NO. 2222. NORTH AMERICAN ONYGHIURINAE—FOLSOAI. 639 



Genus ONYCHIURUS Gervais, Borner. 



Podura Linnaeus 1758 (part). 



Lipura Burmeister 1838. 



Onychiurus Gervais 1841. (See Gervais 1844, p. 397.) 



Anurophorus Nicolet 1841 (part). 



Adicranus Bourlet 1842 (part). 



Aphorura MacGillivray 1893. 



Onychiurus Borner 1901t", 1909. 



Including also the subgenera Protaphorura, DeiUaphorura, and Kala- 

 fthorura (Absolon 19016), and the sections Euaphorura and Ahsohnia 

 "(Borner 19016). 



Body stout or moderately slender. Head relatively large; broader 

 than, or a little narrower than, the prothorax. Antennal base well 

 defined. Postantennal organs (rarely absent) each in a transverse 

 groove, close to the antennal base, with relatively large tubercles, 

 occasionally about fifty in number, but usually not numerous; and 

 simple, tuberculato, or lobed. Sense organ of third antennal segment 

 with usually four or five (0-10) papillae, with guard setae, a pair of 

 sense rods, and two straight or feebly bent sense-clubs, which are 

 smooth, granulate, or tuberculate, and do not curve toward each 

 other. Tarsus with two claws. Furcula absent; represented in a 

 few species by an integumental fold or by a pair of rudimentary 

 mucrodentes on the fourth abdominal segment; in the latter instance 

 the tenaculum also may be represented. Anal spines 0-4, with or 

 without papillae. Fourth antennal segment usually with curving 

 sensory setae and with subapical papilla; usually without apical 

 sense club. 



KEY TO SPECIES OF ONTCHIUEUS. 



1. Anal spines a' >sent. TuV ercles of postantennal organs ccd] p c vr d 



Anal spines present 3 



2. Body stout. Antennal organ with four papillae and two ovate erect sense 



cluls fimetarius, p. G49 



Body slender. Antennal organ with five papillae and two su reniform o lique 

 sense-clu' s pseudo fimetarius, p. 650 



3. Tu' ercles of postantennal organs simple 4 



Tu' ercles of postantennal organs compound 10 



4. Postantennal organs elongate-elliptical with al out 18-44 closely set tu^ ercles. . . 5 

 Postantennal organs with a' out 8-14 separated tubercles 8 



5. Pscudocelli of antennal l)ase3 3+ 3 6 



Pscudocelli of antennal V ases 2-\- 2 or 4-|- 4 7 



6. Tu'iercles of postantennal organ not crowded together. Pseudocelli of antennal 



base arranged in a triangle; those of the fifth a'idominal segment in a straight 



line on each side. Unguiculus as long as the unguis amiaius, p. 644 



Tu' ercles of postantennal organ crowded together. Pseudocelli of antennal 1 ase 

 almost in a straight line; those of the fifth abdominal segment in a triangle on 

 each side. Unguiculus much shorter than unguis psexidarmatus, p. 646 



7. Pseudocelli of antennal 1 ases 2+2. Postantennal organ with a" out 20 tu' er- 



cles lilorcus, p. 644 



Pseudocelli of antennal leases 4-f-4. Postantennal organ with a" out 33-37 tu' er- 

 cles octopunctatus, p. 647 



