62 



HOUSEHOLD INSECTS 



Larvae. As we have already pointed out, the larvae 

 of Culex hang from the surface of the water, as it were, 

 with the head downward. 

 On the contrary, the larvae 

 (Fig. 25) of Anopheles lie 

 in a horizontal position, 

 apparently on the surface 

 of the water. Really, they 

 are just beneath the sur- 

 face film. Their breathing 

 tube is very short, and, con- 

 sequently, they are obliged 

 to lie close to the surface 

 in order to get air. They 

 can be readily recognized 

 by this horizontal position. 

 When disturbed they wrig- 

 gle across the water in a 

 horizontal direction, espe- 

 cially the younger larvae. It 

 will be recalled that the 

 larvae of Culex are con- 

 stantly diving below in a 

 vertical direction. As the 

 larvae of Anopheles become 

 older they more readily 

 wriggle downward. 

 The feeding habits of 



An P he ! es lar are ver y 



interesting and remarkable. 

 The head is joined to the rest of the body by a very 

 slender neck, on which it readily and rapidly rotates, at 



