1 6 NATURE STUDY. 



spiders and little flies which run quickly about on the surface of 

 quiet pools are supported by the surface film. 



To follow the habits of our wriggler in relation to the 

 surface film, we see that despite the fact that the wrigglers 

 are heavier than water they are enabled to hold themselves 

 without efifort at the surface of the water to breathe. And 

 yet, also without effort, they can rest on the bottom, feed* 

 ing on the decaying matter to be found there. Indeed, be- 

 cause they are heavier than water when they are at the surface 

 breathing they alwaj^s hang with head down in the water, and 

 thus can continue feeding on the organic particles that are float- 

 ing everj'where in the foul water, at the same time that thej' are 

 breathing. This is an important saving of time to the mosquito. 

 When we have studied insects more we shall know that insects that 

 go thru transformations like the mosquito — metamorphosis this 

 transforming is called — do almost all of their feeding in their firsi 

 young, or so-called larval stage. For example, the male mosquito 

 eats almost nothing as a flying insect, (the female does take some 

 food, as we are grievously aware), so the insect must not lose 

 much time in its first young stage if it is to store up enough food 

 (as fat) in this stage to sufiice for its existence thru all of its othei 

 stages. And yet so active a creature as the wriggler must have 

 a great deal of oxygen (taken from the breathed-in air) to keep its 

 life fires burning. So you see how admirably arranged the wrig- 

 gler is to take advantage of the natural conditions under which it 

 lives. 



I^et us turn to the other kind of young mosquitoes, the big- 

 headed ones, the pupae (see fig 6). When they are below the sur- 

 face and stop wriggling, what do they do? They rise to the surface. 

 They must be lighter than water then. Are they not so well fitted 

 for their life as the wrigglers? Or is there a difference in the habits 

 of the mosquito in its two young stages? Yes, a great difference. 

 The pupse take no food. All they need is to be able to breathe, and 

 to be able to swim quickly away from any ferocious pursuer. 



