NO. 2037. NORTH AMERICAN SPRINO-TAILS—FOLSOM. 463 



purplish coxae and tibiae. Ungues (pi. 40, fig. 5) quadridentate, occa- 

 sionally five-toothed; unguiculi unidentate, the tooth sometimes 

 obscure or absent, however. Dental spines (pi. 40, fig. 6) normally- 

 six or seven on each side, rarely eight, becoming successively larger 

 distally; formula 0/4-6, 2; two large ovate-lanceolate acuminate 

 transparent lamellae occur near the manubrium, as usual in flavescens. 

 Maximum length, 4 mm. 



Variation. — In a single lot of fifty-five specimens from the Muir 

 Glacier, Alaska, I found some individuals with one large proximal 

 spine on each dens and with ungues either quadridentate or tridentate. 

 These variations into tj^picsd Jlavescens I have discussed in a previous 

 paper ('02, p. 101). 



Distribution. — Hitherto this variety has been known only from the 

 far north (the "arcticus" of Guthrie ['03, p. 791 being americanus). 

 It was discovered by the Vega Expedition in 1878-9 in eastern 

 Siberia, and found by the Harriman Expedition in 1899 in Alaska. 

 The Harriman specimens, now in the U. S. National Museum, were 

 taken at Popof Island, Cook Inlet, Sitka, Yakutat Bay, and Muir 

 Glacier. The folloAving records extend the known range southward. 



Washington. — Olympia, T. Eancaid. 



Oregon. — Corvallis, December 24, H. E. Ewing. 



TOMOCERUS BIDENTATUS, new species. 

 Plate 40, figs. 7, 8. 



Body color yellow, mottled throughout with dark pigment. Eyes 

 six on each side. Antennae shorter than the body; purple through- 

 out, or with first two segments yellow. Unguis (pi. 40, fig. 7) stout, 

 usually bidentate, occasionally tridentate; unguiculus broadly 

 lanceolate, untoothed. Dental spines (pi. 40, fig. 8) thirteen to seven- 

 teen; formula 3-4, 1/4-6, 1, 3-4, 1; basal lamellae present, as in 

 flavescens. Mucrones with four to seven intermediate teeth. Length, 

 2.2 mm. 



Rarely the distal tooth of the unguis is absent. 



The dental spines suggest those of T. vulgaris, but the claws of the 

 two species are quite different, as appears from a comparison of 

 figures 7 and 9 of plates 40 and 41, respectively. 



Twenty-eight cotypes. Yellow Springs, Ohio, August 28. Knox- 

 ville, Tennessee, April 5, H. E. Summers. New Church, Virginia- 

 January 4, W. J. Philhps. 



Cotypes.— C&t. No. 16262, U.S.N.M. 



TOMOCERUS VULGARIS TuUberg. 



Plate 41, figs. 9-11. 



Macrotoma vulgaris TvhLBERG, 1871; 1872. — Uzel, 1890. 

 Tomocerus plumbeus Packard (part), 1873. 



