THE MOSQUITOES OF THE SOUTHEASTERN STATES 



71 



1. Eighth abdominal segment with an elongate air tube (fig. 10, B) ; abdo- 



men without palmate hairs 2 



Air tube lacking (spiracles sessile) ; some abdominal segments with 

 dorsal palmate hairs (figs. 10, A, and 22, B) Anopheles 10 



2. Air tube of normal shape, cylindrical or fusiform 3 



Distal half of air tube attenuated (fig. 23, B), with saw-toothed projec- 

 tions at tip adapted for piercing the roots of aquatic plants- Mansonia 20 



3. Air tube with a pecten (fig. 24, A) 4 



Air tube without a pecten (Megarhinus, Orthopodomyia, Wyeomyia) 8 



4. Head hairs normal, slender, frequently multiple; head wider than long, 



rounded 5 



Head elongate, elliptical; upper and lower head hairs single, stout, 

 spinelike (fig. 25, A). [Eighth abdominal segment with a lateral plate 

 having a row of teeth on its posterior margin ; air tube with one pair 

 of ventral brushes; anal segment ringed by plate.] Uranotaenia 19 



Afouf/f ArusAes 



j4f?fe/i/7a 



Preanfenna/ Aa/r 



lower Aeoc/ Aa/'r 



Upper Aead ' Aa/r 



O.OS/77/77 



Figure 21. — Head of larva of Aedes vexans. 



5. Air tube with several paired ventral hair tufts or single hairs, a row of 



hairs beyond pecten, or a pair of tufts at base (Culex, Theobaldia) — 22 

 Air tube with a single pair of ventral hair tufts, more or less centrally 

 placed (sometimes very small or obsolete in Psorophora; a second 

 very small pair near apex in Deinocerites). [Antennae in most of 

 the species of uniform shape, the hair tuft placed near middle.] 

 (Psorophora, Aedes, Deinocerites) • 6 



6. Anal segment not completely ringed by plate, or, if ringed, tufts form- 



ing ventral brush posterior to plate (fig. 24, A and B) ; air tube not 



inflated 7 



Anal segment completely ringed by sclerotic plate and plate pierced 

 on midventral line by tufts of ventral brush (fig. 23, A) ; mouth 

 brushes formed of stout prehensile hairs (subgenus Psorophora), or 

 air tube large and swollen centrally (except in P. discolor), with few 

 pecten spines. [Comb of few scales in a single row.] Psorophora 33 



7. Head normal, without lateral pouches ; anal gills four ; air tube short 



and stout in most species Aedes 41 



