222 FLASHLIGHTS ON NATURE 



The steering of a Canadian canoe comes very near 

 it. Anybody who has sculled or rowed, indeed, 

 knows well the extraordinary ease with which 

 a boat can be shored off instantaneously from 

 another, or the marvellous way in which gliding 

 curves can be produced on the almost unresisting 

 surface of the water. The whirligig beetle has a 

 perfect steering apparatus in his long and ex- 

 tensible fore-legs, and by their means he per- 

 forms unceasingly his play of merry and intricate 

 evolutions. 



When whirligigs are alarmed, however, they dive 

 below the surface as one of a pair is doing in 

 No. 7, and carry down with them a large bubble of 

 air, for breathing purposes, entangled in the joints 

 of their complicated legs and the under parts of 

 their bodies. On this quaint sublacustrine balloon 

 they subsist for breathing till the danger is past 

 and they can come to the top again. 



Early in April, when the weather is fine, you 

 begin to see the whirligig beetles dancing in and 

 out in companies, like so many water-fairies, on 

 the. still top of the pond. They prefer calm water ; 

 when the wind drives little ripples to the eastern 

 end of the pool, you will find them practising their 

 aquatic gymnastics under lee of the shore on the 

 western side ; when an east wind ruffles the western 

 border, you will find them gyrating and interlacing, 

 coquetting and pirouetting, by the calmer eastern 

 shallows. As they move in their whirls, they form 

 little transient circles on the water's top, which 

 spread concentrically ; and the mutual interference 



