NATURAL HISTORY OF SELBORNE. 151 



" A species of them is familiar to horsemen in the south 

 of England under the name of forest-fly ; and to some of 

 side-fly, from its running sideways like a crab. It creeps 

 under the tails, and about the groins, of horses, which,- at 

 their first coming out of the north, are rendered half frantic 

 by the tickling sensation ; while our own breed little 

 regards them. 



" The curious Reaumur discovered the large eggs, or 

 rather pupce, of these flies as big as the flies themselves, 

 which he hatched in his own bosom. Any person that will 

 take the trouble to examine the old nests of either species 

 of swallows may find in them the black shining cases or 

 skins of the pupae of these insects ; but for other particu- 

 lars, too long for this place, we refer the reader to 

 L'llistoire dlnsectes of that admirable entomologist. Tom. 

 iv., pi. ii." 



LETTER XVL 



SELBORNE, Nov. 2Qth, 1773. 



IN obedience to your injunctions I sit down to give you 

 some account of the house- martin, or martlet ; and if my 

 monography of this little domestic and familiar bird should 

 happen to meet with your approbation, I may probably 

 soon extend my inquiries to the rest of the British 

 hirundines the swallow, the swift, and the bank-martin. 



A few house-martins begin to appear about the 16th 

 April ; usually some few days later than the swallow. For 

 some time after they appear the hirundines in general pay 



