June 29, 1888.] 



SCIENTIFIC NEWS. 



611 



THE STING OF THE SCORPION. 

 One of the most sirgular of all poison-bearing weapons 

 is that curious curved claw which we find at the 

 extremity of the tail of the scorpion ; and it is par- 

 ticularly remarkable in this, that it is a special 

 weapon situated upon a special appendage, and not a 

 modification of some bodily member which ordinarily 

 serves a different purpose. In this respect it differs from 

 all other weapons of its class. The fangs of the 

 venomous serpents are merely modified teeth ; the stings 

 of the bee, the wasp, and the hornet are modified ovi- 

 positors ; the poison-jaws of the centipede are modified 

 legs ; the formidable spines of the weever fish and the 

 sting ray are modified fins. And so on. But in the 



be struck with the sting, must first be seized and held, 

 by the two great claws into which the maxillary palpi - 

 or feelers, are modified; and this obligation implies that 

 the victim, at the moment of receiving the wound, must 

 be in front of the body, whereas the sting is at the back. 

 Hence the necessity for a long and flexible tail, which 

 can be bent over the back when required, and bring the 

 point of the weapon which it carries slightly in advance 

 of the head. 



The terminal joint, again, which bears tha sting, must 

 be endowed with great flexibility and muscular strength, 

 in order that its stroke may be both certain and effectual; 

 for many of the insects upon which scorpions feed so 

 largely are cla-J in coats of shelly mail, and the joints of 

 their armour, so to speak, must be discovered before the 

 fatal puncture can be inflicted. Hence the necss'ty for 

 flexibility, while that for muscular strength is due to the 



The Scorpion. 



case of the scorpion it is not so. The tail, so far as we 

 can ascertain, is primarily and finally an organ with one 

 special office to perform, the claw-like sting itself to be 

 primarily and finally a poison-bearing weapon. Neither 

 seems to be a modification of any member which we 

 are accustomed to find in allied animals in a different 

 form, neither appears to have any supplementary duties 

 to fulfil. Both the tail and the claw which terminates it 

 are peculiar to scorpions alone, special organs provided 

 for a special purpose, and unique both in character and 

 in structure. For in more ways than one is the sting of 

 the scorpion a curiosity, and a curiosity well worthy of a 

 somewhat detailed examination. 



In the first place, its very position at the end of the 

 body necessitates a considerable prolongation of the tail 

 which bears it ; the poison-claw of a scorpion situated 

 at the extremity of such a body as that of a spider 

 would be absolutely useless. For the prej', in order to 



fact that even the membranous hinges, which in such 

 insects connect the various portions of the shell-like 

 covering, are often extremely tough and leather-like, so 

 that a successful puncture can only be brought about at 

 the expense of some little muscular exertion. And even 

 the most casual examination of the tail will suffice to 

 show the admirable manner in which both these qualities 

 are secured, the terminal joint playing upon the pen- 

 ultimate with almost as much freedom as if a ball-and- 

 socket joint were provided, while the muscles which 

 control it are wonderfully well developed, and enable it 

 to deliver a stroke of no little force. 



Finally, the supply of poison must be both potent 

 and extensive, for the victims . upon which the 

 scorpion preys are for the most part very small, 

 and the tail with its deadly claw is consequently 

 called into frequent requisition. And, indeed, almost 

 the whole of the terminal joint — always propor- 



