to the extremity. The sheath, or external articulated portion, is formed by the elongation of the labium or lower lip, and is liable to little variation, except in length. Savigny seems to regard the basal segment alone as representing the true lip. It encloses four slender hair-like pieces, dilated a little at the base, and finely denticulated at the extremity. Of these the superior pair represent the mandibles, and the others the two blades of the maxillæ. They are incapable of horizontal motion, and the latter are destitute of the jointed appendages which they always bear in masticating tribes.[1] Over the base of the rostrum is situate the labrum or upper lip, of a conical shape, and usually very much lengthened, pointed, and frequently transversely striated. Immediately beneath this is sometimes observed another piece of similar form, which Latreille regards as analogous to the epipharynx, and also another portion which should be considered as corresponding to what he calls the hypopharynx. The clypeus is frequently distinct and conspicuous; the reverse is the case with the lingua or tongue, although Savigny has occasionally detected its presence.
The anterior part of the head is sometimes very much produced, forming a long beak, occasionally furnished with spinous projections. This is the case with the Fulgoræ, and in a well known species of that tribe, it is inflated into a large mitre-shaped appendage of a very remarkable appearance.
- ↑ Faint traces of palpi are said to have been observed in Thrips and Nepa.
