1939] 
Mosquitoes of Massachusetts 
123 
2 . 
3. 
4. 
5. 
6 . 
7. 
8 . 
9. 
10 . 
11 . 
12 . 
13. 
14. 
15. 
16. 
Air tube with several dorsal hair tufts, anal gills nor- 
mal: trichurus 
Air tube without several dorsal hair tufts, anal gills 
large and inflated : atropalpv . is 
Pecten with detached teeth outwardly (Fig. 15) 4 
Pecten without detached teeth outwardly (Fig. 16) 9 
Antennae enlarged basally : aurifer 
Antennae not enlarged basally 5 
Antennae as long as head : diantseus 
Antennae not as long as head 6 
Both pairs of head hairs (Fig. 8) double : excrucians 
Both pairs of head hairs not double 7 
Lateral abdominal hairs (Fig. 8) single beyond second 
segment 8 
Lateral abdominal hairs not single beyond second seg- 
ment: vexans 
Air tube 2% to 3 times as long as wide, tuft on air tube 
large : intrudens 
Air tube 3% to 4 times as long as wide, tuft on air tube 
small, located on outer third of tube : cinereus 
Comb scales in a single or in an irregular single row 1 0 
Comb scales in a triangle 13 
Anal segment ringed by plate 11 
Anal segment not ringed by plate : triseriatus 
Air tube five times as long as wide : dupreei 
Air tube 2 to 3% times as long as wide 12 
Dorsal brush of anal segment consisting of two pairs 
of long hairs : implacabilis 
Dorsal brush of anal segment consisting of a pair of 
long hairs and a pair of dorsal tufts : atlanticus 
Anal segment ringed by plate , 14 
Anal segment not ringed by plate 17 
Upper and lower head hairs double : punctor 
Upper and lower head hairs single 15 
Anal gills at least as long as anal segment :....trivittatus 
Anal gills shorter than anal segment 16 
Lateral abdominal hairs double on segments two to five ; 
scale of comb with a stout apical spine : sollicitans 
