DYTICID^S. — GYBISTER. 91 



towards the apex subpunctate, the disc with three striae of minute impressions, 

 the lateral margin broadly luteous : body beneath testaceous, with the sutures 

 of the breast black : sternum with the lacinia? obtuse : legs pale-ferruginous. 

 Female with the thorax and apex of the elytra punctate ; the latter deeply 

 sulcated at the base to the middle. 



Discovered in June, 1824, in Yaxley-fens, by Messrs. Chant and 

 Bentley : since taken in Wliittlesea Mere, and in other parts. " In 

 the pond in the Botanic garden, Cambridge; also in Bottisham- 

 fen : the males appear to be more abundant than the females."—- 

 Rev. L. Jenyns. " Elsemere, and Bomere, Salop." — Rev. F. W. 

 Hope. 



Genus LXXXVIII.— -Cybister, Curtis. 



Palpi, external maxillary with the second and third joints of equal length, 

 elongate-obconic, the fourth longer, slightly dilated externally, truncate: 

 lahrum slightly emarginate : mandibles truncate obliquely : mentum trilobate, 

 the central lobe truncate. Antenna? with the second joint extremely short, 

 third longest : head rounded : scutellum distinct : elytra broad, ovate, smooth ; 

 strigulated at the base in the females: legs natatorial; tibice very short; tarsi 

 five-jointed; posterior monodactyle : anterior tarsi patelliform in the males; 

 intermediate simple. 



The broadly-ovate and very depressed form of this genus well 

 distinguish it from its affinities, but its chief characters are drawn 

 from the form of the terminal joints of the palpi, and the brevity of 

 the posterior tarsi ; in this last particular, as well as by its depressed 

 body, it is closely allied to Acilius ; but from that, as well as the 



B. Elytra with the margin dilated. 



| Sp. 9. latissimus. Niger, subtiis brunneus, elytrorum margine dilatato, vittd 

 laterali, thoracisque limbo toto luteis, sterni laciniis acuminatis. (Long. corp. 

 1 unc. 8 lin.) 



Dy. latissimus. Linne. Steph. Catal. p. 52. JVo. 531. 



Very broad, black above, shining ; head as in Dy. dimidiatus : thorax truncate 

 behind, with a dorsal line, smooth, the entire margin broadly luteous: 

 scutellum ferruginous at the tip : elytra greatly dilated in the middle, the 

 margin depressed and expanded ; above convex anteriorly, depressed poste- 

 riorly, with a luteous streak within the margin, and a transverse one within 

 the apex, the disc with two rows of impressions : body beneath glossy-brown, 

 sternum with its lacinise acuminate at the apex : legs rusty-brown. Female 

 with the elytra deeply and irregularly sulcate nearly to the apex. 



Berkenhout gives this fine species as British, but I know not on what authority. 



