Diagnosis. Distinguished from all other unicolorous Stigmella species in northern Europe by forewing strongly suffused with purple and absence of anal tufts.
Male. Wingspan: 4.0-5.1 mm. Head: frontal tuft ferruginous orange; collar and scape yellowish white; antenna approximately half length of forewing. Forewing: purple fuscous with deepest purple in apical half; terminal cilia concolorous but slightly paler at tips. Hindwing: greyish brown; without androconial scales. Abdomen fuscous with purple tinge. Female. Wingspan: 4.8-5.2 mm. Head: antenna slightly shorter than half length of forewing. Otherwise similar to male. Male genitalia. Vinculum with small lateral corners. Uncus with small latero-posterior protuberances and concave hind margin. Gnathos with short transverse bar, short to very short horns and narrow, pointed anterior process. Valva with short distal process and more or less angular inner lobe. Aedeagus as long as or slightly shorter than genital capsule; cornuti truncate or blunt.
Female genitalia. Bursa copulatrix large, occupying approximately two-thirds of abdomen. Accessory sac relatively large, arcuated and convoluted distally; reticulate field large and distinct. Ductus spermathecae longer than bursa copulatrix.
Host plants: Oligophagous on Rosaceous trees and shrubs from subfamily Maloideae. Occasionally on Prunoideae (Prunus avium only). Most common on Crataegus and Malus. Positively recorded from (cultivated and wild plants not separated): Amelanchier ovalis, A. florida, Cotoneaster spp., Cydonia oblonga, Crataegus laevigata, C. monogyna, many cultivated Crataegus spp., Crataegomespilus dardari, Malus sylvestris, cultivated Malus spp., Mespilus germanica, Pyrus communis, many cultivated Pyrus spp., Sorbus spp. and on Prunus avium. Egg: on leaf underside. Larva: bright green. Mine : long sinuous gallery, starting as very narrow linear gallery; mine tending to follow veins; later mine with brown coiled frass, often becomes contorted, sometimes in very close-set arcs; length of mine variable, depending on leaf thickness; usually much shorter and straighter in thick or sun-exposed leaves, particularly on Malus, Pyrus and Cotoneaster. Cocoon: red brown or red.
In NWJ and eastern Denmark; in Sweden up to Vstm. Not in Norway; we are unable to confirm Grönlien's (1932) record. In Finland in the southern parts. - Widespread throughout central Europe (see Schoorl et al., 1985).
Voltinism: univoltine throughout its range. Larvae feed from mid-September until late October, occasionally as late as November. Adults emerge in May. Earlier records of a summer generation are probably all attributable to mines of S. crataegella.
Description based on Johansson and Nielsen (1990)