Corythoxestis tricalysiella Kobayashi, Huang & Hirowatari

Kobayashi, Shigeki, Huang, Guo-Hua, Nakamura, Akihiro & Hirowatari, Toshiya, 2013, Four new species of Gracillariidae (Lepidoptera) from China and Japan, and description of the pupal morphology of the genera Corythoxestis, Eumetriochroa, Guttigera, and Metriochroa, Zootaxa 3619 (2), pp. 101-129 : 120-121

Corythoxestis tricalysiella Kobayashi, Huang & Hirowatari sp. nov.

Figs. 2 I–J, 6, 11.

Diagnosis. All Corythoxestis species possess a forewing without vein M3, CuA1 and CuA2 ( Fig. 6 A). The forewing pattern of fresh specimens of this species is easily distingished from other species by the costal and dorsal whitish spots and lustrous white apical line ( Fig. 2 J). However, in damaged specimens, this can be difficult to distinguish from other species with dark fuscous forewings. The genital structure of this species is similar to that of C. cyanolampra Vári , but it is distinguished from the latter by slender short valva and needle-shaped aedeagus in the male genitalia ( Fig. 6 C, D) and a small spinal signum on the corpus bursae in the female genitalia ( Fig. 6 F).

Adult. ( Fig. 2 I, J) Wing expanse 6.6 mm in holotype, 6.8, 7.0 mm in paratypes. Frons and vertex dark fuscous to grey-purple. Palpi ochreous to blackish brown; labial palpus mixed with blackish scales; maxillary palpus ochreous. Antennae about 9/8 of forewing, dark fuscous annulated with fuscous to whitish grey. Thorax dark fuscous to grey-purple. Abdomen and anal tuft dark fuscous. Forewing: dark fuscous to greyish-purple with whitish spots; three triangular costal spots: first at 1/4, second at 1/2, third at 3/4; two triangular dorsal spots: one at 1/3, another at 2/3;. cilia dark fuscous to black; lustrous white apical line mixed with fuscous scales. Hindwing dark grey; cilia dark grey to black. Wing venation ( Fig. 6 A, B).

Male genitalia ( Fig. 6 C–E). Tegumen membranous pyriform, about twice length of valva, without lateral arms connected with vinculum, with a concentration of very long setae laterally on both sides. Vinculum tightly united with valvae and a well developed saccus; Fultura superior horn-shaped, strongly sclerotized, slightly curved to caudal apex; basally united valvae short, slender, basally broadened, with fine setae on apical area; saccus about 1/ 2 length of aedeagus, tapering apically. Aedeagus needle-shaped, sharpened apically and thickened basally, slightly curved. Eight abdominal segment weakly sclerotized, glabrous, without any lobe at ventrum.

Female genitalia ( Fig. 6 F). Apophysis anterioris slender, as long as apophysis posterioris. Ostium bursae crescent-shaped, surrounded by a circular genital plate. Antrum sclerotized, tubular, slightly curved. Corpus bursae oblong, membranous, with a small, well screlotized, spinal signum at anterior part.

Pupa. Not examined.

Host plant. Tricalysia dubia (Lindl.) Ohwi (Rubiaceae) .

Distribution. Japan (Okinawa Prefecture (Ishigaki Is.)).

Specimens examined

Type material. 3 (23 1Ƥ).

Adults: Holotype 3, Japan: Maesato, Ishigaki Is., Okinawa, 16.v.2012 em., S. Kobayashi, K. Nakatsuka, T. Yoshida & T. Hirowatari leg., Host: Tricalysia dubia , 11.v.2012 (ex pupa) (genitalia slide no. OPU-SK400) in OPU. Paratypes 13 1Ƥ. Same locality and host plants as holotype, 13& 18.v.2012 em., 11.v.2012 (exs pupa and larva) (SK399 and SK401) in OPU

Etymology. The specific epithet, tricalysiella , is derived from the scientifc name of the host plant, Tricalysia .

Biology. The number of generations and the overwintering stage have not yet been established, because we have only one series of bred specimens. The larvae mine leaves of Tricalysia dubia forming a long serpentine and linear mine; white, about 180~ cm in length, 1–6 mm in width, with brownish to blackish frass line; 0.5–1.5 mm in width. The mines ( Fig. 11 A–D) were only found on the adaxial epidermis of leaves on relatively young trees (~ 1–2 m in tree-height), usually 1–3 mines per leaf. The later instar larva is ~ 6.5 mm long and yellow in coloration ( Fig. 11 F). The final instar is 5.2 mm long and yellow in coloration. A pupal cocoon fold (white to cream white, 12–15 mm in length, 5–6 mm in width) is situated at the end of the mine, usually along the leaf margins ( Fig. 11 G).

Figures

FIGURE 2. Adult of Oecophyllembiinae species from China and Japan. A. Metriochroa symplocosella sp. nov., holotype 3. B. Paratype ♀. C. Guttigera schefflerella sp. nov., holotype 3. D. Paratype ♀. E. Eumetriochroa araliella sp. nov., holotype 3. F. Paratype ♀ mining Evodiopanax innovans. G. Paratype 3 mining Dendropanax trifidus. H. Paratype 3 mining Fatsia japonica. I. Corythoxestis tricalysiella sp. nov., holotype 3. J. Paratype ♀. K. Corythoxestis sunosei (Kumata, 1998) 3 in Japan. L. Corythoxestis yaeyamensis (Kumata, 1998).

FIGURE 6. The wing venation and genitalia of Corythoxestis tricalysiella sp. nov .. A. Forewing 3. B. Hindwing 3. C. Male genitalia, lateral view. D. Aedeagus, lateral view. E. Male genitalia, ventral view. F. Female genitalia, ventral view. Fs: Fultura superior.

FIGURE 11. Biology of Corythoxestis tricalysiella sp. nov. on the adaxial epidermis of the leaves of hostplant, Tricalysia dubia. A. Mines by later instar larvae. B. Young mine and cocoon folds. C, D. Mine and cocoon fold on the leaves. E, G. Cocoon fold. F. Later instar larva. H. Resting posture of the adult.