544 On Aquatic Carnworous Coleoptera or Dytiscida. 
Group 38. 
767. Agabus undecim-guttatus, Aubé, M.C.—Ovalis, sat latus, subdepressus, 
pernitidus, subtilissime reticulatus, niger, antennis pedibusque rufis; supra 
maculis undecim testaceis, parvulis; thorace cum elytris omnino continuo, basi 
utringue ad angulos posteriores haud sinuato, his subacutis haud retrorsum 
spectantibus, margine laterali lato; prosterni processu lato, plano, apice obtuso. 
Long. 62, lat. 4 m.m. 
The male of this species has a slight incrassation of the front and middle tarsi, 
and the three basal joints narrow beneath are clothed with short hairs ; the apical 
ventral segment is quite smooth. There is no sexual difference of sculpture. The 
yellow marks of the upper surface consist of one on the middle of the head, one on 
each side of the thorax near the side, (the anterior angle being more or less reddish), 
and four on each elytron, one at the base near the suture, and another near the 
shoulder, a third near the side beyond the middle, while the fourth is placed near 
the apex. The excessively fine sculpture of the elytra consists of reticulations, 
with a minute puncture in the middle of each mesh. The serial punctures of the 
elytra are fine but quite distinct. 
South America, (Brazil). 826. 
768. Agabus decemnotatus, Aubé, M.C.—Ovalis, latus, subdepressus, pernitidus, 
fere omnino levigatus, subtus piceo-rufus, vel rufus, supra piceus, vel nigro-piceus, 
capite testaceo, utrinque piceo, thorace utrinque late vage testaceo, elytris maculis 
magnis decem testaceis, thorace cum elytris omnino continuo, basi utrinque ad 
angulos posteriores sinuato, angulis posterioribus acutis, margine laterali sat lato ; 
prosterni processu lato, plano, apice obtuso. Long. 7, lat. 4¢ m.m. 
There is very little difference in the sexes of this species, a slight difference in 
the clothing of the basal joints of the front and middle tarsi being all that dis- 
tinguish the male. The diminution of the sculpture reaches its extreme in this 
species, even the marginal punctures of the thorax are extremely fine, while the 
serial punctures of the elytra can scarcely be distinguished. The yellow spots on each 
elytra are placed one near the scutellum, one some little distance from the shoulder, 
one near the suture about the middle, one near the outer margin a little behind 
the middle, and one near the apex. 
South America, (Cayenne). 827. 
769. Platynectes ornatifrons, n. sp.—Ovalis, sat latus, subdepressus, nitidus, supra 
densissime subtilissimeque reticulatus, niger, antennis pedibusque rufis, capite in 
medio testaceo-maculato, thorace ad angulos anteriores rufescente, elytris macula 
subapicali aliaque parvula sublaterali pone medium testaceis ; thorace basi utrinque 
