646 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 53. 



Axelson ('056, p. 790; '12, p. 88) has named as inermis a variety 

 of armahis in which the anal spines and their papillae are absent. 



I have taken this species on damp soil under wood or dead leaves 

 and under the loose bark of decaying logs. In Europe, and doubtless 

 in this country as well, the species occurs also in moss, under stones, 

 in decaying vegetables, in flower pots, on pools of fresh water, on the 

 seashore under stones, wood, or seaweed, and in caves. 



Onychiurus armatus is ver}^ common everywhere in Europe. It 

 has been reported also from Siberia, Greenland, and other Arctic 

 localities, and from East Africa and Chile. 



Maine: Orono, F. L. Harvey 



Illinois: Homer, April 3, May 7, 8, 21, June 6. Urbana, April 

 12, 25. 



ONYCHIURUS PSEUDARMATUS, new species. 



Plate 68, fig. 6; plate 74, figs. 52-60. 



White, slender (fig. 6). Postantennal organs (fig. 52) elongate, 

 elliptical, each with about 40 simple tubercles, crowded together. 

 Pseudocelli of antenna! bases 3+3 (fig. 53), arranged almost in a 

 straight line. Posterior border of head with 2+2 pseudocelh, in 

 obhque pairs. Antennae shorter than the head. Sense organ of 

 third antcnnal segment (fig. 54) with five papillae; five guard setae; 

 a pair of tapering sense rods; two capitate, coarsely tuberculate 

 sense clubs; and a large subovate finely tuberculate accessory club 

 (fig. 54). Dorsal pseudocelh of body segments (fig. 6): 0, 1 + 1, 

 1 + 1, 2+2, 2+2, 2+2, 2+2, 3+3, 0. Those of the first four ab- 

 dominal segments are in oblique pairs ; each group on the fifth abdom- 

 inal segment forms a triangle. Unguis feebly curving, unidentate 

 (fig. 55) or unarmed (fig. 56). Unguiculus extending more than half 

 as far as the unguis, basally suboblong, apically tapering uniformly. 

 Furcula represented by a fold (fig. 57). Anal spines (fig. 58) stout, 

 almost straight, two-thirds as long as liind ungues, on well separated 

 papillae one-third as long as the spines. Clothing (fig. 59) of sparse 

 short setae, stift' or slightly curving, and fewer long stiff setae. 

 Cuticular tubercles large (fig. 60). Length, 3 mm. 



This species is much like the well kno\vai armatus, but shows in 

 addition to the differences given in my key (p. 639) other differences 

 in respect to the antennal sense organs, the length of the anal spines, 

 the form of the rudimentary furcula, the size of the cuticular tubercles 

 and the character of the clothing. 



Alaska. — Saint Paul Island, Pribilof Group, August 6, in moss, 

 Prof. Trevor Kincaid. 



Gotypes.— Cut. No. 20760, U.S.N.M. 



