Carpenter— 7%e Apterygota of the Seychelles. 31 



arrangement of the tubercles of the abdominal segments and their sensory 

 bristles has already been sufficiently described. The spiiiose bristles, 

 characteristic of Neanura, are in tliis species numerous and prominent on 

 all parts of the body. 



Family ENTOMOBRYIDAE. 



Except for Neanura sexoculata, described above, all the Seychelles 

 Collembola belong to this large family, the relationships of whose numerous 

 genera have formed the subject of much discussion among specialists. 

 General agreement exists as to the recognition of three principal sub- 

 families, one of which — the Tomocerinae — is not represented in the present 

 collections. In his latest classification of the Collembola, Borner ('13b) proposes 

 to raise these groups to the rank of families. The most natural definition of 

 these sub-families, as they may more reasonably be regarded, seems to -loe 

 that adopted by Schaffer ('97), and by Borner in his earlier works (e.g. '0.3), 

 and their essential superficial characters may be tabulated thus : — • 



A. Fourth abdominal segment equal, or almost equal, in length to the 



third. Scales wanting. Feeler with third and fourth segments 

 simple and sub-equal in length. Post-antennal organ usually 

 present. Dentes of spring without spines, . . . Isotominae. 



B. Fourth abdominal segment shorter than the third. Body scaled. 



Feeler with third and fourth segments ringed, the former much 

 the longer. Post-antennal organ wanting. Dentes of spring 

 spinose, ........ Tomocerinae. 



C. Fourth abdominal segment usually much longer than the third. 



Body scaled or unsealed — always scaled if the third and fourtli 

 abdominal segments are sub-equal in length. Post-antennal 

 organ wanting, . . . , . . . Eivtomohryinae. 



Borner in his later writings ('06, &e.) transferred from the Isotominae to the 

 Entomobryinae a group including the common European Isotomurtos palustris, 

 because these insects bear on the second, third, and fourth abdominal segments 

 sensory bristles or " bothriotricha," which are characteristic of the latter, but 

 not of the former, sub-family. Now Isotomourus (of which there is a 

 Seychelles species) resembles typical Isotoma and its allies so closely in all 

 the main points of structure that Borner was obliged to call in a theory of 

 "convergence" to account for the likeness. Unfortunately almost all writers 

 on Collembola during the last ten years hastened to accept Borner's new 

 classification, although his " bothrioticha " (one is figured on PI. XIV, fig. 18) 

 are far too slender to carry the weight which he assigned to them. Why 



