762 SUPPLEMENT. 
4. Hydrophilus pollens. 
Ovalis, convexus, niger, supra viridi-olivaceus, parum nitidus, pedibus nigro-piceis, antennis palpisque testaceis ; 
prosterni processu profunde fisso, utrinque anterius dente acuminato deorsum spectante ; femoribus poste- 
rioribus validis; abdomine pubescente, segmento penultimo medio linea levigata et carinata, posterius in 
dente libero producta, segmento ultimo medio spatio parvo, anterius angusto leevigato ; palpis maxillaribus 
maris dilatatis. 
Long. 30-85 millim. 
Hab. Mexico (coll. Laferté), Vera Cruz (Hége).—Soutn America, Demerara (Harper). 
Of this species I have before me three examples, and have no doubt that the 
example from Mexico with the maxillary palpi dilated is the same species as the indi- 
vidual from Demerara with the palpi simple, although in this presumed male there is 
not the slightest incrassation or peculiarity of the front tarsi, which are quite like those 
of the female; the second example from Mexico has unfortunately lost the palpi. 
H. pollens is one of a group of species distinguished by the prosternum in front 
being divided into two lobes, by the hind body being nearly entirely covered with 
pubescence, by the broad hind femora, and by the males possessing peculiar sexual 
distinctions. The species of this group are rather numerous in South America; but 
are apparently scarce, and only two or three have been described. 
5. Hydrophilus violaceo-nitens. 
Hydrophilus violaceo-nitens, Jacq. Duv. in Sagra’s Hist. fisica polit. y nat. de Cuba, vii. Ins. p. 231; 
Chevr. Ann. Soc. Ent. Fr. 1863, p. 205°. 
Hab. Mexico, Vera Cruz (Flohr).—-ANTILLES, CuBa ! ?. 
The two examples of this insect received from Mr. Flohr are extremely mutilated 
and immature, but I expect they will prove to be the same as the Cuban species, of 
which only the female appears to be known. If I am correct in this supposition, 
H. violaceo-nitens is closely allied to H. pollens, but the colour of its upper surface is 
less viridescent, the lobes of the prosternum are quite obtuse, and the penultimate two 
segments are polished along the middle, while the glabrous space on the terminal 
segment is of oblong rather than triangular shape; the pectoral lamina is thick in 
front, and bears a remarkably deep depression ; all the femora are red, but this may be 
due to the immature condition of the two examples. 
These specimens were met with in the Laguna de los Cocos some time ago; but 
though sought for since the species has not again been found there. 
TROPISTERNUS (p. 54). 
Tropisternus mexicanus (p. 55). 
To the Mexican localities given, add :—Mazatlan in Sinaloa, San Juan Bautista in 
Tabasco (//6ge). 
