NA TURA L HIS TOR Y OF SELBORNE. 1 5 5 



[It will be proper to premise here that the sixteenth, eighteenth, 

 twentieth, and twenty-first letters have been published already in 

 the "Philosophical Transactions;" but as nicer observation has 

 furnished several corrections and additions, it is hoped that the 

 republication of them will not give offence ; especially as these 

 sheets would be very imperfect without them, and as they will 

 be new to many readers who had no opportunity of seeing them 

 when they made their first appearance.] 



" The hirundines are a most inoffensive, harmless, entertaining, 

 social, and useful tribe of birds ; they touch no fruit in our gardens ; 

 delight, all except one species, in attaching themselves to our 

 houses ; amuse us with their migrations, songs, and marvellous 

 agility ; and clear our outlets from the annoyances of gnats and 

 other troublesome insects. Some districts in the south seas, near 

 Guiaquil,* are desolated, it seems, by the infinite swarms of 



1. HI1TOBOSCA HIRUND1MS. 2. NIRMI. 



venomous mosquitoes, which fill the air, and render those coasts 

 insupportable. It would be worth inquiring whether any species 

 of hirundines is found in those regions. Whoever contemplates 

 the myriads of insects that sport in the sunbeams of a summer 

 evening in this country, will soon be convinced to what a degree 

 our atmosphere would be choked with them was it not for the 

 friendly interposition of the swallow tribe. 



" Many species of birds have their peculiar lice ; f but the 



* " See Uiloa's Travels." 



t Or Nirmi, n^w fully de?cribed in the " Mr nographia Anoplurorum Britanniae," by 

 Henry Denny ; who has also in readiness for publicatic n materials sufficient for a volume 

 upon the parasites of exotic species, as well as on those which infest many of the foreign 

 mammalia. This volume would be of great interest, and only requires sufficient encourage- 

 ment to be brought out. 



