Metecia Snellen, 1879

Navarro, Fernando R., Barrionuevo, M. Jose & Blas, German San, 2015, A revision of the South American genus Metecia Snellen (Lepidoptera, Noctuidae, Noctuinae), Zootaxa 4007 (4), pp. 567-579 : 568-571

Metecia Snellen, 1879

Metecia Snellen, 1879: 94 ; Nye, 1975: 310; Poole, 1989: 655. Type species: Metecia cornifrons Snellen (1879) , by monotypy.

Diagnosis. Species of Metecia may be recognized by the following combination of characters: distinctive forewing pattern with two dark streaks present and transversal lines and maculation absent; male genitalia with laterally sclerotized anellus covered with short stout spines, and valve with digitus present and corona absent; female genitalia with ductus bursae sclerotized, with dorsal and ventral membranous clefts. The genus includes three species: M. cornifrons , M. lacustris , and M. hypothetica .

Redescription. Adults ( Figs 1–14 ). Antenna of male bipectinate (in lacustris ) ( Fig. 8 ) or biserrate (in cornifrons and hypothetica ) ( Fig. 7 ), doubly bifasciculate; antenna of female simple, with thin ventral hairs; a loose tuft of hairlike scales from occiput hanging between the bases of antennae; vertex and frons covered with bushy long hairlike scales; eyes naked, not lashed; labial palpus unmodified, segments with ventral fringe of scales.

Thorax coated with long hairlike scales; tegula pale brown with longitudinal apical dark brown streak. Prothoracic leg with femur bearing a lateral fringe of hairlike scales; tibia with complete row of spinelike setae laterally on both margins; first tarsal segment as long as tibia or shorter. Mesothoracic and metathoracic legs with ventral margin of femur bearing a fringe of hairs; tibia with tuft of hairs on proximal half; tarsi with three row of setae ventrally and a partial fourth row of setae on the outer margin of the first segment.

Forewing length males 11.8–18.5 mm; females, 12.1–17.1 mm; with two dark brown longitudinal streaks, transversal lines and maculation absent. Underside pale brown, veins and area posterior to Cu vein whitish. Hindwing iridescent. Underside iridescent with costal margin diffuse pale brown.

Abdomen ( Figs 15, 16 ) pale brown, covered with scales but with no noticeable tuft. Tergite VIII a roughly square sclerite, with a weakly sclerotized central section. Sternite VIII a roughly trapezoidal sclerite ( Fig. 15 ), centrally membranous in lacustris ( Fig. 16 ).

Male genitalia ( Figs 17–29 ) with uncus elongate and slender, covered by hairlike setae on basal 2/3, apical 1/3 with long spine-like setae, apex curved upwards and densely covered dorsally with strong small spines ( Figs 17, 18 ). Valve elongate, slightly concave near middle, apex drawn to a blunt point; sacculus expanded to costal margin of valve, 0.6X as long as valve; costa heavily sclerotized, thickened on basal half; corona absent; costal margin of cucullus with several rows of spinelike setae. Clasper vestigial in cornifrons ( Fig. 19 ), absent, restricted to basal sclerite in lacustris and hypothetica ( Figs 24, 27 ). Ampulla moderate, S-shaped, with pointed apex. Costa sclerotized and continuous with the digitus. Clavus absent. Tegumen and peniculus unmodified. Anellus with two broad, well developed, sclerotized, tongue-shaped plates, dorsal half covered by short stout spines on outer margin, stronger on anterior margin and gradually thinner toward posterior margin ( Figs 19, 24, 27 ). Juxta shield shaped, without ornamentation, ventral margin with central section produced triangularly and dorsal margin variably produced into two lateral bars ( Figs 19, 27 ) and one central horn present in lacustris ( Fig. 24 ). Aedeagus membranous posteriorly, with a dorsal right sclerotized bar and a ventral sclerotized plate. Vesica approximately as long as aedeagus, with basal, subbasal, and apical diverticula (apical diverticulum absent in conifrons and lacustris ), one strong cornuti on basal diverticulum and one small cornuti on subbasal diverticulum in lacustris and hypothetica ( Figs 25, 26, 28, 29 ), cornifrons with sclerotized plate ventrally and close to aedeagus ( Figs 20, 21 ) and subbasal diverticulum partially covered with small cornuti ( Figs 20, 22 ), strong cornuti absent.

Female genitalia ( Figs 30–35 ) with flattened anal papillae, covered with setae. Abdominal segment VIII produced into two lateral lobes directed toward the ostium bursae. Anterior apophyses much shorter than posterior ones. Ductus bursae sclerotized, with two membranous clefts on dorsal and ventral margins. Corpus bursae elongate, ovate; signa absent; appendix bursae differentiated, as large as corpus bursae, originating from distal left side of corpus bursae; ductus seminalis originating from appendix bursae apex.

Remarks. Species associated in this work with Metecia have alternatively been placed in either Pareuxoa or Pareuxoina (= Pareuxoa ). Differences between these two genera are as follows. (1) Metecia with laterally sclerotized anellus covered with short stout spines; the anellus in Pareuxoa is unmodified. (2) Metecia with uncus apex upwardly curved and dorsally densely covered with strong small spines; in Pareuxoa uncus slightly upwardly curved and lacking dorsal spines. (3) Vesica of Metecia with single, long basal cornutus and subbasal small cornutus, each on different diverticula ( M. cornifrons with basal plate and numerous small cornuti on subbasal diverticulum); in Pareuxoa vesica with four slender basal cornuti arranged in a row and, distally to them, a single strong and thorn-like cornutus with its base swollen and striate. (4) Appendix bursae of Metecia as large as the corpus bursae; in Pareuxoa appendix bursae elongate and thin but never as large as the corpus bursae.

Bionomics and distribution. Nothing is known of the biology or the immature stages. Metecia occurs in Argentina between 30º and 53º south latitude in the provinces of Buenos Aires, Chubut, Córdoba, La Pampa, Neuquén, Río Negro, and Santa Cruz; and Chile between 36º and 38º south latitude from regions VII (Region del Maule) and VIII (Region del Bio–Bio) ( Fig. 36 ).

Figures

FIGURE 36. Distribution map of Metecia species. White circles = M. cornifrons, red stars = M. lacustris, yellow triangles = M. hypothetica.

FIGURES 1 – 6. Male and female of Metecia. 1, M. cornifrons, male. 2, M. cornifrons, female. 3, M. lacustris, male. 4, M. lacustris, female. 5, M. hypothetica, male. 6, M. hypothetica, female. Scale lines: 10 mm.

FIGURES 7 – 14. 7 – 8, male antenna. 7, biserrate, doubly bifasciculate (Metecia hypothetica). 8, deeply bipectinate (M. lacustris). 9 – 14, Frons projections. 9, M. cornifrons (lateral view). 10, M. cornifrons (anterolateral view). 11, M. lacustris (lateral view). 12, M. lacustris (anterolateral view). 13, M. hypothetica (lateral view). 14, M. hypothetica (anterolateral view).

FIGURES 15 – 18. 15 – 16, male abdominal segment VIII. 15, Metecia cornifrons. 16, M. lacustris. 17 – 18, M. lacustris male genitalia, uncus (lateral view). 17, uncus apex curved upwards. 18, close up of uncus apex showing dorsal strong small spines.

FIGURES 19 – 29. Male genitalia. 19 – 23, Metecia cornifrons. 19, male genitalia. 20, aedeagus (lateral view). 21, sclerotized plate (close up). 22, subbasal diverticulum left margin (close up). 23, aedeagus (dorsal view). 24 – 26, M. lacustris. 24, male genitalia. 25, aedeagus (lateral view). 26, aedeagus (dorsal view). 27 – 29, M. hypothetica. 27, male genitalia. 28, aedeagus (lateral view). 29, aedeagus (dorsal view).

FIGURES 30 – 35. Female genitalia. 30, Metecia cornifrons (lateral view). 31, M. cornifrons (dorsal view). 32, M. lacustris (lateral view). 33, M. lacustris (dorsal view). 34, M. hypothetica (lateral view). 35, M. hypothetica (dorsal view).