TOOLS. 



CHAPTEE III. 



BOEING TOOLS. STKIKING TOOLS. GEASPING TOOLS. 



Tte Bradawl and the Gimlet defined. Natural Bradawls. The Ichneumon-flies. 

 A Pimpla engaged in Boring Operations. Principle of the "Wedge. 

 Resisting Power of Earth. Pitching Tents in Sand. Hidden Forces of 

 Nature. The Aloe-leaf and its Growth. A cruel Punishment. Natural 

 Gimlets. Ovipositor of the Sirex, and its Analogy to a Carpenter's Gimlet. 

 The Auger and the Gad-fly. Striking Tools. The Hammer. Origin and 

 Development of the Tool. The Axe. The Woodpecker and the Nuthatch. 

 The Ivory-billed Woodpecker. Grasping Tools. Pincers and their Modi- 

 fications. Sugar-tongs and Coal-tongs. Natural Pincers. Bivalve Mol- 

 luscs. The Clam's Grip. The Earwig. Crab and Lobster Claws. 



BORING TOOLS. 



NEXT in importance to the edged tools which cut, come the 

 pointed tools by which holes c&n be bored. We have 

 an abundance of such tools, but they can all be reduced to 

 two types, namely, those which, like the Bradawl, are forced 

 between the fibres, and those which, like the Gimlet, cut away 

 the material as they pass through it. 



They may, again, be shown to be different modifications of 

 a single principle i.e. that of the Wedge or Inclined Plane, 

 which, as has already been shown, is identical with that of the 

 screw. The Bradawl is, in fact, a sharp wedge, which is forced 

 through the fibres, sometimes being merely forced between 

 them, and sometimes cutting them, and thus forcing aside the 

 severed fibres. 



A natural example of the Bradawl is to be found in various 

 Ichneumon-flies, especially those with very long ovipositors, 

 which are intended for boring into wood. 



All the Ichneumons are parasitic, laying their eggs in the 

 larvse of other insects, mostly those of moths and butterflies. 



