124 GNATS OK MOSQUITOES CHAPTER VII 



the insect allows it to (hop into the water at the mercy of 

 the wind. 



In speaking thus of " hoat-shaped masses," it nmst be 

 understood that Gulices only are referred to, as Anupheles, 

 Mucidus, PanopUtes, Sterjomyia, and some drop their eggs 

 separately, and in these genera the eggs are provided with 

 separate arrangements to secure flotation. 



In Culex, the eggs are glued together, as they are laid, 

 into canoe-shaped masses, which, in size and colour look, 

 as they float on the water, not unlike caraway seeds. Each 

 boat consists of from 250 to 300 eggs, which latter are 

 oblong, more pointed at their upper extremity as they lie 

 in the boat, larger and more rounded below, and ending 

 abruptly in a bordered edge, much like that of certain 

 liqueur flasks ; the opening of which may be said to be 

 closed by a thin membrane, by the rupture of which the 

 larvae escapes. The lower or immersed end is furnished 

 with a curious opening, or rather thinning of the egg-shell, 

 and is surrounded with some curious radiated markings. 

 The object of this arrangement is probably to enable the 

 embryo to obtain oxygen from the water in which the 

 little raft floats. 



The egg-boats must needs float on the surface of the 

 water, as the embryos perish if they become submerged. 

 Only their neck comes in contact with the water. When 

 just hatched the eggs are entirely white, but they soon 

 become shaded green, and in less than half a day they be- 

 come grey. Usually they are laid between five and six in 

 the morning, but in England Mr. Theobald finds that the 

 evening is also chosen for the purpose, and the larvae escape 

 in two or three days, but the interval varies a great deal, 

 according to the temperature, and the particular species. 

 Those of Mucidus apparently take a long time, as Major 

 Close, I. M.S., at Moradabad, kept some, laid by a confined 

 female for a month without the larvae appearing. As, how- 

 ever, the experiment was conducted in a test tube, and it is 

 possible the embryos may have perished for lack of oxygen, 

 this observation must be taken with reservation. As soon 

 as the larvae of Culex have escaped from the eggs, the egg- 



