if 
H-nn 
151 . 
CYBISTER RCESELII. 
Order Coleoptera. FAM.DyticidaeZetf^. Hydrocan thariZa/. 
Type of the Genus Dytiscus lateralis Fab. 
Cybister Nob .- — Trogus Leach . — Dytiscus Fab. 
Antennae inserted close to the eyes at the base of the mandibles, 
subsetaceous, naked, 1 1 -jointed, basal joint not so long as the 3rd, 
2nd joint very short, 3rd the longest, the remainder decreasing 
in length to the last, which is slightly bent and subconic at the 
apex (fig. 6). 
Labrum transverse, slightly emarginate, with a small fleshy lobe 
beneath in the middle (1). 
Mandibles short, robust, emarginate at the apex, which is trun- 
cated obliquely, with 2 small teeth on the internal margin (2). 
Maxillae small, bent, acute, ciliated internally with rigid bristles. 
Palpi internal short, 2-jointed, basal joint shorter than the 2nd 
which is slightly curved ; external long, 4-jointed, 1st joint half 
as long as the 2nd and 3rd which are of equal length and trun- 
cated, the 4th longer and a little dilated on the external side (3). 
Mentum transverse, bilobed, the centre being slightly produced. 
Palpi arising from cylindric scapes, 3-jointed, 1st joint small, 
2 following long of equal length, clavate-truncate. Labium 
large quadrate-ovate, ciliated (4). 
Head rounded. Thorax transverse. Scutellum distinct. Elytra smooth 
in the males , vermiculated the greater portion of their length from 
the base in the females. Wings two. Tibiae spurred , very short, the 
anterior pair being the longest. Tarsi 5- jointed , anterior patelliform 
in the males, the 3 first joints being dilated, with suckers beneath and 
ciliated, the 4th minute , 5 th not very long (5) j 2nd pair more robust 
in the males, none of the joints dilated, the ls£ and 2nd pubescent 
beneath ; posterior elongated. Claws unequal, posterior monodac- 
tyle (5f, a hind leg). 
Obs. The dissections were made from a male of C. Roeselii. 
Rceselii Fab. Ent. Syst. v. 1. pars 1. p. 188, n. 5 . — dispar Ross. Fn. 
Etrus. 1.199.489. 
Female smooth, shining, olive green. Clypeus and labrum ochra- 
ceous. Thorax sculptured with small curly lines and points, 
with a slight channel down the centre, sides margined with ochre, 
anterior and posterior margins slightly ferruginous : scutellum 
inclining to the same colour. Elytra vermiculated | of their 
length from the base, 2 widely punctured striae on each, only 
visible at the apex, which is quite smooth as well as the suture, 
an ochraceous broad line tapering towards the apex, next the 
external margin, which is the same colour as the elytra. An- 
tennae and legs ferruginous. Tibiae and tarsi castaneous, the 
latter inclining to black. Beneath ochraceous variegated with 
ferruginous. Furcate process of metasternum obtuse. 
In the Cabinet of Mr. Griesbach. 
