included in the genus Tropisternus. 101 



9. Hydrophilus nitidid-us, Brulle. 



Brulle, Voy. d'Orb., Ins., p. 55. 



Brazil (Bio cle Janeiro) ; (Mexico, in coll. Laferte). 



This species is readily to be distinguished from the 

 others of its group by the punctate or crenate epipleural 

 margin, the sculpture not, however, extending to the 

 base. The hind legs are elongate and slender, the mar- 

 ginal series of punctures has the apical punctures so 

 crowded together as to be nearly confluent into a groove, 

 and each bearing a fine, short, erect seta. The apical 

 ventral segment is strongly carinate, and the apex of the 

 carina projects as a short spine. 



The individual, supposed to be from Mexico, is of 

 smaller size than the Brazilian examples, and is of more 

 metallic colour, and the apex of the abdominal carina is 

 less spinose. It may prove to belong to a different 

 species. The specimen is unfortunately in very bad 

 condition. 



Group 3. Sternal spine flat and broad, rather short, but 

 extending backwards a little beyond the first ventral 

 suture ; maxillary palpi elongate ; setigerous punctures 

 on each side of prothorax agglomerated into a small 

 depression ; pubescent area on posterior femur of 

 moderate extent ; posterior tibia tvith its smooth inner 

 face limited above by a series of punctures ivhich do 

 not extend to the extremity, the apical punctures 

 crowded so as to be almost confluent into a groove, 

 ivhich diverges slightly on to the polished inner face, 

 and each bearing a fine, short, erect seta. (Species 

 10 to 13). 



The species of this group are apparently not common, 

 and are very closely allied in all structural points, 

 although one of them is remarkable from the unusual 

 development of the eyes. The size and form of the 

 pubescent area on the hind femur seems very similar in 

 all the species ; at the hind margin its limit extends just 

 beyond the apex of the trochanter, and stretches across 

 the femur in an oblique manner, reaching further out- 

 wards as it goes forwards, so that on the front margin it 

 extends about two-fifths of the length of the femur ; 

 altogether it covers about one-fourth of the whole area 

 of the lower face of the femur. 



