366 On Aquatic Carnivorous Coleoptera or Dytiscide. 
torm ; the dark markings on the elytra consist of one or two lines and several spots, 
or thickened and interrupted lines: the basal ventral segment of the hind body 
shows a single series of punctures on each side and elsewhere is quite smooth. 
The only specimen I have seen is, I think, a female. 
Brazil, (Santa Rita, August, 1850, R. F. Sahlberg). 111. 
315. Bidessus atomarius, n. sp.—Ovalis, angustulus, leevis, nitidus, impunctatus, 
rufo-testaceus, elytris infuscatis, pone basin et ad apicem testaceo-signatis. Long. 
12, lat. $m.m. 
This minute species looks ikea Laccophilus. 1 have seen only three individuals, 
all of which have the front and middle tarsi quite slender. 
Brazil, (Petropolis, May, 1850, R. F. Sahlberg). 112. 
316. Hydroporus liliputanus, Aube. M.C.—Oblongo-ovalis, sat latus, nitidus, 
fuscus, antennis pedibusque testaceis ; elytris versus suturam crebre sub-obsolete 
punctatis, stria discoidali impressa ; coxis posterioribus omnino levigatis. Long. 
Mlle, I wnpin, 
Aubé’s unique type is a little paler than the specimen above described, but 
otherwise I see not the least difference. 
Brazil, (Bahia). 113. 
317. Bidessus texanus, n. sp.—Oblongo-ovalis, angustulus, sub-depressus, dense 
subtilissime pubescens, sub-nitidus, testaceus, abdomine pectoreque nigricantibus, 
elytris sutura fasciisque transversis fuscis, dense subtilius punctatis ; corpore subtus 
fere impunctato. Long. 1%, lat. 1 m.m. 
This species is very similar in appearance to the European Hydroporus minutis- 
simus, (No. 267); I have seen only two individuals, both of which have the front 
and middle tarsi quite slender. 
North America, (Texas, sent by Belfrage). 456. 
318. Hydroporus affinis Say, M.C.—Oblongo-ovalis, sat angustus, sat nitidus, fere 
nudus, fuscotestaceus, pedibus, capite thoraceque testaceis, hoc disco infuscato ; 
elytris plus minusve distincte pallido-signatis, mediocriter punctatis ; coxis 
posterioribus medio parce obsolete punctatis, vel leevigatis. Long. 1s, lat. 1 m.m. 
Obs. species statura, pictura, punctatura coloreque corporis variabilis. 
This species is very variable, and I had at first separated the variations as dis- 
tinct species, but after a repeated study I have been unable to detect any definite 
characters to distinguish the varieties. 
