Page:Jardine Naturalist's library Entomology.djvu/125

Rh in the latter case, they are called spurs (calcaria). The spinous processes are often arranged in a double row on each side of the tibia beneath, having a kind of groove between them; the spurs are most frequently placed in pairs at the extremity or middle. The prevailing arrangement is two at the extremity of each of the tibiæ; sometimes there is only one, and not rarely two on the middle and hinder tibiæ, and one on the anterior.

The terminial division of the leg is the tarsus or foot, which consists of a series of small, usually heart-shaped or triangular joints, never exceeding five in number. It is connected with the tibia by ginglymus, and the joints are closely united to each other, so as to present a uniform surface beneath. It admits of considerable flexure, a property indispensable for executing the functions that have been assigned to it. The first joint is in general longest, and the last next to it in length; the fourth (which is often bilobed) shortest. The terminal joint is commonly clavate, and bears either one or two claws at the tip; the latter number being by far the most general. These claws are simple, bifid, dentate on their under edge, or serrate. Between the claws we often perceive a smaller one, which is named the spurious claw (pseudonychia), and in many families two small membranous cushions are present, which act like sucking cups, and enable the insect to support itself against gravity. Membranous lobes of a similar kind are frequently attached to the underside of the tarsal joints. The whole of the underside (or sole,