256 Introduction to the Synopsis of the Acrididce. 



times the margins are raised so as to inclose a foveola, or shallow cell, 

 between the eyes, -which is called the median foveola, or central foveola, 

 of the vertex. The shape and character of this foveola appear to be 

 constant in the species, and even in some genera, hence its import- 

 ance ; but caution is to be observed in comparing dried specimens, 

 especially dried alcoholic specimens, with descriptions taken from 

 living specimens, and the reverse, as the shrinking often causes con- 

 siderable variation from what it is when living. The lateral foveola are 

 two small cells, situated on the margin of tlie vertex, one on each side, 

 near the front border of the eye, sometimes on the upper surface, near 

 the edge ; in other species immediately below the margin, on the 

 deflexed portion. These are sometimes linear {Sienohothrm) , some- 

 times very small and triangular {CEdlpoda), or quadrangular, but in 

 many genera are wholly absent. 



The face (fades) is the deflexed portion in front, extending down- 

 ward from the antenna to the transverse suture, which separates it 

 from the clypeus ; it is generally transversed, up and down, by three 

 carince or keels, more or less distinct ; the median carina, or frontal coda, 

 is the one extending down the middle from the fastigium,and in which 

 the middle ocellus is placed. This carina is generally more or less sul- 

 cate or channeled ; when the channel is deep, dividing it into two 

 keels, the face is said to be quadricarinate. The two lateral carince ex- 

 tend downward from the front margin of the eyes, often bending^ out- 

 ward toward the corners of the ftice. Between the frontal costa and 

 lateral carina are the antennal foveola, or pits, in which the antennae 

 are inserted. The cheeks (gena:) are the convex portions of the sides 

 below and rather behind the eyes. 



Sometimes the face is deflexed, that is, directed under and back- 

 ward toward the breast, but generally it is vertical or nearly so. 



The portion of the head described constitutes the skull, on which 

 are placed the eyes (ocidi), the simple eyes (ocelli), and the antennae. 

 The position and shape of the eyes afford both generic and specific 

 characters ; as regards position, whether on the sides or advanced near 

 the front, approximate to or distant from each other, prominent or the 

 opposite, oblique or vertical ; in respect to the shape, Avhether they are 

 globose, ovoid, elliptical, elongate, or pyriform. 



There are three simple eyes (ocelli) ; one (ocellus) is placed immedi- 

 ately above the base of each antennae and near the margin of the eye, 

 and one in the frontal costa, between the antennae. 



The antenna; are inserted in the front of the head, a little below the 

 eyes, and consist of a number of joints, varying, according to the spe- 

 cies or genera, from fourteen to twenty-four; they seldom exceed one 



