Such anatomy as I am enabled to present to the public has not been traced without difficulty; the extremely minute size of the objects, the dark colour, Opacity, and excessive hardness and brittleness of the chitinous exo-skeleton, and the softness and delicacy of the internal parts have rendered the task far from easy. In describing the anatomy I have not relied on any previous writ'er without verification; indeed, I have endeavoured to carry the same system into the other parts of the book, and where I have been unable to do so I have called attention thereto.