294 [April 



rectis tenuiter marginatis, elytris piceis fere opacis confertissime punctulatis. 

 Long. -10. 



One specimen from Massachusetts was presented to me by Dr. C. Zimmermann. 

 A little less globose than H. cuspidatus, and readily distinguished by the 

 finer and denser punctuation, and by the epistoma being without a margin. 



6. H. a car o ides, breviter ovalis, postice acutus, parum convexus, ferru- 

 gineus dense suhtilius punctatus, thorace margine basali nigricaate, elytris cos- 

 tula laterali parum elevata ad medium abbreviata, alteraque externa fere obsoleta; 

 sutura, macula magna communi ad medium, alterisque utrinque tribus nigris ; 

 postpectore abdomineque nigro-piceis, segmentis duobus ultimis ferrugineis. 

 Long. -10. 



Illinois., Mr. Willcox ; Kentucky, Mr. Wild. The elevated lines of the elytra are 

 very slight, but may be distinctly traced ; behind them, but apparently in con- 

 tinuation, is a linear brownish cloud which continues to the apex, outside of the 

 three discoidal spots, which surround the large subquadrate common spot at the 

 middle of the elytra. The spots are sometimes extended and become more or 

 less confluent. In H. latissimus the elevated line is very short, so that it appears 

 rather like a fold, limited externally by a moderately deep oblong fovea. 



8. H. granum, breviter ovalis utrinque attenuatus, subconvexus, piceo-tes- 

 taceus nitidus glaber, capite subtiliter marginato, thorace parce punctulato, 

 lateribus rectis subtiliter marginatis, elytris subtiliter parce punctulatis. Long. 

 05. 



One specimen from Louisiana given me by Mr. Guex. Smaller and more con- 

 vex than H. convexus, which it very closely resembles ; the sides of the thorax 

 are, however, not broadly rounded as in that species, and the punctures of the 

 elytra are much smaller and more distant. 



Desmopacbria ni ti d a Babington (Trans. Ent. Soc. Lond. 3, 17, tab. 1, fig. 5) 

 does not appear by its specific characters to be different from H. convexus Aube. 

 The generic characters agree accurately, except, that the posterior tarsi are not 

 four-jointed. This, if true, would be so anomalous, that the correctness of the 

 observer may well be doubted ; nevertheless, in H. convexus the posterior tarsi 

 are more flattened and more gradually attenuated than in the other species of 

 the genus, and therefore the terminal joints are more closely connected ; should 

 the specimen have been mounted in the clumsy manner in which small species 

 are frequently preserved, the articulation might be readily obscured by gum, in 

 such manner as to be overlooked. The claws of the hind feet of the species 

 under consideration are more slender and more bristle-like than in H. cuspi- 

 datus and allies. 



8 1 . H. exiguus Aube. Unknown to me. Said by Erichson (Bericht &c in 

 Wiegm. Arch. 1842, 2, 209) to have as a synonym Anodocheilns maculatus 

 Babington (loc. cit.) from South America. The genus Anodocheilus is described 

 as differing from Hydroporus, in having no tooth at the middle of the emargina- 

 tion of the mentum. 



12. H. pull us, oblongus, po3tice vix acutus, flavo-testaceus nitidus glaber, 

 capite vix punctulato, thorace parce punctulato, basi ad medium nigro-marginata, 

 striola obliqua utrinque notata in elytris brevissime continuata, his distinctius 

 punctatis, sutura vittisque utrinque tribus nigro-piceis, prima antice abbreviata 

 et secunda approximates, stria solita punctorum interna magis distincta. Long. 

 06. 



Louisiana; discovered by Dr. Schaum, to whom I am indebted for specimens. 

 The vittac of the elytra are quite narrow, the second one is confluent with the 

 dark colored suture at the base : all thevittas extend nearly to the tip; the under 

 surface is of a uniform honey yellow color. The faint impressed discoidal line 

 of punctures of the elytra, which may be traced in all the species, is here more 

 distinct than usual and runs along the second vitta. 



17. H. inconspicuus, oblongus, postice subacutus, flavo-testaceus, sub- 

 tiliter pubescens, thorace postice punctulato, basi nigricante, striola utrinque 



