250 BACOT : MOSQUITOES AND THE DANGER OF MALARIA. 
abdominal segments of the Anopheles larvae. These penetrate 
the surface him of the water and supply sufficient floating 
power to buoy up the larva when at rest. A further 
characteristic of the Anopheles larvae is the quick reversibility 
of the head, rendered possible by the flexibility of its neck. 
When the larva rises to the surface of the water, the dorsum of 
its head is uppermost ; but, in order to feed, it may need to 
reverse it, and this is done with lightning-like rapidity. 
In the pupal state, Anopheles mosquitoes are less readily 
separated from those of other groups than in their egg or larval 
FIG 7.—CHARACTERISTIC RES TING-POSITIONS OF MOSQUITOES.— 
A, Anopheles \ B, Culex . 
(By hind permission of the British Museum.) 
condition, but the adult mosquitoes are very easy to distinguish. 
As a rule, the wings of the Anopheles mosquitoes are spotted, 
while the abdomen is hairy and devoid of scales. The female 
palps are nearly, if not quite, as long as the proboscis, while in 
most of the Culicinae genera they are very much shorter. As 
the palps of the female Anopheles are carried in close proximity 
to the proboscis, the naked-eye effect is that of a very much 
thicker proboscis, the Culicinae proboscis appearing slender 
in comparison. Finally, the resting-positions (fig. 7) of the two 
groups differ markedly. Occasionally some species of Culex 
adopt the Anopheles attitude mere or less closely, but their 
proboscis is always held at an angle which differs from. the 
