14 U. S. NATIONAL MUSEUM BULLETIN 212 



2. Terminal segment of body with 1 to 3 pairs of spinnerets; either one or both pairs 



of legs of the 7th segment of males modified into gonopods; sternites free from the 



pleurotergites, the latter usually with long setae Chordeumida (p. 84) 



Terminal segment of body without spinnerets; either both pairs of legs of the 7th 

 segment as gonopods, or one pair missing; sternites usually fused with 

 pleurotergites 3 



3. Stipites of gnathochilarium broadly in contact behind the laminae linguales. 



JULIDA (p. 117) 



Stipites of gnathochilarium separated for their entire length by the mentum and 



laminae linguales , 4 



4. Third segment open ventrally, the 4th and following segments closed; 5th segment 



with two pairs of legs 5 



Third segment closed ventrally; 5th segment with a single pair of legs. 



SpiROBOLroA (p. 151) 



5. Both anterior and posterior gonopods present and functional, posterior pair usually 



with long flagella; laminae linguales completely separated by the mentum. 



Cambalida (p. 172) 

 Posterior pair of gonopods rudimentary or completely absent, anterior pair elaborate; 

 laminae linguales not separated by the mentum (except in Choctellidae) . 



Spirostreptida (p. 169) 



Order POLYDESMIDA 



Polydesmidae Leach, 1815, Trans. Linn. Soc. London, vol. 11, p. 381. — 

 Latzel, 1884, Myr. Ost.-Ung. Monarch., vol. 2, p. 124^Bollnian, 

 1893, U. S. Nat. Mus. Bull. 46, p. 159. 



Polydesmoidea Pocock, 1887, Ann. Mag. Nat. Hist., ser. 5, vol. 20, p. 294. 

 —Cook, 1895, Ann. New York Acad. Sci., vol. 9, p. 4.— Attems, 1899, 

 Denkschr. Akad. Wiss., Wien, vol. 67, p. 227. — Brolemann, 1916, 

 Ann. Soc. Ent. France, vol. 84, p. 583. — Attems, 1937, Das Tierreich, 

 Lief. 68, p. 1. 



Merocheta Cook, 1895, Ann. New York Acad. Sci., vol. 9, p. 4. 



Proterospermophora Verhoeff, 1900, Zool. Jahrb., Syst. Abt., vol. 13, 

 p. 54; 1913, Zool. Anz., vol. 43, p. 57. 



Polydesmida Chamberlin, 1938, Carnegie Inst. Washington, Publ. No. 

 491, p. 174; 1943, Bull. Univ. Utah, biol. ser., vol. 8, No. 3, p. 36. 



KEY TO THE SUBORDERS OF POLYDESMIDA 



1. Opening of sternal gonopod socket more or less constricted between the gonopods, 

 the coxae of which are entirely free of each other . . . STRONGYLOSOMroEA (p. 78) 

 Opening of sternal gonopod socket not medially constricted; coxae of gonopods con- 

 nected to each other by a ligament or a pseudostemite, or else broadly in contact 

 along the median surfaces Polydesmidea (p. 14) 



Suborder POLYDESMIDEA 



Polydesmidi + Leptodesmidi Brolemann, 1916, Ann. Soc. Ent. France, 

 vol. 84, p. 527. 



Polydesmidea Attems, 1926, in Kukenthal-Krumbach, Handbuch der Zool- 

 ogie, vol. 4, p. 132; 1938, Des Tierreich, Lief. 69, p. 1; 1940, Das Tier- 

 reich, Lief. 70, p. 1. 



