. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MOTION. 443 the coxae to the trunk is by cotyloid joints, as in the Rhimophorae, or by ginglymoid joints, as in the Lamellicornes; and between the trochanter and femur, the coxa and tro- chanter, the femur and tibia, the joints are usually ginglymoid : the axis of each of these joints is turned at right angles to the next, so that, as Dr. Iloget remarks,* " there results from the combination of both, a capability in the thigh of executing a circular motion, in a manner almost as perfect as if it had revolved in a sp
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MOTION. 443 the coxae to the trunk is by cotyloid joints, as in the Rhimophorae, or by ginglymoid joints, as in the Lamellicornes; and between the trochanter and femur, the coxa and tro- chanter, the femur and tibia, the joints are usually ginglymoid : the axis of each of these joints is turned at right angles to the next, so that, as Dr. Iloget remarks,* " there results from the combination of both, a capability in the thigh of executing a circular motion, in a manner almost as perfect as if it had revolved in a spherical socket. The principle of this compound motion is the same as that employed on ship-board for the mariner's compass and other instruments which require to be kept steady during the motion of the ship. For this purpose, what are called gimbals are used, the parts of which have two axes of rotation at right angles to each other, so as to enable the compass to take its proper horizontal position, whatever may be the inclination of the ; The remaining joints of the legs of insects are also ginglymoid. The tarsi, which vary in number from two to six, terminate by a double hook; those on the anterior pair of legs are directed backwards; those on the middle pair inwards ; and those on the tail-piece, forwards ; by which disposition the insect is enabled to lay hold of rough surfaces, and to walk up in- clined or vertical planes with security. In the progression of insects, the fore and middle legs are extended, and the hind legs flexed previously to urging the body forwards ; in doing which, the actions of these legs are reversed. The simple hook terminating the locomotive organs of most insects will not en- able them to walk on water, to climb vertically on glass, or stand inverted on ceilings, actions which many can perform, and for this purpose an additional apparatus is therefore provided. The common Gnat and some Coleopterse which walk on the surface of water, h
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