1914] The Ottawa Naturalist. Ill 



The^' gain their common name from their peculiar spring- 

 ing organ. Towards the caudal end of the abdomen are attached 

 a pair of tail-like appendages, together called the furcula, 

 which are normally Sent forward, under tension, beneath the 

 insect, and the ends. are held in a little catch known as the 

 tenacukim. When released from the tenaculum, the furcula 

 kicks forcibly downwards and backv/ards and jerks the insect 

 into the air. Anyone who remem.bers the goose bone jump- 

 ing-jack — a homely toy unknown, I fear, by the present sophis- 

 ticated generation of children — will readily understand the 

 springtail's leaping apparatus. ■ 



At least four species of Collembola occur in the vicinity 

 of Arnprior during the winter: — Isotoma nigra ^la.Q.g., Achoniles 

 nivicola Fitch, and two unidentified species. /. nigra is fairly 

 common, and sometimes forms the majority of the springtails 

 fotmd on the snow, but generally .4. nivicola is in excess, and 

 towards spring often appears in such vast numbers that the 

 most casual observer cannot fail to notice it. From its jumping 

 habit it is popularly known as the "snow-flea," although, of 

 course, it is not related in any way to the real fleas, (Siphon- 

 aptera). 



A. nivicola, which Dr. J. W. Folsom identifies with the 

 A. socialis of Europe, may be described untechnically as a blue- 

 black insect two millimeters long by one-quarter millimeter 

 wide at its broadest part. It has a well marked head, bearing 

 two somewhat divergent short antennae which it keeps in constant 

 motion. Its mouth parts are sunk in the head, a peculiarit}- 

 characteristic of all the Collembola. Its sixteen simple eyes 

 are arranged in two groups of eight each on either side of the 

 head. It has an elongated but stout segmented body, the 

 thorax consisting of three segments each bearing a pair of short 

 legs on which the insect runs very actively. The abdomen 

 has six segments and tapers rapidly towards the tail. The 

 jumping apparatus is as already described. The whole insect is 

 sparsely covered with short fine hairs. 



Any day of the winter, from November to March, when the 

 temperature is not below 30° F., /I. nivicola can be found on 

 the snow near old log fences, and along roads and clearings. 

 They seem always to occur along the edge of open spaces of 

 some kind, and I have never observed them in the middle of 

 a wood of any extent. Although they sometimes come out in 

 considerable numbers in November and December, the reallv 

 great swarms do not appear until the first mild days of spring. 

 Towards the end of March one often .sees them like thickly 



