56 U. S. NATIONAL MUSEUM BULLETIN 212 



KEY TO THE NORTH AMERICAN SUBFAMILIES OF EURYURIDAE 



1. Tibiotarsus of male gonopod expanded into a broad sheath, which shields or partially 

 encloses the solenomerite, and which often has one or more small processes of its 



own Aphelidesminae (p. 56) 



Tibiotarsus of male gonopod very slender or completely rudimentary; no separate 

 solenomerite present Eitryurinae (p. 56) 



Subfamily APHELIDESMINAE Brolemann 



Aphelidesminae Brolemann, 1916, Ann. Soc. Ent. France, vol. 84, 

 p. 584. — Hoffman, 1954, Journ. Washington Acad. Sci., vol. 44, p. 57. 



Genus APHELIDESMUS Brolemann 



Trachelorachis Silvestri, 1898, Bull. Mus. Zool. Anat. Comp. Univ. Torino, 

 vol. 13, No. 324, p. 5 (preoccupied by Trachelorachis Agassiz 1846, 

 an emendation of Trachelorachys Hope 1841) (generotype, T. rivicola 

 Silvestri) . 



Aphelidesmus Brolemann, 1898, Ann. Soc. Ent. France, vol. 67, p. 266. — 

 Attems, 1937, Das Tierreich, Lief. 68, p. 128. 



Trachelacaniha Berg, 1899, Comun. Mus. Nac. Buenos Aires, vol. 1, No. 3, 

 p. 77 (new name for Trachelorachis Silvestri) . 



Generotype: Aphelidesmus hermaphroditus Brolemann, by original 

 designation. 



Range: Northeastern Brasil and British Guiana west to Ecuador, north 

 through Central America and Mexico to southern Texas. 



Species: Twenty-nine, of which but one is known within our limits. 



Aphelidesmus tertius (Chamberlm) 



Semionellus tertius Chamberlin, 1948, Ent. News, vol. 59, p. 269, figs. 1, 2. 



Type : Collection of R. V. Chamberlin. 



Type Locality: Near Kerrville, Kerr County, Texas. 



Range: Known only from type locality. 



Subfamily EURYURINAE Hoffman 



Euryurinae Hoffman, 1954, Joum. Washington Acad. Sci., vol. 44, p. 57. 



Genus EURYURUS Koch 



Euryurus Koch, 1847, in Krit. Rev. Insect. Deutschlands, vol. 3, p. 591. 

 Eutheatus Attems, 1938, Das Tierreich, Lief. 69, p. 294 (new name for 

 Euryurus Koch, thought by Attems to be preoccupied by the nomen 

 nudum Euryurus Rafinesque, 1815) . 

 Generotype: Polydesmus erythropygus Brandt, by subsequent designa- 

 tion of Silvestri, 1896. 



Range : Eastern United States. 



Species: Three, which are probably only geographic races of a single 

 polytypic species. 



