POND, LAKE, AND STREAM 27 



royal. Different other mixtures also keep them off. It is 

 only the female mosquitoes that bite us, or keep us awake 

 by their music. The males can neither bite nor sing. 



Can you tell why mosquitoes are more common in a wet 

 summer than in a dry summer ? Why are there so many 

 in most wild districts and comparatively few in old settle- 

 ments and in cities ? Why are there so many near the 

 water ? What birds have you seen eating them ? Have 

 you seen the large Dragon Flies eat them ? 



17. The Swallows. 



MATERIAL : Pictures of different swallows or mounted birds. Pre- 

 viously observed : Flying of swallows about running and standing 

 water ; how they gather mud for nest building ; how they build their 

 nests and feed their young. 



When mosquitoes and flies appear about our streams and 

 ponds, the swallows arrive too. They travel by night or in 

 the early morning and some fine spring morning, when we 

 look out of our window, they are there. All day long they 

 are on the wing, circling about near creeks and ponds, among 

 cattle and horses, catching insects in the air. TJieir long 

 pointed wings, worked by strong muscles, never seem to tire. 

 But their feet are small and weak, because they make little use 

 of them. When and where have you seen them sit down or 

 perch ? Even the stingiest farmer can find no fault with 

 these lithe denizens of the air ; for not even a single berry 

 do they ever poach from his garden, so exclusively do they 

 live on insects. 



There are three species of swallows very common through 

 the United States and Canada, wherever local conditions are 

 favorable. The best place to observe them is about their 

 nests. 



The smallest, the little mouse-colored Bank Swallow, or 

 Sand Martin, lives in holes excavated into high river banks, 



