Nov., 1902,] Passalus Cornulus. 307 



rated by a sharply defined groove except at the posterior end. At 

 this point it is fused with both the sternum and epimeron to form 

 the lateral articulation for the metathoracic coxa. Anteriorly it 

 gives off a dorsal process which forms part of the wing articula- 

 tion and lies between similar processes on the scutum (5) and 

 epimeron (3). On its dorsal surface it is in contact throughout 

 its wdiole length with the epimeron. The suture separating the 

 episternum from the epimeron is best seen on the dorsal process 

 and on the anterior half of the dorsal surface. Its boundaries are 

 ventrally the sternum, anteriorly the scutum, and dorsally the 

 epimeron. 



The epimeron (3) is a somewhat ill-defined sclerite lying 

 dorsally to the episternum with which it is in contract throughout 

 its whole ventral border. It consists of a strong narrow, chitin- 

 ized bar with an anterior dorsal process which with similar pro- 

 cesses from the episternum and the scutum form the ventral articu- 

 lation for the Vs'ing. This sclerite can be easily separated from the 

 episternum on its anterior half. Its posterior half is fused with the 

 episternum. The dorsal boundaries of this sclerite are less definite. 

 The anterior half bears a large, slightly chitinized triangular area, 

 the posterior end of which articulates with a lateral process from 

 the postscutellum. Excepting this triangular area the dorsal 

 boundaries of this sclerite seem to be membraneous. 



The first abdominal spiracle (25) Hes above the posterior 

 border of the epimeron in a membranous area and is over two mil- 

 limeters in length. It is placed in a slightly more oblique posi- 

 tion than the mesothoracic spiracle, and its hinder border lies di- 

 rectly under the second abdominal spiracle. 



The metanotum (4-7) forms the dorsal wall of the meta- 

 thorax extending from between the wings as far back as the first 

 segment of the abdomen. It is variously marked with chitinized 

 bars and membranous areas so that the boundaries of its separate 

 sclerites are hard to locate. In attempting to determine these dry 

 specimens should be used to determine the sutures and moist ones 

 to determine the articulations. The prescutum (4) lies just back 

 of the meso-scutellum, its median rod-like portion being concealed 

 by the meso-scutellum. It is dumb-bell-shaped and its enlarged 

 ends form part of the anterior squarish end of the metanotum. It 

 extends on either side of the median line to points even with the 

 lateral edges of the meso-scutellum. It is bounded posteriorly by 

 the chitinized bar extending across the body between the articula- 

 tion of the wings. The scutum (5) is a small sclerite lying directly 

 beneath and in front of the articulation of the wings. Its ventral 

 border rests on the meso-epimeron (3). Its posterior border rests 

 on the anterior bar of the met-episternum (2) : dorsally it assists 

 in forming an articulation for the wing, and on the median border 



