528 U- S. NATIONAL MUSEUM BULLETIN 216 



This subspecies is transcontinental, in the Canadian to the Upper 

 Austral zone. In the western half of the continent it is not known 

 from south of Canada. It parasitizes borers in hardwoods. Adults 

 occur from mid-spring to mid-fall. 



20b. Xorides (Xorides) stigmapterus floridanus (Ashmead) 



Xylonomus floridanus Ashmead, 1889, Proc. U. S. Nat. Mus., vol. 12, p. 451; 

 9. Type: 9, Archer, Fla. (Washington). 



Similar to the subspecies X. stigmapterus stigmapterus except that 

 the head and thorax are largely or entirely ferruginous or dusky 

 ferruginous. 



Specimens: d\ Gainesville, Fla., Apr. 10, 1916 (Ann Arbor). 9, 

 Chester's Island, Okefenokee Swamp, Ga., July 7, 1923 (Townes). 

 9, in decayed sweetgum log, Clyo, Ga., May 3, 1922, R. St. George 

 (Washington), cf, Letford on the Cannochee River, Ga., July 29, 

 1913, J. C. Bradley (Townes). 9, Letford on the Cannochee River, 

 Ga., July 29, 1913, J. C. Bradley (Ithaca). 9, Illinois (Cambridge). 

 9, Clemson College, S. C, May 30, 1927, S. E. Jones (Townes). 



The subspecies occurs in the Austroriparian fauna. 



21. Xorides (Xorides) cincticornis (Cresson) 



Front wing of male 6.5 to 11.5 mm. long, of female 9.5 to 16 mm. 

 long; mesopleurum smooth, its punctures small, separated by about 

 1.5 their diameter; first tergite about 3.5 as long as wide in male, 

 about 3.1 as long as wide in female; first sternite of male surpassing 

 spiracle by about 1.5 its average width; first sternite of female sur- 

 passing spiracle by about 1.0 its average width. Structure otherwise 

 as described for X. stigmapterus. 



This is a western species which is closely related to the eastern 

 X. stigmapterus and may possibly be only subspecifically distinct. 

 It contains two sharply different populations which are treated below 

 as subspecies: 



1. Head, abdomen, and thorax black; white band on female flagellum covering 

 about 4.5 segments; range: northwestern United States and adjacent Canada. 



21a. cincticornis cincticornis (Cresson) 

 Head and abdomen ferruginous; thorax more or less ferruginous; white band 

 on female flagellum covering about 3 segments; range: mostly California. 



21b. cincticornis rufus, new subspecies 



21a. Xorides (Xorides) cincticornis cincticornis (Cresson) 



Xylonomus cincticornis Cresson, 1865, Proc. Ent. Soc. Philadelphia, vol. 4, p. 



288; 9. Type: 9, Colorado (Philadelphia). 

 Xylonomus (Moerophora) modestus Rohwer, 1913, Proc. U. S. Nat. Mus., 



vol. 45, p. 358; cf. Type: d\ Skykomish, Wash. (Washington). 



Black or blackish brown. Clypeus and base of mandible brown; 

 palpi dark brown; female flagellum with a white band covering about 



