394 INSECTA. 



Elophorus, Fab. Silpha, L. Dermestes, Geoff. Hydrophilus, De 



Geer. 



The body oval, and the thorax transversal; the eyes but slightly 

 prominent(l). 



HydrochuSj Germ. Elophorus, Fab. 



The Hydrochi are only distinguished from the preceding subgenus 

 by their narrow and elongated form, their thorax, which has the 

 figure of a long square, and the prominence of their eyes(2). 



Sometimes the maxillary palpi are subulate or terminate in a more 

 slender joint, short and conical. 



Octhebius, Leach, Germ. Elophorus, Fab. Hydrsena, Illig. , Lat. 



The thorax is nearly semi-orbicular(o). 



There, the maxillary palpi, terminated by a fusiform joint, larger 

 than the penultimate and pointed at the end, are much longer than 

 the antennae and head. The epistoma is strongly emarginated. 

 Their appearance otherwise is that of the Octhebii. 



HydrjEna, Kugel. Leach(4). 



In the other Hydrophili the body is ovoid or almost hemispherical 

 and generally convex or arched, and the thorax always smooth and 

 wider than it is long; the tibiae are terminated by strong spurs, and 

 the tarsi most frequently ciliated. The extremity of their mandibles 

 is bidentated. They embrace the family of the Hydrophilidea , Leach, 

 or the genus Hydrophilus, Fab. 



Some have but six joints in the antennas; their epistoma is emar- 

 ginated. Such are those which form the 



Spercheus, Fab.(5) 

 In the following the antennas are always composed of eight or nine 



(1) The Elophori of Fabricius, those species excepted which belong 1 to the 

 following subgenera. 



(2) Elophorus elongatus, Fab.,- E. crenatus, Id.; E. brevis, Gyllenh. See 

 Germ., Insect. Spec- Nov., I, p. 90. 



(3) E. pygmxus, Fab.; Hydrsena riparia, Lat.; Hydrsena margipallens, Lat.; 

 Elophorus marinus, Gyll. ; see Germ., lb., p. 90. 



(4) E. minimus, Fab. Gyll.; Hydrsena riparia, Kugel. ; H. longipalpis, Schrenh., 

 Germ., Faun. Insect., Eur. VIII, 6. For the other species, see Germ., Insect. 

 Spec. Nov., I, p. 93. 



(5) Spercheus emarginatus, Fab.; Panz., Faun. Insect. Germ., XCI, 4. M. 



