A Letter from Mr Charles King to Mr Sam. Doudy, F. R. S. concerning Crabs Eyes

Fig. 5. F G H I shows the hinder part of the last mentioned case, where by G H are described the well made sharp Points, which are so useful to that Creature, and to fasten it in the Web, whilst it is a Worm. I shall conclude here, and in the meantime remain, Sir, Your most humble Servant, Anthony Van Leeuwenhoeck. III. A Letter from Mr Charles King to Mr Sam. Doudy, F. R. S. concerning Crabs Eyes. Little Wirley, Decemb. 14. SIR, I cannot give you any satisfactory account of the Stones in the Heads of Craw-fish, for I never made any observations but casually, and without any design of a particular account of them, having not so much as made any note of the months that they first appear, and what time they grow to perfection. I only remember in general, that they are always on the outside of the Stomach, while the old Coat sticks on the back of the Fish, and pass into the Stomach as soon as they cast their Coats, having never seen them on the outside when they have changed, nor within before. And I also remember the Males change their Coats a considerable time before the Females, for they always keep theirs till they have parted with their young young from their Tails. I do not remember that I ever observed any thing of them but what a good and full account is given of in a Book entitled *Gammarologia, of Phil. Jac. Sachs* shewed me by Dr Plot; if upon perusal of that Book, any thing occurs that you desire farther satisfaction in, I shall be ready to give you the best information I can, if you send any Queries to Your Humble Servant, Ch. King. --- IV. Part of Monfieur Poupart's Letter to Dr Martin Lister, F. R. S. concerning the Insect called Libella. It is a flying Insect, called in France *Demoiselle*, from the variety of its Colours, transparency of Wings, and its stately Flight: They also call it *Perle*, from the figure of its Head, or rather from the roundness and colour of its Eyes. It is called by the Latins *Libella*, perhaps because in flying it carries its Body Horizontal; not that it does so always, for it is divided from space to space into rings, by means of which, it composes Angles with its body, whose lines it can make longer or shorter as it finds occasion. These different sections serve to the motion of this Insect, as we know the Tail doth in Birds, and as they are lengthened or contracted, they carry themselves according to their various inclinations, the point or center being fixed between their Wings. All Modern Naturalists know that the great sort of *Libellae* are generated under water, wrapt up in a Membrane, which at length dissolves and turns to nothing. This *Phenomenon* is not only