HABITS. 73 



destines a vivre sous les ecorces des vieux arbres ou 

 dans rinterieur de la terre, les Achorutes et les Annro- 

 pliores n'ont point d'appendices saltatoires ; ils leur 

 seraient inutiles ; mais une queue forte et d'uue action 

 puissante devenait necessaire aux Podurelles qui, 

 vivant dans les broussailles et dans les pierres, avaient 

 souvent des obstacles difficiles a franchir." 



As a matter of fact, however, tbe saltatory and non- 

 saltatory species are habitually found together under the 

 same old board, or in the same decaying heap of leaves ; 

 and in fact the species of the group frequent places 

 where jumping is impossible, so that the saltatorial 

 power is but occasionally exercised. On the other 

 hand, it must be admitted that in certain cases it is 

 very useful, but this still more shows how little we 

 can realise the conditions of Collembolan existence, 

 since it is evident that the non-saltatory species must 

 possess some counterbalancing advantage by which 

 they are enabled to hold their own in the struggle for 

 existence. 



The presence of blind species gives rise to similar 

 reflections. Thus, Beclda albinos and B. argentea, 

 which have no eyes, will be found living together with 

 eyed species, and moving about with equal rapidity 

 and decision. Indeed, B. albinos is a particularly 

 restless and active species. Probably in this case the 

 antennas are peculiarly sensitive. 



Again, it might a lyriori have been considered that 

 the very long antennse of T. longicornis must be very 

 ill suited to its mode of life. 



Lastly, it may be mentioned that the function of the 

 so-called " post-antennal organ " is entirely unknown 

 to us. 



Internal Anatomy. 



According to Nicolet (1. c, p. 46), the digestive 

 organs of the Oollembola consist of six parts — namely, 

 " I'esophage, le jabot, le ventricule chylifere, les vais- 

 seaux hepatiques, I'intestine grele, et le caecum." By 



