Arcilasisa Walker, 1865

Chen, Enyong, Pan, Zhaohui, Volynkin, Anton V. & Saldaitis, Aidas, 2022, Redescription of the genus Arcilasisa Walker with notes on its taxonomic placement (Lepidoptera: Noctuidae: Noctuinae), Zootaxa 5133 (1), pp. 143-150 : 144

Genus Arcilasisa Walker, 1865

Arcilasisa Walker, 1865 , List of the Specimens of Lepidopterous Insects in the Collection of the British Museum, 32: 470.

Type species: Arcilasisa sobria Walker, 1865 , by monotypy.

Taxonomic note. Despite the external similarity to the certain species of the Rhizedra Warren, 1911 genusgroup (sensu Zilli et al. (2005)), namely, the type species of the genus Fabula Fibiger, Zilli & L. Ronkay, 2005 , F. zollikoferi ( Freyer, 1836) , the genus belongs to the Apamea generic complex (sensu Zilli et al. (2005, 2009)) due to such male genitalia features as the sclerotised posterior subuncal lobes of the tegumen, the well-developed cucullus with a corona and a ventral tip, the relatively short aedeagus having a dorsal membranous belt and lacking carina spines, and the more or less conical vesica directed dorsad.

Diagnosis. The only species of the genus ( Figs 1–8 ) is externally reminiscent of the pale form of Fabula zollikoferi (illustrated by Zilli et al. (2005)) but differs in the larger size, the more elongate forewing apex and the more reduced forewing markings. The male genital capsule of the genus ( Figs 9–12 ) is similar to that of certain groups of the genus Apamea (s. str.), namely the A. arabs ( Oberthür, 1881) and the A. furva ([Denis & Schiffermüller], 1775) – A. platinea ( Treitschke, 1825) species groups (illustrated by Zilli et al. (2009)) but can be distinguished by the long and heavily sclerotised apical process of the juxta, a feature characteristic for the genus. The similar sclerotised structure is known in the genus Pseudluperina Beck, 1999 (illustrated by Zilli et al. (2005)), but in the latter it is a heavily sclerotised anellus ( Zilli et al. 2005) while in Arcilasisa , the process is separated from anellus and is a part of the juxta itself. The apical dorsal protrusion of the costa of Arcilasisa lacks a cluster of hairs which is present in Apamea . Additionally, compared to Apamea , the male genital capsule of Arcilasisa has a more massive uncus. The aedeagus of the genus is similar to that of Apamea but in Arcilasisa , the carina is not protruding to the subbasal section of the vesica and lacks dentation. In the vesica of Arcilasisa , the long and broad cluster of numerous spinules is characteristic, whereas the vesica of Apamea bears robust basal cornuti and additional distal cornuti in certain groups. The female genitalia of Arcilasisa ( Fig. 13 ) are characterised by the membranous ductus bursae (it is sclerotised in Apamea ) and the asymmetric antrum bearing a gelatinous lateral protrusion.

Redescription. Adults ( Figs 1–8 ). Large moths with forewing length 35–37 mm in males and 40 mm in females. Antenna ciliate in male and filiform in female. Body pale straw-brown. Forewing relatively narrow with elongate apex and oblique tornus. Forewing ground colour pale straw-brown. Pattern represented by diffuse blackishbrown suffusion. Orbicular and reniform stigmata pale straw-brown, encircled with diffuse blackish-brown scales. Hindwing pale brown with intense dark brown suffusion in terminal area. Discal spot brown, thin, falcate. Male genitalia ( Figs 9–12 ). Uncus narrow but robust, tubular, strongly down curved subbasally and almost straight distally, apically tapered with tiny claw-shaped tip. Tegumen with sclerotised trapezoid posterior subuncal lobes. Peniculus large, trapezoid with rounded corners, densely setose. Vinculum as long as tegumen, with short U-shaped saccus. Valva elongate, somewhat dilated medially. Costa with broad but short dorsal protrusion distally, short but broad ventral crest at the base of cucullus neck, and short but robust, clavate distal process (digitus) directed ventrodistally. Cucullus with broad neck, triangular with elongate and apically rounded apex and short, narrowly triangular and apically rounded ventral tip. Outer margin of cucullus with corona consisting of numerous short and thin setae. Clasper narrow, straight, dilated distally. Ampulla short and thin, stick-shaped with curved and setose tip. Sacculus short, with broad clavus. Ventral margin of valva with short but broad subdistal protrusion. Basal section of juxta trapezoid with tiny, triangular anterio-medial protrusion. Distal section of juxta long, clavate, heavily sclerotised, somewhat constricted and laterally weakly dentate medially, and bearing row of robust triangular spines apically. Aedeagus elongate and narrow, tubular, medially down curved, with longitudinal dorsal membranous belt and long, distally dilated and apically rounded coecum. Carina thick and heavily sclerotised ventrally, with broad but very short protrusion apically. Vesica with short sack-like ventral diverticulum bearing small thorn-shaped cornutus, and more or less conical and dorsally directed main chamber bearing long and broad elliptical cluster of numerous spinules medially. Female genitalia ( Fig. 13 ). Ovipositor posteriorly conical, constricted subanteriorly, with papillae anales fused in anterior two thirds, setose. Apophyses long and thin, flattened and apically rounded, more or less equal in length. Antrum heavily sclerotised, narrow, more or less rectangular with postero-lateral protrusions, asymmetric, with short but broad, rounded gelatinous lateral protrusion on left side. Right postero-lateral protrusion short and broadly rectangular while left one thicker and longer and somewhat dilated medially. Ductus bursae short, tubular, membranous, with short semiglobular rugose appendix anterio-laterally on left side. Corpus bursae teardrop-shaped, weakly rugose, with two long and thin band-like signa of different length. Appendix bursae positioned posterolaterally on right side at the junction with ductus bursae, broad, semiglobular, rugose.

Figures

FIGURES 1–8. Arcilasisa sobria: adults. Depositories of the specimens: 1 in OUMNH; 2–4 in ZSM; 5–8 in TAAHU.

FIGURES 9–11. Arcilasisa sobria: male genitalia. Depositories of the specimens dissected: 9 in OUMNH; 10 and 11 in TAAHU.

FIGURES 12–13. Arcilasisa sobria: male (12) and female (13) genitalia. The specimens dissected are deposited in TAAHU.