MYR1AP0DA. 253 



posterior extremity of the body, as in most of the following 

 Insects. The stigmata are lateral or dorsal, and more appa- 

 rent than in the preceding family. 



The Chilopoda, which, in the system of Leach, form the 

 order Syngnatha, from these last characters, the nature of 

 the respiratory organs and the feet, may be thus divided : 



Some have but fifteen pairs of feet(l), and their body viewed from 

 above presents fewer segments than when seen from beneath. 



Scutigera, Lam. Cermatia, Illig. 



The body covered with eight scutelliform plates, under each of 

 which M. Marcel de Serres has observed two pneumatic sacs or vesi- 

 cular tracheae, which receive air and communicate with lateral and 

 inferior tubular trachea?. The under part of the body is divided 

 into fifteen semi-annuli, each bearing a pair of feet, terminated by a 

 very long slender multi-articulated tarsus; the last pairs are more 

 elongated; the eyes large and compound. 



Their antennae are slender and tolerably long; the two palpi salient 

 and furnished with small spines. The body is shorter than in the 

 other genera of the same family, and the joints of their feet are pro- 

 portionably longer. 



The Scutigerse, which by these characters form the passage from 

 the preceding family to the present one, are extremely agile animals, 

 and frequently part with some of their feet when seized. 



The species found in France(2) conceals itself between the 

 beams and rafters of houses. 



Lithobius, Leach. 



The stigmata lateral; body divided above and beneath into a simi- 

 lar number of segments, each bearing a pair of feet; the superior 

 plates alternately longer and shorter, and overlapping each other 

 close to the extremity. 



L. forficatus; Scolopendraforficata, L. ; Fab., De Geer; Geoff., 



(1) Dr Leach makes two pairs more by including the palpi and the hook-like 

 feet of the head. 



(2) The Scolopendred vingt-huit pattes of Geoffroy which appears to differ from 

 the S. coleoptrata, Panz., Faun. Insect. Germ., L, xii, and from that of Linnaeus; 

 lulus araneoides, Pall., Spicil. Zool., IX, iv, 16; Scolopendra longicornis, Fab., of 

 Tranquebar. See also Leach, Zool. Miscell., Cermatia llvida, CXXXVI, and Lin. 

 Trans. XIV. 



