CALLIPERS. 275 



curved legs. These are termed Callipers, and can be used on 

 a plane as well as on a rounded surface. 



Natural Callipers are plentiful enough, and may be 

 found extensively among the insect tribes. There are, for 

 example, the pincers of the Earwig, which have already been 

 described on page 259, and which are, in the common species, 

 formed exactly like the Callipers of the sculptor. 



Then we have various insect jaws, especially those of the 

 carnivorous species, one of the most curious being the large 

 insect which is shown in the illustration, upon a very reduced 

 scale. In the male the jaws are exceedingly long and curved, 

 as may be seen by reference to the illustration. I have now 

 before me a pair of sculptor's callipers, and the resemblance 

 between them and the jaws of the Sialis is strangely close, the 

 curve being almost exactly the same in both cases. 



The scientific name of this insect is Sialis armafa, and it 

 is a native of Columbia. 



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