OF NATURAL HISTORY. ^i 



infe<fls are naked, and thofe of others are covered with a 

 lilken \veb, fpuii by the animals before their change is com- 

 pleted. In this flate, many of them lie motionlefs, and 

 feemingly inannimate, during the whole winter. When the 

 fpring or fummer heats return, they burfl from their laft 

 prifon, and, from vile reptiles, are transformed into beauti- 

 ful flies. In this perfect ftate they are exceedingly adlive, 

 fly about in quefl of their mates, and, after propagating 

 their fpecies, the females depofit their eggs, and the fame 

 circle of animation and change perpetually goes round. 

 Hence the ftru^ture and figure of the fame individual ani- 

 mals are three-fold, which renders the knowledge of infe6ls 

 extremely complicated, as we muft be acquainted with them 

 in the feveral forms they fucceilively afiiime. 



There is another peculiarity in the ftruiSlure of infe^ls. 

 They are deprived of bones. But that defect is fupplied, 

 in fome, by a membranous or mufcular fkin, and, in otliers, 

 by a cruftaceous or horny covering. In this circumftance, 

 infects refemble the fliell-animals, whofe bones conflitute 

 the external parts of their bodies. 



In general, the bodies of infe(Sts are compofed of a head, 

 trunk, and abdomen. The head is commonly attached to 

 the trunk by a joint or articulation. Befide eyes, feelers, 

 and mouth, the heads of fome infefts are furnilhed with 

 palpi fixed to the mouth ; and they are either four or fix in 

 number. Each of them gonfifls of two, three, or four joints, 

 and are often miftaken for the antennae or feelers. Thefe 

 inftruments feem to ferve the animals inftead of h?.nds ; for 

 they employ the palpi to bring the food to their mouths, 

 and to keep it fleady while eating. It is aflerted by Lin- 

 naeus, and other Naturalifts, that the heads of infecls are def- 

 titute of brains, noftrils and ears. The minutenefs of the 

 animals under confideration may have hitherto prevented us 

 from diftinguifhing thefe organs. If they want a brain, it 



