A new subspecies of Cigaritis (Spindasis) vulcanus Fabricius, 1775, Cigaritis (Spindasis) vulcanus sulawesiana ssp. nov., is described from the main island of Sulawesi, Indonesia. It is smallest in the genus Cigaritis and has a characteristic teardrop-shaped band from the base to discal in space 1b of the hindwing underside. The wing markings and male genitalia distinguish it from other subspecies of vulcanus. This is the first record of this genus from Sulawesi mainland.

様々な昆虫では，オスがメスよりも早い時期に羽化する．この現象は雄性先熟の一形態として知られている．雄性先熟は，オスが先に成虫になって，羽化後間もない未交尾のメスと交尾する繁殖戦略として生じる場合もあれば，単にオスとメスの発育に要する期間の違いによる場合もあると考えらえている．著者は，チョウの雄性先熟は繁殖戦略だと考えて，メスアカミドリシジミChrysozephyrus smaragdinus （鱗翅目：シジミチョウ科）とウラクロシジミIratsume orsedice（鱗翅目：シジミチョウ科）の発育経過を調査した．これら2種の幼虫は卵の殻の中で越冬し，寄主植物の新芽が開く春に孵化する．雄性先熟が繁殖戦略ならば，オスは早く成長して成虫になるために，メスよりも早く孵化することが予想される．

さらに，配偶行動の性質によって，雄性先熟が強まる場合もありうる．メスアカミドリシジミのオスは林内の空間にとどまって飛来するメスに求愛する，待ち伏せ型の配偶行動を示す．そして，成虫の時期の早い段階で待ち伏せ場所に飛来したオスは，侵入してきた他のオスとの相互作用の後もその場所を占有し続ける傾向があることが知られている．したがって，オスはメスだけでなく他のオスよりも早く羽化することが繁殖戦略では有利になる．他方，ウラクロシジミのオスは特定の場所にとどまらず，広い範囲を飛び回ってメスを探す探索型の配偶行動を示す．したがって，オスはメスよりも早く羽化する必要があるが，他のオスよりも早く羽化する必要はない．そこで，雄性先熟の程度は，ウラクロシジミよりもメスアカミドリシジミの方が大きいと予想される．

この二つの予想を確かめるために，著者はその2種を飼育して発育期間を調べた．その結果，2種ともオスはメスよりも発育期間が短く，メスよりも早く成虫になった．また，2種ともオスの幼虫がメスの幼虫よりも早く孵化した．この結果は，雄性先熟がこれら2種の繁殖戦略であることを支持している．また，幼虫期間の雌雄差は2種で違いはなかったが，蛹期間の雌雄差はメスアカミドリシジミの方がウラクロシジミより大きかった．その結果として，雄性先熟の程度はウラクロシジミよりもメスアカミドリシジミの方が大きかった．これは，探索型の種よりも待ち伏せ型の種の方が雄性先熟の程度が大きいという予想に合う．

Thecobathra heppneri Sohn, 2018 is recorded for the first time from Japan. The figures of habitus and female genitalia of the species are provided in addition to the sequence of the mtDNA COI barcode region.

A butterfly species, Purple Emperor, Apatura iris (Linnaeus, 1758), is recorded in Mongolia for the first time. The specimens of two males and three females of this species were collected from the forest steppe in the mountainous area of Sharyngol, Darkhan-Uul Province, Mongolia. On both sides of the dirt road through this forest steppe, there was an abundance of willow trees (Salix spp.), which provided a suitable habitat for this species. The specimens we collected are believed to be A. iris amurensis Stichel, 1908. Sharyngol is located about 300 km south of Lake Baikal, and the forest steppes extend from the southern tip of the Republic of Buryatia and the southern tip of the Zabaikalsky Krai eastward across the border into Mongolia. It is possible that the distribution of this species has extended through these regions to Sharyngol.

Coleophora limoniella Stainton, 1884 is newly recorded from Japan. The female adult specimen and genitalia are illustrated.

Head capsule widths of Curetis acuta paracura larvae collected in Tokyo (Hachioji) and Ibaraki (Tsukuba), Central Japan, were measured. The butterfly passes through four larval instar stages before pupation. The mean head capsule width of the first, second, third and fourth (final) instar larvae were 0.346, 0.574, 0.952, and 1.834 mm, respectively.

Eupoecilia kobeana Razowski, 1968 is newly recorded from Tanegashima Island and the Yaeyama Islands (Ishigakijima Island, Iriomotejima Island, and Yonagunijima Island). Larvae were discovered in flower buds of Ligustrum japonicum (Oleaceae), Ligustrum lucidum Aiton (Oleaceae), and Vaccinium bracteatum (Ericaceae), representing new host records. Geographical differences in morphology and DNA barcode sequences between populations on Yaeyama Islands and other areas are discussed.

A pyraustine Ostrinia sanguinealis (Warren), which has been known only in Kyushu, is discovered in Kyoto City, Honshu, Japan, for the first time. The female genitalia are drawn based on specimens collected in Kyoto, with the male genitalia obtained in the same place. The larva of this species feeds on Saururus chinensis (Saururaceae), boring inside the plant stalk. This is the first host record of this species and the association with Saururaceae is also first for the genus Ostrinia. The larval morphology and biology of O. sanguinealis are given. DNA sequences of the mitochondrial COI barcode region and nuclear histone 3 of O. sanguinealis are examined for comparison with those of the other Ostrinia species, and the inferred tree placed O. sanguinealis as the sister of the “O. nubilatis species group”. The sudden appearance of this species in the center of Kyoto city is discussed.