ELAPHRIDJE. BLETHISA. 35 



Sp. 3. riparius. Mneo-virescens, punctatissimus, thorace suhfoveolato, elytris 

 mamillis cupreo-oeneis, circulo impresso cinctis, quadruplici serie. (Long, 

 corp. 3 — 3^ lin.) 



Ci. riparia. Linne. — Don. ix. pi. 301. El. riparius. Steph. Catal. p. 42. No* 411. 



Dull greenish-bronze : head very thickly punctate : thorax above convex, thickly 

 punctate, with an abbreviated dorsal channel, anteriorly furcate, and an ob- 

 long fovea on each side posteriorly : elytra ovate, slightly convex, greenish- 

 brass or dull brownish-bronze, thickly punctate throughout; each with four 

 rows of catenated striae, as in the two preceding species, but less profound, 

 and the colours rather different, the centre of each circle being purplish, the 

 margin brassy, the elevated patches between are rather obsolete, the four 

 nearest the suture being most evident, quadrate, and of a polished brass : body 

 beneath glossy greenish-brass : thighs the same, the base frequently testaceous ; 

 tibiae testaceous, with the apex and tarsi greenish-brass. 



The colour of the upper surface varies greatly, from various shades of light 

 greenish-brass to dusky; sometimes purplish, with violet patches between 

 the strige on the elytra. 



Abundant in several places near London, especially in Copen- 

 hagen and Battersea-fields; also at Coombe-wood, on the banks 

 of the Thames, near Putney, Richmond; at Hertford, Ripley, &c; 

 in Glamorganshire, and near Bristol, and in Devonshire. 



Genus LXXVI. — Blethisa, Bondli. 



Palpi, external maxillary, and labial elongate-ovate, truncate, the two last joints 

 of equal length : labrum, transverse subtrilobate : mandibles bent, acute, ob- 

 scurely denticulated internally at the base : mentum deeply emarginate ante- 

 riorly, the emargination with a slightly produced bifid lobe. Antennas stout, 

 the three basal and base of the fourth joints naked, the rest pubescent : eyes 

 rather large, slightly prominent: thorax subquadrate, truncate, the sides 

 slightly rounded: elytra very convex, with impressed dots, elongate-ovate: 

 legs rather stout: anterior tarsi of the males with four dilated joints. 



Bonelli judiciously separated Blethisa, as a genus, from the other 

 adephaga, in which subsequent writers have followed him. La- 

 treille, in his genera, &c. and Gyllenhal, associated it with Nebria ; 

 Dr. Leach, however, distinguished it from that genus by the name 

 Helobium, in the Edinburgh Encyclopedia, without being aware 

 of Bonelli's arrangement: its location has also been frequently 

 altered, but I presume that its nearest affinity is Elaphrus, from 

 which it differs chiefly by having the third and fourth joints of the 

 external maxillary and labial palpi of equal length, the labrum 

 rather trilobate, the mentum more deeply notched anteriorly, with 

 a moderately-produced bifid central lobe : it also differs in its qua- 



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