1855.] 373 



of the elytra are placed upon the striae, and not scattered on the interstices as 

 on the two preceding species. 



The European H. fuscipes is said by Kirby (Fauna Bor. Am. 119) and by 

 Mannerheim (Bull. Mosc. 1853) to be found in the northern part of the conti- 

 nent. The descriptions will apply equally well to the three striate species above 

 described, yet, on comparison with European specimens, they all seem to me to 

 be sufficiently distinct. H. insculptus approaches them most nearly, but the 

 thorax is not so short and is narrowed more obliquely towards the tip. 



6. H. digrestus, ellipticus convexus ater, nitidus, capite thoraceque sat 

 dense punctatis, elvtris confertim subseriatim punctatis stria suturali antice ob- 

 literata ; tibiis vix spinulosis, mesosterno antice vix tuberculato, palpis rufo- 

 piceis. Long. -11. 



Lake Superior and Niagara. Though the punctuation of the elytra is as in 

 Laccobius, and the tibiae appear to have no scattered spines, as in the other 

 species of this genus, it would scarcely appear natural to separate this as a 

 distinct genus. The antennae and palpi appear entirely as in the other species. 



B. Antenna? 8-articulatae. 



7 H. subcupreus, ellipticus, convexus, nigro-aeneus, capite thoraceque 

 subtilius, elytris distinctius punctatis, his stria suturali ad basin evanescente, 

 antennis piceis, basi palpisque rufis. Long. -08 -10. 



Hydrophilus subcupreus Say, Journ. Acad. Nat. Sc. 5, 189. 



Lyclonotum subcupreum Lee. Agassiz' Lake Superior. 



Middle States, Nebraska, Lake Superior, and Colorado River, California; com- 

 mon. Although in general appearance and sculpture this species resembles 

 Hydrobius, the antenae have but 8 joints, and are formed as in Laccobiu3 agilis. 

 The posterior tarsi appear to possess an indistinct row of ciliae on their upper 

 margin but are comparatively shorter and more slender. The middle and pos- 

 terior tibiae are furnished with some irregularly scattered spiDes. It is at first 

 doubtful whether this species should be joined with Laccobius, or with Hydro- 

 bius (from which it seems to differ only by the number of joints in the antennae), 

 or whether a separate genus should be established for its reception. From Lac- 

 cobius however, it differs in the sculpture of the ventral segments of the abdo- 

 men, and the form of the posterior trochanter, while in these characters it 

 agrees entirely with Hydrobius. 



In the smaller specimens the punctures of the elytra are sometimes less dis- 

 tinct towards the base. Specimens also occur in which the lateral margin of 

 the thorax and the tips of the elytra are yellowish. 



Cyclonotum Erichson. 



1. C. cacti, latius ovale convexum, atrum nitidum subtiliter punctulatum, 

 elytris punctis vix maioribus obsolete punctato-striatis, stria suturali pone me- 

 dium distincta ; prosterno integro carinato. Long. -22. 



San Diego, California, in putrid Opuntia. The antennae are reddish, with the 

 club dark-colored ; the first joint, as in the next species, is long, being in fact 

 nearly one-half the length of the entire antenna: Erichson has erroneously de- 

 scribed (Kafer Mark. 213) it as being short, but the description given by Mul- 

 sant, (Coleopt. de France, Palpicornes, 148) is correct. The striae of the elytra 

 are very faint, and merely formed by rows of punctures which are scarcely 

 larger than the fine punctures which cover the whole upper surface, and they 

 vanish entirely towards the base of the elytra. The prosternum, though pointed 

 posteriorly, reaches almost to the mesosternum : the carina is more prominent 

 anteriorly. 



2. C. es tri at u m , rotundato-ovale, convexum, atrum nitidum, punctula- 

 tum, elytris stria suturali nulla ; prosterno brevissimo baud carinato: palpis an- 

 tennisque rufis, his clava picea. Long. -15. 



