PSYCHE. 



THE IDENTITY OF THE SNOW-FLEA {ACHORUTES NIVICOLA 



FITCH). 



BY JUSTUS WATSON FOLSOM, CHAMPAIGN, ILL. 



Under the term "snow-flea," several 

 species of Achorutes have been badly 

 mixed. The original description of A. 

 nivicola Fitch is apparently broad enough 

 to entitle three distinct species to the 

 name of "snow-flea," and to make it 

 rather difficult to determine which species 

 Fitch meant. Considerable attention to 

 the subject, however, has enabled me to 

 identify his species to my own satisfac- 

 tion, and, I hope, to that of other stu- 

 dents, because the synonymy of the 

 snow-flea concerns not only our Ameri- 

 can forms, but also involves certain 

 European species. 



The original description of nivicola is 

 becoming inaccessible, but is reprinted 

 in full below, from my copy of Fitch's 

 "Winter Insects of Eastern New York " 

 (1847), and the entire paper has been 

 republished in Lintner's Second Report. 



Podura nivicola. "The Snow-flea." 



Black or blue-black ; legs and tail dull 

 bi-own. 



Length o.oS. 



Body black, covered with a glaucous blue- 

 black powder but slightly adherent, and 

 sparingly clothed with minute hairs ; form 

 cylindrical, somewhat broader towards the 

 tail. Antennae short and thick, longer than 



the head. Legs above blackish, beneath dull 

 brown and much paler than the bodj-. Tail 

 of the same color with the venter, shortish, 

 glabrous on its inner or anterior surface, with 

 minute hairs on the opposite side; its fork 

 brownish. 



Though found in the same situations as 

 the European P. nivalis, ours is a much darker 

 colored species. Say's P. bicolor is a larger 

 insect than the one imder consideration, and 

 differs also in size and in the color of the tail 

 or spring. From the habits of the present 

 species, we should infer that it might be 

 abundant in all the snow clad regions of the 

 northern parts of this continent ; it may 

 therefore prove to be identical with the P. 

 huniicola of Otho Fabricius (Fauna Groen- 

 landica), of which we are unable to refer to 

 any but short and unsatisfactory descriptions, 

 which do not coincide well with our insect. 



This is an abundant species in our forest, 

 in the winter and fore part of spring. At 

 any time in the winter, whenever a few days 

 of mild weather occur, the surface of the 

 snow, often, over whole acres of woodland, 

 mav be found sprinkled more or less thickly 

 with these minute fleas, looking, at first sight, 

 as though gunpowder had been there scat- 

 tered. Hollows and holes in the snow, out 

 of which the insects are unable to throw 

 themselves readily, are often black with the 

 multitudes which here become imprisoned. 

 The fine meal-like powder with which their 

 bodies are coated, enables them to float buoy- 

 antly upon the surface of water, without be- 



