NORTH AMERICAN COLLEMBOLOUS INSECTS OF THE 

 SUBFAMILY ONYCHIURINAE. 



By Justus W. Folsom, 



Of the University of Illinois, Urbana, Illinois. 



Among our most abundant collembolans are species of Onychi; 

 urus. They are white (one species having a yellow variety), elongate 

 (pi. 68) , usually 1 or 2 millimeters in length, nonsaltatorial; they 

 belong essentially to the fauna of the soil and are limited to damp 

 situations. 



The subfamily Onychiurinae comprises three genera: Onychiurus- 

 Tullbergia, represented in North America by a single Californian 

 species; and TetrodontopJiora, a European genus with one described 

 species. 



The forms discussed in this article are: 



Onychiurus similis, new species. 



Omjchiurus cocklei Folsom. 



Onychiurus suhtenuis, new species. 



Onychiurus litoreus, new species. 



Onycliiurus armatus Tullberg. 



OnycMurus pseudarmatus, new species. 



Onycliiurus octopunctatus Tullberg. 



Onychiurus dentatus Folsom. 



Onychiurus ramosus, new species. 



OnycMurus firnetarius Linnaeus, Lubbock. 



Onychiurus pseudofimetarius, new species. 



Tullbergia collis Bacon. 



These are all the species of the subfamily that are at present 

 knoNvn in our fauna. I expect, however, that many more species 

 will be brought to light. In Europe armatus, firnetarius, and amhu- 

 lans are everywhere abundant. In North America the first two 

 species are widely distributed, but amhulans is imlmo\\Ti in collec- 

 tions. Packard (73) recorded amhulans from Washington, but 

 his specimens are lost, and his description is broad enough to include 

 abnost any of our species with anal spines. Subsequent records of 

 the occurrence of amhulans in this country have either followed 

 Packard or have been based upon misidentifications. Amhulans 



Proceedings U. S. National Museum, Vol. 53— No. 2222. 



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