38 CLASSIFICATION. 



think, regard the Crustacea and Insecta as continents, 

 importance, but and Collembola as islands — of less 

 the Myriapoda still detached. 



Or if we represent the divisions of the Articulata like 

 the branching of a tree, we must picture the Collem- 

 bola and Thtsanura as separate branches, though 

 small ones, and much more closely connected with the 

 Insecta than with the Crustacea or the Arachnida. 



From the point of view which we occupy the extre- 

 mities alone of such branches are visible, and, con- 

 sidering the delicacy of the Collembola, and the 

 consequent improbability that we shall ever acquh"e 

 any satisfactory knowledge of the extinct forms, it is 

 not likely that the connecting stems will ever be 

 fully known to us. 



The classification of the Collembola adopted in the 

 present work is shown in the following table. 



As a matter of convenience, no doubt, several of the 

 proposed families might be consolidated. The charac- 

 ters, however, by which they differ from one another 

 are of considerable importance, and the great object in 

 all classification should be to attain to the most natural 

 system. Moreover, as far as the paucity of species is 

 concerned, we must remember that the number will 

 doubtless ere long be considerably increased. 



