so 



shell, dark brown and elastic, but more brittle, and bent to a cer- 

 tain extent, fractures short, like a pipe stem. The edges and points 

 of the side pieces are serrated, Jorming perfect saws, while their flat- 

 tened surfaces form rasps equally perfect. When the instrument is 

 protruded and examined by the microscope, the denticulations of 

 the saws are clearly perceived. There are fijteen teeth on each 

 side, symmetrically arranged, tapering aw r ay in fineness towards the 

 point, where we find three or four more, so small that it is scarcely 

 possible to determine, by the best glasses, whether there are three 

 or four. In some there appeared to be three, in others four. 



Previous to the application of the instruments, the female de- 

 posites a fluid on the part to be operated on. It seems to be in- 

 tended as an emollient, and probably to mark the extent of her 

 work. It is a secretion from the inner surface of the oviduct, so 

 exquisitely fine that it is only to be seen by a fine glass. The prac- 

 tice of softening the place of deposite for eggs is not uncommon 

 among insects and amphibious animals. Some of the tortoises use 

 their urine to soften the surface of the ground, that they may ex- 

 cavate the hard soil with more ease, and deposite their eggs 

 quicker. 



When the female selects a limb, she goes formally and indus- 

 triously to work, and soon finishes it. She raises her body, ex- 

 tends the point of the instrument, and with her whole weight pierces 

 the bark with the upper point of the centre piece or chisel, which is 

 like the flattened point oj a thumb lancet, making way for the side 

 pieces or saws. Though the puncture is very minute, scarcely 

 perceptible a it is sufficient for a place of entry, and a quick sawing 

 motion now commences, and continues till the apertures are large 

 enough to admit the other side piece, which follows with the like 

 motion. As soon as the blade point is fairly inserted, say the 

 twelfth of an inch, she presses on the part attached to her body, 

 and then, by a lever, raises the ends of the divided fibre ; she then 

 adjusts the three different parts of the instrument, forming two saws 

 by its edges, two rasps by its flattened sides, and a perforator or chisel 

 by its point. The uses of the perforator and saws are easily per- 



