53 MISC. PUBLICATION 336, U. S. DEPT. OF AGRICULTURE 



55. Two species that are difficult to separate except by male characters. 



Male terminalia: 



Stem of claspette long, greatly enlarged in middle, and densely 

 hirsute ; filament stout, much shorter than stem — Aedes atlanticus 

 Stem of claspette long and slender, slightly pilose; filament much 

 shorter, with a short, pointed, slightly hooked tip 



Aedes tormentor 



56. Mesonotum with a prominent patch or stripe of pale scales on each 



side, dark centrally 57 



Mesonotum with two broad submedian stripes of yellowish-white 

 scales, dark centrally and along lateral edges (fig. 12, E). [Dark 

 portions of femora not speckled with white; tibiae and first tarsal 

 segments slightly pale on one side.] Usually rare in South 



Aedes trivittatus 



57. Tibiae and tarsi almost entirely dark-scaled; dark portions of femora 



not speckled with white; abdominal tergites with lateral pale 



spots 58 



Tibiae and first segments of tarsi pale on one side for nearly their en- 

 tire length ; dark portions of femora speckled with white ; ab- 

 dominal segments sometimes with basal pale bands that widen 

 laterally. [Mesonotum broadly pale-scaled for its full length on 

 each side, the disk also with pale scales ; posterior pronotum with 

 lanceolate scales.] Rare in Southern States Aedes sticticus 



58. Posterior pronotum densely covered with broad, appressed, white scales ; 



mesonotum with silvery-white scales along sides, the median area 

 broadly dark-scaled (fig. 12, F). A common woods species, breed- 

 ing in tree holes Aedes triseriatus 



Posterior pronotum with lanceolate scales, not closely appressed; 

 mesonotum with broad patches of yellowish-white scales anteriorly, 

 reduced to narrow lateral stripes posteriorly by an abrupt widening 

 of the median dark-scaled area (fig. 12, D) . A fairly large species, 

 usually rare Aedes tMbaalti 



59. (42) Hind legs without markings; segments 3 to 5 of midtarsi white 



on one side. The pitcherplant mosquito, rare Wyeomyia smithii 



Hind-tarsal segments with basal spots or streaks of white scales under- 

 neath; midtarsi as in W. smithii, Two species found in the United 

 States only in southern Florida, breeding in the water in. air plants 

 (Bromeliacea) 60 



60. Anterior pronotal lobes silvery-scaled Wyeomyia vanduzeei 



These scales darker, with purplish reflections (difficult to distinguish 



from the preceding) ^.__ Wyeomyia mitehellii 



KEY TO DARK-LEGGED SPECIES OF CULEX BY MALE TERMINALIA ■ 



1. Tenth sternites with an apical tuft of short bristles or spines; sub- 



apical lobe of sidepiece not divided Subgenus Cidex 2 



Tenth sternites comb-shaped apically, with a row of short, stout teeth— 6 



2. Subapical lobe of sidepiece with eight appendages; base of tenth 



sternite produced laterally into a blunt point or a short, nearly straight 



arm 3 



Subapical lobe with five or six appendages; base of tenth sternite pro- 

 duced into a long, stout, strongly curved arm 4 



3. Ventral arm of mesosomal plate long, ribbonlike, curved sharply out- 



ward toward sidepiece at about the outer third and tapered to a point ; 

 dorsal arm slender, pointed, lying more or less parallel with the inner 

 margin of the ventral arm and extending little if any beyond the 



curved shoulder of this arm Culex quinquefasciatus 



Ventral arm of mesosomal plate of same general shape as above but 

 somewhat shorter ; dorsal arm broader, semicylindrical in appearance, 

 with a truncate, slightly upturned tip; this arm placed obliquely, 

 usually extending to or toward tip of ventral arm Culex pipiens 



8 Illustrations of these structures have not been included, on the assumption of some 

 familiarity with this specialized subject on the part of those using this key. 



