254 lU'uwis St((tc Tjdlxn-Ktori/ of Natural Hisfori/. 



the distal part of the inner margin with long delicate hairs. 

 This segment is much simpler than the corresponding seg- 

 ment of lacustris and nevadensis. 



Fifth pair of legs of the female uniramose, three-segmented. 

 First segment snbquadrate, somewhat longer than wide, 

 armed near the onter distal angle with a hair or delicate 

 spine. Second segment somewhat narrower than the first 

 and slightly longer ; armed at the outer apical angle with a 

 small sharp spine. Third segment slightly narrower than 

 the second and barely one and a half times as long ; armed 

 with five or six spines*, two (one) outer, one inner, and three 

 apical. Of the outer spines, the upper one is at a])out the mid- 

 dle of the segment and the lower one is directly opposite the 

 inner spine. Of the apical spines, the middle one is spinu- 

 lose on l)otli margins and the outer one on the inner margin. + 



Length of female 1.9 mm. ;t that of male 1.1 mm. 



The aljove description was prepared from specimens kindly 

 sent me l)y Dr. Lillejeborg, the measurements, however, with 

 the modification explained in the foot-note, being those given 

 in the original description. The material w'as a part of that 

 collected by Dr. C. Nystrom, a member of the Nordeuskiold 

 expedition to Greenland in 1871, and was not in the best 

 state of preservation, owing no doubt to the length of time 

 since its collection. 



Figures of this species may be found in de Guerne and 

 liichard's "lievision" ('89b), and imperfect copies of these 

 in Herrick's "Synopsis" (Herrick and Turner '95). The 

 fifth pair of legs of the male are correctly represented in the 

 "Eevision" except that the spine at the outer apical angle of 

 the right leg is not shown; indeed it is not mentioned in the 

 description. The spine figured on the outer margin of the 



* The armatu''e of this segment differs somewhat in different specimens. See on 

 a subseiiuent page the discnxsion In regard to the fifth leg of the female. 



t Having only a few s]iecimens to study, I could not satisfactorily determine 

 whether the other sjiines were also spinnlos'e or not. bnt I am quite [lositive with re- 

 gard to the two mentioned. J think it likely that tliey are armed as In lacustris. 



X U is quite evident that a mistake was made in regard to the measurements given 

 in the original de.scription: •■ Length of female, caudal seta- excepteil, about 2.9 mm., 

 and of male 1.1 mm." In the siiecimens I examined there was no such difference in 

 length in favor of the female: in fact the single entire female I had the opportunity 

 to measure was 1.3.33 mm. in length, while the average length of five males was con- 

 siderably above this— l.G'.ls mm. I have hesitated to substitute these measurements 

 because of the limited number examined, and have altered Lillejeborg's figures to 

 what 1 think they were intended to be. 



