50 MANB1BULATA. — COLEOPTERA. 



Frequently met with in ditches and streams near London, Hert- 

 ford, Ripley, &c. : also in South Wales and Norfolk. 6i Common 

 at Rottisham." — Rev. L. Jenyns. " Wandsworth-common and 

 Copenhagen-fields." — Mr.Ingpen. 



Genus LXXXI. — Hybroporus, Clairville. 



Palpi, external maxillary with, the terminal joint sub-cylindric, truncate: labrum 

 minute : mandibles slightly emarginate at the apex, and denticulated inter- 

 nally towards the base: mentum tridentate. Antennas with the two basal 

 joints elongate, the remainder nearly equal in length: head broad, gibbous; 

 body oval, rather depressed, broader than high : elytra ovate : legs slender ; 

 the four anterior tarsi with four, the two posterior with five joints; all 

 didactyle. 



This genus, which consists of several closely approximating 

 species, may be known from Hygrotus by the truncate terminal 

 joint of the external maxillary palpi, by the depressed body, which 

 is broader than high, by the slighter emargination at the apex of 

 the mandibles, and by the nearly equal length of the nine last 

 joints of the antennae : from Noterus and Laccophilus it is distin- 

 guished by the four anterior tarsi possessing four joints only. 



From its extent, I have subdivided the genus into sections, in 

 order to facilitate the investigation of the species. 



A. With the sides of the thorax rounded, 

 a. Elytra with the apex dentate. 



Sp. 1. frater. Plate XI. f. 4. Oblongo-ovatus, niger, thorace Jlavo baseo medio 

 macula bilobd nigra, elytris limbo, maculis lineisque Jlavis. (Long. corp. l| — 2 

 lin.) 



Dy. frater. Spence MSS.—Steph. Catal. p. 45. No. 439. 



Oblong-ovate, convex, black beneath; above rusty-testaceous, rather opaque, 

 very finely punctulated : thorax with a faint dusky margin anteriorly, and a 

 large geminated black spot at the base in the middle ; elytra with the suture, 

 and several regular longitudinal lines, black; the apex obliquely truncate, 

 with the outer angle denticulated : legs and antennae ferruginous, the latter 

 dusky at the tip. 



Var. 13. With the body entirely ferruginous beneath, or black, with the mar- 

 gins of the abdominal segments testaceous-red. 



Not very common: found in ditches and rivulets in Norfolk, 

 Suffolk, Yorkshire, and occasionally near London. " Near Carlisle, 

 in rivulets."— Dr. Leach. " Netley, Salop."— Rev. F. W. Hope. 

 " Whittlesea Mere." — Messrs. Chant and Beniley. 



