Nov., 1902.] Passalus Cornulus. 305 



is a long rod-like sclcrite 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 ecjual to the scutellum. Its lateral ex- 

 tremity articulates with the metathoracic prescutum. 



The scutum is not well detined 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 intlexed 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 tits between the scutellum and episternum. In study- 

 ing the elytron it should be extended at right angles to the body 

 as in flight. When thus extended there caii 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 inflexed 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 ( i ) 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 wnth 

 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 



