PROCEEDINGS OF SECTION D. 267 



1.— APTERA OF AUSTRALIA. 



By W. B. Alexander, B.A., Assistant in the Western Australian Museum. 



(Summary.) 



So far as I have been able to discover the following are the only 

 papers on the Aptera of Australia which have been published : — 



(1) " On some Australasian Collembola," by Sir John Lubbock, 



in the Journal of the Linnean Society of London for 1899. 

 In this paper three species of Anoura collected by 

 A. Dendy in Tasmania are described : — A. tasmanise, A. 

 dendyi, and A. spinosa. 



(2) " Two new species of Collembola," by W. J. Rainbow, in 



the Records of the Australian Museum, Sydney, Vol. VI., 

 p. 313. 



The species described are Isotoma troglodytica, fr«m 

 a pool in the Yangobilly Caves, and Achorutes speciosus, 

 from the surface of a pond at Bathurst. 



(3) " Thysanura of South-west Australia," by Prof. Silvestri, 



in Die Fauna Sud-west Australiens, Vol. II., containing 

 descriptions of the Thysanura collected by the Hamburg 

 Expedition to that district. 



(4) The chapter on Aptera in Froggatt's Australian Insects, which 



indicates that certain other Australian species have been 

 described by Silvestri. Mr. Froggatt informs me that 

 these descriptions are contained in several papers in 

 . Italian journals. 



The object of the present paper is chiefly to point out the affinities 

 of those species which are known to inhabit Australia. I do not 

 propose to describe any new species. 



The Aptera, or Apterygota, are now usually regarded as a primitive 

 group of insects contrasted with the remainder of the class which may 

 be united under the name Pterygota. 



The Apterygota comprise two orders — the Thysanura and Col- 

 lembola. The latter are in many respects highly specialized, and are 

 sharply distinguished by only possessing six abdominal segments. 

 The former are probably an ancestral group intermediate in many 

 respects between the most primitive Pterygota (Orthoptera and Neurop- 

 tera) on the one hand, and the Myriapoda on the other. 



One of the Myriapoda, Scolopendrella, approaches the Thysanura 

 very closely in its appearance and structure ; en passant I may notice 

 that a species of Scolo-pendrella is extremely common in the neighbour- 

 hood of Perth, in damp earth under stones and logs. 



The Thysanura, or Bristle-tails, are small insects, of which the well- 

 known silver-fish is one of the largest. They have been divided into 



