159 . 
HYDROPHILUS CARABOIDES. 
Order Coleoptera. Fam. Hydrophilidse Leach., Lat . 
Type of the Genus Dytiscus caraboides Linn. 
Hydkopiiilus Geoff., Fab., Lat., Leach .- — Dytiscus Linn. 
Antennae inserted at the base of the mandibles, close to the eyes, 
under the c.lypeus ; shorter than the head, naked, 9 -join ted, 
basal joint robust bent, 2nd slender as long as the 3 following 
united, which are subquadrate, the remainder forming a per- 
foliate, velvety club, the 1st joint the smallest, 2nd and 3rd 
transverse, 4th ovate, truncated obliquely (fig. 6). 
Labrum very short and broad, naked, emarginate (1). 
Maydibles rather large, bent acute and bifid at the apex, internal 
edge thin and ciliated (2) . 
Maxillae small, producing 2 lobes, external one large, composed 
of 2 joints the 2nd membranous and ciliated with strong hairs 
at the apex ; internal lobe cleft, the superior portion minute ci- 
liated, and terminated by a rigid bristle, the inferior lobe pro- 
ducing strong bristles at the apex, and ciliated on the margin. 
Palpi very long, naked, 4-jointed, basal joint minute, 2nd long 
robust clavate, 3rd not so long, 4th shorter subfusiform, slightly 
bent (3). 
Mentum transverse quadrate, sinuated at the anterior angles. 
Lip broad bilobed, ciliated, coriaceous in the disk, sides mem-, 
branous. Palpi remote, attached to the membranous sides of 
the lip, short, 3 -jointed, basal joint minute, 2nd clavate, 3rd bent, 
subfusiform (4). 
Clypeus large entire, covering the mouth. Eyes remote prominent , 
reniform. Thorax keeled beneath, terminated in a spine at the ex- 
tremity of the poststernum not extending beyond the trochanters . 
Scutellum triangular. Coleoptra ovate very convex. Wings ample , 
formed for flying. Legs rather long. Tibiae furnished with strong 
spurs at their apex. Tarsi simple, alike in both sexes, anterior the 
slenderest (5) ; 4 posterior longer, compressed, producing hair down 
the sides for swimming ; 5- jointed , basal joint nearly obsolete (5 fa), 
3 following short in the anterior pair , the 2nd longer than the termi- 
nal one in the posterior. Claws very much bent, dentate at their base. 
Caraboides Linn. Syst. Nat. 2. 664. 2. — Faun . Suec. 765. — Marsh . 
402. 2. 
Black shining, minutely but not deeply punetured. Head and 
thorax with a few large punctures on their sides, the former with 
an impression close to the eye, the latter with 2 in the disk. 
Elytra irregularly punctured on the outer margin, each having 
4 irregularly-punctured striae. Beneath dull, pubescent. An- 
tennae and palpi ferruginous, the club of the former black. Tibiae 
and tarsi castaneous black, the hair upon the latter ferruginous. 
In the Author's and other Cabinets. 
