28 DEFINITION OF THE TERM INSECT. 



Sub-kingdom — Annulosa a . 

 Class — Insecta. 

 First Definition — From their external Organization. 

 Body — divided into Head-^-Trunk— Abdomen. 



Head. — Principal seat of the organs of sensation. 



Organs of sight. Immoveable eyes, simple or com- 

 pound, varying in number. 



Organs of hearing uncertain, probably connected 

 with the antennae. 



Organ of taste. Ligula or palate within the mouth, 

 accompanied by the organs of manducation — a pair 

 of mandibles and maxillae and an upper and lower 

 lip, or their representatives. 



Organs of touch. Principally two jointed antennas 

 or their representatives, and four jointed feelers — 

 two maxillary and two labial. 



Trunk. Principal seat of the organs of motion. 

 Organs of walking, runnings or jumping. Six or 



eight jointed thoracic legs, in pairs. 

 Organs of fight. Four wings or their representa- 



a It may not be without use to give here a short definition of the 

 Annulosa ; I mean excluding the Vermes, which Mr. W. MacLeay 

 has included ; and the Annelida, which Latreille has made the fifth 

 of his Annulose classes. Ann. du Mus. 1821. 



Annulosa. Animal invertebrate, oviparous ; external integument of 

 a firmer consistence than the internal substance, serving 

 as a general point of attachment to the muscles ; ci/es 

 immoveable ; legs more than four, jointed. 

 Classes. 



1. Crustacea. Gills external ; more than eight legs. 



2. Arachnida. Gills internal ; spiracles ; eight legs. 



3. Insecta. Tracheae; spiracles; six to eight thoracic legs. 



