5 '- /t2t 
240 , 
BEROSUS TRICEPS. 
U 
Order Coleoptera. Fam. Hydrophilidae Leach , Lat. 
Type of the Genus Dytiscus luridus Linn, 
Berosus Leach , Sam .— Hydrophilus DeG., Fab., Oliv., Lat., Gyll., 
Marsh . — Dytiscus Linn. 
Antenncc inserted close to the eyes at the base of the mandibles, 
8-jointed, basal joint long, robust, slightly bent, subclavate, 2nd 
shorter, slightly attenuated, 3rd and 4th small, somewhat obtri- 
gonate, 5th cup-shaped, the remainder forming a perfoliated pi- 
lose club, the Gth and 7th joints equal somewhat bowl-shaped, 
the terminal one large subglobose (6). 
Labrum transverse, anterior margin semi-oval and ciliated (l). 
Mandibles subtrigonate, bent, tridentate at the apex, producing 
2 broad lobes on the inside, each being tridentate at the apex, 
the lower one ciliated at the base (2). 
Maxillce small, producing a broad rounded lobe on the inside and 
an indexed one at the apex, both ciliated with coarse hairs. Palpi 
very long, 4-jointed, basal joint minute, 2nd long, clavate, 3rd 
shorter, narrowed at the base, 4th nearly as long as the 2nd, 
subfusiform-truncate (3). 
Mentum transverse, broadest at the base, the anterior margin 
forming an obtuse angle. Lip very broad and short, sides an- 
gulated, anterior margin curved and ciliated, slightly notched in 
the centre. Palpi very remote short and triarticulate, basal joint 
minute, 2nd and. 3rd of equal length, the former obovate-trun- 
cate, the latter subovate, producing a bristle externally (4). 
Head bent down. Eyes globose, rather prominent. Thorax convex 
broader than the head. Scutellum small. Elytra globose , considerably 
broader than the thorax. Wings very ample. Anterior feet the 
shortest. Thighs very much dilated at the base. Tibiae spurred . 
Tarsi 3-jointed; 1 st joint obsolete, 2nd large, and 3rd slightly di- 
lated in the males ; 4 basal joints short of equal size in the females, 
ciliated beneath with bristles, 3th very long. Four Posterior legs 
natatorious, the Tarsi long attenuated, ciliated, 3 -jointed, basal joint 
small obscure, 2nd the longest. Claws slightly denticulated at the 
base, with a membranous slender Pulvillus the apex (5, fore 
leg of B. aericeps fern .from which all the dissections were taken). 
.Ericeps Spence MSS . — luridus Oliv. No. 39. pi. 1 .Jig. 3. c,f. 
Ovate, shining, dull ochreous. Head and thorax thickly and 
finely punctured, the former green with a cupreous tinge, the 
latter with a small oval greenish black spot on the back, divided 
longitudinally by a ferruginous line. Scutellum black. Elytra 
with a few hairs beyond the middle, having 1 1 crenated striae on 
each, the 2nd from the suture abbreviated, the surface punctured, 
the spaces between the 3rd and 4th, 5th and 6th, and 7th and 
8th striae being the strongest ; each elytron has also 6 rather 
obscure black spots, one towards the base, the next nearer the 
suture, the others beyond the middle. Underside dull blackish $ 
Legs ochraceous, the 4 posterior coxae fuscous. 
In the Author's and other Cabinets . 
