Superficially, adults of Syntozyga are similar to many species of Olethreutini, especially members of the subtribe Olethreutae, but they lack secondary sexual structures on the wing and legs in the male, that makes it easy to identify them from Olethreutae. In the male genitalia, Syntozyga is readily separated from most genera of Olethreutini by the absence of an uncus and by strongly reduced socii. In the Olethreutinae, reduction of the appendages of the tegumen is also found in the tribe Grapholitini, but their valvae are extremely simple in structure and evenly spined. In contrast, Syntozyga is characterized by a valva with a broad sacculus projecting distally and carrying varied vestiture such as spine clusters and strong bristles or thorns; sometimes a naked lobe (or two) is present between the cucullus and the apex of sacculus (S. cerchnograpta Razowski, 2014, S. triangulana Aarvik, 2008, S. spirographa, S. similispirographa sp. nov., and S. apicispinata sp. nov.). Detailed descriptions of the morphology of Syntozyga were provided by Diakonoff (1968, 1973) and Horak (2006).

China, Hainan Prov.: 1♂, Datian Reserve, 19°06'N, 108°47'E, alt. 25 m, 1 Jul. 2009, leg. Zhaohui Du and Linlin Yang.

India, Indonesia, Thailand, Malaysia, China (Hainan).

This species is newly recorded for China. The male genitalia accord well with those of the lectotype of Eucosma familiaris from Java figured by Diakonoff (1973).

Holotype: China, Tibet: Motuo County, Bengbeixiang, 29°24'N, 95°17'E, alt. 990 m, 12 Aug. 2017, leg. Mujie Qi and Xiaofei Yang, genitalia slide no. YWX18246. Paratypes: China, Tibet: 6♂, same data as holotype; 2♂, same data as holotype except 29°25'N, 95°18'E, alt. 810 m, 15 Aug. 2017; 3♂; same data as holotype except alt. 750 m, 31 Jul.–1 Aug. 2018, leg. Mujie Qi; Yunnan Prov.: 1♂, Xishuangbanna, Guanping, 22°46'N, 100°59'E, alt. 1200 m, 18 Aug. 2005, leg. Yingdang Ren; 1♂, Xishuangbanna, Yexianggu, 22°10'N, 100°52'E, alt. 760 m, 11 Jul. 2015, leg. Kaijian Teng and Xia Bai; 1♂, Mengla, Bubeng, 21°36'N, 101°35'E, alt. 650 m, 31 Jul. 2020, leg. Yongyan Li and Wenxu Yang.

TORTR001-20, TORTR008-20, TORTR009-20, TORTR010-20, TORTR011-20.

Externally, S. apicispinata is similar to S. spirographa (Diakonoff, 1968) and S. similispirographa, but the relatively paler striae derived from the costal strigulae and the brown or pale brown hindwing can be used to separate it from the latter two species. The male genitalia of S. apicispinata are very different from those of S. spirographa and S. similispirographa. It can be best distinguished by a distally broad, ovate valva, a finger-like prominence on costa, the absence of a cluster of long spines on apex of sacculus, the presence of a cluster of short spines below apex of cucullus and a stout phallus with minute cornuti apically. Within the genus, this species resembles S. episema (Diakonoff, 1973) from Java and Sumba in the male genitalia, but it can be separated from S. episema by the valva with its ventral edge not concave in the middle and without long thorns, a sacculus with a sharp, triangular prominence on ventral margin of basal excavation, and a cucullus bearing a cluster of short spines below apex. In S. episema, the ventral edge of the valva is concave medially and is densely set with several long thorns, there is no prominence on the ventral margin of the basal excavation and the apical part of cucullus has no prominent spine clusters. Syntozyga apicispinata also resembles S. negligens (Diakonoff, 1973) from Java and Sulawesi in the male genitalia, but it can be distinguished from the latter species by the valva with its apical part broader than its basal part and having a sharp triangular prominence on the ventral margin of the basal excavation. In S. negligens, the apical part of the valva is narrower than its basal part, and there is no projection from the ventral margin of the basal excavation.

Male (Fig. 6). Forewing length 5.5–6.5 mm. Head (Fig. 2): ocellus well developed; chaetosemata present. Frons smooth, creamy white; vertex roughly scaled, creamy. Antenna with scape creamy, flagellum dark brown, dusted with pale brown distally. Labial palpus porrect, creamy suffused with pale brown, median segment expanded slightly, terminal segment 1/2 times of median segment in length, brown apically.

Thorax: creamy, dusted with brown and dark brown medially; posterior crest distinct. Collar creamy. Tegula dark brown basally and creamy suffused pale brownish yellow distally. Hind tibia not expanded, without hair pencil in male. Forewing elongate subrectangular, costa evenly arched, apex blunt, termen oblique; upperside general ground color creamy, with markings dark brown and dusted with pale brownish yellow; costal strigulae creamy white, the fifth and sixth pairs suffused with gray brown; basal fascia broken into two parts, a small blotch on costa and an obliquely arched streak extending to inner margin of wing; subbasal fascia consisting of three parts, an oblique blotch on costa, an irregular blotch between upper edge of cell and 1A+2A, and an indistinct spot or shadow on base of dorsum; a discontinuous pale streak present between pairs of strigulae three and four, extending to dorsum; media fascia broken medially, anterior half fused with costal part of postmedian fascia forming a conspicuous subtriangular patch on costa, extending to midwing, lower part present between midwing and distal half of dorsum, indistinct and intricate, confluent with the surrounding spots and pretornal patch; postmedian fascia obliquely arched, indistinct between 2/3 length of R₂ and midlength of R₅, lower part elongate, extending to termen between M₂ and CuA₁; a short line present on costa between strigulae seven and eight; preterminal fascia and terminal fascia as two elongate streaks confluent to termen; cilia pale brown fixed with dark brown and creamy; underside yellowish brown to brown. Hindwing subtriangular, brown; cilia pale brown; underside pale brown.

Abdomen: male genitalia (Fig. 10): tegumen low, with ear-like shoulders laterally and a moderately broad, rounded triangular top with some hairs; vinculum a sclerotized band, strong, somewhat W-shaped; uncus absent; socii strongly vestigial, indicated by a narrow patch of sparse spines on ventrodistal margin of tegumen; gnathos a weakly sclerotized band; valva broad, oval, costa with a folded ridge from the base to the apex, a short finger-like prominence protruding from the middle of the ridge bearing long thorns basally and apically, basal excavation large, sacculus narrow with three sclerotized, naked lobes (Fig. 10a): one small subtriangular sitting on the ventral margin of the basal excavation medially, the other two large, rounded, occupying the distal half of the sacculus, positioned right next to each other, the inner one with its edge smooth, the outer one with its edge serrated; a patch of thin, short bristles present beyond the basal excavation; cucullus membranous, roughly as long as basal part of valva, broadly rounded, with bristles along margin, a short conspicuous lobe proximal to apical margin, carrying a dense cluster of spines; phallus short and stout, with tiny spiny cornuti apically (Fig. 10b).

Female unknown.

The specific name is derived from the Latin prefix apici- (= apical) and the adjective spinatus (= spiny), indicating the apical spine cluster of the valva.

China, Chongqing: 2♂, Mt. Jinfo, 29°02'N, 107°11'E, alt. 1100 m, 5 May 2013, leg. Xiaofei Yang; Fujian Prov.: 1♀, Xiamen, 24°35'N, 117°55'E, alt. 40 m, 11 Jul. 2010, leg. Bingbing Hu and Jing Zhang; 1♀, same data except 28 Jun. 2012, leg. Zhibo Wang; Guangxi Prov.: 4♂, Yizhou, Pingxin village, 24°40'N, 108°21'E, alt. 150 m, 16 Aug. 2011, leg. Shulian Hao and Yinghui Sun; 8♂, 1♀, Pingxiang, 22°01'N, 106°51'E, alt. 190 m, 300 m, 550 m, 26 Jun.–2 Aug. 2011, leg. Bingbing Hu; 1♂, same data except alt. 280 m, 15 May 2012, leg. Xiaofei Yang; 1♂, same data except 23 Mar. 2013; Guizhou Prov.: 1♂, Libo, Banzhai village, 25°13'N, 108°10'E, alt. 530 m, 9 Aug. 2018, leg. Meiling Zheng, Jiaqi Deng and Xiaoju Zhu; 1♂, same data except alt. 510 m, 24 Jul 2019, leg. Mengran Xing, Baixue Zhao and Hao Sun; Hainan Prov.: 1♂, Lingao County, Mt. Duowenling, 19°47'N, 109°45'E, alt. 120 m, 9 May 2009, leg. Bingbing Hu and Qing Jin; 2♂, Lingshui, Mt. Diaoluo, 18°39'N, 109°56'E, alt. 80 m, 21–22 Apr. 2013, leg. Yinghui Sun, Wei Guan and Tengteng Liu; 1♂, Changjiang County, Qichazhen, 19°6'N, 109°4'E, alt. 130 m, 4 May 2013, leg. Yinghui Sun, Wei Guan and Tengteng Liu; 1♂, Baisha County, Hongxin village, 19°40'N, 109°31'E, alt. 460 m, 1 Jul. 2014, leg. Peixin Cong, Linjie Liu and Sha Hu; 1♂, Ledong, Jianfengzhen, 18°41'N, 108°46'E, alt. 50 m, 12 Jul. 2014, leg. Peixin Cong, Linjie Liu and Sha Hu; 1♂, Dongfang, Datian village, 19°3'N, 108°50'E, alt. 120 m, 2 Jan. 2018, leg. Mujie Qi and Shuai Yu; 1♂, Dongfang, Lemei village, 19°8'N, 108°84'E, alt. 80 m, 3 Jan. 2018, leg. Mujie Qi and Shuai Yu; Yunnan Prov.: 3♂, 1♀, Mengla, River Nanla, 21°59'N, 101°58'E, alt. 650 m, 12–14 Jul. 2013, leg. Shurong Liu, Yuqi Wang and Kaijian Teng.

TORTR003-20, TORTR004-20, TORTR005-20, TORTR006-20.

Philippines, Indonesia, China (Chongqing, Fujian, Guangxi, Guizhou, Hainan, Yunnan, Taiwan).

In China, previously Taiwan was the only area where S. spirographa had been collected (Heppner and Inoue 1992). In the present study, we identified this species from six provinces of the Chinese mainland for the first time, with a distribution to the south of latitude 30°N and between longitudes 100°E and 118°E.

Holotype: China, Yunnan Prov.: 1♂, Longling, Xiaoheishan Reserve, 24°52'N, 98°84'E, alt. 1970 m, 30 Jul. 2015, leg. Kaijian Teng and Baixia, genitalia slide no. YWX18337. Paratypes: China, Yunnan Prov.: 3♂, same data as holotype except 17–19 Jul. 2013, leg. Shurong Liu, Yuqi Wang and Kaijian Teng; 1♂, Pu’er, Mt. Yunpan, 22°41'N, 100°39'E, alt. 1400 m, 9 Jul. 2013, leg. Zhenguo Zhang; 1♂, same data except alt. 1620 m, 6 Aug. 2020, leg. Wenxu Yang; 1♂, Pu’er, Sun River Reserve, 22°35'N, 101°06'E, alt. 1600 m, 11 Jul. 2013, leg. Zhenguo Zhang; 16♂, same data except alt. 1450 m, 13 May–3 Jun. 2014; 8♂, 2♀, Pu’er, Sun River Reserve, 22°60'N, 101°11'E, alt. 1630 m, 6–7 Jul. 2013, leg. Shurong Liu, Yuqi Wang and Kaijian Teng; 1♂, Pu’er, Sun River Reserve, 22°68'N, 101°03'E, alt. 1450 m, 6 Jul. 2015, leg. Kaijian Teng; 1♀, Jingdong, 22°60'N, 101°11'E, 18 Aug. 2009, leg. Xicui Du.

TORTR002-20, TORTR007-20.

Syntozyga similispirographa is very similar to S. spirographa in external appearance. The shape of the hindwing termen is the only stable superficial character to identify the two species, it is concave at M₂ in S. similispirographa and straight in S. spirographa. However, the genitalia in both sexes are distinct. In S. similispirographa, the apical part of the cucullus is obviously narrow, less than half the width of the median part of the valva; the basal excavation is short, reaching only to mid length of sacculus; the naked triangular lobe is adjacent to the spine patch of cucullus, its base is distant from the cluster of long spines of sacculus; the phallus is moderately wide, with its width at middle about 1/5 its length. In S. spirographa, the apical part of cucullus is rounded, more than 2/3 the width of the median part of the valva; the long basal excavation is extending to 2/3 length of sacculus; the naked, triangular lobe is situated between the spine patch of cucullus and the cluster of long spines on sacculus, its base is adjacent to the spine cluster; the phallus is slender, its width in middle is about 1/8 its length. In the female genitalia of S. similispirographa the sterigma is complex and not flat, including the anteriorly raised, spinulose lamella antevaginalis and two naked, concave lateral extensions. In S. spirographa, the sterigma is relatively uniform structure, indicated by the large, wholly spinulose lamella antevaginalis which is extending posteriorly and laterally. Externally S. similispirographa also resembles S. apicispinata, but the leaden striae on the forewing and the relatively darker, more grayish hindwing separate it from the latter species.

Adult (Fig. 8). Forewing length 5.0–7.0 mm in male, 5.5–7.0 mm in female. Head (Fig. 4): ocellus well developed; chaetosemata present. Frons smooth, white; vertex roughly scaled, creamy. Antenna with scape creamy, flagellum brown. Labial palpus porrect to ascending, pale creamy, median segment widened in distal half, dusted with brown and dark brown laterally, terminal segment slender, about half length of median segment, sparsely or slightly dusted with brown.

Thorax: creamy, dusted with brown medially; posterior crest distinct. Collar creamy. Tegula dark brown basally and creamy suffused with yellow and pale brown distally. Hind tibia not expanded, without hair pencil in male. Forewing elongate subrectangular, costa lightly curved throughout, apex rounded-rectangular, termen oblique; upperside ground color creamy white, markings dark brown dusted densely with yellow; costal strigulae creamy white, basal two pairs suffused with yellow; basal fascia broken, indicated by a small blotch below base of costa and a short streak on inner margin of wing; subbasal fascia represented by a darker brown spot on costa, an oblique blotch between 2/5 length of cell and 1/3 length of 1A+2A, and several faint ripples above the basal part of dorsum; leaden striae from strigulae three and four distinct on disc of cell and extending obliquely to 2/3 length of dorsum and confluent with significant leaden striae from strigulae five and six below distal part of lower edge of cell, thus separating media fascia; upper part of media fascia fused with costal part of postmedian fascia, forming a large, somewhat inverted triangular patch, lower part of media fascia between distal part of cell and dorsum, oblique triangular; a darker brown dot on outer edge of cell often present; pretornal patch distinguishable, oblique elongate; lower part of postmedian fascia oblique, present between midlength of R₄ and 2/3 length of M₂, surrounded by leaden striae from distal five pairs of costal strigulae, which broadly extend to tornus; preterminal fascia indistinguishable; terminal fascia a narrow streak, extending along termen to M₂; cilia pale brown mixed dark brown and creamy; underside yellowish brown to brown. Hindwing subtriangular, termen nearly straight (Fig. 8a); pale gray-brown to pale brown; cilia gray to pale brown; underside pale gray to pale brown.

Abdomen: male genitalia (Fig. 12): tegumen low, with a rounded or triangular top; vinculum a narrow band; socii indicated by a narrow spine patch, below margin of tegument apex; gnathos a weakly sclerotized band; valva somewhat triangular, basal half gradually widening, medially about twice as wide as distal part of cucullus; basal excavation short, distal edge reaching about 1/2 length of sacculus; sacculus broad, almost naked except for prominent and rounded apex bearing a cluster of very long spines; cucullus triangular, gradually narrowed to apex, apex rounded-acute, disc area with an elongate semicircular patch of spines, an acute triangular lobe proximate to this spine patch ventrally, naked, with its base distant from the cluster of long spine on sacculus (Fig. 12a); a rounded lobe projecting along basal half of ventral margin, short, sparsely set with fine spines; apex with dense spines dorsally; phallus moderately long and wide, tapering towards apex, without cornuti. Female genitalia (Fig. 14): papilla analis narrow and elongate. Sternum 7 weakly sclerotized and with a concave hind margin. Sterigma an irregularly shaped complex structure, lamella antevaginalis broad, spinulose, raised medially and with a longitudinal groove anteriorly, ostium flanked by two concave, naked and petal-shaped pockets. Ductus bursae membranous and smooth, with weakly sclerotized and ill-defined colliculum, faintly widening towards corpus bursae. Corpus bursae ovate, weakly granular, without signa.

This specific name is derived from the Latin prefix simil- (= similar) and the taxon name spirographa, referring to the similarity of this new species to S. spirographa (Diakonoff).