THE COMMON GNAT. 59 



perhaps the greater part may have left that element 

 only the same day. The female gnat is a regular boat- 

 builder. How the last race of the summer, that are 

 to people the air during the following year, dispose of 

 their eggs, is not completely known ; but no sooner is 

 the surface of the water loosened from the fetters of 

 the winter's ice, than the larvce, or young of the gnat 

 make their appearance in every piece of stagnant 

 water, with their tails at the surface, and reclining 

 their bodies below. If they be disturbed they natu- 

 rally sink, and thus one would be led to conclude that 

 they are hatched at the bottom ; and yet as the eggs 

 which are produced in the warm season cannot be 

 hatched except upon the surface of the water, it is not 

 easy to see how those that are produced in the cold 

 season can be hatched under the water either. That 

 they are hatched in some way or other is clear, and 

 they find their way to the surface with the first gleam 

 of heat. In this state, though they can dive, they 

 must come to the surface to breathe, which they do 

 through the tail as long as they are in the larvae state. 

 When they change to the chrysalis, the body turns and 

 acquires two breathing apertures, which stand up and 

 are open above the surface of the water. After they 

 have remained about ten days in this state, the upper 

 part of the case of the chrysalis begins to open, and 

 the perfect gnat to protrude the fore part of its body. 

 As it works away at its extrication, the case, which 

 though empty does not collapse, answers the purpose 

 of a little boat, as the perfect insect is not adapted for 

 living in, or even on, the water. The body serves as a 

 mast to the tiny vessel, the wings for sails, and the 



