Pseudopostega bicornuta Davis & Stonis 2007

Pseudopostega bicornuta

ADULT. Figure 230. Length of forewing 4.6 mm. Small, mostly white moth with white forewings marked with a pair of brown, subapical costal strigulae, a very faint brown, tornal strigula, and a small, dark brown to fuscous apical spot. Male gnathos triangular, gradually tapering to a deeply divided, caudal lobe; basal fold narrow, sharply arched (Figure 405). Female unknown.

Head: Vestiture white. Scape white; flagellum light golden brown, 72-segmented. Palpi white; labial palpus with suffusion of brown dorsally and laterally.

Thorax: White; tegula with light brown suffusion on anterior margin. Forewing white, marked with a pair of brown, subapical costal strigulae and a very faint brown, tornal strigula; strigula 1 with faint suffusion of very pale, yellowish brown along inner margin, fading just before dark brown to fuscous apical spot, strigula 2 curving around apical spot and terminating near tornus; tornal strigula extending from apical spot to tornus; terminal and dorsal cilia white; venter of forewing light brown, with basal, subhumeral white area. Hindwing and cilia light brown dorsally and ventrally. Legs mostly white to cream; foreleg with dorsal surfaces partially suffused with light brown; basal, dorsal half of tibia light brown, apical half entirely cream; tarsomeres 1–2 light brown dorsally; remainder of tarsi cream; mid- and hindlegs white to cream.

Abdomen: Light golden brown dorsally, cream ventrally.

Male Genitalia: Figures 405, 406. Socii a pair of relatively small, rounded, setose lobes, widely separated by a distance ~0.5× length of cucullar lobe; caudal rim of uncus deeply concave, U-shaped. Vinculum broadly V-shaped; anterior margin slightly concave. Base of gnathos broadly triangular; anterior margin slightly concave; basal fold narrow, sharply arched, with a prominent, acute, median lobe projecting caudad, well separated from base; gnathos gradually narrowing caudally to a pair of slender, acute, caudal lobes directed slightly dorsad. Valva with elongate cucullar lobe ~0.4× length of genital capsule, bearing a pectinifer consisting of 40–41 blunt spines; distal apex of cucullar lobe extended as a rough, narrowly rounded, setose lobe; pedicel broad, ~0.4–0.5× length of cucullar lobe; valva moderately long, length along sacculus ~0.65× length of genital capsule; saccular lobe rough, tapering to narrow, setose apex; basal process of valva tapering to acute apex, exceeding length of costal lobe. Juxta undeveloped.

FEMALE, LARVA AND PUPA. Unknown.

HOLOTYPE. ♂; MEXICO: CHIAPAS: Villa Las Rosas, 1300 m: 27 Jun 1981, V. O. Becker, slide USNM 32258 (USNM).

HOST. Unknown.

FLIGHT PERIOD. June (unique record).

DISTRIBUTION. (Map 18) Known only from the type locality in southern Mexico.

ETYMOLOGY. The species name is derived from the Latin bi (two) and cornutus (horn) in reference to the dorsally curved, furcate apex of the male gnathos.

DISCUSSION. The male gnathos of this species resembles that of P. suffuscula in the development of a relatively slender, deeply bifurcate caudal lobe. Their genitalia differ in several characters, particularly by the more lobiform, lateral expansion at the base of the gnathos and deeply excavate caudal margin of the uncus in bicornuta. The forewing of bicornuta differs from that of suffuscula in being basically white and not suffused with grayish brown as in the latter.

Pseudopostega bicornuta is a moth of the family Opostegidae. It was described by Donald R. Davis and Jonas R. Stonis, 2007. It is known from southern Mexico.

The length of the forewings is about 4.6 mm. Adults have been recorded in June.