192 ENTOMOLOGICAL NEWS. [October, 



A NEW SPECIES OF POLYXENUS. 



By TREVOR KINCAID, University of Washington. 



In 1821 Thomas Say described a diplopod from the Southern 

 States to which he gave the name Polyxemis fasciculatiis* Since 

 that time the geographical range of this species has been con- 

 siderably extended, but it has remained the sole representative 

 of the suborder Pselaphognatha found within the limits of the 

 United States, although at least one species has been recorded 

 from the West Indies. 



During the past few years the writer has collected at various 

 points in western Washington specimens of a small, hairy myri- 

 opod belonging to the genus Polyxemis. A study of Say's de- 

 scription of Polyxemis fasciculatus, supplemented by specimens 

 of the same supplied by Mr. Nathan Banks, showed that the 

 Washington species was quite distinct from the form described 

 by Say. In Po lyxenus fasciculatus the antennae are short and 

 clavate, whereas in the species described below these organs are 

 elongate and filiform. In this respect the new form resembles 

 the common European Polyxenus lagums De Geer, as described 

 by Bode.f 



Polyxenus pugetensis n. sp. Color above yellowish white, the lateral 

 portions of the dorsal segments and external margin of the head brown; 

 ventral surface and legs pure white. Body narrow, sides of the dorsal 

 segments parallel; head semicircular in outline, deflexed, the mouth-parts 

 at postero-ventral margin ; antennae elongate, filiform, widely separated 

 at base, arising from beneath the anterior margin of the head, composed 

 of eight joints; first and second joints cylindrical and equal, third joint 

 a little shorter, the succeeding four somewhat swollen in the middle, 

 eighth joint only one-fourth as long as penultimate and bearing distally 

 a group of four minute processes. Ocelli six on each side; two groups 

 of five each are borne upon dark oval prominences in the middle of the 

 lateral margins of the head; the sixth members lie in lobate, ventral ly- 

 directed extensions of the main ocellar prominences, and are not visible 

 from above. Vibrissse, two on each side, placed just anteriorly to the 

 ocellar areas. Setae brownish, except terminal pencil, which is silvery; 

 each of dorsal segments t\vo to ten bears near its posterior margin two 

 rows of oppositely-directed, serrated setae, the rows uniting externally, 

 and the seta; in this region being directed outwardly; on the first segment 

 the setae are arranged in two irregular dorsal groups; from the middle of 

 posterior margin of the eleventh segment a loose tuft of long seta- 



* Jour. Phila. Acad. ii, 108 (1821). 



t Zeitschr. fur d gesammte Naturwissensch. xlix, 1877. 



