126 CLASS INSECTA. 



to indicate the separation of the trunk and abdomen. With 

 regard to the other myriapods in which the sexual organs 

 are posterior, we remark that in an analogous portion of the 

 body of certain species ( Scolopendra morsitans), an inver- 

 sion takes place in the successive order of the stigmata, 

 which would seem to announce the same distinction. 



The myriapods live and grow a longer time than the other 

 insects, and according to M. Savi, two years, at least, are 

 necessary to some of them, (the iuli,) for the genital organs 

 to become apparent. 



From this assemblage of facts, we may conclude, that these 

 animals, on the one side, approximate to the Crustacea and 

 arachnida, and on the other, to the insects ; but considered 

 with regard to the presence, form, and direction ot the tra- 

 cheae, they certainly appertain to the last class. 



We shall divide them into two families, perfectly distinct, 

 both by reason of their organization and habits, and com- 

 posing, in Linnaeus, two generic sections. 



The first family of the Mykiapods, that of 



The Chilognatha, Latr., or the genus of the Iuli of 

 Linnaeus, 



Has the body generally crustaceous, and often cylindrical; 

 the antennae a little thicker towards the end, or almost of 

 an equal thickness, and composed of seven articulations; 

 two thick mandibles without palpi, very distinctly divided 

 into two portions, by a medial articulation, with imbricated 

 teeth, and implanted in a concavity of its upper extremity ; 

 a sort of lip (lanquet), situated immediately below them, 

 covering them, crustaceous, plane, divided at its exterior 

 surface, by longitudinal sutures and emarginations, into 

 four principal areas, tuburculated at the upper edge, and 

 of which the two intermediate ones are more narrow and 

 short, situated at the upper extremity of another area, serv- 



