristles as well, 
although it is frequently very difficult to see them. In Psorophora, 
however, the dorsal or lateral pale scaling of the abdominal segments 
is apical or diffuse, whereas in Aedes it is generally basal or extends 
from the base. In Psorophora, subgenus Grabhamia, the femora and 
tibiae are speckled, and at least the hind femur has a narrow white 
ring near the apex. In subgenera Psorophora and Janthinosoma the 
mesonotum is partially or completed covered with broad, fiat scales, 
and some of the leg scales frequently are erect. The subgeneric 
divisions of Aedes are not easily defined on markings, and these group- 
ings have not been included. The subgenera of Culex have been 
referred to in the discussion of that genus. 
Difficulties may arise from the separation of the species of Wyeo- 
myia on the pale tarsal markings, as these are easily overlooked. 
The species are of extremely limited distribution, however, and are 
rarely collected. The positive means of identification of the genus 
is by the presence of postnotal bristles. 
Keys To ADULTS 
All the known southeastern species are included in the first key. 
Following this is a short key to the male terminalic characters of the 
dark-legged Culex and then a separate key giving a synopsis of gen- 
eric characters. 
SPECIES KEY 
In the species key the characters apply primarily to the female, 
unless the male is mentioned. Although the markings of the male are 
generally similar to those of the female and the males of most species 
can be identified by the characters given, some differences occur in 
the distribution of the pale scales. The white bands on the abdominal 
segments, for example, cannot be used satisfactorily in identifying 
the males of the subgenus Culex. This key is preceded by a synopsis 
of the principal divisions. 
Mosquitoes: having lonepalpi_in- both (sexes= Se Couplet 2 
Genus Anopheles_________ fe Sees AS) Se Bee 
Mosquitoes having a rigid proboscis, down-curved on outer half; very large, 
ITIGeSCENt: -SPCCIEG ME. eke = ee ee ee saree MeN ed hee 3) 
Genus -Megarhinus. =. - 5 Boe 8 Ee ere 
Mosquitoes having the second marginal cell very short; very small species 
having iridescent..thoracie@ markings "o> See ee eee eee 12 
Genus: CU 7anctcentae 22 See eS ee eee 12 
Mosquitoes without tarsal or mesonotal markings________________________ 14 
Genus D ein0Cerites 2222 268 as eee ae ee ee 14 
Genus Psorophora (P. cyanescens) ; Aedes (A. cinereus)_____________ 16 
Genus Culex (except C. bahamensis and C. tarsalis) ; Theobaldia______ a bY 
Mosquitoes with tarsal or mesonotal markings, or both___--_____-___________ 26 
Large species, with long, erect scales on femora and tibiae; the galli- 
MIP PETS. 282 a ee See Ee ee a a OE eee 7 
Genus Psorophora, .(Psorepne7a) Se ae 27 
Bright yellow-species == ==) ee ee 28 
Genus. Aedes ¢AY Gimaculatws) 2 a en ee ee 28 
