170 GRAMMAR OF ENTOMOLOOY. 



are symmetrically arranged on the two sides of an 

 axis ; in this division, these organs are disposed 

 like rays round a centre ; their respiratory organs 

 are seated on the surface of the body : many 

 animals of this division are a mere homogeneous 

 pulp : this is a double group.* 



628. It will be evident to every one who has 

 read the preceding Book, that insects must belong 

 to the third of these divisions — the annulated 

 animals. This division comprises two very distinct 

 groups : first, worms {apoda), which have soft 

 bodies without legs ; secondly, condylopodes {con- 

 dylopoda), which have their bodies in a hard case, 

 and have articulated legs. 



629. The province of condylopoda is divided 

 into tribes by the number of legs, thus : insects 

 Qiexapoda) have six legs ; spiders (octopoda) 

 have eight legs ; shell-fish, as crabs (anisopoda), 

 have from ten to eighteen legs ; and centipedes 

 {myriopoda), which have twenty to two hundred 

 legs : the last is a single group ; each of the others, 

 double. 



630. Insects are divided into two tribes, by the 

 circumstance of possessing wings or wanting them ; 

 those which have wings are termed winged insects 

 (teiraptera) ; those which are without wings are 

 termed wingless insects (aptera), 



631. The winged insects are again divided into 



• The characters of the four provinces of animals are from 

 Cuvier's " Regno Animal." 



