LTS1ANASSA COST.®. 
75 
appendage of only two. The inferior antennae do not 
reach beyond the extremity of the superior ; they are 
much more slender, and have a considerable portion of 
the peduncle covered by the lateral walls of the head. 
The epistoma considerably projects, and is formed into 
a wedge-like process, rounded and projecting above, 
receding towards the inferior margin, where it corre- 
sponds with the lower extremity orcutting margin of the 
mandibles. 
The mandibles, d , are long and narrow, narrower 
a little towards the cutting margins than at the base, 
which articulates with the head ; the molar tubercle is 
long, narrow, and slightly curved : the incisive margin 
is smooth, a form which, as far as we are aware, is 
peculiar to this subfamily, and suggests the idea of 
its being adapted for cutting vegetable substances ; the 
blade is hollow, or cup-shaped, being separated from the 
remainder of the mandible by a sudden constriction or 
neck ; the anterior margin, where it is increased in 
width, is produced into a small tubercle ; the man- 
dibular appendage is three-jointed, which is a very 
common form in the Order. The pair of foot-jaws, 
g , have the fifth joint very long, being much longer 
than the sixth. The third and fourth joints are pro- 
duced into large squamiform plates, which nearly reach 
to the extremity of the fifth joint; the inner margin 
of the squamous plate of the fourth joint is slightly 
scalloped, and furnished with rudimentary spinules 
which respectively correspond with the scollops at the 
margin of the plate. These spinules, although of a 
very obsolete character, appear to differ very consi- 
derably in different species ; and we think that they 
may be found of very considerable service in detecting 
the relative value of species, where it may be desirable 
