15. Phytoliriomyza falcata Kato sp. nov.

Figs 29, 30

Material examined.

Holotype: Japan: 1♂ (MK-AG-a19), Kanna-gawa, Nakatsugawa, Chichibu, Saitama Pref. (36.0044°N, 138.8108°E, 760 m asl), 14-XI-2010 (as larva), emerged on 23-IV-2011, NSMT-I-Dip 31972. Paratypes: Japan: 1♂2♀ (MK-AG-423, 807, a18), same data as holotype, emerged on 28-23-IV-2011, NSMT-I-Dip 31973-31975; 1♀ (MK-AG-a376), Ukawa, Tango, Kyotango, Kyoto Pref., 5-III-2021 (as larva), emerged on 12-IV-2021, NSMT-I-Dip 31976; 1♂ (MK-AG-a287), Seya-gawa, Miyazu, Kyoto Pref., 18-IV-2013 (as larva), emerged on 25-IV-2013, NSMT-I-Dip 31977; 1♂ (MK-AG-803), Ryugakyo, Yamashiro, Miyoshi, Tokushima Pref., 1-II-2014 (as larva), emerged on 25-IV-2014, NSMT-I-Dip 31978; 1♀ (MK-AG-444), Yasui-keikoku, Niyodogawa, Agawa, Kochi Pref., 27-II-2011 (as larva), emerged on 28-IV-2011, NSMT-I-Dip 31979; 1♀ (MK-AG-795), Chiromo, Toyotama, Tsushima, Nagasaki Pref., 11-XI-2011 (as larva), emerged on 28-IV-2012, NSMT-I-Dip 31980.

Other material.

Japan: 17♂22♀, Kanna-gawa, Nakatsugawa, Chichibu, Saitama Pref., 14-XI-2010 (as larva), emerged on 14-IV-2011; 6♂11♀, Oochi-gawa, Chichibu, Saitama Pref., 13-III-2017 (as larva), emerged on 25-28-IV-2011; 1♂2♀, Ukawa, Tango, Kyotango, Kyoto Pref., 5-III-2021 (as larva), emerged on 9-17-IV-2021; 1♀, Doro-kyo, Totsugawa-mura, Nara Pref., 29-III-2019 (as larva), emerged on 3-IV-2019; 1♂4♀, Tazukawa-keikoku, Katsuura, Tokushima Pref., 30-III-2021 (as larva), emerged on 23-30-IV-2021; 2♂1♀, Kurase-keikoku, Tanbara, Saijo, Ehime Pref., 2-II-2014 (as larva), emerged on 20-26-IV-2014.

Diagnosis.

A medium-sized yellow species (wing length 1.6-2.0 mm) having subshiny brown scutum with an oval yellow pattern extending from the mid-posterior margin to the scutellum, a yellow 1st flagellomere, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-laterally with a long hypertrophied arm which apically bears a dark, long, apically flattened, obliquely truncated tubercle-like seta. Larva mines the thallus of Reboulia hemisphaerica orientalis .

Description.

Adult male (Fig. 29A-E).

Head: Head entirely yellow, with ocellar tubercle brown, and back of head dark brown (Fig. 29C). Antenna porrect, first flagellomere black, pedicel yellow and scape light yellow. Arista subbasal, brown, pubescent. Frons with brownish pruinosity. Face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus yellow, cylindrical (Fig. 29C). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 29B). Orbital setulae minute and erect, in a single row.

Thorax: Thorax subshiny, with a brown medial stripe on anterior 2/3, and a pair of adjacent wide brown bands on anterior 7/8 (Fig. 29D). Scutellum and subscutellum yellow. Mediotergite brown, anatergite and katatergite yellow. Pleuron largely yellow; propleuron with small brown patch on mid-anterior corner; anepisternum with two small spots on anterior and posterior corners; anepimeron with an oblique narrow brown patch on anterior corner; katepisternum and meron with brown patches on venter (Fig. 29B). Haltere yellow. Calypter margin and hairs gray. Leg segments yellow; tibia and tarsus darker (Fig. 29B). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 29D). Acrostichal setulae 6-8 pairs in two rows. Wing: Wing length 1.6-1.9 mm, costa reaching M1 (Fig. 29A). Length of ultimate section of vein M4 divided by penultimate section 1.5-1.8.

Abdomen: Abdomen dorsally subshiny yellow (Fig. 29E). Genitalia: (Fig. 29G-L) Epandrium dark brown, rounded apically; inner-anterior margin with two short tubercle-like setae; inner-lateral surface with a basally enlarged, extremely extended, ventrally curved arm, bearing an apically flattened, obliquely truncated, tubercle-like seta borne (Fig. 29I, J, L). Surstylus long, narrow, setose apically. Cercus narrow, setose. Subepandrial sclerite consisting of a pair of dorsal and ventral arms; ventral arm narrow, extended, plate-like, with hooked apex and a long basal seta; dorsal arm also plate-like but shorter, with a seta basally (Fig. 29I). Hypandrium thin, slightly sclerotized along outer margin (Fig. 29G). Postgonite bare and goose barnacle-shaped, with sideward pointed apex (Fig. 29H). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 29H). Basiphallus with a pair of expanded lightly sclerotized lateral plates. Hypophallus broad, membranous, and bilaterally asymmetrical; right margin sclerotized; medially with a pair of dark fused sclerites (Fig. 29H). Paraphalli lobate, lightly sclerotized; diverging and angled anteroventrally (Fig. 29H). Mesophallus dark, cylindrical, widest subbasally, as long as distiphallus (Fig. 29H). Distiphallus comprising one pair of stout tubules; basal half composed of lateral dark slender sclerite and weaker medial region; covered by membrane bearing four pairs of minute arrowhead-like lateral sclerites; distal half cylindrical, dorsally and laterally pigmented, with truncated, shortly flared apex (Fig. 29H). Ejaculatory apodeme pale and fan-shaped with broad stalk; base wide to one side; sperm pump clear (Fig. 29K).

Female (Fig. 29F). Similar to male, but larger, the lateral bands on scutum more grayish and more pruinose. Wing length 1.8-2.0 mm. Postabdomen: (Fig. 30A, B) Oviscape dark brown, setigerous (Fig. 29A). Tergite 10 trifurcate, laterally uniting narrow pleural sclerites (Fig. 29B). Each cercus with two stout, apical, trichoid sensilla, ½ length of cercus (Fig. 29B). Spermathecae semi-orbicular, with truncate proximal ends (Fig. 29A).

Immatures. (Fig. 30D-F) Puparium internal, slender, and pale brown, with anterior spiracles just protruded from epidermis of mined thallus.

Etymology.

The specific name (falcata = sickle-shaped) refers to the sickle-shaped tubercle-like seta on the male epandrium.

Japanese name.

Naginata-jingasagoke-hamoguribae.

Host plant.

Reboulia hemisphaerica orientalis ( Aytoniaceae).

Mine.

Larvae construct linear-blotch mines in the thallus, and pupate in the mines (Fig. 30E-I).

Biological notes.

The habitats of this species are rocky cliffs in warm temperate evergreen forests. This species is sympatric with P. argentifasciata in some localities. Our rearing records suggest that it is bivoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Honshu, Shikoku, Tsushima Island (Fig. 31).

Remarks.

This species resembles P. arcus, P. plagiochasmatos and P. aratriformis in having a pair of brown lateral bands and pale yellow mark on the scutum; it is distinguished from them by the absence of an extremely extended, forked tubercle-like seta on the subdistal margin of the male epandrium. This species is sympatric with P. aratriformis on Reboulia, and can be distinguished from the latter by the yellow mark on the scutum; the mark is large and well defined by lateral stripes in P. falcata but small and obscure in P. aratriformis .