TRACHEARI^. 319 



front of the trunk, or are inferior, and always terminating in a di- 

 dactyle forceps, preceded by one or two joints. 



They have two filiform palpi, composed of five joints, the last of 

 which is terminated by a small nail ; two distinct eyes ; two jaws 

 formed by the prolongation of the radical joint of the palpi, and fre- 

 quently four more *, which are also a mere dilatation of the hip of the 

 two first pairs of legs. The body is oval or rounded, and covered, 

 the trunk at least, with a firmer skin ; there is also an appearance of 

 annuli or plicae on the abdomen. The legs, of Avhich there are always 

 eight, are long, and distinctly divided, like those of insects f At the 

 origin of the two posterior legs, at least in several — Phalangium — 

 are two stigmata, one on each side, but hidden by their hips. 



Most of them live on the ground, at the foot of trees, and on plants, 

 and are very active ,• others conceal themselves under stones and in 

 moss. Their sexual organs are internal, and placed under the mouth. 



Phalangium, Lin., Fab. 



The chelicerae projecting, much shorter than the body ; eyes placed 

 on a common tubercle. 



Their legs are very long and slender, and when detached from the 

 body show signs of irritability for a few moments. The two sexes 

 in coitu are placed opposite to each other ; this occurs at the latter 

 end of summer. The penis of the male is formed like a dart, and has 

 a demi-sagittal termination. The female has a filiform, flexible, 

 annulated and membranous oviduct. The tracheae are tubular. 



Ph. cornutum, L., the male ; Opilio, Id., the female ; Herbst., 

 Monog. Phal., I, 3, the male; lb., 1, the female. Body oval, 

 reddish or cinereous above; black beneath; palpi long; two 

 ranges of small spines on the ocular tubercles, and spines on the 

 thighs ; corneous chelicerse in the males ; a blackish band with 

 a festooned margin on the back of the female J. 



A celebrated English entomologist, M. Kirby, under the name of 

 GoNOLEPTEs, has formed a particular genus of the species with spi- 

 nous palpi, the two last joints of which are nearly equal, sub-oval, and 

 terminated by a stout nail, and in which the hips of the two posterior 



* If we suppose that the two superior jaws, with their palpi, represent the mandi- 

 bles of the Crustacea Decapoda, the other four will also represent the jaws of the 

 same animals, and the two jaws and inferior lip of the triturating (Broyeiirs) Insects. 

 From M. Marcel de Serres we learn that the ganglion which immediately follows the 

 brain is opposite to the third pair of legs, which, according to these approximations, 

 are analogous to the first pair in Insects ; now, there also we find the same ganglion 

 in the latter. See Myriapoda. 



t The hips, thighs, tibis, and tarsi are the same as in the preceding families. 

 But the legs of the Arachnides Tracheariae are composed of short joints, whose rela- 

 tive proportions differ very gradually, so that these distinctions of parts are less 

 apparent. 



X See the Monograph of this genus, published by Latreille at the end of the His- 

 toire des Fourmis, and those of Herbst., and Hermann, Jun., Mem. Apter, 



