Adult thorax, lateral aspect. Abbreviations: em. mesepimeron; pii. pronotal bristles; ps. post-spiracular area; /. spiracle; sb. spiracular 

 bristles. 



Fig. 22. — Mainotiia perturbaiis. FiG. 23. — Aeiles stimulans. FiG. 24. — Psorophora confiti'iis. 



Fig. 25. — Culiseta inornata; 25A shows enlarged view of pronotal and spiracular bristles. 



15. Hind tibia enlarged and shaggy toward apex, with 



setae or hairs not longer than width of tibia at 

 apex (Fig. 15); spiracular bristles present (Fig. 



24) or absent Psorophora 



Hind tibia slender to apex, not shaggy, often with 

 a scattering of setae longer than width of tibia 

 at apex (Fig. 14); spiracular bristles absent (Fig. 

 23) Aedes 



16. Post-spiracular area of thorax bare and spiracular 



bristles lacking, as in Fig. 22 Culex 



Thorax either with post-spiracular area ha\ing bris- 

 tles or scales (Fig. 23), or with spiracular bristles 

 present (Fig. 25), or with both 17 



17. Spiracular bristles present; post-spiracular area of 



thorax sometimes with scales but never with hairs 



(Fig. 25) Culiseta 



Without spiracular bristles; post-spiracular area of 

 thorax with hairs or hairs and scales (Fig. 23) . . . 

 Aedes 



Key to Species of AEDES (Females) 



1. Hind tarsus with white ring at base or apex of some 



or all segments (Fig. 14, 26) 2 



Hind tarsus without white ring at base or apex of 

 any segment ( Fig. 27, 28) 17 



2. Hind tarsus with white rings at both ends of some 



segments (Fig. 34) 3 



Hind tarsus with white rings only at basal ends of 

 segments ( Fig. 26) 6 



3. All wing scales dark, except sometimes at the ex- 



5. 



6. 



treme base of costa; mesonotum brown or red- 

 dish 4 



Most wing scales white, with a small mixture of black 

 scales; mesonotum and abdomen predominantly 

 cream color (Fig. 42) 5 



Costa with black scales extending to extreme base; 

 outer side of hind femur with some pale areas at 

 base, grading to all dark at apex, the extreme tip 

 with a few white scales. A widespread species 

 common in woods throughout Illinois, especially 

 in May; seldom collected at light canadensis 



Costa with white scales along extreme base, hevond 

 this with black scales (Fig. 35); outer side of 

 hind femur very dark except for a conspicuous 

 band of white scales at apex. A woodland species 

 widespread in eastern and south-central states; 

 known from Missouri and Wisconsin, hut not 

 yet recorded from Illinois atropalpus 



Apical portions of veins R,. M,, and M, with nu- 

 merous black scales and few white scales. A 

 Holarctic prairie species local in several areas in 



Illinois; associated with industrial wastes 



dorsalis 



Apical portions of veins R,. M,, and M._, with white 

 scales predominating. Known from prairies of 

 Michigan, Iowa, and westward; not yet recorded 

 from Illinois campestris 



Proboscis dark but with a definite white band (Fig. 

 19) .7 



Proboscis nearly uniformly colored throughout. . .9 



