CLASS V. ARACHNIDA. 



and spiders, which they capture with their powerful pedipalps 

 and sting to death with their poison sting. The metasoma is 

 carried turned forward over the mesosoma when they run. The 

 stories of their deliberately committing suicide when surrounded 

 by a ring of burning coal are fabulous, though in their pain they 

 lash their tails about and may wound themselves. 



Geologically scorpions are very old though there are but few 

 fossil representatives. Palaeophonus, apparently an aquatic 

 form, in the arrangement of its walking legs and the number of 

 its gnathobases is primitive. It and Proscorpius are Silurian, 

 Eoscorpius Carboniferous and Tityus Oligocene. 



There are 6 families amongst which are divided some 300 

 species, neglecting a good many doubtful ones. 



Fam. 1. Buthidae. Triangular sternum (p. 801), narrowing anteriorly, 

 basal spurs external and internal, the former often with an accessory spine . 

 Tarsal spur often on 3rd as well as 4th pair of legs. Lateral eyes 3 or 5. 

 Buthus with some 25 Old World species ; Parabuthus African and Arabian ; 

 Grosphus with but 2 species both from Madagascar ; Odonturus East 

 Africa and Madagascar, 2 species ; Butheolus Mediterranean and Central 

 and Southern Asia. The following six genera each have one species, Micro- 

 buthus from the Gulf of Aden ; Nanobuthus E. Africa ; Charmus Ceylon ; 

 Stenochirus Ceylon ; Isometroides Australia ; Ananteris Brazil ; Archiso- 

 metrus with 20 species from Asia, Africa and Australia ; Uroplectes 16 

 species all African with the exception of one Oriental species ; Babycurus 

 6 Central African species ; Isometrus 6 cosmopolitan species ; Zabius 1 

 S. American species ; Tityus 30 American species ; Centrums 13 also New 

 World species. 



Fam. 2. Seorpionidae. Sternum with parallel or almost parallel sides, 

 usually pentagonal. Basal spur only on outer side. . No tarsal spur on 

 3rd and 4th legs. Lateral eyes 2 or 3. Nebo one Syrian and Arabian 

 species ; Oeclus 1 species W. Indies ; Diplocentrus 6 Neotropical species ; 

 Urodacus 6 Australian species ; Heterometrus 12 Indian species ; Pandinus 

 9 species from Africa and Arabia ; Scorpio Mediterranean, Africa and Asia 



2 species ; Opisihophthalmus S. African with 29 species ; Hemiscorpion, a 

 single species Bagdad and Aden ; Hadogenes 5 South African and Malagasy 

 species ; Opisthacanthus 8 species from Africa and America ; Cheloctonus 



3 S. African species ; Ischnurus 1 species from some East African islands ; 

 Hormurus 2 species Oriental and Australian ; lomachus 2 Indian and East 

 African species. 



Fam. 3. Chaerilidae. An inner and an outer tarsal spur, two rows of 

 bristles beneath the terminal lobe of the legs, which is not rounded. T\vo 

 lateral eyes with a yellow spot behind. Theprosoma narrows anteriorly. 

 The movable claw of the chelicerae bears a row of low teeth and that of 

 the pedipalps a row of obliquely overlapping ridges. Stigmata circular. 

 Sternum as long or longer than broad, with a median groove ending in a 

 pit. Chaerilus 5 Oriental species. 



Fam. 4. Chactidae. An inner and outer tarsal spur, terminal lobe not 

 rounded. Often blind but when present the lateral eyes are two in 



