496 U. S. NATIONAL MUSEUM BULLETIN 216 



Cushman 1933, Xylonomus investigator Smith 1874, Xylonomus jezoen- 

 sis Matsumura 1912 (with Xylonomus lineatus Matsumura, 1912, 

 as a synonym), Xylonomus jakolevi Kokujev 1903, and Xylonomus 

 rufipes Gravenhorst 1829. All or most of these are new combinations 

 with either the generic name, subgeneric name, or both. 



7. Subgenus Exomus, new subgenus 



Body slender; female flagellum with a subapical curve that involves 

 several articulations; occipital carina complete; temple with strong 

 striae, the striae in its lower third oblique, elsewhere longitudinal 

 (fig. 315,g); tooth at upper end of epomia exceptionally strong and 

 projecting; prepectal carina present; median lobe of mesoscutum with 

 a broad median longitudinal groove; areola transversely pentagonal, 

 basad of which the median longitudinal carinae are fused for a con- 

 siderable distance; posterior mesosternal carina incomplete, broadly 

 interrupted in front of each middle coxa; apex of area dentipara some- 

 times making a low blunt tooth; median longitudinal carinae fused at 

 base of areola; nervulus beyond basal vein by about 0.3 its length 

 (fig. 314, e); intercubitus less than 0.3 as long as second abscissa of 

 cubitus, very short or almost obliterated by approximation of radial 

 and cubital veins; second trochanter of front leg with a strong project- 

 ing thorn on its front side; front tibia of female moderately inflated 

 (fig. 313, a); bristlelike hairs on front tibia very numerous but so weak 

 as to be hardly differentiated; comb on front of apex of front tibia 

 weak and inconspicuous; nervellus broken near the middle; first 

 tergite coarsely punctate, about 3.1 as long as wide in male, about 2.9 

 as long as wide in female, rather evenly enlarged from base to apex, 

 sometimes with a trace of a lateral constriction just beyond spiracle; 

 median and sublateral longitudinal carinae of first tergite distinct 

 for most of length of the tergite in male, distinct only basad of spiracle 

 in female; second tergite coarsely punctured, with a sharp oblique 

 groove cutting off its basolateral corner. 



Genotype: Anomalon humeralis Say, as interpreted in this paper. 



The name is from the Greek "exomos" having the shoulders stick- 

 ing out, in allusion to the prominent epomia. 



This subgenus contains a single polytypic Nearctic species: Anomalon 

 humeralis Say, 1829. 



1. Xorides (Exomus) humeralis (Say), new combination 



Figures 313,a; 314,e; 315,g 



Front wing of male 4.8 to 9.5 mm. long, of female 8.3 to 16 mm. long. 

 Structure as described for the subgenus. 



