310 NATURAL HISTORY 



while they have young, discover a little 

 lump of insects in their mouths, w^hich they 

 pouch and hold under their tongue. In 

 general they feed in a much higher district 

 than the other species : a proof that gnats 

 and other insects do also abound to a con- 

 siderable height in the air : they also range 

 to vast distances ; since loco-motion is no 

 labour to them, who are endowed with such 

 wonderful powers of wing. Their powers 

 seem to be in proportion to their levers ; 

 and their wings are longer in proportion 

 than those of almost any other bird. When 

 they mute, or ease themselves in flight, 

 they raise their wings, and make them 

 meet over their backs. 



At some certain times in the Summer 1 

 had remarked that swifts were hawking 

 very low for hours together over pools and 

 streams ; and could not help inquiring into 

 the object of their pursuit that induced 

 them to descend so much below their usual 

 range. After some trouble, I found that 

 they were {diking phrt/gmiecBj epheinercB^ and 

 /i5£//«7<F(cadew-flies, may -flies, and dragon- 



