1855.] 359 



berculo magno obliquo gibbosis, et tuberculis duobus alteris in iatersiitio 4to 

 ornatis. Long. -22. 



Mulsant, Ann. Sciences Phys. Nat. Lyon, 7, 373 (1844). 



Hydrochus gibbosus Mels. Proc. Acad. Nat. Sc. 2, 99. (Oct. 1844). 



Middle and Southern States : sometimes quite abundant. The interstices of 

 the elytra are flat, and much wider than the striae. 



2. H. c al 1 o s u s, subelongatus, griseo-niger, thorace latitudine sublongiore 

 postice angustato, lateribus suUsinuato, disco inaequali sat puuctato, trisulcato, 

 sulco medio maiore et profundiore, elytris profunde punctato-striatis, vage biim- 

 pres3is, luterstitiis angustis, 4to tuberculis duobus parvis, serieque postica 

 obliqua ornatis, palpis tarsisque runs. Long. -17. 



One specimen from Louisiana, sent me by Mr. Wapler. This species is allied 

 to the preceding, but is narrower, the punctures of the elytra are much larger, 

 so that the striae are as broad as the interstices : they are less declivous behind, 

 and the tubercles, although similar in position, are less elevated. 



3. H. squamifer, elongatu3, supra griseus, acnescens, capite tboraceque 

 confertim punctati3, granulatis, squamulis fuscis vestitis, thorace latitudine paulo 

 longiore, lateribu3 sinuatis antice vix rotundatis, utrinque vage sulcato, medio 

 vage trifoveato, elytris profunde crenato-striatis, interstitiis angustis, sutura 

 pluribusque postice elevatis, ad medium extrorsum fovea obliqua impressis, 

 pedibus palpisque obscure rufis femoribus piceis. Long. -15. 



One specimen found at Lake Superior. The suture is elevated for its whole 

 length: the third interstice is a little higher than the second: the fourth is elevated 

 from the middle halfway to the apex : the fifth is elevated like the third, but is 

 interrupted adjacent to the elevation of the fourth : the lateral oblique fovea 

 extends over the 8th and 9th interstices, and at that place the strice are slightly 

 sinuous. 



4. H. rugosus, elongatus, supra griseo-argenteus cupreo-micans, capite 

 thoraceque rude punctatis, hoc latitudine baud longiore, trapezoideo, lateribus 

 fere rectis, dorso vage 5 foveato, foveis anticis tribus maioribus, elytris thorace 

 parum latioribus profunde striatim punctatis, interstitiis alternatim s-ubelevatie, 

 calloque parvo postico parum elevato instructis, striis 7ma et 8va ad medium 

 sinuatis, subtus niger, tibiis tarsisque rufis. Long. -24. 



Mulsant, Ann. Sc. Phys. Nat. Lyon, 7, 373. 



Middle States, not common. This species is the largest I have seen, and is 

 readily distinguished. The two posterior foveae of the thorax are the basal im- 

 pressions, the two inner ones which are usually immediately behind the dorsal 

 one are hardly apparent. Although the interstices of the elytra are not elevated, 

 they are hardly wider than the rows of punctures. 



5. H. i n ae q u a 1 i s, elongatus, griseo-aeneus, thorace rude sat dense puuctato, 

 postice angustato, latitudixe paulo longiore, lateribus crenulatis subsinuatis, dorso 

 5-foveato, foveisque basalibus externi3 parvis, elytris profunde crenato-striatis, 

 interstitiis pluribus elevatis et interruptis, pedibus rufis, femoribus ob3Curis. 

 Long. '12. 



One specimen from Louisiana, Mr. Wapler. Of the same size and form as 

 several of the following ones, but distinguished by the greater inequality of the 

 elytra. 



Head and thorax coarsely and moderately densely punctured, the latter a little 

 longer than wide, gradually narrowed to the ba3e, sides subsinuate, distinctly 

 crenulated : disc with three anterior and two posterior foveae, which are large 

 and moderately deep : at the posterior angles, which are obtuse, are other small 

 but deep foveae. The elytra are elongate, wider than the thorax, strongly crenato- 

 striate, with the interstices narrow ; the suture, the 5th, 7th and 9th are elevated, 

 the three latter interrupted behind the middle, giving the appearance of a lateral 

 transverse impression ; the fourth is elevated adjacent to the interruption of the 

 third : on the 3d and 4th interstices near the middle is seen a broad fovea tinged 

 with purple, and a slight impression is also seen behind the humerus, and yet 



