their evolution, viz. amongft the hair and on the 
fkins of quadrupeds, the feathers of birds, &c. &c. 
After the fpace of about a week they are hatched 
into fmall larvae, which are of a whitifh colour, 
with a flight tinge of reddifli, and arc extremely 
locomotive; and on being difturbed, throw them- 
felves into various fudden contorfions. When ar¬ 
rived at their full fize, they are about the fifth of 
an inch in length. At this period they prepare 
themfelves for their pupa or chryfalis (late, by en- 
cloling themfelves in a loofely fpun web or diffufed 
envelopement of a very foft, filky, or rather cotton¬ 
like appearance, and of a white colour. In this the 
larva changes into a chryfalis, out of which, in 
about the fpace of twelve days emerges the animal 
in its complete flate. 
Notwithftanding the inconveniences attending 
this little in feci, and the general difapprobation 
which its frequency occalions, there is fomething 
pleating : n the appearance of the Flea. All its 
motions are elegant, and all its potlures indicate 
agility. The fiielly armour w r ith which it is inve- 
lopcd, is in a ftatc of perpetual cleanlincfs; while 
the mufcular power which it is capable of exerting 
is fo extraordinary, as juftly to excite our wonder at 
fo much flrcngth confined, and concentrated, as it 
were, in fo fmall a fpace. Perhaps of all animals 
the Flea poflefies the greateft mufcular ftrength, 
and far exceeds in point of exertion all the infedls 
of the loculi tribe; being able to fpring, on the 
inoft moderate computation, to the diftance of at 
leaft 
