On Aquatic Carnivorous Coleojytera or DytiscidiB. 7ft 7 



1210. Colymbetes alpinus, Motsch., Schrenck Reise, p. 102, pi. 7, f. 2. Mongolia. 



" Elongato-ovalis, antice posticeque sequaliter attenuatus, nitidus, scarificatus, supra nigro-fuscus, 

 subtus niger ; capite thoraceque antice, elytrorum basi angustissime, lateribus, palpis, antennis pedibusque 

 testaoeis. Long. 2i 1., lat. \\ 1." 



" Trts voisindii C'olymb. arcticus, Payk., dont U se distingue par une forme plus attenuee posterieurement, 

 la tache posterieure du corselet plus developpee et un couleur un pen plus foncee. Peut-etre seulement 

 une variete alpine du premier. Je I'ai pris sur les glaciers du Hamar-Daban en Mongolia " 



This is most probably, as indicated by the describer himself, a variety of Dytiscus arcticus. (No. 

 736).— D. S. 



1211. Colymbetes (?) angusticollis, Curt. Tr. Linn. Soc. XVIII, 1839, p. 195, p. 15, f. E. Chili. 



" Ochreus ; oculis, capite, clypeo excepto, scutello subtusque nigris ; thorace angusto ; elytris longissimis 

 nigro-lineatis reticulatisque. Length 4-J^, breadth 2 lines." 



" Ochreous, shining ; head and eyes black, leaving a semiorbicular ochreous space on the clypeus ; 

 thorax short, a little broader than the head, transverse-oblong, a line of punctures before and behind 

 near to the margins, a short channel on the disc, sides a little depressed. Elytra nearly twice as broad as 

 the tliorax at the base, and seven times as long, elliptical, apex truncated a little obliquely ; some scattered 

 punctures in lines, a short black streak on each side of the scutellum, three long ones down the disc, and 

 two or three oblique ones on the sides ; the spaces between somewhat reticulated with black, leaving a 

 broad marginal space free ; underside piceous." 



" A male from Port St. Elena. The narrow thorax and very long elytra depart so far from the typical 

 form of Colymbetes, that I have little doubt of this being a good genus ; but as I have no specimen to 

 dissect I have not ventured to establish it as such." 



This is a very distinct species of Lancetes, ^vith very peculiar thorax. — D. S. 



1212. Colymbetes annulatus, Zoub., Bull. Mosc. VI, 1833, p. 318. Turcomania. 



" Long. 3J 1., larg. 1 J lig. La tete et le corselet sont ferrugiueux ; Les elytres sont d'uu brun jaunatre 

 a la loupe ils paraissent ponctues. Le dessous du corps et les pieds sont ferrugineux. Chaque anneau 

 de I'abdomen et la poitrine sont hordes de noir." 



This should perhaps be placed in the genus Agabus. — D. S. 



1213. Colymbetes assimilis, Kirb., Faun. bor. Am. IV, p. 70. North America. 



" Obovatus, depressus, Iffivis, niger ; prothorace flavescenti, immaculato ; elytris flavescentibus, nigro 

 creberrime irroratis ; pedibus flavis ; brachiis brevissimis piceis. Length of body 5f lines." 



" This species represents C. notatus, which it is very like, but the elytra are wider towards the apex 

 which gives the insect an obovate shape, the black dots of the elytra are more numerous and minute ; 

 the prothorax is without spots, and the arms or forelegs are shorter and of a different coloui"." 



This is not noticed by Crotch in his "Revision of the North American Dytiscidse" ; it is no doubt a 

 species of Rhantus, but apparently not one known to me. — D. S. 



1214. Colymbetes basalis, Gebl, Ledeb. Reis. II, p. 65. Sibei-ia. 



" Niger, thorace subquadrato elytrisque lividis, illo apice et lateribus, his basi margineque palUdis, 

 pedibus ferrugineis. Long. 4 lin., lat. 2 1. Nitidus, supra subtilissime punctulatus caput nigrum," 

 &c., &c. 



" Semel ad lac. Noor-Saisan captus." 



The Munich Catalogue has referred this to the genus Agabus. — D. S. 



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