206 THE CANADIAN NATURALIST. 



Noctiluca) its purpose is to direct the winged male to the 

 wingless female. But it is surely forgotten that other insects 

 have no difficulty in finding the females which are stationary, 

 but that, on the contrary, they possess a peculiar power of 

 discovering them, even when totally concealed from sight, as 

 when enclosed in boxes, and even coming down chimneys, 

 and beating against windows, to obtain access to them ; on 

 which power, the plan of taking males, called " sembling," 

 is founded. And whether or not, the explanation of the 

 phenomenon would not answer in this instance, where both 

 sexes are winged. 



C. — It is not without a parallel in other insects, such as 

 some Elaters and Fvlgorm ; and in those very curious mol- 

 lusca so abundant in the ocean, which make the ship's path 

 a path of light and splendour. Have you ever observed these 

 marine illuminations with any attention ? 



F. — I have not had any opportunity of making micro- 

 scopic observations on them ; but my curiosity and attention 

 have often been excited by the appearances, and I have 

 occasionally made some notes on their peculiarities. In 

 crossing the Atlantic from Newfoundland to England, I 

 have noticed three distinct kinds of light in the water, all 

 visible at the same time. One was the cloudy, milky ap- 

 pearance of the sea under the stem and in the wake, just as 

 if the ship had disturbed a quantity of chalk at the bottom : 

 another kind consisted of an innumerable multitude of mi- 

 nute bright sparks, appearing at the sides of the vessel, and 

 among the former cloudy light, though perfectly distinct 

 from it. These two sorts appeared to be caused by the 

 ploughing of the ship through the water, but the third sort 

 was evidently quite independent of this cause. It may be 

 described as broad flashes of light on the surface of the waves, 

 coming and going like sudden fitful flashes of lightning. 



