THE MOSQUITOES OF THE SOUTHEASTERN STATES 79 



Pecten with four to six spines, each with a small tooth, subequal in 

 size, on each side of the long central spine; tuft of air tube larger, 

 placed in line with the pecten; comb of five scales. (From published 

 descriptions, 68, 102) P. varipes 



39. Spines at tip of air tube short and inconspicuous 40 



Spines at tip of air tube long and conspicuous P. cyanescens 



40. Pecten with four teeth P. signipennis 



Pecten with six teeth P. pygmaea 



(The larva of Psorophora horrida has not been described.) 



AEDES 



41. Upper head hairs multiple, lower ones double or multiple (fig. 21). 



[Anal segment not completely ringed by the sclerotic plate; tuft of 



air tube beyond pecten.] 42 



Either the upper or the lower head hairs single (both pairs single 

 except as shown under individual species) 47 



42. Pecten with one to three distal teeth more widely spaced (fig. 24, A) ; 



comb of few scales in a single irregular or partially double row 43 



Pecten with evenly spaced teeth ; comb scales in a triangular patch 44 



43. Upper head hairs with three to five branches, lower ones usually with 



two or three; lateral abdominal hairs double or triple on segments 



3 to 5 . A. vexans 



Upper and lower head hairs with more than four branches; lateral 

 abdominal hairs single on segments 3 to 5 A. cinereus 



44. Lower head hairs double 45 



Lower head hairs with three or more branches 46 



45. Single comb scale with a long apical spine A. sticticus 



Single comb scale with lateral spines nearly as long as apical spine 



A. grossbecki 



46. Upper lateral hairs on abdominal segments 1 and 2 double, lower hairs 



single or double; antennae much shorter than head and little longer 

 than preantennal hair ; comb scales rounded and fringed with sub- 

 equal spinules A. canadensis 



Upper lateral hairs or both pairs on segments 1 and 2 multiple ; 

 antennae nearly as long as head and much longer than preantennal 

 hair ; comb scales with apical spine somewhat longer and stouter 

 than other spines A. thibaulti 



47. Pecten with outer teeth more widely spaced 48 



Pecten with evenly spaced teeth : 50 



48. Tuft of air tube within pecten ; comb of many scales in a patch, single 



scales with apical fringe of subequal spinules 49 



Tuft of air tube beyond end of pecten ; comb of about nine scales, each 

 with a long apical spine. [Anal segment completely ringed by 

 plate.] A. nigromaculis 



49. Both head hairs single ; lateral hairs multiple on segments 3 and 4 ; 



sclerotic plate on anal segment small, covering about half the segment ; 



body glabrous A. atropalpus 



Lower head hairs double; lateral hairs usually single on segments 3 

 to 5 ; anal segment completely ringed by plate ; body spicular- 

 pilose A. bimaculatus 



50. Anal segment not completely ringed by the sclerotic plate. [Lateral 



hairs normally double or triple on segments 3 to 5.] 51 



Anal segment completely ringed by the plate 54 



51. Antennal hair single (rarely forked) ; comb of few (8 to 15) scales 



in a single or partly double row 52 



Antennal hair multiple ; comb of many scales in a patch 53 



52. Single comb scale with a stout apical spine and shorter side spines 



(fig. 26, C) ; head hairs and preantennal hair single; tuft of air tube 

 with three or more branches ; lateral hair of anal segment single 



or double A. aegypti 



Single comb scale elongate, evenly fringed with short spinules (fig. 26, 

 D ) ; lower head hair with two to four branches ; preantennal and 

 lateral hair of anal segment multiple ; tuft of air tube usually single 

 or double , A. triseriatus 



