On Aquatic Carnivorous Coleoptera or Dijtiscidie. 337 



I. 19.— Genus EETERHYDRUS. 



Labrum conspicuously exserted on under surface of head ; middle coxse rather 

 widely separated ; prosternal process broader than long, its obtuse hind margin 

 reaching the metasternum. Hind tibite straight, the basal portion not con- 

 spicuously narrower than the apical one. 



A single species forms this genus. 



223. Hyphydrus senegalensis, Aube, M.C. — Ovalis, subtus convexus, subopacus, 

 niger, antennis rufis, pedibus piceis ; elytris sat crebre et sat fortiter punctatis ; 

 pectore parce subtiliter, abdomine crebrius et niagis distincte punctato. Long. 

 6 m.m., lat. 3i m.m. 



Antennse 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 of 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 difliercnt 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 Aube described his Hyphydrus senegalensis : this individual 

 agrees exactly with Aube'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 bis description is insufficient for independent 

 recognition, and we have no idea where his type was preserved, I have cited Aub^ 

 as the authority for the species name, and the reference to Laporte de Castlenau 

 should for the future pass unnoticed. 



Madagascar. 154. 



