18 MTSCELLANEOUR FOEEST INSECTS. 



bined length of the (k:)rsal or tergal areas of the thoracic segments is 



also slightly greater than the tergal area of the abdomen. The 



pronotum is slightly longer than the inesotergum and metatergum 



together. The prosternal area is much longer than the mesosternal 



and about equal to that of the metasternal area. The metapleura 



show the same relative proportions as the sterna, and together are 



much longer than the abdoininal pleura. The anterior dorsal margin 



of the pronotum is not greatly extended beyond that of the sternum, 



as it is in Dendroctonus; the posterior margin of the metatergum is 



but slightly extended anteriorly beyond the posterior ventral margin 



of the same segment, but it is much in advance of the posterior 



margin of the metapleura. (For a discussion of the divisions of the 



thoracic segments of insects and of the nomenclature, see Hopkins, 



1909, pp. 23-35.) 



The Prothorax. 



As is usual in the rhynchophorous beetles, the tergal, pleural, and 

 sternal areas are fused into a continuous band. In addition to the 

 preceding description of the i)ro7iotum there is usually a median ele- 

 vated line extending from the anterior impression to tlie posterior 

 margin, and each side of this line toward the middle there are two 

 distinct impressions filled with whitish or yellowish scales, thus 

 forming distinct subdorsal spots. There is also a broad, posterior, 

 dorsal impression near the posterior margin. The lateral areas are 

 usually marked with spots of scales, which are more or less distinct 

 and variable in size and form. The anterior margin is usually evenly 

 curved, but is sometimes slightly emarginate. The anterior ventral 

 margin is never emarginate or distinctly produced toward the sides. 

 The posterior dorsal margin is slightly bisinuate, and the posterior and 

 lateral declivities of the notum are vertical. The posterior ventral 

 margin is elevated and uniformly curved. The episternal and 

 epimeral areas are not indicated by surface sculpture, but the pre- 

 episternal area is plainly indicated by a transverse elevation anterior 

 to a distinct transverse pleural groove. This groove also extends 

 across the sternal area and thus defines the presternal area, which is 

 strongly convex. The sternum is fiat to subconvex, subdeclivous, 

 the posterior section terminating in an acute point between the 

 coxse. The sternellum is represented by a small but distinct inter- 

 coxal piece and the poststerneUum ("epimerum" of authors) by the 

 narrow posterior area which incloses the coxae. The coxal cavities 

 are large, with the inner margins but slightly separated. 



The Mesothorax. 



The mesothorax is short and partially liidden from view b}^ the 

 prothorax, wdiich covers the anterior third of the sternites, pleurites, 

 and tergites, while the base of the elytra normally covers the posterior 



