H4 The Under-Water World 



deposited singly on some nearby situa- 

 tion. The larvae lead an active existence. 

 They are legless, but are able to move 

 rapidly by a series of lashing movements 

 of the body. On the eighth segment of 

 the abdomen is a breathing-tube, or 

 siphon, and when the larva rises to the 

 surface for air the tip of this siphon 

 breaks through the surface-film. The 

 majority of mosquito larvae hang head 

 downwards when at rest, but those of 

 the genus Anopheles, to which the malaria 

 mosquito belongs, rest parallel with the 

 surface. The pupa also is active, being 

 able to descend rapidly from the surface 

 if disturbed. It floats head upwards, 

 the breathing apparatus, in the form of 

 a pair of horn-like processes, being situ- 

 ated on the top of the thorax. The 

 adult insect emerges direct from the 

 floating pupa, using the empty skin as a 

 raft. There is one remarkable form in 

 this country that obtains its oxygen 



