64 ADEPHAGA. [PtcrOSticluiS. 



cordiform, rounded in front contracted behind, posterior angles right 

 ajigles, with their apex slightly produced and obtuse, disc with a deep 

 central furrow, and a very strong impressed oblong depression on each 

 side, and a smaller one, sometimes obsolete, close to angles ; elytra oblong 

 ovate, deeply striated, interstices convex, the third with three impres- 

 sions ; the male has a longitudinally elevated ridge on the last abdominal 

 segment which forms at its apex a small tooth ; legs brown-black. L. 

 14-16 mm. 



Very local ; the only locality appears to be the Northumberland and Durham dis- 

 trict, wliere it occurs occasionally in numbers near Newcastle, Sunderland, Ravens- 

 worth. Long Benton, and other places. 



(Sub-Gen. Ziyperus, Chaudoir. Lyperosomtis, Mots.) 



P. aterrixnus, Payk. Very deep shining black, winged ; antennse 

 black, apex slightly fuscous ; thorax subquadrate, rather broader than 

 long, with sides feebly rounded, very slightly contracted towards base, 

 posterior angles rounded, margins broadly reflexed especially at posterior 

 angles, central furrow very distinct, continued to base, but interrupted 

 in front by a strong semicircular furrow, base depressed with a large 

 punctured fovea on each side near angles ; elytra oblong, not mucli 

 broader than thorax, parallel-sided, with moderately strong stria3 near 

 suture, which become very feeble on the sides ; the strisp, are more or 

 less punctured, and are much weaker in the female than the male ; the 

 third interstice has three large round impressions, but the position of 

 these is variable, as one or two of them are often situated in the stria 

 or on the second interstice; legs black. L. 11-12 ram. 



Very local, but formerly abundant in Whittlesea Mere ; also found in various places 

 in the Cambridgeshire Fens, Horning Fen, Norfolk, &c., " basking iu the sun, on the 

 soft mud, at the edge of the turf pits" (Stephens, Illust. i. 113). It is also said to 

 have occurred in Ireland, near Cork : it has become exceedingly scarce, and I do not 

 know of any record of its capture for many years past. 



(Sub-Gen. Omaseus, Ziegler. Alelanms, Bon. pars) 



I. Antennae with joints 4-10 slender, elongate ; thorax with 

 sides almost straight from middle to base. Length 



18-20 mm P. NIGEE, Schall. 



II. Antennae with joints 4-10 shorter and thicker in com- 



parison J thorax with sides rounded almost to base, 

 i. Lateral border of thorax widened behind. Length 



15-17 mm P. TiTtaAEis, L. 



ii. Lateral border of thorax not widened behind. Length 



not exceeding 11 mm. 



l.Apex of elytra at suture furnished with a little tooth 



(female) or sharply angled (male); anal segment of 



abdomen in male with a large deep, round or oval, 



depression P. antheacinus. III. 



2. Apex of elytra at suture bluntly rounded ; anal seg- 

 ment of abdomen in male without depression. 

 A. Abdomen punctured on the sides ; auid segment of 



abdomen iu mulo with a small raised tubercle . . P. NIQEITA, F. 



