VAEIOUS PARTS OF NATURE 343 



foot after another, and disengage their hollow caps from the 

 slippery surface. ^ 



Upon the same principle that flies stick and support themselves, 

 do boys, by way of play, carry heavy weights by only a piece of 

 wet leather at the end of a string clapped close on the surface of 

 a stone. 



TIPULiE, OR EMPEDES. 



May. 2 Millions of empedes, or tipulce, come forth at the close of 

 day, and swarm to such a degree as to fill the air. At this junc- 

 ture they sport and copulate ; as it grows more dark they retire. 

 All day they hide in the hedges. As they rise in a cloud they 

 appear like smoke. 



I do not ever remember to have seen such swarms, except 

 in the fens of the Isle of Ely. They appear most over grass 

 grounds. 



APHIDES.8 



On the 1st of August, about half an hour after three in the 

 afternoon, the people of Selbome were surprized by a shower of 

 Aphides which fell in these parts. They who were walking the 

 streets at that time found themselves covered with these insects, 

 which settled also on the trees and gardens, and blackened all 

 the vegetables where they alighted. These armies, no doubt, 

 were then in a state of emigration, and shifting their quarters ; 

 and might perhaps come from the great hop-plantations of Kent 

 or Sussex, the wind being that day at North. They were 

 observed at the same time at Famham, and all along the vale to 

 Alton. 



^ [The walking of flies on smooth surfaces, either vertical or looking downwards, 

 has now been shown to depend upon a sticky fluid exuded from the glandular hairs 

 of the feet. The hairs have been seen to be tipped with drops ; the drops have 

 been drawn out into transparent threads, or left upon slips of glass over which the 

 fly had walked. See Blackwall, Trans. Linn. Soc, xvi. , pp. 487-492, 767-770"(i83i) ; 

 and Dewitz, Pflilger's Arch., xxxiii., pp. 440-481 (1884).] 



'[This word is not found in the original (ed. 179s)'] 



' [This extract is not found in the original (ed. I79S)0 



