M I C RO S CO PICA h 



Essay s, 



and blood tliirfty difpofition of the flea, of the caution with which 

 it comes to the attack, and the readinefs with which it avoids 

 purfuit. It belongs to the clafs aptera, has two eyes, fix feet, 

 particularly conflrutled for leaping, the feelers are filiform, the 

 roilrnm is inflected, fetaceous, and armed with a fling ; the belly 

 is comprefled. This creature is produced from eggs, which they 

 depofit on the animals that afford them food, or affix them to the 

 wool of blankets, rugs, &c. of thefe eggs are hatched white 

 ■worms,- which adhere clofely to the body of the animal, or other 

 fubflance on which they are produced ; in a fortnight they come 

 to a tolerable fize, and are very lively and active; but if they 

 are touched at this time, they roll themfelves up in a ball. After 

 about eleven days from the time of their being hatched, they feek 

 a place to hide iru and if viewed by a microfcope,-will be found 

 weaving a covering or bag, in which they affume the pupa ftate, 

 where they continue from nine days to a fortnight, when having 

 acquired fufficient flrength, they burft from their confinement, 

 perfectly formed,, and armed with powers to djfturb the peace of 

 an emperor. 



The flea when examined by the microfcope is not an unplea* 

 fing object : it is difficult, however, to obtain fuch a view of it as 

 will difplay the mechanifm and apparatus belonging to the head. 

 Thefe parts are but imperfectly reprefented in the celebrated 

 drawing of Dr. Hooke. The neck is long, finely arched, and 

 much refembles the tail of a lob Iter ; the body is covered all over 

 with a fuit of fable armour, formed of a hard Ihelly fubflance, 

 curioufly jointed and folded over one another, and yet yielding 

 to all the nimble motion of the little animal : the edges of the 

 fcales are curioufly fet with fhort fpikes or hairs : it has two 



