
14 THE AMERICAN NATURALIST. [Vor. XXXVI. 
is that in some cases a named area includes several sclerites, 
while in other cases only a portion of a sclerite is included. 
This nomenclature, however, is sufficient for the needs of 
describers of species, and will doubtless continue in use. It 
is worth while, therefore, to review it briefly and to attempt 
_where necessary to make it more definite. 
The best landmark from which to start 
for this purpose is the epicrantal suture, the 
inverted Y-shaped suture on the dorsal 
part of the head, in the more generalized 
insects (Fig. 1, ¢.sz.). Behind the arms of 
this Y there is a series of paired sclerites, 
which meet on the middle line of the dor- 
sal wall of the head, the line of union being 
the stem of the Y; and between the arms 
of the Y and the mouth there are typically three single sclerites 
(Fig. t, A C, L). It is with these unpaired sclerites that we 
will begin our definitions of the areas of the head. 
The Front (frons, Kirby; clypeus posterior, Newport). — 
The unpaired sclerite between the arms of the epicranial 
suture (Fig. 1, F). 
In the more generalized insects at least, if not in all, the 
front bears the median ocellus; and in the a the 
paired ocelli also. Frequently the suture 
between the front and the following 
sclerite, the clypeus, is obsolete; but as 
it ends on each side in the invagination 
which forms the anterior arms of the 
tentorium (Fig. 2, a7), its former position 
can be inferred, at least in the more gen- 
eralized insects, even when no other trace 
of it remains. In Fig. 2 this is indicated 
by a dotted line. 
The Clypeus (clypeus, Fabricius; chaperon, Straus-Durckheim ; 
clypeus anterior, Newport). — The intermediate of the three 
unpaired sclerites between the epicranial suture and the mouth 
— (Fig. 1, C). To this part one gente (the d of the 
andis articulates. 





Fic. 1. — Head of a cricket. 

OA 


