62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



In the classification of the Scolytidae, based on the chitinous skele- 

 ton of the penis by Nuesslin. Gnathotrichus would have been in con- 

 trast to all the other genera. This is easily explained by the fact that 

 only this one character was used in placing the genera. The author 

 has no reason to believe that Gnathotrichus is not a highly specialized 

 genus of the Pityophthorinae. 



Specific modifications: — 



A — Parameren without ventro-caudad knob, metula long but slender ; 

 laminae dorsales with their dorsal margin straight, the dorso- 

 caudad angle obtuse and broadly rounded, the posterior mar- 

 gin is directed ventro-caudad from this angle ; the laminae 

 ventrales with their ventral margin straight, only slightly 

 projecting caudad farther than the laminae dorsales, caput 

 weakly developed, nearly in line with the dorso-caudad mar- 

 gin of the laminae dorsales, rostrum obsolate; peduculi penis 

 about as long as the laminae ventrales, very slender, only 

 very slightly widened at the cephalad end, basal part narrow. 

 Gn. materiariiis Fitch. 

 AA — Parameren with ventro-caudad knob opposite the metula, the 

 latter variously modified ; laminae dorsales with the dorsal 

 margin broadly arcuate, the dorso-caudad angle variously 

 modified either slightly acute but rather broadly rounded or 

 almost evenly arcuate with the dorsal margin of the laminae 

 dorsales ; the laminae ventrales with their ventral margin 

 distinctly incurved, much farther projecting caudad than the 

 laminae dorsales, caput strongly developed, rostrum distinct ; 

 peduculi penes vary in length, stouter, more strongly widened 

 at the cephalad end, basal part distinctly widened. 

 B — Metula short, weakly developed ; the dorso-caudad angle 

 slightly acute but rather broadly rounded, the pos- 

 terior margin is directed ventro-cephalad from this 

 angle, caput not evenly rounded caudad, more tube- 

 like, ventro-caudad margin oblique, the dorsal angle 

 of the rostrum extending to about half of the 

 width of the combined laminae dorsales and ven- 

 trales, between the cephalad margin of the rostrum 

 and the caudad margin of the laminae dorsales, 

 a wide, rectangular space memliranous ; peduculi 

 penis as long as the laminae dorsales on the dorsal 

 margin. Gn. retusus Lee. 



