58 



THE SCOLYTID BEETLES. 



presence of clearly defined front, clypeus, and labrum, in the articu- 

 lation of the mandibles, and in their rudimentary hypostoma. 



Labrum (figs. 40, 41). The labrum is prominent, the dorsal area 

 twice as broad as long, about one- third narrower than the clypeus, | 

 but nearly as long, with the apical margin broadly rounded, truncate 



or faintly emarginate, and with several apical papillae. The median 

 dorsal area bears several long hairs and two slightly elevated dark spots 

 where the epipharyngeal bracons are attached. The latter somewhat 

 resemble the mandibular hooks of dipterous larvae, and may or may 

 not represent paired elements of the head of a primitive arthropod. 



