3204 THE JOINTED ANIMALS 



and form pincers; the mandibles being small, and also pincer-like, while all the legs 

 are of the ordinary locomotor type. There is, moreover, no waist separating the 

 thorax from the abdomen, and the latter is distinctly jointed. All these character- 

 istics impart a considerable superficial likeness to scorpions, and formerly the two 

 groups were looked upon as closely allied, although there are in reality many im- 

 portant, deep-seated differences between them. The abdomen, for instance, in the 

 Pseudoscorpiones, is practically the same width throughout, none of the posterior 



segments being narrowed to form a tail, and the last bears 

 no skeletal piece at all comparable to the scorpion's sting. 

 The breathing organs in the false scorpions are structur- 

 ally of the same nature as those of the Solifugce, consist- 

 ing of tracheal tubes, which open by two pairs of stigmata, 

 situated upon the third and fourth abdominal segments. 

 Like the true spiders, the false scorpions possess silk 



' .... glands, but these are situated, not in the abdomen, but in 

 BOOK SCORPION, Chehfer 



cancroides. t^ 6 cephalothorax, and open by minute apertures at the tip 



(Much enlarged. ) of the movable fingers of the mandibles. In addition to 



these glands, there are others in the abdomen termed 



cement glands, which open upon the second and third sternal plates. The function 

 of these is not known, but it has been suggested that they may secrete the gummy 

 material which causes the eggs to adhere together. The eyes, either two or four in 

 number, are placed on the sides of the fore part of the head region. 



The false scorpions, which occur in all temperate and tropical countries, live 

 for the most part under stones and the bark of trees, or hidden in moss or vegetable 

 rubbish; only two European species, namely, Chelifer cancroides and Chiridium 

 museorum, are commonly found in human dwellings, in dark corners and the wainscot- 

 ing of rooms, in herbaria, or even in boxes of insect collections. Under these con- 

 ditions the former is but rarely met with, but large numbers have been taken 

 together in old beehives, wasp nests, and badly kept pigeon houses. The two 

 species, however, are by no means found exclusively in habitats of this nature, both 

 having been observed under the bark of trees, far from the abodes of men. In 

 South America it is by no means uncommon to find species of Chelifer living be- 

 neath the elytra of the large longicorn beetles. Some species frequent caves and 

 grottoes, and many of these, from dwelling permanently in the dark, have lost all 

 trace of eyes. L,astly, there are others which occur exclusively upon the seashore. 

 Garypus littoralis, for instance the giant of the order, so far as Europe is con- 

 cerned being found in Spain and Corsica at the foot of the cliffs and beneath sea- 

 weed, while, on the south coast of England Obisium maritimum may be met with 

 under the same conditions. The Chelifer idee are, for the most part, slow in their 

 movements, walking with the pincers extended to feel the way, although they also 

 progress with facility sidewaj'S or backward. The Obisiidce, on the contrary, are 

 much more agile, darting backward with great speed when alarmed. Some species 

 of the genus Chithonius, indeed, are said to possess leaping powers of no mean order. 



Although possessing silk glands, the false scorpions have not learned the art of 

 insnaring prey after the manner of spiders. They merely use the silk for construct- 



