56 HYDROPHILIDA. 
5. Tropisternus crassus. 
Robustus, latus, convexus, niger, superne viridi-violaceo micans, antennarum basi palpisque testaceis, pedibus 
piceis; his crassis parum elongatis, femoribus intermediis et posterioribus subtus ex parte majore pube- 
scentibus; abdominis apice spina elongata armato. 
Long. 11, lat. 65 mm. 
Hab. Guatemaa, Torola 1000 feet (Champion). 
This insect, although closely allied to 7. nitidus, is distinguished by a comparatively 
shorter form, less attenuate behind; it also has the hind legs shorter and stouter, 
and their femora have a larger portion of their area covered with pubescence, this 
pubescence extending a little more than halfway to the apex, while in 7. nitidus the 
extension is a little less than halfway. It is one of a group of species extremely 
difficult to distinguish from one another, and of which several are found in South 
America; but none of the South-American individuals I have seen agree with the four 
individuals found by Mr. Champion. 
6. Tropisternus brevicollis. (Tab. II. fig. 4.) 
Subdepressus, subellipticus, sat elongatus, niger, subeeneo-micans, fere impunctatus ; spina sternali fere brevi, 
lata, deplanata, parum punctata; femoribus area parva pubescente, tibiis posterioribus haud ciliatis ; 
elytrorum linea pleurali omnino levigata; abdominis apice in medio carina sat elongata perparum 
elevata. 
Long. 54, lat. 3 lin. 
Hab. Mexico (coll. Sharp), Ventanas 2000 feet (forrer). 
This is a very distinct and peculiar species, with unusually short thorax, and with 
the sculpture of the upper surface much diminished, and with very short palpi. The 
usual looped series of punctures on each side of the head is wanting, or rather only 
the external portion of the series (near the antenne) exists; and at the margin of the 
eye there is only a single large puncture. The usual minute punctuation of the head 
and thorax is scarcely to be detected; and the wing-cases too are nearly destitute of 
punctuation. The epipleural margin is entirely without punctures or spines. 
I have a specimen of this peculiar species from Laferté’s collection; and recently 
_ two others have been received from Mr. Forrer, one of which is figured. These two 
latter have the joints of the maxillary palpi black, but marked with yellow. 
7. Tropisternus nitens. 
Tropisternus nitens, Cast. Hist. Nat. 1. p. 54°. 
Hab. Mexico, Oaxaca (Hodge), Juquila, Cordova, Vera Cruz! (Sallé), Ventanas 
2000 feet (Forrer); Guatemata, Purula, San Gerénimo, Paso Antonio 400 feet, Torola 
1000 feet, Pantaleon 1700 feet (Champion); Nicaragua, Chontales (Belt & Janson).— 
Sours America, from Caraccas to Rio-:de Janeiro. 
This species is variable in size and form and in the details of colour, but may be 
