96 FOLSOM [98] 



Cream yellow when denuded of scales. Eyes six on either side, on 

 black patches close behind the bases of the antennae. Antennae shorter 

 than the body; basal ring prominent; first segment yellow or pur- 

 plish ; second and third yellow, frequently purplish apically ; third 

 often purple throughout ; fourth segment purple. Legs yellow, ex- 

 cepting the tibiae, which are purplish distally ; superior claws (fig. 46) 

 long, slender, uniformly tapering, straight, pseudonychiate, inner mar- 

 gin bidentate, or, less than half as often, tridentate ; inferior claws half 

 as long, straight, tapering, acuminate, inner margin unidentate near the 

 middle; tenent hair knobbed. Furcula yellow. Dental spines (fig. 

 47) seven to nine, becoming successively smaller toward the base of 

 each dens until the large proximal spine is reached ; the distal spine is 

 more lateral than the rest and there may be two of them on either 

 side ; a lanceolate acuminate transparent scale occurs near the proximal 

 spine or spines. Clothing of scales, with numerous clavate setae on 

 head and legs, interspersed with many long stiff hairs, especially on 

 femora and manubrium ; mesonotal collar of stiff setae, finely barbel- 

 late apically ; similar setae occur on the manubrium among the short 

 reclinate bristles ; the furcula bears scales above and long plumes 

 beneath. Length, 5 mm. 



Twenty-one specimens, Yakutat, June, 1899 (Nos. 57, 69) ; three, 

 Cook Inlet, 1899 (No. 60) ; one, Popof Island, 1899 (No. 96) ; one, 

 Juneau, 1899 (No. 56) ; four, Sitka, June, 1899 (Nos. 64, 71) ; three, 

 Berg Bay, June 10, 1899 (No. 72) ; fifty-five, Muir Glacier, west side, 

 June 12, 1899 (No. 63), comprising intergradations between niger, 

 arcticus and americanus, but consisting principally of typical arcticus. 



Many of the specimens from which the preceding description was 

 made conformed to authoritative descriptions and figures of the well- 

 known T. Jlavescens (more properly termed niger), of Europe, and 

 also agreed with eight examples of the species given me by Dr. Schaf- 

 fer. Most of the Harriman specimens varied greatly, however, in the 

 characters of accepted specific value for example, those of the claws 

 and dental spines. These variations, bearing importantly upon the 

 interrelations of three members of the genus, are tabulated below. 



Tullberg's (1872, pp. 36-37, taf. 5, figs. 1-6) diagnosis of T. jla- 

 vescens is, "Antennae corpore non longiores. Spinae dentium sim- 

 plices 7-8, intima magna. Unguiculus superior dentibus 2 instructus, 

 inferior lanceolatus. Long. 4 millim." Tullberg adds that the infe- 

 rior claws are unidentate. With this description compare the follow- 

 ing records. The figures after the + signs refer to the number of 

 large spines beside each dental scale. 



