178 



CLASS VII. INSECTA. 



(INSECTS.) 



THOUGH this is, beyond all comparison, the 

 most populous Class of animals, embracing as it 

 does more than ten times as many species as all 

 other living beings put together, the sea is sin- 

 gularly destitute of them. It has been frequently 

 said that no true Insect is marine ; and though 

 this is not literally true, the minuteness of the ex- 

 ception makes the rule even more striking than it 

 would have been if absolutely universal. Of the 

 hundreds of thousands of Insects known to exist, 

 but two live in the sea, and both of these may be 

 found on our own coasts. Both are Beetles, dis- 

 tinguished from other Insects by having jaws, and 

 a pair of membranous wings folded and concealed 

 under a pair which assume the form of leathery 

 sheaths, meeting in a straight line along the 

 middle of the back, but not overlapping. 



The habits of these two little species, neither of 

 which exceeds an eighth of an inch in length, are 

 alike. They haunt under stones at the verge of 

 low-water, and are consequently covered by the 

 tide for many hours every day, and at the time of 

 neap-tides are not exposed even for several succes- 

 sive days. It is believed that the air which they 

 need for breathing is entangled among the pebbles 



