10 A BOOK OF INSECTS 



chapter I shall have more to say about water insects and 

 their ways. They form a very numerous group ; but 

 while some of them are entirely aquatic, the majority 

 spend only their youth in stream or pond, and join the 

 ranks of flying insects when they become adult. A very 

 few insects actually dwell in hot springs, disporting them- 

 selves, so to speak, in a life-long Turkish bath. Many 

 species, especially beetles, inhabit the sea-shore, and are 

 submerged twice daily by the tides. They lurk under 

 stones or among weeds, and the close-set hairs of their 

 bodies entangle sufficient air for their needs until the 

 waters abate. For the time being they dwell in a kind of 

 air jacket, after the manner of the well-known water- 

 spider. Water-skating bugs, near relatives of those 

 which skim the surface of the village pond, glide over the 

 calm seas of the tropics, often hundreds of miles from 

 land. They make their home upon the waste of waters, 

 and rest upon weeds or wreckage. Their eggs have been 

 picked up attached to the floating feather of a sea-bird. 

 Yet insects as a whole have not taken kindly to a sea- 

 faring life. Not one species is known to dwell continually 

 in salt water ; while those which frequent the shore, or 

 are otherwise associated with the sea in the course of 

 their lives, constitute a very small part of the world's 

 total insect population. 



We have seen that the wonderful geographical range 

 of the insect is due to its exceptional natural endowments, 

 especially to its power of flight. Aided by the wind, 

 insects are known to accomplish astonishing journeys. 

 Swarms of migratory locusts have been met with at sea 

 a thousand miles from land, while there is reason for 

 thinking that the Biblical locust actually crossed over in 

 prehistoric times to the Old World from South America, 

 in which continent it still persists. Certain supremely 



