Mosquitoes 



93 



and are provided with a characteristic membranous 

 expansion near the middle. 



The larvae may be found at the proper season 

 and in the localities where they are abundant in 

 almost any kind of standing water, in clear little 

 pools beside running streams, in the overflow from 

 springs, in swamps and marshy lands, in rain- 

 barrels or any other places or vessels where the 

 water is quiet. They do not breed in brackish 

 water. As they feed largely on the algae or green 

 scum on the surface of the water they are espe- 

 cially apt to be found where this is present. We 

 have already noted that their positions in the water 

 differ from that assumed by other species (Fig. 82). 



As the breathing-tube is very short the larvae 

 must come close to the surface to breathe, and 

 when they are feeding we find them lying just un- 

 der and parallel to the surface of the water with 

 their curious round heads turned entirely upside 

 down as they feed on the particles that are float- 

 ing on the surface (Figs. 83, 84). 



The pupae do not differ very much from the 

 pupae of other species although the breathing-tubes 

 on the thorax are usually shorter and the creature 

 usually rests with its abdomen closer to the sur- 

 face, that is, it does not hang down from the surface 

 quite as straight as do other forms (Fig. 85). 



