Smicridea (Rhyacophylax) iguazu Flint 1983

Smicridea (Rhyacophylax) iguazu

This species does not seem to have any clear relationships within the genus. No other species known to me has such a bizarre modification of the tenth tergites. Although I consider all the males here recorded as belonging to the same species, it is by no means absolutely certain, because all differ in the shape of the modifications of the tenth tergite. Variability in the spinous processes of the tenth tergites, however, is found in other species of the genus, and some of the examples of S. iguazu are even bilaterally asymmetrical.

ADULT.—Length of forewing, 4.5–5.5 mm. Width of eyes of male in dorsal aspect that of interocular distance. Color brown, head and thorax dorsally fuscous; forewing dark brown, faintly darker along chord and terminally, which area is bordered inwardly by a white band (of the pinned males, 2 are dark brown, 1 stramineous, and 1 almost white, but all show the same pattern). Male abdomen with anterolateral process of fifth sternum length of sternum; without internal reticulate sacs.

Male Genitalia: Ninth segment with anterolateral process angulate. Tenth tergum with apex divided in dorsal aspect, tergite produced into a narrow process; ventrolateral margin greatly modified, with a ventral process of varying length bearing apical spinules, above which is a very variable lobe bearing spinules. Clasper with basal segment moderately long, parallel-sided; apical segment bluntly pointed. Aedeagus with inflated basal portion very high, stem very long and angled slightly ventrad; tip slightly upturned, usually with a few lateral spicules, internal sclerite long and threadlike.

MATERIAL.—Holotype (male): ARGENTINA, PCIA. MISIONES, Río Iguazú, Camp Nañdu, 25 Nov 1973, O.S. Flint, Jr., USNM Type 100532.

Paratypes: Same data as holotype, 15, 7; Arroyo Piray Guazú, N San Pedro, 22 Nov 1973, O.S. Flint, Jr., 2. BRAZIL, EDO. SANTA CATARINA, Nova Teutonia, Oct 1964, F. Plaumann, 1. EDO. RIO DE JANEIRO, Rio Pirai, Mun. Rio Claro, 8 Apr 1979, C.M. and O.S. Flint, Jr., 6, 5 (USP).