AQUATIC GNAT LAflVA. 63 



compass of a basin filled from an adjacent pond. When com- 

 plete, the boat consists of from 250 to 350 eggs, of which, 

 though each is heavy enough to sink in water, the whole com- 

 pose a structure perfectly buoyant, so buoyant as to float 

 amidst the most violent agitation. What is yet more wonder- 

 ful, though hollow, it never fills with water, and even if we 

 push it to the bottom of our mimic pool, it will rise unwetted 

 to the surface. This cunning craft has been likened to a Lon- 

 don wherry, being sharp and high fore and aft, convex below, 

 concave above, and always floating on its keel. In a few days 

 each of the numerous "lives" within having put on the shape 

 of a grub or Larva, issues from the lower end of its own flask- 

 shaped egg, but the empty shells continuing still attached, the 

 boat remains a boat till reduced by weather to a wreck. 



Here let us leave it, and follow the fortunes of one of the 

 crew after he has left his cabin, which he quits in rather a sin- 

 gular manner, emerging through its bottom into the water. 

 Happily, however, he is born a swimmer and can take his 

 pleasure in his native element, poising himself near its surface 

 head downwards, tail upwards. Why chooses he this strange 

 position ? Just for the same reason that we rather prefer, when 

 taking a dabble in the waves, to have our heads above water, 

 for the convenience, namely, of receiving a due supply of air, 

 which the little swimmer in question sucks in through a sort of 

 tube in his tail. 'This breathing apparatus, as well as the tail it- 

 self, serves also for a buoy, and both end in a sort of funnel, com- 



