Taxonomic study of Thiotricha Meyrick (Lepidoptera, Gelechiidae) in Japan, with the description of two new species

Abstract A part of Japanese species of the genus Thiotricha Meyrick, 1886 are reviewed. Three species described by Omelko (1984) in the genus Cnaphostola Meyrick, 1918 are placed in combination with Thiotricha; Thiotricha biformis, T. angustellacomb. nov. and T. venustaliscomb. nov. These species are redescribed, and two new species, T. elaeocarpiella Kyaw, Yagi & Hirowatari, sp. nov. and T. flavitermina Kyaw, Yagi & Hirowatari, sp. nov. are described based on external morphological characters of adults and genitalia of males and females. Thiotricha chujaensis (Park, 2016), comb. nov. described in Cnaphostola from Korea, is newly recorded in Japan feeding on Mallotus japonica (Euphorbiaceae). One of the new species, T. elaeocarpiellasp. nov. has been associated with two different plants, Elaeocarpus zollingeri (Elaeocarpaceae) and Rhaphiolepis indica (Rosaceae). This paper presents the ﬁrst comprehensive description of the morphology, pupal morphology and biology of species previously treated in the genus Cnaphostola and their relatives in Japan.


Introduction
The family Gelechiidae is one of the largest families of Microlepidoptera in the world and includes more than 4,700 described species belonging to approximately 500 genera (van Nieukerken et al. 2011). In the Palearctic region, there are more than 1,500 species (Piskunov 1990). In Japan, 288 species of this family have been recorded, including 41 unidentified species (Jinbo 2016). There is a great number of species that remain to be described, as Gelechiidae is one of the least studied Lepidoptera families. Currently, this family is thought to consist of seven subfamilies: Anacampsinae, Dichomeridinae, Apatetrinae, Thiotrichinae, Anomologinae, Gelechiinae, and Physoptilinae, mainly based on molecular analyses .
The subfamily Thiotrichinae includes the genera Thiotricha Meyrick, 1886, Macrenches Meyrick, 1904, Palumbina Rondani, 1876and Polyhymno Chambers, 1874. Among them, Thiotricha Meyrick, 1886 and Polyhymno Chambers, 1874 have a long taxonomic history with various opinions about their separation. The genus Thiotricha includes globally nearly 100 described species and is most diverse in Asia (Karsholt et al. 2013). In Japan, 15 species have been recorded and were later treated as Polyhymno (Suzuki and Komai 1984;Oku 2003). In 2005, Ueda and Fujiwara described the new species Thiotricha prunifolivora Ueda & Fujiwara, 2005 from the host plant Symplocos prunifolia (Family: Symplocaceae), with a biological note on the immature stages. Then, this species and the 15 previously recorded species were tentatively treated in the genus Thiotricha, together with a taxonomic comment that mainly follows Omelko (1999) and Park (2004). In 2009, Thiotricha was synonymized with Polyhymno by Ponomarenko (2009), without further comments. Recently, Karsholt et al. (2013) conducted a molecular analysis of the Gelechiidae without Polyhymno species in their analysis. However, they compared the type species, P. longistrigella Chambers morphologically with species of Thiotricha. This resulted in the recognition of both Thiotricha and Polyhymno as valid genera. Moreover, also their biology differs, the larvae of Polyhymno are leaf-spinners and leaf-webbers in Fabaceae (Busck 1900), but larvae of Thiotricha, as far as known, make a portable case and feed on flowers and seeds (Robinson et al. 1994, Ueda andFujiwara 2005).
Another genus, Cnaphostola Meyrick, 1918, was described for the single species C. adamantina Meyrick, 1918, collected in Assam, North India. Three additional species; C. biformis Omelko, 1984, C. angustella Omelko 1984, and C. venustalis Omelko, 1984, were described from the Primorsky Territory in the Russian Far East (Omelko 1984). These three species have also been recorded from Japan (Oku 2003;Ueda 2013). In 2016, Park described C. chujaensis from Chuja Island, Korea, tentatively placing it in Cnaphostola. Today, therefore, this genus comprises five species in total (Park and Kim 2016). Kogi (2004Kogi ( , 2008 observed and reported the larval feeding of C. venustalis and C. angustella on the host plant Quercus dentata (Fagaceae), in Hokkaido, Japan. Otherwise, the biology of the immature stages of this genus has not been studied in detail. The members of Cnaphostola are very similar to those of Thiotricha or Polyhymno. Meyrick (1918) noted that the genus Cnaphostola probably belongs to the Thiotricha group; however, it was not included in the molecular analy-sis of Karsholt et al. (2013). Then, Sohn et al. (2015) combined Cnaphostola biformis as Thiotricha biformis without any explanation.
Although the phylogenetic relationship and synonymy of the genera Cnaphostola, Thiotricha and Polyhymno is not fully resolved to date, we place all Japanese species here in Thiotricha, we review the Japanese species and compare the morphological characters, including head parts, wing marking, venation, and genitalia, to solve the aforementioned taxonomic problems. Further, we describe two new species with photographs of male and female adults, wing venation, and genitalia. We also report the biology of immature stages of some species, the pupal morphology of T. chujaensis (Park, 2016) comb. nov. and T. elaeocarpiella Kyaw, Yagi & Hirowatari sp. nov. and discuss the larval feeding mode of this group.

Materials and methods
Dried specimens deposited in the Entomological Laboratory, Kyushu University, Fukuoka (ELKU); Osaka Prefecture University, Sakai (OPU); the Entomological Laboratory, Kagoshima University, Kagoshima (KGU); the National Museum of Nature and Science, Tsukuba, Japan (NSMT); and T. Oku's collection, Morioka (TO) were examined. Field research was also conducted across Japan from Hokkaido to Okinawa. Larval portable cases were collected from host plants and light traps were used to collect adults. External morphological characteristics were first observed under a stereo microscope (Nikon SMZ-U), and then genitalia slides were prepared as follows: the abdomen was detached, placed in a glass tube with 10% potassium hydroxide (KOH) solution, and boiled in water for ca. 10-15 mins, depending on the size of the genitalia to macerate. After that, the boiled abdomen was neutralized in acetic acid, stained with Chlorazol Black E, and then rinsed with 70% ethanol solution to remove residual scales and internal soft parts. Then, the abdomen was dissected by cutting its intersegmental membrane between T7 and T8 with fine small insect pins. The genitalia were separated and transferred to a glass plate with 50% glycerol solution for observation. After observation, the genitalia and the abdomen were dehydrated in a 70%-100% ethanol series and mounted on a microscope slide in Euparal. Photographs of adults were taken using a Leica S8APO with a digital camera (Canon EOS 7D), and focus stacking was performed in Combine ZP (Hadley, 2010). Photographs of male and female genitalia were taken using a biological microscope (Olympus BX43) with a digital camera (Olympus E5).
Unless otherwise noted, the specimens are deposited in the Entomological Laboratory of Kyushu University (ELKU).

Terminology
The descriptive terminology follows Park and Kim (2016) for wing markings, and Karsholt et al. (2013) and Ueda and Fujiwara (2005) for genitalia. The scientific names of plants follow Yonekura and Kajita (2003). Diagnosis. The forewing is white with broad, dark brown fascia, a rather large yellow patch before the apex, and a black rounded apical spot demarcated by a white line. The anellus lobe of the male genitalia is a short and heavily sclerotized beak-shaped lobe basally, armed with a small claw-like process apically, which is a unique characteristic of this species. The apopyhsis posterioris of the female genitalia is ca. 1/2 the length of the papilla analis and approx. two times longer than the apophysis anterioris; the signum is absent in the corpus bursae.
Head: covered with shiny, creamy white appressed scales. Antennae filiform; basal segment (scape) elongate without pecten, creamy white; flagellum creamy white on dorsal surface before middle, then entirely grayish brown beyond on its dorsal and ventral surface, with rather long and fine cilia ventrally. Labial palpus white, long, and recurved; first segment shortest with creamy white scales; second segment thickened, ca. 2.5 the thickness times of first, covered entirely with white scales; third segment white on dorsal surface, sparse brown scales medially on ventral surface, as long as second segment, apex sharply acute.
Thorax: creamy white. Tegula shiny, creamy white dorsally, with brown scales along anterior margin.   Legs: white; forefemur, tibia, and tarsus suffused inwardly with brownish tinge, white on outer surface; mid legs entirely white; hind femur and tibia white, with a row of long, stiff, stout white bristles on upper and lower surfaces; all tarsal segments brownish gray. . Adults of Thiotricha spp. A T. biformis, male B ditto, female C T. angustella comb. nov., male D ditto, female E T. venustalis comb. nov., male F ditto, female G T. chujaensis (Park, 2016) comb. nov., male H ditto, female. Scale bars: 2 mm.
Forewing: eleven veins, R 3 + R 4 stalked, M 1 separate, R 5 absent, anal veins furcate (Fig. 7A). Forewing broader in this genus, ground color white to middle, followed by a dark brown fascia, rather large yellow patch before apex not protruding to costal margin; small brown area in costal margin, intercepted by oblique white lines with a rounded black apical spot; small scattering of yellow scales below apical point at outer margin, small brown scale in tornal area; cilia blackish brown at inner margin of apex, outer margin with brown through inner base of wing.
Hindwing: darker grayish brown with tiny black apical dot at apex; cilia wellfringed, grayish brown, with dark brown at tip of wing.
Male genitalia: (Figs 8A, B, 9A) eighth abdominal sternite rather semicircular, broadly concave with strongly sclerotized margin. Uncus semicircular with a few hairs on top. Gnathos sickle-shaped, short and stout, wide and flattened posteriorly, and then curved at middle toward apex. Tegumen long, slightly concave medially, bearing dense hairs on dorsal surface at approx. the midpoint. Anellus lobe, a short and heavily sclerotized beakshaped lobe, approx. half the length of valva, slightly narrow at base, and then abruptly dilate with short and small claw-like process apically, with a few sclerotized spines at approx. the midpoint on inner dorsal surface. Valva elongate, slender, and curved inwardly, somewhat broad basally, narrowly elongate from base to 2/3 of its length, then distended again at apex, bearing thin and fine setae on its inner surface. Vinculum moderately broad, median process rising to a pair of transverse ridges of short, thorn-like spines on edge of posterior surface, rather long and short fine setae emerging around and below the ridge surface. Saccus broad basally, somewhat triangularly produced. Phallus short and sclerotized, clavate basally and straightly elongate with a round tip distally.
Thiotricha angustella (Omelko, 1984)  Diagnosis. The forewing is white with pale brown in the distal part, without an apical black spot. The anellus lobe of the male genitalia is a pear-shaped lobe basally, long, strongly sclerotized, and spine-like apically; the valva is narrow and elongate. The apophysis posterioris of the female genitalia is approx. two times of the length of papilla analis and approx. three times longer than the apophysis anterioris; the signum is long, narrow, and arch-shaped.
Head: shiny creamy white with appressed scales. Antennae filiform, basal segment elongate without pecten and creamy white; flagellum creamy white on dorsal surface before middle, then grayish brown beyond, with extraordinarily long and fine cilia on its ventral surface. Labial palpus white, long, and recurved; first segment shortest, creamy white suffused with brown scales on outer surface; second segment thickened, up to 2.5 times the length of the first and white; third segment nearly as long as second, creamy white evenly on both surfaces, apex sharply acute.
Legs: white; forefemur, tibia, and tarsus suffused inwardly with brown; hind tibia creamy white, with a row of long, stiff, stout white bristles at approx. the midpoint anteriorly, with dark brown bristles at ca. 1/4 posteriorly on dorsal surface, with white bristles ventrally.
Forewing: eleven veins, R 4 + M 1 stalked, R 5 absent, anal vein furcate (Fig. 7B). Forewing ground color shiny creamy white, somewhat rounded and pointed apically, with a brownish hue apically 1/5 of the way beyond costal margin; cilia well-fringed, brown from costal area before apex and brownish white along outer margin to inner base of wing.
Hindwing: narrower than forewing, white to whitish brown; cilia well-fringed, white to brownish white; apex produced conspicuously.
Male genitalia: (Figs 8C, D, 9B) eighth abdominal sternite triangular, long, slightly broadened at base, and then tapered toward posterior with a blunt tip. Uncus swol-len, like a small tubercle, short and fine hairs on its top. Gnathos short and stout, its posterior margin closer to base with a hump-like outgrowth; closer to top, somewhat expanded, with a blunt tip. Tegumen much longer than uncus, with dense hairs at approx. the midpoint of its length on dorsal surface. Anellus lobe quite long and pearshaped basally, bearing a rather long and strongly sclerotized spine-like process at apex, slightly acute and curved inward. Valva elongate, slender, slightly expanded basally, narrow to 3/4 of its length, moderately dilated, and lobate with fine, dense hairs on its inner surface apically, moderately curved inwardly, exceeded apex of tegumen. Vinculum narrow, bearing a few rather long spines on median process of vinculum. Saccus broad basally and U-shaped. Phallus long, small, and spherical at base, and extended distally.
Female genitalia: (Fig. 10B) papillae anales nearly half the length of the apophysis posterioris, with two lobes and long and short fine setae on its entire surface. Apophysis posterioris as much as three times the length of apophysis anterioris. Ostium opening near posterior margin of 8 th sternite. Ductus bursae narrow, nearly equal in length to corpus bursae and moderately sclerotized. Ductus seminalis arising from the posterior third of ductus bursae. Corpus bursae oblong; signum long and a narrow arch shaped at left side wall of posterior end.
Distribution. Japan (Hokkaido, Honshu), Russia, Korea. Host plant. Quercus dentata (Kogi 2008), Q. mongolica (Fagaceae) (new host record). Biology. Kogi (2008) reported that the larvae of T. angustella occur in August until the following June and make a portable case with fragments of a host plant leaf. The mature larvae use a larger piece of leaf like a hat. Dr. T. Oku collected a case from Q. mongolica in Iwate Prefecture in July. (Omelko, 1984)  Diagnosis. The forewing is white with a small orange patch and a black rounded spot apically. The anellus lobe of the male genitalia is narrow, slender, and longer than the valva, with a sharp and thorn-like spine at the apex, which is a unique characteristic of this species. The apopyhsis posterioris of the female genitalia is ca. 1/3 of the length of papilla analis and approx. half the length of the apophysis anterioris; the signum is absent in the corpus bursae.
Head: shiny, creamy white with appressed scales. Antennae filiform, basal segment elongate and white; flagellum whitish brown on dorsal surface before middle, then entirely grayish brown beyond, with rather long and fine cilia ventrally. Labial palpus white, long, and recurved; first segment shortest, creamy white; second segment thickened, as much as 2.5 times the length of the first, covered evenly with creamy white scales; third segment as long as second, creamy white, apex sharply acute.
Thorax and tegula: creamy white. Legs: white; forefemur, tibia, and tarsus suffused inwardly with dark brown, white on outer surface; mid legs entirely white; hind femur and tibia white, dispersed inwardly with brown; with compact ventral and dorsal rows of long, stiff, stout white bristles; all tarsal segments grayish brown.
Forewing: eleven veins, R 3 + R 4 stalked, M 1 separate, R 5 absent, anal vein furcate (Fig. 7C). Forewing ground color creamy white to white to ca. 3/4 of the way from base, large orange patch of more or less inverted triangular shape along costal margin, extending to apex of wing; large round black spot apically, bordered by a white line with an orange patch; outer margin blackish brown; small brown scales below api-cal point; diffused brown scales below orange patch at tornal area; cilia well-fringed, brown-white on costal margin before apex, dark brown with fuscous median band from apex to termen, grayish brown through inner base of the wing.
Hindwing: narrower than forewing, brown with tiny dark brown apical dot; fringe around apex darker in color, long, and brown, cilia well-fringed on inner region of hind wing.
Male genitalia: (Figs 8E, F, 9C) eight abdominal sternite mucronate, short and wide surfaces, anterior 2/3 broadly concave, and then narrow beyond, slightly sharpened basally. Uncus swollen and rounded with short, fine setae on apex. Gnathos sickle-shaped, short and stout, flattened at base posteriorly and then slightly curved toward apex. Tegumen long, nearly three times length of uncus, with dense hairs at approximately its midpoint on dorsal surface. Anellus lobe, a pair of slender processes, slightly longer than valva, slightly broadened and elbowed basally, then narrowly elongate and slightly swollen 1/4 of the way before apex, with rather long and weakly sclerotized thorn-like spine at tip. Valva enlarged at base, with long fine setae on rim of inner surface, gradually narrowing from base to 2/3 of length, slightly curved inwardly, a few setae at corner of anterior margin, rhomboid with a blunt tip apically, short and fine setae on inner and outer surfaces. Vinculum slightly narrow and enlarged surface, a few setae on its median process. Saccus broad basally, somewhat inflate and convex. Phallus large and clavate basally, narrowly elongate in distal half.
Female genitalia: (Fig. 10C) papilla analis bilobed, ca. twice length of apophysis anterioris, with long and short fine setae on its entire surface. Apophyses short but apophysis anterioris ca. two times longer than apophysis posterioris. Ostium opening near anterior margin of 8 th sternite. Ductus bursae nearly as long as corpus bursae and weakly sclerotized. Corpus bursae slightly oblong; signum absent.
Distribution. Japan (Hokkaido, Honshu, Kyushu), Russia, Korea. Host plant. Quercus dentata (Kogi 2004), Q. crispula (Fagaceae) (new host record). Biology. Kogi (2004) reported that adults of this species fly in July in Hokkaido and larvae live in portable cases in summer until the following spring. In late fall, the larvae move to the underside of twigs of the host plant for hibernation. The next spring, the larvae create triangular cases like hats with fragments of host plant leaves and skeletonize the leaves.   Diagnosis. This species is similar to T. biformis, which is known in the Russian Far East and Japan but can be distinguished by markings in the distal yellow zone of the forewing with a distinct black streak below the middle of the yellow zone. The male genitalia is similar to those of T. epiclista Meyrick, 1908 described from Khasi Hills, India, but can be distinguished by the basally broadened valva and the presence of a thumb-like basal process bearing numerous setae, the lack of a pre-apical spine on the costal process of the valva, and the slender posterior part of the phallus.
Female genitalia: (Fig. 10D) see Park and Kim (2016) for detailed descriptions of the adults and genitalia. In the present study, intraspecific variation observed was the presence or absence of a blackish streak on the yellowish zone of the forewing markings in all examined specimens. Additionally, in contrast, the biggest size of the adult moth of Japanese specimens (wing span 8.8 mm) is quite smaller than that of Korean specimens (wing span 12 mm in Park and Kim's description). In the female genitalia also, Park and Kim described the shape of the signum forming as an elongate plate with dense spicules and located at posterior end; however, that of the Japanese specimens is developing as a pentagonal shape at the posterior end in our observation.
Distribution. Japan (Honshu, Shikoku, Kyushu, Ryukyus), Korea. Host plant. Mallotus japonica (Euphorbiaceae). Biology (Fig. 11). Although the host plant of T. chujaensis is unknown, we found that some specimens of this species preserved in OPU were labeled as having been reared on Mallotus japonica (Euphorbiaceae). In the present study, we confirmed that the larvae feed on this plant in the field. The larvae also make portable cases with flower buds or attack the leaf bud (young shoot) of the host plant. The larva uses the flower buds at flowering time to make a case from the plant. After making the portable case, the larva moves from one place to another and attaches the case to the lower surface of the leaf for pupation (Fig. 11C). When there is an early leaf bud (young shoot) on the host plant, the larva penetrates the petiole of the young, newly emerged leaf and feeds inside (Fig. 11E-G). There is no external injury during the feeding period until the leaf is fully grown. Before pupation, the larva cuts the petiole and makes a portable case. After that, it fixes the portable case sideways. Pupation also takes place inside the cases and pupal exuvia is left after the adult emerges.
Pupa (Figs 13A-C, 14A-D). Length ca. 3.2 mm, cylindrical. Color yellowish brown; dark brown before emergence. Vertex armed with many minute spines. Prothorax with a pair of not truly triangular projections on anterolateral corners of tergite. Antenna reaching to posterior margin of 6 th abdominal segment. Forewing reaching the mid-way of 6 th abdominal segment. Forelegs extending to 3 rd abdominal segment; midlegs extending to mid-way of 5 th abdominal segment; hindlegs also extending to near posterior margin of 7 th abdominal segment. Abdominal segment 7 th armed with a row of distinct tergal spines directed posteriorly on anterior margin and indistinct short tergal spines on caudal margin. Seventh abdominal sternite with a pair of oval pads also armed with a row of spines directed anteriorly.
Tenth abdominal segment with a pair of triangular projections at middle, no true cremaster present.
Remarks. This species was described by Park (in Park and Kim 2016) from Chuja Islands which is one of the largest islands among 42 islands in the Jeju Strait, approximately halfway between Jeju Island and the southern coast of the Korean Peninsula. In the present study, it was found that this species is very common and widely distributed in southern Japan. Diagnosis. At a glance, the external features are similar to those of T. chujaensis (Park, 2016) comb. nov. but it can be distinguished by wing markings in the distal yellow zone of the forewing, which lacks a distinct blackish streak below the middle of the yellow zone and features grayish scales at the costal margin before the apex and the area beyond the tornus. Additionally, it can easily be distinguished based on the male genitalia; the uncus is more rounded apically; the gnathos is U-shaped and acute apically; the valva is narrowly elongate with a sharped pre-apical process ca. 1/4 of the way along its length and the vinculum lacks thumb-like lobes posteriorly; the saccus has a rounded base. The shape of the phallus is also different. However, the male genitalia are similar to those of Thiotricha clidias Meyrick, 1918, which was described from Khasi Hills, India, although they differ in the shape of the phallus. In T. clidias Meyrick, 1918, the phallus is rounded basally, abruptly sinuate and slender in distally but as a cucurbit-shaped in T. elaeocarpiella sp. nov.
Head: shiny creamy white with appressed scales. Antennae filiform, basal segment elongate and creamy white, sparsely speckled with brown scales; flagellum grayish white on dorsal surface before midpoint, then brownish gray beyond on its dorsal and ventral surfaces, with extraordinarily long and fine cilia ventrally. Labial palpus white, moderately long and recurved; first segment approximately half the length of the second, with blackish gray scales on lateral surface; second segment as much as 1.5 times the length of the first, creamy white throughout on outer surface; bundle of hair pencils arising from apex of first and second segment, appressed on dorsal surface to near the end of the third segment; third segment as thick as second, with blackish gray scales medially on lower surface ventrally, shiny creamy white evenly on both surfaces, apex sharply acute (Fig. 6A).  Thorax: creamy white. Tegula shiny, creamy white dorsally, ornamented with blackish gray scales along anterior margin.
Legs: white; forefemur, tibia, and tarsus suffused inwardly with blackish brown; scattered with white scales on outer surface; mid femur entirely white; mid tibia and tarsus white but slightly speckled with blackish brown scales on outer surface; hind femur white; hind tibia creamy white, with a row of long, stiff, stout, creamy white bristles above and below, suffused with a small blackish gray scale on lateral outer surface posteriorly; first tarsal segment entirely blackish gray; second and third segment white with blackish gray apical ring; last two segments white.
Forewing: eleven veins, R 4 + M 1 stalked, R 5 absent, anal vein furcate (Fig. 7E). Forewing ground color shiny grayish white to white to ca. 3/4 of the way from base; distinct orange zone in distal 1/4, deeply concave along costal margin; costal margin and area beyond tornus grayish colored; small black spot at apex, narrowly connected to another black spot in tornus; cilia before apex to tornus brown, creamy yellow from tornus to inner base of wing.
Hindwing: narrower than forewing, creamy white to grayish white, with pale orange apical zone; apex sharply produced, with small apical black spot; cilia well-fringed to base, fringe around apex creamy white, with broad, dark brown median band.
Male genitalia: (Figs 8I, J, 9E) eighth abdominal sternite more or less triangular, emarginate at the tip, slightly broadened basally with moderately sclerotized margin anteriorly, gradually narrow toward apex. Uncus directed backwards, with broad basal expansion, then narrowly elongate, forming a furrow on lower surface medially, bearing short spines on its lateral margin and abruptly rounded with short and fine setae evenly on its apical dorsal surface. Gnathos U-shaped, stout, strongly bent at basal 1/3, sharply acute apically. Tegumen longer than uncus, slightly concave medially on lateral margins with dense hairs on dorsal surface beyond middle. Anellus lobe, a large process, as much as 1/2 the length of process of valva, ovate membranous pouch at base, with short sclerotized apical spine and short fine setae around apical spine. Valva slender, elongate, broad basally, narrow along 2/3 of length, then dilated apically with dense, long, fine hairs hanging down from its inner surface and developing a sclerotized point, spine-like pre-apical process arising from its base, nearly 1/4 of apex. Vinculum long and slightly narrow, with few rather long setae on its lateral margin. Saccus roundly produced basally. Phallus cucurbit-shaped in basal half, slightly sinuate, slender and recurved upwardly in distal half.
Female (Figs 5B, 6B). Forewing length 2.5-3.3 mm. Wing expanse 5.3-7.1 mm. Similar to male but differs as follows: Labial palps of first segment shortest, with creamy white scales, as thick as second segment; second segment as long as third segment and with white scales on lower surface and grayish or grayish brown scales on upper surface; third segment slender and acute with gray to grayish-brown scales on both surfaces (Fig. 2B) Female genitalia: (Fig. 10E) papillae anales with long and short fine setae on its entire surface. Apophysis posterioris longer than apophysis anterioris; apophysis anterioris ca. 1/3 the length of posterioris. Ductus bursae rather long, narrow, slightly sclerotized along the posterior half of its length. Corpus bursae clavate in shape; signum rounded at center.

Distribution. Japan (Kyushu, Ryukyus).
Etymology. The name refers to its main host plant, Elaeocarpus zollingeri. Host plant. Elaeocarpus zollingeri (Elaeocarpaceae), Rhaphiolepis indica (Rosaceae). Biology (Fig. 12). The larva uses the flower bud or the young shoot of its host plant to construct portable cases. When it utilizes a flower bud, at first, the larva penetrates the bud and then lives and feeds within it. After that, it moves from one flower to another by carrying the bud and attaching it to other flower buds to complete its life cycle (Fig. 12D, E). When the larva is ready to pupate, it attaches the case to the underside of a leaf with silk. When it utilizes a young shoot (Fig. 12C), the larva leaves small dot-like traces of feeding after making cases by the shoot. Pupation also takes place inside the portable cases. After completing development, the adult emerges from the case, leaving the pupal exuvia inside.
Pupa (Figs 13D-F, 14A-D). Length ca. 3.2 mm, cylindrical. Color yellowish brown. Vertex armed with many minute spines. Prothorax with a pair of triangular projections on anterolateral corners of tergite. Antenna and forewing reaching to pos-  terior margin of 6 th abdominal segment. Forelegs extending to 3 rd abdominal segment; midlegs reaching to mid-way of 5 th abdominal segment; hindlegs also extending to just beyond the anterior margin of 7 th abdominal segment. Seventh abdominal segment armed with a row of distinct tergal spines directed posteriorly on anterior margin and indistinct short tergal spines on caudal margin. Seventh abdominal sternite with a pair of oval pads also armed with a row of spines directed anteriorly. Tenth abdominal segment with a pair of triangular projections at middle, no true cremaster present.
Remarks. Although this new species was found on two different plants in the present study, it may be that E. zollingeri is mainly utilized as the host plant and occasional feeding on R. indica occurs when individuals happen to come into contact with this plant. See discussion. Diagnosis. The external morphological character of this new species is quite similar to that of T. angustella; the wings of both species are shaded brown apically. However, the two can be differentiated based on the brightness of the color of the apical wing markings. In the new species, the wings feature a huge dark brown area distally, so it can be recognized easily at a glance. Likewise, in the male genitalia, the anellus lobe is a small membranous spherical lobe basally with a delicate, thread-like spine apically. Also, the size of apophyses and shape of the signum in the female genitalia are different to those of T. angustella. On the other hand, the male genitalia are quite similar to those of Thiotricha xanthodora Meyrick, 1923, which was described from Pyinmana, Myanmar, but differ in terms of the uniformly elongate valva, spherical-shaped and straight phallus. In T. xanthodora, the shape of the valva is dilated along 1/3 of its length apically whereas the phallus is slightly rounded basally and twisted forward.

Thiotricha flavitermina
Description. Male (Figs 5C,E,7F). Forewing length 3.3 mm in holotype, 2.5-3.2 mm in paratypes. Wing span 6.2 mm in holotype, 5.6-6.9 mm in paratypes Head: shiny creamy white with appressed scales. Antennae filiform, basal segment rather large and elongate, white, sparsely speckled with brown scales on dorsal surface; flagellum creamy white on dorsal surface before middle, then entirely grayish brown beyond on both surfaces with extraordinarily long and fine cilia ventrally. Labial palps white, long, and recurved; first segment shortest, creamy white with brown scales medially on outer surface; second segment thickened with white scales evenly on both surfaces, as much as 2.5 times the length of the first; third segment as long as second segment, entirely grayish brown, considerably acute and slender.
Thorax and tegula: creamy white. Legs: white; forefemur and tibia inwardly suffused with brown and white on outer surface; fore tarsus completely brown; mid femur and tibia entirely white; mid tarsus with brown; hind femur and tibia creamy white, with long, stiff, white bristles until the midpoint anteriorly, brown bristles on upper surface at ca. 1/4 beyond half of its length posteriorly, with white bristles ventrally; all tarsal segments dark grayish in color.
Forewing: eleven veins, R 3 + R 4 stalked, M 1 separate, R 5 absent, anal veins furcate. (Fig. 7F). Forewing rather broad, rounded and slightly pointed apically, ground color creamy white from base along 2/3 of wing, significantly occupied with a huge dark brown or pale-yellow area along costal margin to apex at ca. 1/3 apically; cilia well-fringed and dark brown or yellowish brown before apex to inner base of wing.
Hindwing: narrower than forewing, brownish white, pale brown; cilia well-fringed around apex and then white to anterior rim of base.
Male genitalia: (Figs 8K, L, 9F) eighth abdominal sternite obtuse, slightly emarginate at the tip, short, and broadened from base toward apex. Uncus swollen and rather small, like a tubercle, with long and short fine setae on its dorsal surface. Gnathos short and stout, slightly flattened posteriorly, then moderately curved apically. Tegumen extremely long and larger than uncus, with a cluster of dense hairs at approximately its midpoint dorsally. Anellus lobe, a small membranous rounded lobe basally, bearing a flexible and weakly sclerotized thread-like spine, reaching toward nearly 2/3 of valva, slightly curved inwardly, a few spines arising around it. Valva simple, uniformly elongate, broad basally, narrowly elongate from base toward apex, with numerous long fine hairs on its ventral surface. Vinculum narrow and elongate, with long and short fine hairs on rim of its surface posteriorly. Saccus somewhat rounded   and triangular in shape. Phallus spherical basally, becoming narrow and straight, then slender in distal half.
Female genitalia: (Fig. 10F) papillae anales nearly equal in length to posterior apophysis, with long and short fine setae on its entire surface. Apophysis posterioris longer and apophysis anterioris nearly half the length of posterior. Ostium opening close to anterior margin of 8 th sternite. Ductus bursae rather broad, uniformly elongate, nearly same length as corpus bursae. Ductus seminalis arising ca. 1/3 of posterior of ductus bursae. Corpus bursae oblong in shape with narrow; signum short and archshaped at left side wall of posterior end.
Distribution. Japan (Ryukyus). Etymology. The name refers to the coloration of the forewing (yellow apically). Host plant. Unknown.
Remarks. There are two alternative types of wing markings at the distal portion: the brown form collected from Okinawa-jima Island, and the yellow ones from Amami-oshima Island. As mentioned above, individuals with these wing color variations were separately collected from these two islands in the same season. Therefore, this difference may be due to geographical variation. In addition, we studied the pupal morphology, and found that characters of T. chujaensis and T. elaeocarpiella were congruent with those of T. prunifolivora as described by Ueda and Fujiwara (2005). However, we point out here that Ueda and Fujiwara (2005) erroneously described that tergal spines are present on the 6 th and 7 th abdominal segments of the pupa of T. prunifolivora. In contrast, these spines are exactly on the caudal and anterior margins of 7 th abdominal segment. This condition was also detected in T. pancratiastis Meyrick, 1921 andT. trapezoidella (Caradja, 1920) in our observations (Kyaw et al. unpubl. data 2019). Although the pupal morphology of T. angustella and T. venustalis could not be studied, their pupae may also possess such spines which may assist in protrusion of the pupa from their cases; both species were reported to be case bearers (Kogi 2004(Kogi , 2008. Based on the reasoning above, we conclude that Japanese species of Cnaphostola should be treated in the genus Thiotricha, because they share morphological characters of the antenna, labial palps, wing venation and the anellus lobe in the male genitalia with the type species Thiotricha thorybodes Meyrick, 1886 and with some other species in that genus (Table 1).
On the other hand, species of Thiotricha are also similar to those of Polyhymno. Ueda and Fujiwara (2005) noted a difference in forewing venation: R 5 is present (5 radial veins are present) in the type species of Polyhymno, whereas R 5 is absent (4 radial veins are present) in the type species of Thiotricha. Therefore, it may be appropriate that all species previously treated as Cnaphostola should be combined in Thiotricha, having 4 radial veins. According to Karsholt et al. (2013), the type species of Polyhymno have posteriorly non-bifurcated sternum VIII, a simple valva with reduced anellus lobe, and shorter ciliae on the male antennae. However, we observed that these characters are also shared by some Thiotricha species. For example, the sternum VIII is not bifurcate in some Thiotricha species, e.g., T. prunifolivora, T. pancratiastis, T. pontifera, T. indistincta  Omelko, 1993, T. celata Omelko, 1993, T. attenuata, and T. synodonta Meyrick, 1936. Therefore, reexamination of the diagnostic characters of these genera is necessary.
In the present study, although we could not find any definite diagnostic character for separating each genus, we confirmed that the presence of anellus lobe in the male genitalia would provide one of the possible characters for Thiotricha which is also shared by all examined species. Furthermore, the pupal morphological characters also support the genus Thiotricha. In future studies, a molecular analysis would hopefully clarify the phylogenetic relationships between genera and species and solve the taxonomic problems of the generic delimitation.

Host utilization and feeding habits of larva
Although Thiotrichinae are known to utilize plants of ten families (all in eurosids), the host range of each species is usually restricted to one genus or a few related genera (Kuroko 1957;Sattler 1982;Huemer 1993;Omelko 1993;Oku 2003;Ueda and Fujiwara 2005;Kaiser et al. 2008;Fujita et al. 2009;Ueda 2011Ueda , 2013. Therefore, the host utilization of Thiotricha elaeocarpiella is unusual for this subfamily. In the present study we observed T. elaeocarpiella larvae making portable cases on two different unrelated host plants, Elaeocarpus zollingeri (Elaeocarpaceae) and Rhaphiolepis indica (Rosaceae), in Okinawa-jima Island and Kyushu. First, we discovered that this species made portable cases with parts of R. indica in May 2017 in Fukuoka, Kyushu (Fig. 12C). In the same place in July and August 2017, where E. zollingeri grew next to R. indica, we also found many differently shaped portable cases made of the flower buds of E. zollingeri (N = 14) and some portable cases made of R. indica under the leaves of R. indica (N = 2). Secondly, on Okinawa-jima Island, we found many portable cases on E. zollingeri in August 2017. Although most of the flower buds were already blooming, we found a certain number (N > 20) of portable cases attached to flower buds, most with pupal exuviae inside. We consider E. zollingeri to be the main host plant of this species because a great number of portable cases were found on E. zollingeri in Kyushu and Okinawa-jima Island.
However, whether the larvae of T. elaeocarpiella consumed both plants or accidentally shifted host plants is a controversial matter. Based on shape, the portable case found in May seems to be made of a young shoot of R. indica, and we also observed some holes on the leaf near the portable case. These holes are similar to the feeding trace made by T. prunifolivora, and the larvae of T. elaeocarpiella actually feed on the leaf of R. indica. Therefore, we concluded that this species can utilize both of these two plants. In T. chujaensis, we found that the larva penetrates the leaf bud (young shoot) of the host plant and then enters entirely and feeds inside (Fig. 11E-G). The last instar larva uses the petiole of the young leaf as a portable case before pupation. Additionally, the larva uses the flower bud at flowering time and makes a portable case on the plant (Fig. 11C, D). After making the portable case, the larva moves and attaches it to the lower surface of a leaf until pupation. Some Thiotricha species showing similar larval feeding habits have been identified. Ueda and Fujiwara (2005) reported that T. prunifolivora has three generations per year, and the larvae of each generation have different feeding habits and make a different type of portable case. In the overwintering generation, the hatched larva penetrates the flower bud of the host plant, Symplocos prunifolia (Symplocaceae), then uses it as a portable case and attaches the case to the apex of another flower bud with silk. In the first generation, the larva bores into the developing seed and uses it as a portable case, usually accumulating five developing seeds before pupation. In the second generation, the larva bores into the developing seed at first, then after feeding on (usually) two developing seeds, the larva moves to the underside of the host plant and makes several circular holes by feeding. Another species, T. pancratiastis, known as a foliage feeder (leaf miner) of Morella rubra (Myricaceae), is also reported as a seed predator; the larvae of this species bore into the fruit and, after hollowing it out, utilize it as a portable case. This species probably has two generations annually in Honshu and more in the Ryukyus (Fujita et al. 2009;Ueda 2011Ueda , 2013as Polyhymno pancratiastis).
In T. elaeocarpiella, T. chujaensis, T. prunifolivora, and T. pancratiastis, the larval feeding mode and behavior are different among generations. These species occur in Honshu, Kyushu, and Ryukyus, have more than two generations a year, and utilize different parts of host plants that grow in temperate climates. On the other hand, T. venustalis, T. angustella, and some species of Thiotricha in the cool climate of the East Palearctic have one generation a year and one mode of feeding (Omelko 1993;Oku 2003;Ueda 2013).
Hence, we presume that the larval feeding mode in Thiotricha usually involves the creation of portable cases on host plants, whereas the larvae of Polyhymno are leafspinners and leaf-webbers ). There are some exceptions, such as T. trapezoidella and T. indistincta; the larvae of T. trapezoidella bore into the petiole of Juglandaceae and do not make a portable case (Oku 2003;Ueda 2011Ueda , 2013, and T. indistincta is a leaf-webber in Carpinus spp. (Betulaceae) (Omelko 1993;Oku 2003). In T. trapezoidella, however, we confirmed that the larvae make a portable case by cutting the surface of the leaf transversely around the upper tip of the leaf and folding it as a case when the larva is nearly grown to the late instar (Kyaw et al. unpubl. data, 2019). This shows that it is necessary to reinvestigate the larval feeding mode of Thiotricha and Polyhymno species in detail.
From the results of our taxonomic study together with an exploration of the biology of these species, the evolution of host plant utilization can be elucidated based on species relationships in this genus and its relatives. In future studies, it will be necessary to clarify the biology and DNA sequences of most species. Tosio Oku (Morioka, Iwate), Takahiro Mano (Toyota, Aichi), Hajimu Shimizu (Fujiidera, Osaka), Kota Sakagami (Graduate School of Agricultural Science, Kobe University), Shunsuke Tomura (ELKU), Shin-ichi Sameshima (Oshima-gun, Kagoshima) for providing specimens used in this study. We are indebted to Satoshi Kamitani (ELKU), Toshiharu Mita (ELKU), and Munetoshi Maruyama (Kyushu University Museum) for giving some advice on our study. We also thank Erik J. van Nieukerken, Mark Metz and Oleksiy V. Bidzilya for improving the manuscript as an editor and reviewers. Finally, we would like to say thanks to all the laboratory members for their kind support throughout our study. This research was supported by JSPS KAKENHI Grant Number JP16H05766. This is a contribution from the Entomological Laboratory, Kyushu University, Fukuoka (Ser. 7,No. 66).