8 GENERIC SYNOPSIS. 
ILYBIUS Erichs. Cotymserres p. Steph. 6 sp. Dyt. fenestratus Fab. 
Labial palpi with the second and third joints subequal ; claws subequal ; scutellum 
distinct ; anterior male tarsi slightly dilated. Panz. F. I. G. 38. 16. 
AGABUS Leach. Acasus p. Erich. 1 sp. Dyt. serricornis Payk. 
Antenne ¢ with the terminal joints dilated ; maxillary palpi with the last joint 
subulate ; anterior male tarsi slightly dilated. Ahrens, F. 5. f. 3. 
HYDATICUS Leach. Dyvicus p. Fab. 4sp. Dyt. Hybneri Fab. Curt. 95. 
Antenne setaceous; anterior ¢ tarsi patellated; female with smooth elytra. 
Obs. Hydaticus cinereus Fab. is the type of Eschscholtz’s subgenus Graphoderus. 
ACILIUS Leach. Dyticus p. Linn. 2sp. Dyt. sulcatus Linn. Curt. 63. 
Anterior ¢ tarsi patellated; claws didactyle; female with furrowed elytra ; 
max. palpi with the second and third joints unequal. 
CYBISTER Curtis. Trocus Leach. 1 sp. Dyt. virens Mull. (Roeselit Fab.) 
Anterior ¢ tarsi patellated; posterior tibiz very short; posterior ungues mono- 
dactyle. Curt. 151. 
DYTICUS Geoff. Dyriscus p. Linn. 8 sp. Dyt. marginalis Linn. Curt. 99. 
Anterior ¢ tarsi patellated; claws didactyle; maxillary palpi with the second 
and third joints equal. 
Family 2. GYRINIDZ Leach. (Gyrinus Linn.) 
GYRINUS Geoff. Dyriscus Linn. olim. 8 sp. Gyr. natator Linn. Curt. 79. 
Body depressed; elytra glabrous ; maxillary internal palpi distinct. 
ORECTOCHEILUS Esch. Poramosius Leach, MSS. 1 sp. Gyr. villosus Ill. 
Body subconyex ; elytra pubescent ; maxillary internal palpi obsolete. 
Subtribe 2. Rypophaga Stephens. 
Stirps 1. Philhydrida MacLeay. (Palpicornes and Clavicornes p. Latr. ) 
Familyl1. HETEROCERIDZ Mach. (Acanthopoda Latr.) 
HETEROCERUS Bose. Dermestes p. Thunb. 7 sp. Het. marginatus Fab. 
Body oval, subdepressed ; tibize spinose; antennz with the seven terminal joints 
forming a serrated club. Curt. 224. 
Family 2. PARNIDZ Mach. (Macrodactyla Latr.) 
Subfamily 1. Parnides Westw. (Parnide Steph.) 
PARNUS Fabr. Dryors Oliv. 5sp.  P. prolifericornis Fab. Curt. 80. 
Thorax with longitudinal fossule; legs rather short; antennz 9-jointed*, with 
the second joint produced on the inside into a very large lobe, forming a 
lateral shield, defending the terminal joints. 
DRYOPS Oliv. —————— 1 sp. D. Dumerilii Latr. Aud. and Br. 5. pl. 14, 
Thorax without impressed lines ; legs elongate ; antennz with the clava pectinate, 
the teeth being acute. 
(in Dejean’s Catal. 2d edit.), without any characters having been published by the 
former author. Mr. Stephens ( //lustr. vol. v. Suppl.) has, however, supplied this 
deficiency. I have only adopted the two following subgenera described by Erich- 
son and Leach. Eschscholtz’s groups are — Cymatopterus (C. fuscus, &c.), Rantus 
(C. agilis, adspersus), Leiopterus (C. oblongus). 
* M. Dufour states that the antenne are in reality 10-jointed, the two terminal 
ones not being distinguished by the serrated appearance of the preceding. I have 
observed the distinction between these two terminal joints very clearly on macerat- 
ing and slightly compressing the antenne. 
