406 



GLEANINGS. 



many uncivilised nations, upon being deprived of their husbands, had, 

 like them, sought death by self-inhumation. 



On the humming of gnats. (Culicidce.) — It appears to me 

 very probable that the humming noise emitted by the gnat when flying 

 about in a dark room is useful to the insect itself, for, as it would be 

 differently modulated according to its distance from, or nearness to, 

 surrounding objects, it may have the effect of preventing its injuring 

 itself by knocking against obstructions to its flight. As a proof of the 

 great difference in sounds arising from even but trifling causes, we have 

 only to take a card in hand and whistle against its edge at a little 

 distance, then at a greater distance, and then against its flat surface at 

 a greater or less distance, and we shall observe that the tone widely 

 differs under each of these circumstances. Now, if we suppose that the 

 gnat knows, from either instinct or experience, that sounds thus differ 

 according to such circumstances as the above, it may learn its situation 

 in a dark room by the variation produced upon its piping noise (which 

 may thus be as serviceable to it in the dark as its sight in the day time), 

 and avoid breaking its wings, or otherwise hurting itself by flying 

 against anything in its way. In the same manner, I think, one may 

 explain the utility of the humming of the cockchafer (Melolontha 

 vulgaris), the dung-beetle (Geoirupes slercorarius), and many other 

 insects. 



The wagtail does not always shun noise. — The common 

 wagtail in general seeks a quiet cottage or other retired place to build 

 in, and shuns all noise, but in the instance I now relate, a pair of these 

 birds built their nest in perhaps the noisiest place they could have 

 selected. Some years since, when I was a pupil of Mr. Bicknell's at 

 Tooting in Surrey, a couple of these birds built between the roofing of 

 the school-room, which was detached from the house. On one side of 

 the building there was a pond partitioned off from the play-ground, and 

 thither the birds frequently resorted, flying from this backwards and 

 forwards to their nests, quite regardless of the gambols and shouts of 

 the boys at play. In this situation, no doubt, they would have remained, 

 had not one of the boys more ornithologically mischievous than the rest, 

 by means of a ladder and a net, entrapped the old birds whilst flying 

 out from between the tiles. 



Laytonstone, July, 1833. 



