Nov., 1902 .] 
Passalus Cornulus. 
3°5 
is a long rod-like sclerite and is fused with the posterior border 
of the scutellum by which it is partly concealed. From the pos- 
terior apex of the scutellum it extends laterally and anteriorly. 
Its total length is about equal to the scutellum. Its lateral ex- 
tremity articulates with the metathoracic prescutum. 
The scutum is not well defined in Passalus and seems to be 
divided into two portions, which are located on the anterior and 
lateral extremities of the scutellum. These small pieces are elon- 
gated and indexed anteriorly, and laterally, come into contact with 
the episternum. Posteriorly they pass into the articular membrane 
of the elytra. 
The elytra (15) are articulated to the body by a triangular 
base which fits between the scutellum and episternum. In study- 
ing the elytron it should be extended at right angles to the body 
as in dight. When thus extended there can be seen in the articu- 
lar membrane which connects the inner surface of the basal tri- 
angle with the body a small sclerite called the paraptara (14). The 
elytron bears ten longitudinal grooves and is indexed slightly on 
the lateral margin to form the epipleuron. The inner margins 
are bevelled so that the edges fit closely when the wing covers are 
at rest. There is in addition to this a clasp which fits in between 
the lateral margins of the scutellum and the postscutellum. This 
clasp lies on the inner border of the triangular base of the elytron 
and can be demonstrated by slowly separating the wing covers and 
observing the manner in which the clasp slips from under the 
edge of the scutellum. 
The mesothoracic sternum (1) lies on the median ventral 
portion of the mesothorax anterior to the mesothoracic leg and is 
kite-shaped. It is truncated at the anterior end and on its anterior 
lateral border is in contact with the episternum (2). Its lateral 
tip touches the epimeron and its hinder border is in contact with 
the meta thoracic epimeron and the coxal cavities. It ends pos- 
teriorly in a narrow neck between the coxal cavities. Just in front 
of the outer half of the coxal cavity is a crescent-shaped area 
separated from the sternum by a slight depression. 
The episternum (2) forms the side wall of the constricted 
region of the meso-thorax. It is triangular in shape, its base being 
anterior and free. On its ventral surface it is in contact with the 
sternum. On its dorsal surface it is in contact in front with the 
articular region of the elytron and posteriorly with the small epi- 
meron (3) throughout about half of its length. 
The epimeron (3) is a small sclerite lying at the posterior 
angle of the episternum and is visible at the anterior ventral bor- 
der of the wing cover when it is closed. It is roughly triangular 
with the apex directed up and forward. It is in contact anteriorly 
throughout its whole length with the episternum. ventrally with 
