330 On Aquatic Carnivorous Coleoptcra or DijtiscidcB. 



204. Hjdrovatus acutus, n. sp. — Latus, subtiliter reticulatus, subopacus, in elytris 

 crebre evidenter punctatus, testa ceo-ferrugineus supra leviter infuscatus ; clypeo 

 indistincte marginato, subtruncato; coxis posterioribus minus crebre fortiter 

 punctatis. Long. 22, lat. l5 ni.m. 



Mas, antennis longioribus ante medium incrassatis. 



Extremely similar to H. subtilis (No. 203), but with the incrassate joints of the male 

 antennce different, the fourth and fifth joints being thicker than the others, while 

 the sixth is a little and the seventh decidedly narrower than the preceding ones : 

 the extremity of each wing-case is very slender and acuminate so as almost to 

 form a spine. 



Celebes, (Jan., 1874, Beccari). Sumatra. 448. 



205. Hydrovatus fractiis, n. sp. — Ferrugineus, latus, subnitidus, crebre fortiter 

 punctatus, prothoracis lateribus subparallelis. Long. 2^, lat. 1| m.m. 



The mai'gin of the clypeus is extremely obsolete ; the elytra are closely and 

 coarsely punctured, the coxre not closely, and not so coarsely. The size is nearly 

 that of H. cuspidatus (No. 180) but the form is not quite so broad in the middle. 

 The antennae are very slender and quite simple ; the front tibiee not quite so broad 

 as in H. cuspidatus. The species may be readily distinguished from its allies by 

 the diff'erence in the outline when looked at from the sides, it is then seen that 

 this insect has the thorax a good deal more parallel-sided, and the elytra are more 

 curved in and contracted at the shoulders, so that the lateral outline of the thorax 

 and elytra is less continuous. 



T am not at all sure of the sex of the individual described, the front tarsi are 

 broad, but the basal joint is scarcely so broad as the following one. 



Siam. 15. 



20G. Hydrovatus crassulus, n. sp. — Ferrugineus, nitidus, crebre fortiter punc- 

 tatus, convexus, sat latus, postice acuminatus. Long. 2h, lat. ll m.m. 



A very convex species, a good deal smaller than H. clypealis (No. 179). The 

 antennoe are modei'ately long and stout. The thorax becomes but little broader 

 towards the base, and the epipleural line of the elytra is much curved behind the 

 shoulder. The coxae arc closely and coarsely punctured. 



Brazil, (Santa Rita, August 1850, Dr. E. F. Salilberg). 17. 



207. Hydrovatus parallelus, n. sp. — Angustulus, subparallelus, minus convexus, 

 testaceus, subnitidus, sparsim punctatus, ad apicem breviter acutus. Long. 2, 

 lat. 1b m.m. • : 



