500 CLASS ARACHNIDA. 



The third family of the Trachean Arachnides, 

 that of 



HoLETRA, Hermann, 



Has the thorax, and abdomen united in a mass, under a com- 

 mon epidermis \ the thorax is mostly divided into two, by a 

 strangulation, and the abdomen presents only in some the 

 appearances of rings, formed by some folds of the epidermis. 



The anterior extremity of their body is often advanced in 

 the form of a muzzle, or bill. The majority have eight feet, 

 and the others six. 



This family is composed of two tribes. 



The first tribe, that of Phalangita, Zrti., has very ap- 

 parent forceps, either projecting in front of the trunk, or in- 

 ferior, and always terminated by a didactylous pincer, pre- 

 ceded by one or two articulations. 



They have two palpi in the form of a thread, of five articu- 

 lations, the last of which is terminated by a small claw ; two 

 distinct eyes ; two jaws formed by the elongation of the radical 

 articulation of the palpi, and often four additional ones, which 

 are likewise nothing but a dilatation of the haunch of the first 

 two pair of feet ; the body oval, or rounded, covered, at least 

 on the trunk, with a more solid skin ; some appearances of 

 rings, or folds, on the abdomen. The feet, always eight in 

 number, are long, and distinctly divided after the manner of 

 those of insects. Many at XeSi^i fphalangnim J have, at the 

 origin of the two posterior feet, two stigmata, one at each side, 

 but concealed by the haunches. 



The majority live on the ground, on plants, at the bottom 

 of trees, and are very agile ; others conceal themselves under 

 stones, and in moss. Their sexual organs are placed under 

 the mouth, and internal. 



