203 



shorter abdominal plates, more strongly sculptured metasternum,. 

 rather more sparing puncturation of the upper surface where there 

 is less difference, moreover, than usual in the genus between the 

 punctures on the prothorax and those on the elytra, and in the 

 dark elytral epipleurse (those of R. insipidus show up as of a pale- 

 brown colour in strong contrast to the reddish pitchy metaster- 

 num and hind body), besides other differences of colour, &c. 

 Port Lincoln. 



R. venfralis, Er. I have taken near Poi-t Lincoln, and also' 

 near Adelaide, examples of an insect which I cannot doubt is- 

 this remarkably coloured species, but if so, it is desirable to point 

 out that Erichsen is in error in calling it " oblongo-ovalis," as it 

 is rather exceptionally wide. It is, of course, possible that I 

 have not the genuine thing before me, but my specimens agree 

 perfectly with the description in every character except that I 

 have named, including the unusual character of having the 

 anterior angles of the prothorax membranous. Mulsant uses a 

 similar expression in his (apparently independent) description, 

 but afterwards furnishes measurements that certainly do not 

 justify it, but show the species to be of much broader proportions 

 than others to which he applies the same term. 



The insect before me is rather unlike Rhizobius in facies, but 

 does not differ structurally in any respect so far as I can discover- 

 Since many of the species of this first section of Rhizobius are 

 closely allied inter se, the following tabulation may be service- 

 able : — 



A. Elongate subparallel species. 



B. Prothorax and elytra brown or ferruginous. 



discolor, Er. ? (var. proj)rius, Blackb.)- 

 BB. Prothorax and elytra cyaneous. cya7ieus, Blackb.. 



AA. Oval species. 



B. Upper surface clothed with long erect hairs as well as- 

 short pubescence. 

 C. Prosternal ridge sharply pointed in front. 

 D. Epipleurse of elytra dark coloured. 



ruficollis, Blackb.. 

 DD. Epipleurae of elytra pallid (in contrast with the- 

 much darker under surface of body). 



insipidus, Blackb. 

 CO. Prosternal ridge not sharply pointed in front. 



D. Elytra strongly punctulate (more strongly than 

 those of R. liturus. Fab.) Evansi, Muls.- 



DD. Elytra very finely punctulate ; prosternal ridge- 

 with parallel sides. debilis, Blackb. 



DDD. Elytra distinctly but not very strongly punc- 

 tulate ; prosternal ridge narrowed forward. 



Lindi, Blackb, 



