456 



POPULAR SCIENCE MONTHLY. 



hundred eggs upon the surface of some quiet water, and in a day or 

 two these eggs develop into the larval or second stage (see Fig. 2). 

 It will be noticed that Culex hangs with its head down, and from 

 its tail upward to the surface of the water extends a small tube. 

 Through this tube it breathes. Anopheles rests just beneath and par- 

 allel to the surface of the water, and its breathing tube is much shorter 



than that of Culex. These resting 

 positions are quite different, and 

 each is characteristic of its kind. 

 Except when disturbed. Anopheles 

 is generally to be found at the sur- 

 face, breathing and feeding in this 

 position. Culex, on the other hand, 

 comes to the surface only occasion- 

 ally to breathe. It stays below the 

 water for the greater part of the 

 time, and is often found feeding 

 from the bottom. 

 At the end of a few days the larvae change into the pupal or third 

 stage (see Fig. 3). To the left is seen the larval skin out of which 

 this pupa has just come. The difference between Culex and Anopheles 

 in this, the final stage of 'wiggler' existence, is very slight. Both now 



Fig. 3. A Pupa, the Third Stage in a 

 Mosquito's Life. Three times as large 

 as life. 



Fig. 4. An Adult Mosquito ( A/iophelcs) TRAtOivoiiynsG ikom a I^ui'A and coming out of 



THE Water. Three times as large as life. 



live at the surface of the water, and they breathe through two funnel- 

 shaped tubes situated one on each side of the thorax, or 'head.' Unless 

 disturbed, they remain motionless in this position at the surface until 

 the time comes when, as adult mosquitoes, they leave the water (see 

 Fig. 4). This is the critical period of a mosquito's life; for, should 



