516 TRANSACTIONS OF THE 



on each side, dorsal line none ; elytra black, very obscure rufous 

 each side near the base, strise or maculae none ; epipleura rufous ; 

 pectus and postpectus black; feet rufous; venter black, seg- 

 ments slightly piceous at tip. 



4, H. CATASCOPiUM. — 'Black, obsolete, spotted and lineated 

 with rufous; feet rufous. 



Length three-twentieths of an inch. 



Body black, obscure, with villous punctures, hairs adpressed to 

 the surface ; head obscure rufous, dilated orbits and base black, 

 indented frontal spots each side instead of impressed lines and 

 punctures ; antennae, terminal joints blackish at their tips ; palpi, 

 terminal joint black ; thorax black, a central longitudinal spot, 

 and irregular submarginal one each side, rufous, dorsal impressed 

 line none ; elytra black, margin rufous, with a transverse irregu- 

 lar process at base, and another at the middle, and common 

 apical band, a double sutural line, an abbreviated line arising 

 from the middle of the base, and a subsutural spot near the mid- 

 dle, rufous, a distinct sutural stria and an obsolete one near the 

 middle ; feet rufous. 



[Afterwards described as H. parallelus and H. mferi'uptus Say. 

 — Leg.] 



5. H. LACUSTRis. — Rufous, obscure ; a common impressed, 

 [104] longitudinal line each side on the base of the thorax and 

 elytra. 



Length more than one-twentieth of an inch. 



Dytiscus lacustris Melsh. Catal. 



Body rufous, obscure, with minute punctures ; head with 

 slightly impressed frontal spots ; antennse, terminal joints tipped 

 with blackish ; maxillary palpi blackish at tip ; thorax blackish 

 at base and tip, base each side with an impressed, acute, oblique 

 line not attaining the anterior margin ; elytra with a blackish 

 suture, base, and submargin, an impressed, acute, longitudinal 

 line as long as the thorax arises from the middle of the base of 

 each elytron, appearing to be a continuation of the lateral thoracic 

 line ; pectus and feet pale rufous ; postpectus blackish ; venter 

 pale rufous. 



Var. a. Postpectus rufous. 



[Afterwards described as //. pnUcarms Aube. — Lec] 



[Vol. II. 



