SmiNG TAILS. 405 



xlff ^^^^ ^° ^^^^ ^^^^ know what is the special purpose for which their 

 most striking peculiarity, their spring tails, is given. 



As Sir John Lubbock says, the possession of a powerful salta- 

 tory apparatus appears to be a fantastic provision, for a species 

 which lives in the chinks and crannies of bark, in the interstices of 

 fungi, or buried among decaying leaves, in other words, in places 

 where the saltatory power can only be occasionally exercised, and 

 the anomaly is by no means diminished by the circumstance that, 

 as a matter of fact the jumping and non-jumping species are con- 

 tinually found together under the same old board, or in the same 

 decaying heap of leaves. Still we know that it must serve a pur- 

 pose, and one useful to the creature endowed with it. 



The Collembola are divided by Lubbock into six families, for 

 the scientific characters of which we must refer the reader to his 

 work. It is only exceptionally that we give detailed characters in 

 this work. As far as they go we endeavour to supply their place 

 by illustrations, and we shall merely note one or two salient 

 points which may serve to guide the reader to the family to 

 which his species belongs. And here let us begin at the begin- 

 ning. Supposing we have in our hands a species of Thysanura, 

 how are we to tell whether it is one of the Collembola or one of 

 the Lepismidse? If it has either two- or three-jointed bristles at 

 the tail, then it belongs to the latter— if not, then to the former. 



In the next place it may have a jumping apparatus, or it may 

 not It is not, however, to be taken for granted that it is not g 

 jumper, because it has not jumped and no jumping apparatus is 

 visible. This is packed away under the body from the tail for- 

 wards, and will be seen when searched for. Let us suppose then 

 that our species has got the jumping apparatus. It then belongs 

 to the first section of Collembola. Further, it may be of an elongate 

 cylindrical shape, or it may have a globular body, seemingly 

 composed of a head and a bag. If the latter, it must either be a 

 Smynthurus or a Papirius. In both the antennce are four-jointed, 

 but in the former the terminal joint is long, in the latter short. 



