75 MISC. PUBLICATION 336. U. S. DEPT. OF AGRICULTURE 



ANOPHELES 



10. Abdomen with plumose lateral hairs on first three segments only ; head 



with plumose frontal hairs 11 



Abdomen with plumose lateral hairs on first six segments; frontal 

 head hairs single. [Palmate hairs well developed on segments 2 

 to 7.] A. barberi 



11. Outer clypeal hairs branched 12 



All clypeal hairs simple ; postspiracular plate with a long tail poste- 

 riorly on each side. [Inner clypeal hairs well separated; functional 

 palmate hairs on segments 3 to 7, the leaflets ending in long slender 

 filaments.] A. pseudopunctipennis 



12. Outer clypeal hairs sparsely feathered or branched (5 to 10 short 



branches) on apical half. [Inner clypeal hairs forked or sparsely 



feathered at tip.] 13 



Outer clypeal hairs thickly branched, the branching dichotomous 14 



13. Inner clypeal hairs closely approximated ; lateral hairs on abdominal 



segments 4 and 5 branched, usually in threes ; palmate hairs well 

 developed only on segments 4 to 7, the leaflets with notched or 



serrated edges A. atropos 



Inner clypeal hairs widely separated (by about one-third the distance 

 between the outer clypeal hairs) : lateral hairs on segments 4 and 5 

 simple ; palmate hairs developed on segments 1 to 7, sometimes a pair 

 on the metathorax also ; leaflets long and slender, with smooth 

 margins A. aJbimcnus 



14. Abdominal segments with but one conspicuous hair anterior to palmate 



hair ; this hair (the antepalmate hair, or hair 2) usually single or 

 double, but sometimes with three branches, on segments 4 and 5 ; 



hair undeveloped or very much smaller than hair 2 15 



Abdominal segments with two conspicuous tufted hairs (hairs 2 and 0) 

 anterior to palmate hair ; these hairs usually approximately equal in 

 size and with four to nine branches on segments 4 and 5. [Lateral 

 hairs of segments 4 and 5 usually branched at about basal third; 



palmate hairs developed on segments 3 to 7.] A. crucians 



(fresh water) 



15. Basal tubercles of inner anterior clypeal hairs separated by at least 



the diameter of one of the tubercles 16 



Basal tubercles of inner anterior clypeal hairs separated by less than 

 their diameter : occipital hairs usually with no more than five 

 branches 17 



16. Palmate hairs of second abdominal segment usually well developed 



and more or less pigmented, although smaller than succeeding ones ; 

 occipital hairs with a long stem and usually 8 to 10 side branches. 

 [Antepalmate hairs usually single ; antennal hair tuft usually at- 

 tached near middle, the hairs reaching base of apical spines or 



beyond.] A. quadrimacuTatus 



Palmate hairs of segment 2 rudimentary ; occipital hairs with a short 



stem and usually three to five branches A. crucians (salt water) 



(Specimens of the salt-water variety in which the inner clypeal hairs 

 are well separated; see also couplet 18.) 



17. Inner anterior clypeal hairs simple (rarely forked toward tip) ; hair 



1 of prothorax short, single or weakly branched at tip; palmate 



hairs rudimentary on segments 1 and 2 18 



Inner clypeal hairs with sparse, minute feathering toward tip; hair 

 1 of prothorax with three to five strong branches from near base. 

 [Hair on abdominal segments comparatively large, with three to 

 seven branches ; palmate hairs on segments 1 and 2 partially de- 

 veloped; antepalmate hairs on segments 4 and 5 usually single, 

 sometimes double or triple.] A. walkeri 



18. Leaflets of palmate hairs on segments 3 and 7 slender, usually some- 



what smaller than those on segments 4 to 6 and mostly with smooth 

 margins. [Antepalmate hairs on segments 4 and 5 single or double; 

 distance between clypeal hairs variable.] A. crucians (salt water) 



