Polyplectropus dubitatus Flint 1983

Polyplectropus dubitatus

At first sight this species seems to be intermediate between P. elongatus (Yamamoto) and P. hamulus Flint; however, the discovery of three collections from widely separated localities, all in complete agreement, has convinced me of the validity of the taxon. The narrow, hooked ventromesal lobe of the cercus is similar to that of P. hamulus, the more rounded, posteromesal angle of the ventral lobe of the clasper is similar that that of P. elongatus, but the two long, subequal spines that arise from a common base in the aedeagus are distinctive.

ADULT.—Length of forewing, 5–6 mm. Color brown; antennae and appendages stramineous; forewing mottled with shades of brown. Hind wing with R2 and R3 fused to margin.

Male Genitalia: Ninth sternum rounded anteriorly. Tenth tergum membranous. Cercus trilobate; a small, rounded dorsal lobe, a long, slender, pointed mesal lobe, and a ventromesal lobe that is slender, elongate, and slightly hooked apically. Clasper bilobed; a slender, terete, dorsolateral lobe and a ventromesal lobe rounded in lateral aspect, in ventral aspect with posteromesal angle not sharply angled. Aedeagus with an internal structure bearing a pair of pincer-like apicolateral arms, and a pair of subequal, elongate spines arising from a common base.

MATERIAL.—Holotype (male): ARGENTINA, PCIA. MISIONES, Río Iguazú, Camp Nañdu, 25 Nov 1973, O.S. Flint, Jr., USNM Type 100493.

Paratypes: Same data as holotype, 2. BRAZIL, EDO. SANTA CATARINA, Nova Teutonia (27°11′S, 52°23′W), Feb 1964, F. Plaumann, 1. URUGUAY, DPTO. SALTO, Río Uruguay, Salto Grande, 10 Nov 1955, C.S. Carbonell, 2 (FHCU).

Cernotina is a genus of small polycentropodids known only from the New World. Species are found from southern Canada south to central Argentina, including the West Indies but not the Chilean Subregion. Some three dozen species have been described from the Neotropics, with more being found all the time, especially in the lowland river basins.

No firmly associated larvae have yet been described, but it seems virtually certain that the larva described as polycentropodine species (Flint, 1964b) is an unknown species of the genus. Adult collection sites suggest that larvae are most likely to be found in slowly flowing rivers, streams, and backwaters. Their food is unknown.