Diduga sphaeracephalus Bayarsaikhan & Bae, 2020

Diduga sphaeracephalus Bayarsaikhan & Bae , n. sp.

( Figs 1a, 1b View FIGURES 1–7 , 8a, 8b View FIGURES 8–14 , 15 View FIGURES 15–17 )

Type materials. Holotype: 1♂, Thailand, Chantaburi, Kaosoi Dao , 14.VIII.1981 (leg. H. Kuroko, S. Moriuti, Y. Arita & Y. Yoshiyasu), Gen. Slide No. OPU˗037(INU˗10280) Thailand ( Coll. OPU) . Paratype. ( 1 ♀) Thailand: 1 ♀ , same to holotype, Gen. Slide No. OPU˗028(INU˗10281) Thailand (Coll. OPU).

Diagnosis. By the wing pattern of this species, it is hardly distinguishable from many others of the genus Diduga . However, in male genitalia, membranous, rounded apex of valva with a upper angle’s spine, and aedeagus vesica with a large stout spine˗shaped and dentate plate˗shaped cornuti; in female genitalia, weakly sclerotized os- tial plate irregularly V˗shaped, and acorn˗shaped corpus bursae heavily covered with small spines wholly, and with diverse sized, strongly sclerotized spines based to strongly sclerotized two bands in thickened top of acorn˗shaped corpus bursae separates this species well from all the other known Diduga .

Description. Adult ( Figs 1a, 1b View FIGURES 1–7 ). Length of forewing 5˗5.5 mm in both sexes. Head, patagium and tegula deep yellow. Thorax dark brown. Forewing ground color dark brown, with broad, deep yellow costal margin, which hind border broadly waved; with row of small, dark brown dots in costal and terminal area; cilia deep yellow. Hindwing ground color pale brown; cilia pale brown. Abdomen brown, except deep yellow ventral, with deep yellow anal tuft in male. Male genitalia ( Figs 8a, 8b View FIGURES 8–14 ). Uncus waved, heavily covered with setae, apex strongly hook˗shaped, with small apical spine, almost same length with tegumen. Tegumen triangular, weakly sclerotized. Valva stout, symmetric; weakly sclerotized costal margin of valva with roundly broadened in median area, and apex of costal margin finished to a strongly sclerotized, large (1/3 length of costal margin), triangular plate, which plate with a sclerotized apical spine; apex of valva rounded, membranous, with a weakly sclerotized, small, semicircular spur in medial area of membranous apex, and heavily covered with setae. Apex of juxta broadly heart˗shaped. Saccus roundly U˗shaped. Aedeagus stout, and vesica with a large (almost same length with aedeagus), stout spine˗shaped cornutus in apical area and a band˗shaped plate covered with diverse sized spines in opposite side (near apex of aedeagus). Female genitalia ( Fig 15 View FIGURES 15–17 ). Papillae anales weakly covered with setae. Ostial plate weakly sclerotized, irregularly V˗shaped. Ductus bursae tubular, weakly sclerotized in first 1/3 of length, and strongly sclerotized near cervix of corpus bursae. Corpus bursae membranous, acorn˗shaped, heavily covered with small spines wholly, except top of acorn, which top thickened, with diverse sized, strongly sclerotized spines based to strongly sclerotized two bands.

Distribution. Thailand ( Chantaburi and Kaosoi Dao Provinces).

Etymology. The species name is derived from the Greek sphaera (= ball) and cephala (= head), referring to the rounded apex of valva in male genitalia.