NO. 3557 SUBGENUS CULEX—BRAM 11 
The general arrangement of the comb scales is frequently utilized, 
as well as the number and conformation of the individual scales. 
Siphon: The air tube of the typical nonanopheline mosquitoes; 
morphologically includes part of the abdominal segments VIII and 
IX. Several features of the siphon are utilized as taxonomic 
characters. 
Siphonal index: The ratio between the length of the siphon and the 
basal width. 
Siphonal tufts: Pairs of setae inserted on the siphon. The number, 
location, and condition of the siphonal tufts are diagnostic. 
Pecten: A paired, comblike row of spiculate teeth along the ventro- 
lateral border of the siphon. The number, arrangement and con- 
formation of individual teeth is diagnostic. 
L/S ratio: The ratio of the length of the siphon to the dorsal length 
of the saddle. This ratio was originally proposed by Colless (1957) 
and is used as a supplementary character in the larval key. 
Keys 
In this study emphasis has been placed on characters of the male 
terminalia because of the scarcity of material, particularly larval 
skins associated with adults, and because many species are known 
only from the male terminalia. Of the 61 species recognized in this 
study, 59 have been included in the key to male terminalia. Culex 
delys is known only from the female and C. pseudojanthinosoma is 
known only from the female and a description of the larval stage. 
A key to New World subgenera of the genus Culex based on the male 
has been constructed utilizing many of the characters suggested by 
Foote (1954). 
Due to the scarcity of reliable data, the key to larvae is extremely 
tentative. In 18 species the larval stage is unknown. Descriptions 
of the larvae in many other species are incomplete or questionable. 
A thorough understanding of larval morphology and affinities awaits 
future individual rearings. Only by this technique can correlations 
between immature and adult stages be conclusively established. A 
list of larval characters separating the subgenus Culex from other New 
World subgenera of the genus was prepared instead of a formal key, 
because some difficulty was encountered in separating the subgenera 
Carrollia and Microculez. 
Morphological and colorational characters of adult females in the 
subgenus Culex are extremely difficult to differentiate. As pointed 
out by Lane (1953), a key utilizing adult females serves only to 
approximate species because the characters are variable. In this 
study few species were represented by a suitable sample of positively 
determined specimens, and the amount of material obtained from 
