108 AUSTRALIAN PKDICUI.IDS. 



Neumann (I9(X), p. 51;>-7) has described a new 

 species Hcemato^inus [Polyplax) hidentatus as infesting^ 

 a Mus rattus from Lake Torrens, South Austraha 

 (Rothschild collection). Fn connection with this form 

 Dr. Cleland has made certain inquiries, the result of 

 which has been to make- known the following facts.. 

 Dr. Borthwick, Commissioner of Public Health, Adelaide, 

 forwarded to the Wow. Rothschild, through Professor 

 Stirling, Director of the Adelaide Museum, a collection 

 of ectoparasites from rats. Amongst them were fleas 

 from the common rats, and pediculids from a water 

 rat, Hydromys chrysogaster, captured at Torrens Lake,, 

 a sjieet of fre»h water in the vicinity of Adelaide. Lake 

 Torrens is a depression, sometimes containing saline 

 water, in the central portion of South Australia. It i& 

 safe to assume that this is the collection which Pro- 

 fessor Neumann handled. The host of this new species 

 of pediculid is thus an Australian rat and, not, as far 

 as we are aware, the introduced house rat Mus rattus^ 

 Owing to the collector's name not having been recorded 

 along with the description, some diflicultv might have 

 been experienced in tracing the specimens but for Dr. 

 Cleland 's kindness. One of us has received from the 

 Bureau of Microbiology, Sydney, a pediculid, one 

 millimetre long, taken from //. chrysogaster , caught on 

 the shore of Sydney Harbour. The head is injured, 

 but the general form of the ])arasite agrees with that 

 described by Neumann. The seta? on the pleura are 

 longer in our specimen, as they extend beyond the 

 stigmata. 



Water Rat. {Hydromys chrysogaster.) 

 Polyplax hidentatus, Neumann. 



S. Aw&tralia, Sydney. 

 (See under Mus rattus and decumanus.) 



No doubt many of the forms here recorded as occurring- 

 in certain States of Australia are also present in others. 



Mr. A. S. Le Sbuef and Dr. Cleland of Sydney, and Mr. 

 Desmond, of Adelaide,, have been kind enough to forward 

 material to us. 



