242 THE CANADIAN ENTOMOLOGIST 



Africa, Brazil and Chile, Ceylon, Sumatra, and New Zealand. I once heard a 

 shantyman describing the camp he worked in as being in such an out of the 

 way place in the woods, that even the chickadees had not discovered it. If this 

 man's tastes had been entomological, he would certainly have found that he 

 was not beyond the range of A. armatus. The genus Isotoma, however, holds 

 the distributional record. It is not only known all over the globe from the 

 shores of the Arctic Ocean to the remote islands of the Antarctic, but one of its 

 species, Isotoma klovstadi Carpenter, shares the honour with another Collem- 

 bolan, Gomphiocephalns hodgsoni Carpenter, of constituting the entire land 

 fauna of the great Antarctic continent. Excluding as essentially pelagic the 

 sea-birds that visit those desolate shores merely to nest, these two tiny and 

 primitive insects are, so far as known, the only indigenous form of terrestrial 

 animal life on Antarctica. 



How these delicate, wingless insects have reached such widely separated 

 stations is an interesting question. They are feeble and uncertain travellers, 

 and their dispersal by their own efforts must be very slow. They have, of course, 

 been transported to a certain extent by man alon'g trade routes, but Dr. Folsom 

 regards running water as the chief meansj)f their spread over land areas, and 

 some may be carried for limited distances by ocean currents along coasts and 

 to outlying islands. But this does not explain how they have managed to cross 

 vast ocean spaces and reach far distant and isolated archipelagoes in the Indian 

 Ocean and the Pacific. Their presence in the nests of gulls and puffins on de- 

 tached rocks on the coast of Ireland, as noticed by Carpenter, indicates the 

 possibility of their transfer in some instances by birds. But the fact, also 

 recorded by Carpenter, that they are plentiful on the ancient granite- formed 

 islands of the Seychelles while nearly absent from the more recent coral islands 

 of the same group, would suggest that their spread by birds must be both slow 

 and limited in extent. It seems most probable that in some cases they have 

 travelled to their present stations by land connections that have since disap- 

 peared. It is significant, too, that only the Arthropleona, the more primitive 

 of the two sub-orders, have been found on the Seychelles and Hawaii. Ap- 

 parently these islands were cut off from the rest of the world before the more 

 specialized Symphypleona had been evolved. The Collembola are of an ancient 

 race, and were old settlers in the world even in the inconceivably far-off days 

 of those strange continents that geologists tell us existed where the oceans are 

 now, and which they map out to the bewilderment of plain people who have 

 been brought up on Mercator's Projection. 



Heat and moisture, in some degree, are absolutely essential to all forms of 

 life, vegetable or animal. The Collembola evidently regard moisture as a 

 prime necessity, but many of them are not so particular about heat, and low 

 temperatures affect them less than any other hexapod. This is shown by the 

 habit of numerous species in coming out on the snow — a practice which has 

 earned for them the popular name of "snow- fleas." Like most popular- names, 

 the designation is inaccurate, for the Collembola are not in any way related to 

 the true fleas (Siphonaptera) and the species that come out on the snow occur 

 in the summer also. But as the term is convenient to distinguish the insects 

 in their snow- frequenting phase, its use persists. 



