264 
SYSTEMATIC ARRANGEMENT. 
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 maxillae. They are 
incapable of horizontal motion, and the latter are 
destitute of the jointed appendages which they always 
bear in masticating tribes.* Over the base of the 
rostrum is situate the labrum or upper lip, of a coni- 
cal 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 epipliarynx, and also another portion which should 
be considered as corresponding to what he calls the 
hypopharynx. The elypeus 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 Fulgorse, 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. 
