included in the genus Tropisternus. 99 



on the thorax occupies the greater portion of its area, 

 leaving frequently only a narrow irregular border pale. 

 The specimens before me seem to indicate that there may 

 possibly be two distinct species mixed in collections, one 

 characterised by the complete confluence of the metallic 

 lines on the wing-cases, and the large development of 

 the metallic colour on the thorax would then be new. I 

 have an individual of this dark form labelled as being 

 from New York, but I do not know whether this be 

 correct, and Leconte records the species only from the 

 Southern States. The Mexican habitat requires con- 

 firmation, as it is given on the authority of an individual 

 from an old French collection labelled " H. strigatus, 

 Chevrolat, Mexique." 



6. Tropisternus par ananus, n. s. 



Superne viridi-fuscus, pernitidus, limbo testaceo ; 

 pedibus testaceis, femoribus basi nigricantibus. Long. 

 9 mm. 



Parana. 



This species is similar in colour to Hydrophilus strio- 

 latus, but in sculpture to H. collaris. The head and 

 thorax are of a metallic colour, with the front margin of 

 the former and the sides of the latter yellow. The stripes 

 on the elytra are placed as in the South American 

 species, but are connected by fuscous colour into a large 

 mass of dark colour, leaving only the lateral margin 

 yellow. The sculpture of the epipleural margin is quite 

 as indistinct as it is in H. collaris. 



I have before me only a single individual. 



Group 2. Sternal spine flat and broad, quite sliort, not 

 extending further backwards titan the first visible 

 ventral suture ; maxillary palpi shorter than in any of 

 the other sj)ecies ; setigerous punctures on each side of 

 prothorax agglomerated into a small depression having 

 the appearance of a single large puncture; pubescent 

 area on posterior femur almost absent. (Sj^eeies 7 

 to 9). 



The species of this group appear to be rarer than the 

 other Trojyistenti ; their individuals have the upper sur- 

 face unicolorous, and the epipleural margin is either 



