10 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
possessed a leaf-shaped seta; however, this division seems to represent 
an oversimplification of the complex interrelationships of terminalic 
structures. The basic setal arrangement on the apical lobe appears 
to be: three strong, basal rods followed by a leaf-shaped seta; a 
straight, pointed seta; and a curved, pointed seta. Variations to 
this basic pattern range widely from a simple group of straight, 
pointed setae in Culex usquatus to elaborate modifications and setal 
arrangements in C. apicinus. 
FEMALE CHARACTERS.—Historically, adult female mosquitoes have 
been extremely difficult to identify accurately. This is due mainly 
to the limited number of distinctive characters, intraspecific varia- 
tion of characters, and similarity of closely related species. In the 
subgenus Culex primary taxonomic characters are concerned with 
body ornamentation and scale color patterns. In this study 13 
different colorational characters have been selected and are listed in 
table 1. For many of the species, positively determined material 
was not available (due to lack of associated, individual rearings) and in 
these cases reference was made to the original descriptions. These 
characters were not incorporated into a formal key because, for most 
species, data on intraspecific variation are not available at the present 
time. ‘Terminology used in describing these colorational characters 
is that of Carpenter and LaCasse (1955). 
LARVAL CHARACTERS.—In the larval stage many stable morpho- 
logical structures are available for use as taxonomic characters. As 
in the case of female characters, the terminology utilized in describing 
these characters is that of Carpenter and LaCasse (1955). Morpho- 
logical larval characters utilized in this study are as follows: 
Antenna: In all but two species examined the antennae are con- 
stricted near the outer third, beyond the insertion of the antennal 
tuft. Degree of spiculation of the antennal shaft is also utilized as 
a taxonomic character. 
Head hairs: The arrangement, length, and condition of the four 
primary head hairs are characteristic. The following head hairs are 
utilized as taxonomic characters: postclypeal head hair 4; upper 
frontal head hair 5; lower frontal head hair 6; and preantennal head 
hair 7. 
Mentum: This structure is the strongly sclerotized and pigmented, 
toothed plate of the labial-hypopharyngeal complex. It is character- 
istic in the number and conformation of the lateral teeth. 
Integument: The presence or absence of spicules on the thoracic 
and abdominal integument is frequently diagnostic. 
Comb: This structure is a row or patch of enlarged specialized 
spicules in the middle of each side of the eighth abdominal segment. 
