454 The Natural History of Se I borne 



MUSCLE. FLIES. 



IN the decline of the year, when the mornings and evenings 

 become chilly, many species of flies (Muscce) retire into houses, 

 and swarm in the windows. 



At first they are very brisk and alert; but as they grow 

 more torpid, one cannot help observing that they move with 

 difficulty, and are scarce able to lift their legs, which seem as 

 if glued to the glass ; and by degrees many do actually stick 

 on till they die in the place. 



It has been observed that divers flies, beside their sharp 

 hooked nails, have also skinny palms, or flaps to their feet, 

 whereby they are enabled to stick on the glass and other 

 smooth bodies, and to walk on ceilings with their backs down- 

 ward, by means of the pressure of the atmosphere on those 

 flaps ; the weight of which they easily overcome in warm 

 weather, when they are brisk and alert. But in the decline of 

 the year, this resistance becomes too mighty for their dimin- 

 ished strength ; and we see flies labouring along, and lugging 

 their feet in windows as if they stuck to the glass, and it is 

 with the utmost difficulty they can draw one foot after another, 

 and disengage their hollow caps from the slippery surface. 



Upon the same principle that flies stick and support them- 

 selves ; 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. WHITE. 



TIPUL^E, OR EMPEDES. 



MAY. 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 

 juncture 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 remember to have seen such swarms, except in 

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

 grounds. WHITE. 



