Genus Nousia Navas 1918

= Atalonella Needham & Murphy 1924 Type species: N. delicata Navas 1918 .

Larva. Clypeus parallel-sided or slightly widened anteriorly (Figs 1, 24); labrum not widened, with median incision shallow or non-expressed; number of median denticles odd—5 or 3; both dorsal transverse setal rows straight and located near anterior margin, distal row very dense and irregular, proximal row more or less regular (Fig. 1). Mandibles with outer margin smoothly curved, with hair tuft near middle (Figs. 25, 26). Maxilla slightly broad apically, with 8–12 pectinate setae in ventro-apical row (Fig. 27). Labium with glossae partly inserted in cavities of paragossae, not projected neither ventrad, nor dorsad of paraglossae (Fig. 28). Patella-tibial suture developed on middle and hind legs, being absent on fore leg (Figs 5–7). Tergalii of all pairs I–VII similar, each tergalius with both lamellae pointed, without additional processes; shape of tergalii varies from thread-like (Pescador & Peters 1985: Fig. 54) to wide-lanceolate (Finlay 2000: Fig. 23) or oval (Figs 10, 30).

Subimago. Pigmented area anteriad of mesonotal suture forms a narrow stripe along medioparapsidal suture (Fig. 18). First tarsal segment covered with microtrichia; tarsal segments II–V covered with pointed microlepides.

Imago. Patella-tibial suture developed on middle and hind legs, absent on fore leg. On each leg both claws pointed. Hind wing without prominent costal projection and with subcostal vein long (Fig. 20). Penis with peculiar structure (Figs 13, 14): dorsal surface of each penis lobe crossed by a transverse semicircular ridge, with mediallydirected sclerotized process close to this ridge; unpaired proximal portion about 1/2–2/3 of total penis length (Figs 12–14; Demoulin 1955: Figs 6 b', 7b', 8c'; Pescador & Peters 1985: Fig. 7; Finlay 2000: Figs 8, 27).

Remarks. Among larval characters of Nousia, an enlarged distal denticle of the claw is mentioned (Pescador & Peters 1985); in various species it is either strongly enlarged, or indistinctly enlarged (Pescador & Peters 1985: Figs 50 and 48), or non-enlarged (Fig. 4).

In the key to leptophlebiid genera of South America, Nousia imagos are separated from Penaphlebia Peters & Edmunds 1972 and Rhigotopus Pescador & Peters 1982 by the absence of a direct joining of vein ICu1 with vein CuA on the fore wing (Domínguez et al. 2006). This statement is based on the diagnosis of Nousia by Pescador & Peters (1985), who stated that "vein ICu1 free or attached at base by a cross vein to vein CuA ... ". Actually, the vein ICu1 is often directly jointed with CuA (Fig. 19; Needham & Murphy 1924: Fig. 97; Demoulin 1955: Figs 6 a, 7a, 8a) and occasionally can have a free base (Pescador & Peters 1985: Fig. 1; Finlay 2000: Fig. 2) or be attached at the base by a cross vein to vein CuA (Demoulin 1955: Fig. 9).

Subgenus Araucophlebia subgen. n.

Type species: Nousia (Araucophlebia) latifolia sp.n.

Diagnosis. Larval characters:

(1) Long spine-like setae on outer margin of tibia are present not only on hind legs, but also on middle legs (Fig. 6) (in contrast to most other Leptophlebiidae).

(2) Tergalii have dorsal lamella oval, with sharply separated slender apical process (Figs 10, 30). In other Nousia tergalii have both lamellae lanceolate and without terminal process (Pescador & Peters 1985: Figs 51–54; Finlay 2000: Fig. 23).

(3) Denticles on posterior margins of abdominal terga I–IX are reduced. In other Nousia denticles on posterior margins of abdominal terga are well developed (Pescador & Peters 1985: Fig. 58; Finlay 2000: Fig. 22).

Male imaginal character:

(4) Penis has simple outline of lateral sides; median sclerotized processes (peculiar for Nousia — see above) are massive (Fig. 12). In other Nousia lateral sides of penis have protuberances, and median sclerotized processes are small (Pescador & Peters 1985: Figs 6–13; Finlay 2000: Fig. 26).

Egg character:

(5) Eggs have unusual disk-like shape (Figs 21–23). In other Nousia eggs have a usual ellipsoid shape (Pescador & Peters 1985: Figs 56–57; Finlay 2000: Fig. 28).

Composition. One species, Nousia (Araucophlebia) latifolia sp. n.