354 INSECTA. 



dinal sutures and emarginations into four principal area;, tubercu- 

 lated on their superior margin, the two intermediate of which, 

 narrower and shorter, are placed at the superior extremity of another 

 area, serving as a common base: the feet very short, and always ter- 

 minated by a single hook. 



The Chilognatha move very slowly, or slide along, as it were, and 

 roll themselves spirally or into a ball. The first segment of the 

 body, and in some the following one, is the largest, and has the form 

 of a corselet or little shield. It is only at the fourth, in some, and 

 at the fifth or sixth in others, that the duplication of the feet com- 

 mences; the first two or four feet are even entirely free to their ori- 

 gin, where they merely adhere to their respective segments by a 

 median or sternal line. The last two or three rings are without 

 feet. A series of pores is observed on each side of the body, which 

 were considered as stigmata, but, according toSavi,they are simply 

 designed to afford a passage to an acid fluid of an extremely disa- 

 greeable odour, which appears to serve as a means of defence; the 

 respiratory apertures, for whose discovery we are indebted to him, 

 are situated on the sternal part of each segment, and communicate 

 internally with a double series of pneumatic sacs strung together 

 like a rosary, extending along the body, from which proceed tracheal 

 branches that ramify over the other organs. According to an ob- 

 servation of Straus, the sacs or vesicular tracheae are not, as usual, 

 connected with each other by a principal trachea. 



These Insects feed on dead and decomposed animal and vegetable 

 matters; they deposit in the ground a large number of eggs. Ac- 

 cording to the system of Linnaeus they form but one genus, that of 



IULUS, Lin. 



Some have a crustaceous body without terminal appendages, and antennae 

 enlarged near the end. 



GLOMEHIS, Lat. 



Resembling Onisci; oval, and rolling into a ball; the body convex above, 

 and concave underneath, with a range of little scales analogous to the 

 lateral divisions of the Trilobites along each of its inferior sides. These ani- 

 mals are terrestrial, and live under stones in hilly places. 



IULUS, Lin. 



The body of the true lull is cylindrical and very long, and has no ridge 

 or trenchant edge on the sides of the annuli; they roll themselves up spirally. 



