640 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.53. 



8. Pseudorjelli of antennal bases 2+ 2, rarely 3+3 subtenuis, p. 642 



Pseudocelli of autennal bases 1+1 9 



9. Anal spines contiguous. Sense clulis of antennal organ sul. ovate, o' lique. 



similis, p. 640 



Anal spines separated. Sense clu'jsof antennal organ disklike, erect. coci^Zfi, p. 640 



10. Tubercles of postantennal organs distinctly 1 ranched (fig. 76). Anal papillae 



large ramos2is, p. 648 



Tubercles of postantennal organs with hundreds of closely set papillae (fig. 65). 

 Anal papillae reduced to rings dentotus, p. 647 



ONYCHIURUS SIMILIS. new species 



Plate 68, fig. 1; plate 70, figs. 12-18. 



White. Body slender (fig. 1). Postantennal organs (fig. 12) each 

 with eight to ten simple tubercles. Pseudocelli of antennal bases 

 (fig. 1) 1 + 1. Posterior border of head without pseudocelli. Anten- 

 nae shorter than the head. Sense organ of third antennal segment 

 (fig. 13) with five slender papillae, four guard-setae, a pair of sense 

 rods and two sense clubs, each consisting of a coarsely tuberculato 

 ovate head attached obliquely to its stalk. Dorsal pseudocelli of 

 body (fig. 1) successively: 0, 1 + 1, 1 + 1, 1 + 1, 1 + 1, 1 + 1, 1 + 1, 2 + 2, 

 0; those of the fifth abdominal segment bemg in two oblique pairs. 

 Unguis (fig. 14) slender, curving, untoothed. Unguiculus about one- 

 half as long as unguis; basal haK broadly lamellate, apical half acu- 

 minate. Anal spines (figs. 15, 16) two, stout, arcuate, subequal to, 

 or a little shorter than, hind ungues, on low contiguous papillae 

 Supra-anal lobe rounded (fig. 15). Clothing (fig. 17) of sparse short 

 curving setae and few longer and stiffer setae, Cuticular tubercles 

 small (fig. 18). Length, 1.2 mm. 



This species is close to cocTclei, from which it may be distinguished 

 by the following key: 



Body slender; unguiculus one-half as long as unguis; anal papillae contiguous; anal 

 segment as in figure 15; papillae of antennal sense organ slender, sense clu a su" ovate 

 and o lique; cuticular tubercles small similis. 



Body not slender; unguiculus two-thirds as long as unguis; anal papillae separated ; 

 anal segment as in figure 23; papillae of antennal sense organ stout, sense clu' s disk- 

 like and erect; cuticular tubercles large cocklei. 



Abundant under damp logs, Homer, Illinois, November 25. 

 Goty pes. —Cut. No. 20763, U.S.N.M. 



ONYCfflURUS COCKLEI Folsom. 



Plate 68, tig. 2; plate 70, figs. 19, 20; plate 71, iigs. 21-28. 



Aphorura cocklei Folsom, 1908. 

 Aphorura montis Bacon, 1913. 

 Aphorura lutea Bacon, 1913. 



White or lemon-yellow; rather slender (fig. 2). Postantennal 

 organs (fig. 19) wth 8 to 11 simple tubercles, which are usually ovate, 



