82 Mr. D. Sliarp on some 



of Mr. Blackburn. The structural cliaracters which have 

 justified the formation of a new generic name for this 

 species may be enumerated as follows : — 



Head short and broad, truncate and depressed in front, 

 so that the small eyes project as subangular projections ; 

 the short very broad labrum quite exposed. Antennae 

 9-jointed, the 1st joint elongate, the 2nd rather short, the 

 three following very small, short and equal, the 6th joint 

 short and strongly transverse, closely applied to the base 

 of the 7th joint, this and the 8th and 9th joints forming 

 a large very compact club. Maxillary palpi formed much 

 as in Megasternura, the 2nd joint being a good deal iu- 

 crassate, the 3rd and 4th slender, the latter acuminate. 

 Prosternura short, and unarmed ; intermediate cox^e 

 approximate, separated by the greatly-elevated meso- 

 sternal lamina ; this lamina is linear, and perfectly on a 

 level with the metasternum, to which it is amalgamate 

 Avithout any trace of suture remaining ; the metasternum 

 not in the least carinate. Legs short, the tarsi extremely 

 short, the basal joint of the posterior ones quite short, 

 and not easily distinguished, the 2nd longer than the 3rd. 



I am quite unable to find any near ally for this minute 

 insect ; it must be located at present in the Ilijdrobiides 

 of Lacordaire between AnaccBna and Volvulus, but it is 

 widely separated from each of those genera. In respect 

 of its hind tarsi it is more approached by CiuBtarthria, 

 which is in other respects widely diflTerent. 



Only three other species of Hydrophilidce have been 

 yet found by Mr. Blackburn, they are — 



1. Hydrajjliilus semicylindricus , Esch. 



This species should at present be located as a member 

 of the genus Hydrohms of the Munich Catalogue : it 

 departs, however, in some important particulars from our 

 European species ; the posterior and intermediate tarsi 

 are furnished above with long ciliffi ; the prosternum is 

 finely carinate along the middle, and the undersides of the 

 femora are polished, there being on the front and middle 

 ones merely a small punctate space near the trochanter. 

 In these respects it agrees with the one or two Australian 

 allies, from which it is, however, as a species, abundantly 

 distinct. In the form and development of the mesosternal 

 protuberance the Hawaiian species agrees wdth our Euro- 



