Anacroneuria debilis (Pictet)

Figs. 1–5

Perla (Perla) debilis Pictet, 1841: 255; Anacroneuria debilis, Zwick, 1972: 1155; Zwick, 1973: 486; Froehlich, 2002: 76.

Material examined. Brazil, Rio de Janeiro (RJ), Parque Nacional do Itatiaia (PNI): 2 males, Sítio das Acácias, 23– 24.xi.2001, RWH, RJB, HP; 2 males, Tributário do Rio Taquaral, 6.iii.2002, RWH, RJB, ALP; 1 male, Rio Campo Belo, 24.xi.2001, RWH, RJB, HP; 1 male, Rio Campo Belo, 7.iii.2002, RWH, RJB, HP, ALP; 2 males, Rio Campo Belo, 23.xi.2001, RWH, RJB, HP. BR, RJ, Macaé: 17 males, Junção dos Rios Macaé e Bonito, 10.iii.2002, RWH, RJB, HP, ALP; BR, RJ, 4 males, Rio Macaé (Macaé de Cima), 8.iii.2002, RWH, RJB, HP, ALP.

Redescription. General color brown; head brown, M-line pale (Fig. 1) with diffuse limits in some specimens; postfrontal line U-shaped; compound eyes and posterior ocelli black; parietalia and anterior part of clypeal area ochraceous; antennae with scape and pedicel brown, flagellum pale; labial and maxillary palpi varying from ochraceous to brownish. Pronotum brown with rugosities. Forewings with membrane and veins brownish. Legs brownish with tibia and tarsi darker. Cerci light brown. Abdomen yellowish. Male: forewings mean length of males 12 mm (10 to 14.5 mm). Hammer conical (Fig. 2). Penial armature with a pair of distal membranous vesicles (Figs. 3–5); hooks relatively large, regularly curved, apex pointed (Fig. 5); keel transverse in dorsal view (Fig. 3), prominent in lateral view (Fig. 4). Female: described by Zwick (1973), the subgenital plate four-lobed. Illustrations of the female subgenital plate (sternum 8) and sternum 9 are presented in Zwick (1973) and Froehlich (2002).

Remarks. Zwick (1972, 1973) redescribed the male and female of A. debilis . Froehlich (2002) commented on the variation in shape of the lobes of the female subgenital plate. This species has a wide distribution including Missiones and Entre Ríos (Argentina), Paraguay, and southern and southeastern Brazil (Froehlich, 2002). The species has a characteristic penial armature, which includes a transversal dorsal keel in dorsal view, prominent in lateral view. In lateral view, the apex of penial armature is triangle-shaped and, in some specimens, the extremity is directed dorsally.