262 "TERRA NOVA" EXPEDITIOlSr. 



former description (1908). The manubrium of the spring (figs. 12, 13, ma) is short 

 and stout, exceeding slightly in length the pointed, distal segments (fig. 12, 13, d) 

 each of which represents the dens and mucro fused together. This condition of the 

 spring agrees closely with that found in several species of Xenylln. The catdi 

 (fig. 12, R) has each of its paired distal segments with two minute teeth. 



Termikal Abdominal Segments. — The opening of the reproductive organs is 

 situated close to the hinder edge of the fifth abdominal sternum (fig. 14, gn), a 

 somewhat cruciform slit in a delicate plate beset with numerous short hairs. Just 

 behind, on the sixth abdominal segment, may be seen the rounded edges of the paired 

 sternal plates which mark the position of the anus (fig. 14, a). These structures 

 correspond closely with those of Achorutes and Xenylla. 



Specific Characters. — The specific diagnosis given in my previous paper (1908, 

 p. 3) needs no amendment, except that the largest extended specimens attain a length 

 of 1'3 mm., and that the intersegmental cuticle is pale ; otherwise the colour of the 

 insects is a dense blue-violet, indeed, almost black in many of the preserved 

 specimens. 



AFFINITIES OF GOMPHIOCEPHALUS. 



From the foregoing descriptions, students of the Collembola will realise that 

 Gomphiocephalus is allied to Achorutes {= Hyjyogasirura), Becker ella and Xenylla. 

 It is especially close to the last-named, from which it is distinguished by possessing 

 a post-antennal organ, seven ocelli on each side instead of five, and a simpler sense- 

 organ on the third segment of the feeler. In all these characters, Gomphiocejjhalus 

 is more primitive than Xenylla. The simple post-antennal organ resembles that found 

 in the Entomobryidae (Isotominae), but Gomphiocephalus is not peculiar among the 

 Poduridae in possessing such an organ ; one of somewhat similar build characterises 

 Becker ella, a genus lately established by Linnaniemi (1912, pp. 39-40, PI. IV., 

 figs. 13-17) for Achorutes inermis, TuUberg, a North European species readily dis- 

 tinguished from most Achorutinae by the absence of anal spines. Gomphiocephalus 

 does not differ, therefore, to any great extent, from other genera of its sub-family. 

 The habits also of the Granite Harbour insects — crowding on the surface-film of 

 water, or on ice or snow, lurking under stones, or sheltering among the moss which 

 affords them food — recall those of our North European species of Achorutes and 

 Xenylla. 



DISTRIBUTIONAL NOTES. 



The presence of this springtail and also of an Isotoma [sens, lat., see Carpenter, 

 1902) on the continental area of South Victoria Land, raises some interesting dis- 

 tributional questions, both insects being related to allies that have a wide range 



