178 BLLLETIN 16, UNITED STATES NATIONAL MUSEUM. 



IJtymoliHjt/. — »SVu-, six; npinonux, spiny. 



Comparisons of iioitlu'rii .iimI southoin si>e<'iiii«Mis show, aH we pro- 

 ceed soiitlnvai«ls, tiie foUowin*;' <lirtVieiices: 



(1). An increase in size, especially in the anal lej;'s, which are more 

 slender. 



(2). An increase in size in the femoral spines of anal legs. 



(.'J) A tendency amonjj^ some of the more sonthern specimens for the 

 coxa^ of the prehensorial legs to become dentate. 



(4) A tendency for the lateral margins of anal segment to become 

 more calhms an«l slightly serrulate. 



{'}) All increase in tlu; density of the general coloration and an in- 

 crease in the paleness of the anal legs beneath. 



The following table shows the increase in size of the anal pair of legs : 



Ha. tilt. 



Winonn. Minn 



Chiciijio, 111 



lUiMniiiiijilton, Iu<l 



H^i'.tiiiion-, M(l 



riiapt'l Hill. N. (J 



Mossv Civi'k, Tfim... 



Little) Uook, Ark 



Eajrloton. Indian Tor. 



iDtlian S|triiiK.s, (Ja 



Do 

 IVnsacola, Fla 



Totalleujith. 



mm. 

 45 

 .37 

 .% 



:!2 

 48 



5r. 



42 



:>n 



65 

 35 

 :!5 



Length of 

 anal. 



mm. 



7.8 

 8.4 

 9.4 

 7.7 



11. 5 



17. 



10.7 



14.6 



18. 

 7.7 



10. 



The increase in length of legs is more noticeable in specimens from 

 the southeast portion of the United Slates, while toward the southwest 

 they tend to be more like the northern. 



As all my specimens from Pensacola are small I have compared them 

 with one of the same size from (leorgia. 



Some specimens from Winona and Chicago ha\e the interior spine 

 of anal legs absent. 



The specimen from Jialtimore has the tibia and tarsi of anal legs 

 pilose, the hairs being much longer than those of other specimens; the 

 other legs are rather sparsely pilose. 



Those from Indian Springs seem to represent tScoJop. georfiicffi of 

 Meinert; although the anal legs are hmger, the Ursl 4 dorsal plates im- 

 marginate, and tlie i)rosternum slightly dentate, I believe it should not 

 be considered as a good species. 



14/>. Scolopocryptop sexspinosus spiiiicaiidus. • 



1862 — Scolopocniptopb )*p'micauda Wood. Joiini. Acad. Nat. Sci. I'hila., ^^^{Shoal Water 

 Bay, W. T.; Oregon); Wood, Trans. Amer. Phil. Soc, 174,1865; Wood, Proc. 

 Acad. Nat. Sci. Phila., 128, 1867 {San Johc. Cal.). 



Habitat. — Shoal Water Bay and Cheh.ilis, W. T. ; Oregon; San Jose 

 and San ^Mateo. California. 

 Etymology. — Latin, spina, spine; cauda, tail. 



