(Figs. 6-8)

Material examined. MEXICO: Oaxaca, Mpio. Santiago Comaltepec, Sierra Juárez, Localidad "La Esperanza", 17°38'28.20" N, 96°22'02.81" W, 6 May 2016, 1750 m a.s.l., A. Mayorga, R. Turrent, 1♀ (CNIN-PLH-4).

Adult habitus. General body color yellow and dark brown. Head pale yellow, locally hirsute. Pigment pattern over ocelli and M-line defined by short setae; a lightly pigmented T-shaped area extends from compound eyes medially and caudally toward occiput; a well-defined, basal transverse line posterior to ocelli; a wide, curved V-shaped pattern extends onto clypeus; lappets dark brown with long vertical rows of thick setae extending from foot of lappets to anteromedial corners of compound eyes; circumantennal ridges connect lappets to anterior margin of eyes, forming a right triangle; white rhomboid-shaped plate present anterior to ridges; darkened area posterolateral to compound eyes formed by long, stout setae. Pronotum with narrow medial band; mediolateral pale bands wide and setose centrally; lateral discs dark brown with slightly lighter rugose areas; russetted areas laterally occupy length of pronotum. Antennae dark, scape in dorsal view with discrete yellow, basal rugosity. Wing membranes brown, veins darker. Fore legs mostly pale, femur distally ringed with dark pigment extending medially on dorsal surface. Tibia dark at basal and distal rings, these usually connected dorsally.

Male. Unknown.

Female. Forewing length 20 mm. Subgenital plate 4- lobed; lobes connected by a white membrane; inner lobes shorter than wide, posterior margins obscure and truncate, separated by a wide, shallow, Vshaped notch, margins well sclerotized. Outer lobes narrow and square posteriorly, margins wellsclerotized; a narrow, V-shaped notch separating outer and inner lobes. A large, V-shaped bulge present anterior to median notch, bulge covered with scattered bristles. Mesal field of sternum 9 with dispersed fine setae, anterior margin closely follows subgenital plate lobes; posterolateral margins of segment darkly pigmented.

Larva. Unknown.

Distribution. Mexico, Oaxaca, Sierra Juárez, La Esperanza.

Diagnosis. This species differs from other Mesoamerican Anacroneuria species because of the complexity of the subgenital plate, the densely setose areas around the lappets, and a unique pigmentation of the head.

Comments. This species was the only stonefly that came to our light trap the day we collected at La Esperanza, Oaxaca. This location was about 1 km from the nearest stream source, supporting that species in the genus are capable of moderate dispersal. A pinned, similarly pigmented, female specimen was found in the CNIN from Oaxaca, 1955. Unfortunately, its poor condition negated positive identification. We hope to discover additional specimens, including males, and formally describe this species.