Trifurcula headleyella (Stainton, 1854)
Diagnosis. Easily separated from other Trifurcula species by shining metallic spots and dark head. Males can be separated from other Trifurculini by 'velvet' patch on underside hindwing, and females by combination of a black head and metallic basal part of forewing. Male genitalia differ from those of S. thymi by shape of vinculum, larger gnathos, length and shape of cornutus and size. Female genitalia differ from other Trifurcula species by straight basal part of long ductus spermathecae and 2 convolutions.
Male. Wingspan: 5.0-5.8 mm. Head: frontal tuft and collar dark ferruginous to fuscous; scape white, often with some black scales; antenna with 35-41 segments. Forewing blackish fuscous, with shining metallic silver tornal and dorsal spot, the dorsal being at approximately two-thirds; cilia-line conspicuous, terminal cilia silvery white. Hindwing: grey. Abdomen with grey anal tufts. Female. Wingspan: 4.2-5.4 mm. Head: frontal tuft black or dark fuscous; antenna with 35-38 segments. Forewing black, slightly darker than in male, but basal third shining dark silvery or lead grey. Male genitalia. Vinculum narrowed anteriorly, with clear concavity. Tegumen pointed or truncate, occasionally slightly bilobed. Uncus pointed. Gnathos with large and rounded central element. Valva approximately triangular, with distinct, curved, distal process, transverse bar absent, but some membranes might resemble it; basal dorsal corners of valvae joined by sclerotized bar. Aedeagus with one long and straight, pointed cornutus of variable length and two lateral rows of spines near posterior opening. Female genitalia. T VIII with scales and a few setae on either side; anal papillae with 12 setae each. Bursa not very long, covered with pectinations and elongate signa without distinct margins. Ductus spermathecae relatively long, about half as long as bursa, with two convolutions and straight basal part.
Host plants: Prunella vulgaris, P. grandiflora and P. laciniata, in central Europe often on P. grandiflora growing amongst tall grass. Egg: on upper surface of a leaf. Larva: pale yellow, very long and slender. Mine : a very long narrow gallery, often with irregular margins, frass linear; larva usually mining through two or three leaves, via petiole and stem, mine becoming increasingly irregular and staining the leaves purple. Cocoon: dark brown.
A very local species known from one locality in LFM in Denmark, from Sk., öl., Gtl. and Vg. in south Sweden and from Al, N and Ta in south Finland; not in Norway. Occurring in scattered localities in southern England, West and East Germany, Poland, France, Switzerland, Austria, Italy and Yugoslavia. Usually found in limestone grasslands.
Voltinism: univoltine, with extended periods of emergence and larval feeding; larvae most plentiful in September, throughout its range. Adults from mid June to August.
Description based on van Nieukerken and Johansson (1990)