(Figs. 11-15)

Material examined. Holotype ♂, PARAGUAY: Amambay Department, Rio Ypane, cerca Pedro Juan Caballero, 25 November 1956, C.J.D. Brown (USNM).

Adult habitus. General color brown, patterned with areas of pale pigment. Head with a large area of dark pigment extending from ocellar region over central frons (Fig. 11); dark pigment area expanded laterally in central frons where a small oval pale area is located; lappets and antennae dark brown. Pronotum mostly dark but with a narrow pale median stripe and pale lateral areas. Hind femora dark brown in apical third but pale basally; hind tibia with small dark bands basally and apically but pale for most of length. Wing membrane brown, veins (particularly R vein) dark brown.

Male. Forewing length 10 mm. Hammer thimble shaped, apical diameter less than height (Fig. 12). Aedeagal apex a short, simple, truncate scoop bearing a ventral pair of prominent membranous lobes (Fig. 13); dorsal margin of apical area expanded into a pair of small rounded lateral lobes near point where hooks cross (Fig. 15); dorsal keel lines absent, apex bent strongly dorsad, giving a foot-like shape in lateral aspect (Fig. 14). Hooks slender.

Female. Unknown.

Larva. Unknown.

Etymology. The species name, used as a noun in apposition, is based on the type locality of Rio Ypane.

Diagnosis. This species is related to the Anacroneuria atrifrons Klap á lek group of species (Froehlich 2008) which includes at least A. azul Rojas & Baena (Stark et al. 1999), A. canchi Stark & Sivec (Stark & Sivec 1998) and A. pastaza Stark (Stark 2001). Of these species, the aedeagus of A. ypane is most similar to that of the Colombian species, A. azul, but the membranous lobes in that species are smaller and a small transverse dorsal keel is present. The latter species also differs from A. ypane in having a much smaller area of dark head pigment.

Comments. Froehlich (2002) reported A. debilis (Pictet) from a single male collected in Parque Nacional Ybycui and A. trimacula Jewett from a single female collected at the same locality. Thus, Anacroneuria ypane becomes only the third member of the genus to be confirmed for Paraguay, and the first to be described from a Paraguayan specimen.