NORTH AMERICAN SPRING-TAILS OF THE SUBFAMILY 

 TOMOCERIN.E. 



By Justus W. Folsom, 



Of the University of Illinois, Urbana, Illinois. 



Collectors who are not especially interested in Collembola often 

 have their attention attracted by large and agile specimens of Tomo- 

 cerus. The species of this genus are among the largest " spring- tails " 

 that we have, attaining often a length of 5 mm. They occur under 

 loose bark, in damp, decaying logs, in moss, and generally on the 

 ground, under dead leaves, logs, or other objects. Some species are 

 lead-colored before they lose their scales; others are purplish or 

 blackish, and the scales give the insects a metallic appearance, with 

 more or less iridescence. After the scales are lost the body-color is 

 frequently yellow, but is highly variable, even in individuals of the 

 same species. 



The forms of North American Tomoceringe discussed in this paper — 

 few in number, but all that are known at present — are as follows: 



Tomocerus jlavescens Tullberg. 



Tomocerus jiavescens Tullberg, var. separatus, new variety. 



Tomocerus Jlavescens Tullberg, var. americanus Schott. 



Tomocerus Jlavescens Tullberg, var. arcticus Schott. 



Tomocerus hidentatus, new species. 



Tomocerus vulgaris Tullberg. 



Tomocerus minor Lubbock. 



Triiomurus calif ornicus , new spec'es. 

 T. Jlavescens, vulgaris, and minor are common and well known in 

 Europe. Triiomurus is a rare and little-known European genus, to 

 which belong several specimens that I have received from California. 

 For much of my material I am indebted to many collectors, whose 

 names appear beyond, and especially to Dr. A. D. MacGillivray. All 

 specimens recorded without a collector's name were collected by 

 myself. The ownership of specimens is designated in parentheses, 

 the omission of which indicates that specimens are contained in my 

 private collection at present. Cotypes have been deposited in the 



Proceedings U. S. National Museum, Vol. 46-No. 2037. 



451 



