THE GENUS PISSODES. 19 



areas of the tergites, leaving only the scutellar process or scutelliim 

 exposed between the basal angles. This process is densely clothed 

 with white or yellow scales. 



When the prothorax and elytra are removed the 7nesotergum is 

 found to be rectangular in form; the prescutum is clearly defined as a 

 convex strongly chitinized notal plate, occupying about two-tliirds 

 of the tergal area. The anterior margin is acutely emarginate and the 

 anterior angles strongly produced. The prephragma is strongly 

 flexed beneath the posterior dorsal area. The scutum appears to be 

 represented by a narrow dorsal area between the median process of 

 the scutellum and the posterior limit of the prescutum, and by the 

 lateral submembranous areas between the oblique lateral margin 

 of the prescutum and the scutellum. The scutellum is represented 

 by the prominent median process and laterally by the chitinous 

 piece just posterior to the. scutal area. The postscutellum is repre- 

 sented by the subventral and flexed margin of the scutellum and by 

 a slender lateral arm. 



Mesopleura. — The episternum, preepisternum, epimerum, and 

 postepimerum are all clearly defined. The preepisternum is similar 

 to that of Dendroctonus. It is nearly as large as the episternum, 

 narrowed toward the sternum, and very broad toward the opposite 

 extremity, where it projects over the anterior dorsal angles of the 

 episternum and epimerum. The surface is testaceous and opaque. 

 Its posterior margin is clearly defined by a distinct but narrow lateral 

 impression, which is densely clothed with fine whitish scales. The 

 anterior is strongly declivous, concave, shining, and the preepistemal 

 process is prominent and broad, but not stout as it is in Dendroctonus. 

 The oblique ventral margin is thickened, but the posterior dorsal 

 section is very thin and without a distinct arm connecting it with the 

 articulating condyles. In this respect and in the strongly dilated 

 dorsal section the preepisternum is very different from that in Den- 

 droctonus. The episternum forms an isosceles triangle with the 

 anterior dorsal margin narrowly produced and disappearing beneath 

 the dilated end of the preepisternum. The ventral and posterior 

 angles are equal and acute. The surface is coarsely punctured and, as 

 is common over the entire ventral area of the body, each puncture 

 bears a broad scale. The epimerum is narrow, oblique, and broad 

 at its junction with the anterior dorsal angle of the metepisternal 

 plate. The ventral end is truncate, while the dorsal end is strongly 

 narrowed and produced forward beneath the preepisternum, where 

 it joins with the angle of the episternum to form the articulating proc- 

 esses. The postepimerum is narrow, declivous, and shining. 



The mesosternal area is short, with the anterior margin bisinuate, 

 the intercoxal piece elevated and truncate at apex, and the exocoxal 

 pieces distinct. The preepisternum is represented by a narrow shining 



