190 NATURAL HISTORY. [cH. XT 



CHAPTER XI. 



Gnat— Bug— Fly-bug- Flea— Chigoe — Louse — Mites and Ticks — 



Gad-fly. 



There are few insects with whose form we are 

 better acquainted than that of the gnat. It is to be 

 found in all latitudes and climates ; as prolific in the 

 polar as in the equatorial regions. In 1736 they 

 were so numerous, and were seen to rise in such 

 clouds from Salisbury cathedral, that they looked 

 like columns of smoke, and frightened the people, 

 who thought the building was on fire. In 1766, they 

 appeared at Oxford in the form of a thick black 

 cloud; six columns were observed to ascend the 

 height of fifty or sixty feet. Their bite was attended 

 with alarming inflammation. To some appearances 

 of this kind our great poet Spenser alludes, in the 

 following beautiful simile : — 



As when a swarm of gnats at eventide, 



Out of the fennes of Allan doe arise, 



Their murmurring small trumpets sownden wide, 



Whiles in the air their cHist'ring army flies, 



That as a cloud doth seem to dim the skies ; 



Ne man nor beast may rest or take repast, 



For their sharp wounds and noyous injuries, 



Till the fierce northern wind, with blustering blast, 



Doth blow them quite away, and in the ocean cast. 



In Lapland their numbers have been compared to 

 a flight of snow when the flakes fall thickest, and the 

 minor evil of being nearly suffocated by smoke is 

 endured to get rid of these little pests. Captain 

 Stedman says, that he and his soldiers were so tor- 

 mented by gnats in America that they were obliged 

 to dig holes in the ground with their bayonets, and 

 thrust their heads into them for protection and sleep. 

 Humboldt states, that "between the little harbour 



