364 



PHYLUM ARTHROPODA. 



Order i. SCORPIONTD^E 



Scorpions are elongated Arachnoids, restricted to warm 

 countries, lurking under stones or in holes during the day, 

 but active at night. The Scorpio afer of the East Indies 

 attains a length of 6 inches, but most 'are much smaller. 

 They feed on insects, spiders, and other small animals. 

 The " tail," with the venomous sting at its tip, is usually 



curved over the anterior part 

 of the body, and can reach 

 forward to kill the prey caught 

 by the anterior appendages, or 

 can be suddenly straightened 

 to strike backwards. When 

 man is stung, the poison seems 

 to act chiefly on the red blood 

 corpuscles, and, though never 

 or very rarely fatal, may cause 

 much pain. It has been said 

 that scorpions commit suicide 

 when surrounded by fire or 

 otherwise fatally threatened, 

 but it has been answered that 

 they do not sting themselves, 

 that they could not if they 

 would, and that, even if they 

 could, the poison would have 

 no effect ! 



The body is divided into 



/ \ i_ i ..i 



genital operculum ; /., pectines ; (l) a CCphalothoraX OF " pro- 



abdot of l. IU s n t!n b g ook orV s h t: *oma " of six segments, whose 

 anal piece. terga fuse into a carapace, 



and (2) an abdomen, which includes a broad seven- 

 segmented "mesosoma," and a narrow five - segmented 

 " metasoma." At the end of the latter there is a post-anal 

 curved spine or " telson," containing a paired, compressible 

 poison gland opening at the sharp tip. There is a strong 

 cuticle of chitin, and also an interesting internal piece of 

 skeleton (the endosternite), partly chitinoid, but also 



FIG. 191. Scorpion, ventral 



surface. 



ch., Chelicerae ; #J>., pedipalps ; 0., 

 genital operculum ; ^., 



