of Dytiscid(B Darwiniance. 15 



reliquis inter se sequalibus tertio brevioribus obconicis, ultimo 

 fusiformi acuminaio, Labrum paulo emarginatum. Palfi 

 maxillares externi aniculis 1, 2 et 3 obconicis, subsequalibus, 

 tertio paulo longiori ; 4to maximo, elongato, fusiformi, trun- 

 cato ; p. m. interm 2-arliculati, articulis elongatis attenuatis, 

 Imo subclavalo, 2do cylindrico. Mentum lobo intermedio 

 denliformi obtuso. Palpi lahiales articulis Iitio et 2do trans- 

 versis, 3tio quam prsecedentes longiori, obconico; 4to elon- 

 gato, ventricoso, truncato. Scidellum breve, latum, triangulare. 

 Pedes 4 anteriores tarsis 4-articulans,* postici tarsis 5-articu- 

 latis unguicub'sque 2 aequalibus mobilibus. 

 [PI. I. fig. 3 a, labium i 3 6, mandible; 3 c, maxilla; 3 d, labium; 3 e, fore 

 leg; 3/, middle leg.] 



Differs from Hydroporus by the structure of the internal max- 

 illary and labial palpi, and by the presence of a scutellum. 



1. (21.) H. parallela, Bab. (PI. 1, fig. 3.) 

 Oblonga, antice obtusa, postice acuminata, lateribus parallelis, 

 supra rufa, (horace antice et postice elytrisque (apice mar- 

 ginibusque exceptis) fuscis ; corpore subtus, antennis, pedi- 

 busque fusco-ruiis. (L. c. 2 ; lat. | lin.) 

 Head short, transverse, rounded in front, with two longitudinal 

 slightly impressed foveae between the eyes. Thorax transverse, 

 short, broadly emarginate in front ; the angles acute ; lateral 

 margins rounded ; posterior margin straight, very slightly pro- 

 duced in the middle over the scutellum ; disk smooth, with a 

 transverse row of punctures in front, and a similar one behind, 

 the latter broadly interrupted in the middle ; rufous, with the 

 anterior and posterior margins fuscous. Scutellum small, triangu- 

 lar, transverse, fuscous. Elytra of the same width as the thorax, 

 oblong, the sides parallel for three-founlis of their length, then 

 strongly rounded to the apex, which is acute and prominent; 

 disk coarsely punctured, with one central row of more regular 

 punctures upon each ; fuscous, with the exception of the apex 

 and external margins, which are rufous. Body beneath, legs and 

 antennae, dull rufous. 

 Hab. Rio de Janeiro. 



Anodociieilus, Bah.^ 

 Corpus ovatum, depressum. Caput fronte antice carind trans- 



* [It appears to me that the tarsi of this genus are 5-jointed, a minute nodose 

 joint being placed at the base of the long terminal joint. — J. O. W.] 

 t Derivatio nominis, a non, oJauv dens, x"^"? margo. 



