Euryobeidia Fletcher, 1979

Liu, Bo, Stüning, Dieter & Han, Hongxiang, 2025, Further taxonomic studies of the mimetic genus Euryobeidia Fletcher, 1979 (Lepidoptera, Geometridae, Ennominae, Baptini), with descriptions of four new taxa and two status changes, ZooKeys 1260, pp. 313-343 : 313-343

publication ID	https://doi.org/10.3897/zookeys.1260.157773
publication LSID	lsid:zoobank.org:pub:2069CF50-6C1A-46DC-97AE-5932C7BC40CC
DOI	https://doi.org/10.5281/zenodo.17669344
persistent identifier	https://treatment.plazi.org/id/06859937-768E-5FF6-AE5E-640871AC9B9E
treatment provided by	ZooKeys by Pensoft
scientific name	Euryobeidia Fletcher, 1979
status

Treatment

Euryobeidia Fletcher, 1979 View in CoL

Euryobeidia Wehrli, 1939 View in CoL , in Seitz, Gross-Schmett. Erde 4 (Suppl.): 269. Unavailable, type species not designated.

Euryobeidia Fletcher, 1979 View in CoL , The Generic Names of Moths of the World, 3: 84. Type species: Abraxas languidata Walker, 1862 View in CoL .

Generic description.

General appearance. Medium-sized ennomine moths, forewing length 17–27 mm. Included species are separated into the following two groups based on ground color: 1 st group, including the type-species E. languidata , with ground color white to grayish-white; 2 nd group orange, often fading to yellow over time. Wings with a large number of black, dark gray or dark brown spots, arranged in a similar pattern, with the exception of Euryobeidia yakushimensis stat. nov. Head. Antennae filiform in both sexes, flagellomeres of a short proximal part cylindrical, more distally they are laterally flattened, ventrally elongated, wedge-shaped, homogeneously covered with very short setae and with a pair of long, straight, spine-like setae, arising mid-laterally on either side near distal margin of each segment. Antennae of females similar, but thinner. Frons narrow, covered with slightly elongated or almost hair-like scales, the latter basally arranged around a tiny, central protrusion of the head-capsule; a concentric arrangement of scales on top of frons, between the bases of antennae, has been observed in some specimens of different species. Vertex covered with slightly longer and broader, distally dentate, obliquely erect scales. Labial palpi slender, roundly curved upwards, just reaching or protruding slightly beyond the frons, third joint small, but clearly visible. Proboscis rather short. Chaetosemata small, near eye margin. Thorax. Dorsum orange, yellow or grayish-yellow, typically with black dots: one on each patagium, two on each tegula, and two on mesothorax; slight variation occurs among species or individuals. Patagia and tegulae with lamellar, partly elongated scales, tegulae in addition with long hair-scales. Legs slender, pale yellow or orange, with a few dark gray or black dots. Index of spurs 0-2 - 4, hind tibia not dilated and without scent-brush (hair-pencil) in males. Forewing not or slightly elongate, arched at basal part of costa, apex angled, termen smoothly curved. Fovea absent. Hindwing with a large white area at the basal ⅔ – ¾ (except for E. tigratoides tigratoides and E. yakushimensis ), and a broad, rarely narrow, yellow, submarginal band with multiple black streaks or dots. Marginal line with black dots at vein-ends, absent in forewing of 1 st group, absent or strongly reduced in species of 2 nd group. Apex of hindwing rounded, termen minutely concave between vein-ends, posterior margin slightly truncated from the end of vein 3 A to tornus and also on termen from vein-end of CuA 2 to tornus. Venation (Fig. 1 View Figure 1 ). Forewing: costal area very broad at basal ⅔; Sc evenly curved, but rather abruptly bent upwards near the distal 1 / 5 (most clearly noticeable in E. tigratoides , see Fig. 1 View Figure 1 ); R 1 arising from upper vein of cell rather close to the common stem of R 2-5; R 1 also often exhibits a distinct curvature opposite to the basal ends of R 2 and R 5 and a second curvature more distally and therefore reaches the costa closer to the apex; R 2, as a typical character for the tribe Baptini , arises from the common stem of R 3-5; stem R 2-5 arising on a rather large distance from anterior angle of cell (origin of M 1); M 2 from the middle of the discocellulars; CuA 1 widely separated from posterior angle of cell; CuP represented by a rather distinct fold, but with a very short and weak sclerotized vein near the base. Hindwing: Sc + R 1 running closely parallel but not anastomosing with upper vein of cell at base (a common character of most ennomine moths); Rs arising at a rather small distance from anterior angle of cell; M 2 absent; CuA 1 arising at a longer distance from posterior angle of cell; 3 A present. Pregenital abdomen. Abdomen densely covered with fine, whitish, orange, or pale yellow scales. Dorsal side usually with dark spots or transverse bands on each segment from T 1 to T 8, the spots vary in coloration and size between species and also individually, and rarely may even be absent in some or all segments (e. g. Euryobeidia tigratoides tigratoides ). Laterally, a row of dark spots present, reduced or absent. Ventral side often with a small number of dark spots and patches of various size and shape, especially in the species-group with white or grayish-white ground color, fewer or even absent in the group of orange / yellow specimens. Integument with most tergites and sternites not conspicuously modified. T 1 narrower than T 2, appendages of intersegmental tergal phragma T 1 / T 2 very long, strap-like. The 8 th segment in males slightly elongate, broader than the 7 th segment, posteriorly slightly sclerotized. In females, the 7 th segment distinctly enlarged, 8 th segment very small, tergite T 8 rather membranous, with a cup-shaped, round or oval invagination of unknown function (See the black arrow on Fig. 50 View Figures 50–55 ; visible on dorsal side, behind the right arm of lamella postvaginalis; so far only observed in E. languidata ). Tympanal organs of moderate size, shallow, without lacinia. Setal comb on third sternite and sterno-tympanal process both absent, which is consistent with the absence of dilated hind-tibiae with scent-brushes. Coremata not developed.

Male genitalia. Very heterogeneous, especially the uncus with various peculiar shapes among species. It may exhibit the shape of a bird’s head, densely covered with setae, with a small or larger beak-shaped apex, pointed in lateral view, and a narrow neck of differing length. In addition, large, plate-like appendages from “ head ” may be present. The base of the uncus mostly is a transverse straight or triangular bar, with lateral socii, covered with fine setae. Only one species ( E. largeteaui ) exhibits a rather unmodified uncus. Common characters are rare, e. g. the weak gnathos, reduced to fine, sclerotized lateral arms, not fused at middle, or the large tegumen, consisting of two narrow, elongate arms, which are rather common also in other genera of Baptini . In Euryobeidia , the tegumen sometimes is swollen distally and curved ventrad, in other species it is not swollen, but stronger distally and narrower caudally. Transtilla sinuous, broad, band-shaped, slightly to heavily sclerotized. Vinculum short and strong, fused laterally with tegumen. Saccus short, rounded. Juxta groove-like. Valva long and slender, with a well-developed cucullus, reaching from apex back to center of valva, ending with a small, setose knob. Valva distally strongly curved dorsad, apex with a smaller or larger, sometimes lobe-like protrusion, resulting in a more ventral notch. Costa smooth or slightly protruding or with a large, broad process. Base of sacculus often with a lamellar, oval or triangular projection, dorsally more or less dentate and variable in size among species. Aedeagus elongate, apically narrowed, and sclerotized ventrally, often with a pointed process of variable length (extremely long in E. largeteaui ). Cornuti spine-like or replaced by sclerotized folds and patches of vesica of various shapes. Bulbus ejaculatorius shorter than the aedeagus shaft; proximal part (near aedeagus) tube-like and short; central part U-shaped, open ventrally; distal part cap-shaped, large, with a long rectangular extension distally (Figs 40 View Figures 38–43 , 45 View Figures 44–49 , 46 View Figures 44–49 , 49 View Figures 44–49 ).

Female genitalia. Ovipositor short, papillae anales slightly elongated, densely and shortly setose, tip rounded. Posterior apophyses long and narrow, anterior apophyses shorter, strong, ~ ⅓ – ½ the length of posterior apophyses, their bases dilated or narrow. A triangular sclerite present between the bases of posterior apophyses, its size and shape vary considerably between species and subspecies. Sterigma well developed, sclerotized; lamella antevaginalis spined on posterior margin and more strongly so laterally; lamella postvaginalis a sclerotized plate of different shape, consisting of two layers of plates, connected proximally. Introitus bursae strongly sclerotized, more or less twisted, usually placed asymmetrically on left side in ventral view (situated in the center in E. largeteaui only). Ductus seminalis arising close to the end of the short, narrow, strongly sclerotized posterior part of bursa copulatrix (ductus bursae of authors). Anterior part of bursa large, oval or pyriform, distal ½ – ¾ abundantly spined inside, remaining proximal portion membranous, without spines.

Distribution.

China, Korea, Japan, India, Nepal, Vietnam (new record).

Diagnosis.

Euryobeidia species are very similar in appearance to certain species and subspecies of the Obeidia - complex ( Inoue, 2003) of genera (mainly of the genus Epobeidia Wehrli, 1939 ) and the genus Abraxas Leach, [1815] , which probably serve as models in a mimicry relationship. However, they are easily distinguished from the previously mentioned genera by their less elongate, basally arched forewings and markedly different genitalic structures. Within the tribe Baptini , Euryobeidia species can be easily identified by the pattern of prominent dark spots on the wings and the distinctive genitalic structures, particularly the peculiar uncus of the male genitalia.