vi ARACHNOIDEA SYSTEMATIC REVIEW 509 



CLASS III. Arachnoidea sice Chelicerota Spider-like Articulata. 



Systematic Review. 

 Order 1. Scorpionidae (Fig. 359, p. 512). 



The body is divided into a compact unsegmented cephalo-thorax and a long seg- 

 mented abdomen. In the abdomen again a thick and broad pre- abdomen of 7 

 segments is marked off from a long slender post-abdomen of 5 segments. The 

 terminal segment of the latter carries a poison stiug. On the ventral side of the 2d 

 abdominal segment there is on each side a comb-like appendage. The jaw-feelers 

 (chelicera) and jaw-palps (pedipalps) are provided with pincers. The pedipalps are 

 leg-like, with large pincers. There are 4 pairs of book -leaf trachea (lungs), whose 

 stigmata lie on the ventral side of the 3d to the 6th abdominal segments. Euscorpius, 

 Buthus, A ndroctonus. 



Order 2. Solpugidse (Fig. 358, p. 511). 



Head separate. Thorax of 3 segments, hind body cylindrical, of 10 segments. 

 Chelicera with pincers, pedipalps long and leg-like. Tubular trachea?. Stigmata in 

 pairs on the 1st thoracic, and 2cl and 3d abdominal segments. Galcodes, Sotyuga. 



Order 3. Pseudoscorpionidse (Chernetidse) (Fig. 360, p. 513). 



Cephalo-thorax unsegmented or with two transverse furrows, abdomen broad, flat, 

 of 11 segments. Neither poison stings nor caudal cerci present. Chelicera and 

 pedipalps like those of the Scorpionidce. Tubular trachea?. Two pairs of stigmata, 

 on the 2d and 3d abdominal segments. With spinning glands. Small animals. 

 Cherncs, Chclifcr, Obisium, Chthonius. 



Order 4. Pedipalpi (Thelyphonidae) (Fig. 364, p. 519). 



Cephalo-thorax unsegmented, distinctly marked off from the hind body. The 

 latter flattened, consisting of 11-12 segments. Chelicene claw-shaped. Pedipalps 

 large, ending either in claws or pincers. First pair of legs with flagellate ends, like 

 feelers. Two pairs of book-leaf trachea, whose stigmata lie on the ventral side of the 

 2d and 3d abdominal rings. Thdyphonus (last 3 abdominal segments form a truncated 

 portion clearly marked off from the rest of the abdomen and carrying a long jointed 

 caudal cercus). Phrynus. 



Near the Pedipalpi are perhaps to be classed the small and insufficiently known 

 divisions of the Tartar idee and MicrothelyphonidcK. 



Order 5. Phalangidae. 



Cephalo-thorax unsegmented, hind body of 6 segments, compact, applied along 

 its whole breadth to the cephalo-thorax. Chelicera pincer-like, pedipalps leg- 

 like. Legs often extraordinarily long and thin. Tubular trachea with one pair of 

 stigmata which lies ventrally at the junction of the cephalo-thorax and abdomen. 

 Without spinning glands. Phalangium, Lciobunum, Gonyleptus. 



Order 6. Cyphophthalmidse (often placed as a family of Order 5). 



Cephalo-thorax unsegmented, abdomen of 8 segments. Of the pseudoscorpionid 

 type. Chelicera and pedipalps like those of the Phalangidcc. Tubular trachea. 

 Cyphophthalmus (without spinning glands, with one pair of stigmata on the ventral 

 side of the 1st abdominal segment). G-ibbocellum (spinning glands at the base of the 



