INSECTS AND THEIR NEAR RELATIVES 



seven segments; and a slenderer tail -like division, the post-abdomen, 

 consisting of five segments. At the end of the post-abdomen there is a 

 large poison-sting, which appears like a segment. 

 The chelicerae and the pedipalpi are provided with 

 pincers. The pedipalpi resemble in a striking man- 

 ner the great claws of lobsters. The cephalothorax 

 bears from three to six pairs of eyes. Scorpions 

 breathe by means of lung sacs, of which there are 

 four pairs, opening on the lower side of the third 

 to the sixth abdominal segments. 



Full-grown scorpions possess a pair of comb-like 

 organs on the lower side of the second abdominal 

 segment. The function of these organs may be 

 tactile. 



The sexes of scorpions differ in that the male has 

 broader pincers and a longer post-abdomen. Scor- 

 pions do not lay eggs, the young being developed 

 within the mother. After the birth of the young, 

 the mother apparently shows great regard for them, 

 carrying them about with her for some time, at- 

 tached by their pincers to all portions of her body. 



Scorpions live in warm countries. They are com- 

 mon in the southern portion of the United States, 

 but are not found in the North. They are nocturnal, remaining concealed 

 during the day, but leaving their hiding-places at dusk. When they run 

 the post-abdomen of some species is bent upwards over the back. They 

 feed upon spiders and large insects, which they seize with the large pin- 

 cers of their palpi, and sting to death with their caudal poison sting. 



The sting of a scorpion rarely if ever proves fatal to a grown man, 

 although the larger species, which occur in the Tropics, produce serious 

 effects by their stings. 



Fig. 8. — A Scorpion. 



Order PSEUDOSCORPIONIDA 



The Pseudoscorpions 



The pseudoscorpions are small arachnids which resemble scorpions in 

 the form of their pedipalps and of their body, except that the hind part 

 of the abdomen is not narrow, as is the post-abdomen of scorpions, 

 and they have no caudal sting. The abdomen is broad, 

 flat, and thin and only one or two pairs of eyes are present 

 on the cephalothorax. 



The pedipalps are enormously developed and are chelate, 

 resembling those of the scorpions (Fig. 9). The pseudoscorp- 

 ions are especially interesting because they possess silk glands 

 in the cephalothorax which open near the tip end of each 

 chelicera. The silk which they spin is used for making a 

 fig. 0. — a Pseu- web or cocoon in which the pseudoscorpion can retreat dur- 

 ing the moulting period and during the winter. 

 There are many species of pseudoscorpions in the United States, found 

 in the North as well as in the South. They live under stones, beneath 

 the bark of trees, in moss, under leaves on the ground, in the nests of 



