20 H Canadian Arctic Expedition, 1913-18 



Ethopolys Chamberlin. 1 



This genus includes a group of North American species known at present 

 only from the region west of the Rocky mountains where they are common and 

 range from southern California, Nevada, and Utah northward into Alaska. 



Ethpolys integer, n. sp. 



Dorsum mostly dark brown with the caudal plates darker; major plates 

 often darkened over the lateral and caudal borders; major plates of posterior 

 half of body typically with a distinct longitudinal median black stripe, this 

 becoming more indistinct on the anterior plates. Head, as also in part the first 

 dorsal plate in some, reddish brown to chestnut; a blackish median longitudinal 

 stripe extending from caudal margin to frontal suture. Antenna? brown to light 

 chestnut, paler distad. Venter light brown, the fourteenth and fifteenth 

 stern ites commonly of chestnut tinge. Prosternum and prehensors also of light 

 chestnut tinge. Legs testaceous, the posterior pairs darker, brown to light 

 chestnut. 



Hody of same form in male and female. About eight times longer than 

 width of tenth plate. Head and first dorsal plate of same width and narrower 

 than the tenth plate. 



Head distinctly wider than long (86 : 79) ; widest a little caudad of lateral 

 breaks. A V-shaped impression on caudal half of plate. Entire surface sub- 

 densely punctuate, the punctse distinct. 



Ocelli from twelve to nineteen in three or four series, but by far most com- 

 monly in four; e.g., 1 + 5, 6, 4, 3; 1 + 6, 5, 4, 3; 1 + 5, 5, 4, 2; 1 + 5, 4, 3, 2; 

 1 + 5, 4, 2; 1 + 6, 5, 3. Single ocellus much largest, clearly separated by a. 

 space from the others. Seriate ocelli distinct, regular, decreasing moderately 

 ventrad and cephalad. 



Antennae reaching to from fifth to eighth segments, but mostly to the sixth 

 or seventh. Articles twenty to twenty-four, long and cylindric. Ultimate 

 article long and slender, a little shorter than the two preceding taken together. 



Prosternum about 1 7 times wider than long. Chitinous lines well devel- 

 oped excepting toward caudal ends. Finely densely punctuate. Spine inserted 

 on ventral surface a little caudad of the anterior edge; moderately short, uni- 

 formly attenuated to an acute point; much stouter than the ordinary bristles. 

 Teeth conical; those adjacent to the diastema on each side largest. Most 

 commonly three or four teeth ectad of diastema but also sometimes only two. 

 Examples of dental formulae are the following, the left side being represented 

 first: 3 7 + 6 3, this being the commonest of number and arrangements; 

 3-6 + 6-3; 3-5 + 6-3; 4-6 + 6-4; 2-6 + 6-3: 2-6+6-2; 2-6 + 5-2. 



All dorsal plates distinctly and rather coarsely punctuate, and, especially 

 the caudal ones, rather finely rugose and irregularly tuberculate toward lateral 

 borders, the median portion remaining -nearly smooth excepting on the fifteenth 

 plate. 



,. ,. . . 0, 0, 3, 2, 1 0, 0, 3, 2, 2 , .. 



Opines of first legs f to - ; of the second to tenth pairs, 



U, U, Z, o, Z U, U, Z, Oj Z 



f the eieventh > ' of the twelfth - or 



accessory claws; of the anal, T , claw single or with a very minute 



1, 1, 6, Z } 1 



-ory claw. Last two pairs, or occasionally only the last pair, of coxae 

 laterally armed. 



l Can. Entomologist, 1912, p. 13. 



