348 On Aquatic Carnivorous Coleoptera or Dytiscida;. 



252. Bidessus insignis, n. sp, — Ovalis, latus, subtus convexus, capite thoraceque 

 rufescentibus, elytris testaceis, basi plagaque magna irregular!, pectore abdomineque 

 nigricantibus, antennis pedibusque testaceis; thorace crebre, basi fortius, punctate ; 

 elytris striis duabus sutiiralibus abbreviatis punctorum impressorum, plica discoidali 

 ultra medium ducta sat elevata, prsetereaque subobsolete punctatis ; coxis 

 posteriori bus punctis magnis. Long. 2 1, lat. \h m.m. 



This species by its form and sculpture suggests itself as a connecting link between 

 the very dissimilar Dytiscus geminus(No. 269) and Hydroporus bicarinatus,(No. 247). 

 There seems to be scarcaly any difference between the sexes. 



Western Arabia, (Hedjaz). 1131. 



253. Bidessus (Anodochilus) maculatus, Bab. Tr. Ent.Soc. Lond. Ill, 1841, p. 16. — 

 Brevis, sine pubescentia, rufo-testaceus, elytris fuscis, indeterminate testaceo-signatis; 

 prothorace brevi, fere impunctato, basi plicula utrinque fortiter elevata, inter 

 pliculas canalicula profunda transversa ; elytris sat crebre, fortiter, irregulariter 

 subseriatim punctatis, crista tenui elongata; subtus pectore abdomineque basi 

 utrinque grosse punctatis. Long. 2, lat. li m.m. 



Brazil, (Santa Rita, Aug., 1850, Sablberg). 128. 



254. Hydroporus exiguus,Aube, Spec. p. 490. — Brevis, sine pubescentia, rufo-testa- 

 ceus, elytris obscurioribus indeterminate fusco-maculatis ; prothorace brevi, fere im- 

 punctatOjlateribus rugulosis,basi utrinque pliculafortiter elevata, inter pliculas canali- 

 cula profunda transversa ; elytris crebre fortiter punctatis, crista tenui elongata ; 

 subtus pectore abdomineque basi utrinque grosse punctatis. Long. If, lat. 1 m.m. 



Closely allied to Bidessus maculatus, but rather shorter and broader, and with 

 the elytra a good deal more regularly and evenly, and not so coarsely punctured. 



United States of North America. 136. 



Group 4. 



255. Hydroporus cinctellus, Lee, M.C. — Obi ongo-ovalis, fere sine pubescentia; sat 

 nitidus, ferrugineus, capite elytrisque infuscatis, his fascia interrupta sub-basali, 

 signaturaque ante-apicali testaceis ; thorace crebre evidenter punctato, elytris et coxis 

 crebre fortiter punctatis; antennis fusco-testaceis. Long. 2, lat. Is m.m. 



North America. 137. 



256. Hydroporus pictodes, n. sp. — Sat latus, ovalis, convexus, subtilissime et 

 omnium brevissime pubescens, vix nitidus, piceo-rufus, thorace testaceo, basi late 



