Diagnosis. Similar to S. poterii and S. filipendulae; ulmariae is often slightly larger than filipendulae, fascia broader and more weakly defined than in filipendulae. The male genitalia of ulmariae, S. poterii and S. filipendulae all have a large apical cornutus and fine proximal spines; ulmariae differs from poterii in its shorter aedeagus and from filipendulae in its more numerous fine spines in aedeagus. The female genitalia of ulmariae, S. dryadella, S. poterii and S. filipendulae probably not reliably separable.
Male. Wingspan: 4.0-5.0 mm. Head: frontal tuft ochreous; vertex brown; collar dark bronzy brown; scape pale yellow; antenna three- quarters length of forewing, dark grey. Thorax dark bronzy brown. Forewing: area proximal to fascia bronzy brown; fascia postmedial, relatively broad, pale golden; distal to fascia bronzy brown, slightly darker than proximal half; terminal cilia dark grey-brown. Hindwing and cilia pale grey, markedly darker around termen. Abdomen dark grey to black. Female. Wingspan: 4.0-5.0 mm. Male genitalia. Vinculum with anterior margin distinctly emarginate. Uncus small, with distinct deep medial U-shaped notch and distinct paramedial notches. Valva with rounded inner lobe with protuberances, distal process strong, pointed. Transtilla with distinct, broad and blunt sublateral processes. Juxta absent. Aedeagus shorter than genital capsule; near tip a large cornutus with broad base, proximal part with at least 100 needlelike spines. Female genitalia. Corpus bursae small, without pectinations. Vestibulum moderate, bilobed. Accessory sac at least as large as corpus bursae. Ductus spermathecae without spines. Apophyses short. Ovipositor not protruding.
Host plants: Filipendula ulmaria. Egg: on upperside of leaf, usually close to a vein. Larva: dark yellow. Mine : first half of mine narrow, usually along a vein; second half gradually widening, frass line occupying two-thirds width of mine. Cocoon brownish.
Denmark: F, LFM and NEZ. In Sweden up to Vstm. Norway: Ns. Widely distributed in Finland. - S. England, Poland, The Netherlands and C. Europe.
Voltinism: in Sweden probably univoltine, mines found late September to early October, bivoltine in more southern localities.
Description based on Johansson and Nielsen (1990)