10 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
the spiracle. In descriptions, the fringe will be referred to as the 
' hairs of anterior margin of posterior spiracle,' the cover as the * spirac- 
ular cover.' The meta-episternum is a narrow plate lying along the 
lower edge of the meropleurite between the meta-epimeron and the 
middle coxa. Its lower posterior portion bears a groove along which 
lies a small projection of the posterior coxa. 
Certain areas, sclerites, and sutures of the thorax have been vari- 
ously named by systematists. Although most of these are of no value 
in this paper, those commonly used are defined. All are paired. 
Humeral callus or Humerus: the upper swollen portion of the 
pronotal lobe (PI. 3, fig. 18, p7il.). 
Presuhiral depression: an irregularly triangular impression at the 
postero-lateral portion of the prescutum, the apex of which is formed 
by the junction of the transverse suture where it dips downward at the 
side with a bend in the chitin extending backward and slightly upward 
from the region of the humerus (PI. 3, fig. 20; PI. 4, fig. 25, pd.). 
Sutural ridge: I use this term to designate that part of the pre- 
sutural depression which lies posterior to the last notopleural bristle 
and dips do\sTiward and backward to meet the transverse suture 
(P1.3, fig. 20; PI. 4, fig. 25,5/-.). 
Pre-alar callus: a slightly prominent protuberance of the scutum 
which lies above the attachment of the wing and bears the supra-alar 
bristles (PI. 3, fig. 20; PI. 4, fig. 25, prac). 
Postalar callus: a narrow, slightly convex, ridge-like area of the 
scutum which extends somewhat diagonally and laterally' downward 
from the anterior dorsal corner of the scutellum. It bears the postalar 
bristles (PI. 3, fig. 20; PI. 4, fig. 25, ?;flc.). 
Scufellar bridge: the vertical, almost flattened surface extending 
downward from the posterior limit of the postalar callus and ending 
anteriorly just back of the wing base. This area is anatomically 
designated as the juxtascutellum (PI. 3, figs. 18, 20, jsl.). In some 
species of the group a tuft of long hairs is borne on a slight impression 
just anterior to the middle; in other species these hairs are short or 
wanting. 
Supra-alar groove: a groove in the scutum just between the wing 
base and the mesonotum. It extends upward from the wing base to 
the anterior limit of the postalar callus. 
The regions of the side of the thorax which are used by systematists 
and their anatomical equivalents are given below: 
