On Aquat Carnivorous Coleoptera or Dytiscide. 337 
I, 19.—Genus HETERHYDRUS. 
Labrum conspicuously exserted on under surface of head; middle cox rather 
widely separated; prosternal process broader than long, its obtuse hind margin 
reaching the metasternum. Hind tibiz straight, the basal portion not con- 
spicuously narrower than the apical one. 
A single species forms this genus. 
223. Hyphydrus senegalensis, Aubé, M.C.—Ovalis, subtus convexus, subopacus, 
niger, antennis rufis, pedibus piceis; elytris sat crebre et sat fortiter punctatis ; 
_ pectore parce subtiliter, abdomine crebrius et magis distincte punctato, Long. 
6 m.m., lat. 33 m.m. 
Antennee moderately long and slender; clypeus broadly rounded in front, with 
a sharply defined edge, indistinctly margined; the surface of the head finely and 
rather sparingly punctured, and with no distinct depressions. Thorax very short 
and broad, but little longer in the middle than near the sides, the front angles, 
however, very produced, the lateral margins distinct, the surface rather finely, 
irregularly and sparingly punctured. 
The type ef Heterhydrus agaboides communicated to me by M. Fairmaire has the 
surface dull and rather strongly punctured, and is perhaps a female ; if so the specimen 
in my collection, (for which I am indebted to Herr Wehncke), must be the other sex, 
for it is shining and but little punctate. On the other hand it is possible that these 
individuals may belong to different species : the latter individual, (the shining one), 
seems to agree exactly with a specimen from Senegal, now in the collection of 
Count Mnizech, who obtained it from Dupont’s collection, it being one of the 
individuals on which Aubé described his Hyphydrus senegalensis : this individual 
agrees exactly with Aubé’s description and measurement, but it does not accord 
very well with Laporte de Castlenau’s few words of hurried description, nor with 
his measurements, (Et. Ent. p. 106), and it is possible that Laporte may have had 
some other insect in view ; as however his description is insufficient for independent 
recognition, and we have no idea where his type was preserved, I have cited Aubé 
as the authority for the species name, and the reference to Laporte de Castlenau 
should for the future pass unnoticed. 
Madagascar. 154. 
