160 MISCELLANEOUS OBSERVATIONS. 



Many species of birds have their peculiar lice : but the 

 Mrundines alone seem to be annoyed with dipterous insects 

 which infest every species, and are so large, in proportion to 

 themselves, that they must be extremely irksome and inju- 

 rious to them. These are the Jiippobosc(B hirundinis, with 

 narrow subulated wings, abounding in every nest ; and are 

 hatched by the warmth of the bird's own body during incu- 

 bation, and crawl about under its feathers. 



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 particulars, too long for 

 this place, we refer the reader to EHistoire d'lnsectes of that 

 admirable entomologist. Tom. iv. pi. 11. 



LETTEE LIT. 



TO THOMAS PENNANT, ESQ. 



SELBORNE, Nov. 9, 1773. 



DEAR SIR, As you desire me to send you such observations 

 as may occur, I take the liberty of making the following 

 remarks, that you may, according as you think me right or 

 wrong, admit or reject what I here advance, in your intended 

 new edition of the British Zoology. 



The osprey* was shot about a year ago at Frinsham Pond, 

 a great lake, at about six miles from hence, while it was 



* British Zoology, vol. i. p. 1 28. This beautiful bird, the Falco haliceetus 

 of Pennant, has been frequently seen and destroyed in this country. ED. 



