308 ARACHNIDA SCORPIONIDEA PEDIPALPI CHAP. 



There are three sub -families, Megacorminae, Euscorpiinae, 

 and Chactinae. 



The MEGACORMINAE include but a single Mexican form, 

 Megacormus granosus. There is a single toothed keel under 

 the " tail," and all the under surface is spiny. There is a row of 

 long bristles under the tarsus. 



In the EUSCORPIINAE the upper surface of the hand is divided 

 into two surfaces almost at right angles by a strong finger -keel. 

 This is a small group of about six species found. in the Mediter- 

 ranean region. The two genera are Euscorpius and Belisarius. 



The CHACTINAE are without any marked keel on the hand. 

 The scorpions of this sub-family are found in equatorial South 

 America and the West Indies, where there are more than 

 twenty species divided about equally between the four genera 

 Chactas, Broteas, Broteocliactas, and Teuthraustes. 



Fam. 5. Vejovidae.^ No tibial, but two pedal spurs. A single 

 row of hairs or papillae under the tarsus. Sternum generally 

 broader than long. Elongate stigmata, and three lateral eyes. 



Seven of the eight genera of this family include only 

 American forms, the principal genus being Vejovis, with about 

 ten species. The genus Scorpiops, however, belongs to the 

 Indian region and numbers more than ten species. 1 



Fam. 6. Bothriuridae, Sternum much reduced aqd some- 

 times hardly visible, consisting of two slight, nearly transverse bars. 



Of the seven genera of this family one, Cercophonius, is 

 Australian. The other six genera include some dozen South 

 American forms, Bothriurus having four species. 



Order II. Pedipalpi. 



Arachnids with non-chelate, two-jointed chelicerae, powerful 

 pedipalpi, and four pairs of legs, of which only the last three are 

 ambulatory, the first being used as tactile organs. The cephalo- 

 thorax is usually covered by an undivided carapace, but the pedun- 

 culated abdomen is segmented. Respiration is by lung-books. 



The Pedipalpi are a little-known group of animals of nocturnal 

 .habits. Though rarely seen they are widely distributed, being 

 found in India, Arabia, the greater part of Africa, and Central 



1 Pocock, Fauna of British India, "Avachnida." London, 1900. 



