Coleophora niveicostella Zeller, 1839
from Toll (1962a)
Larva in a slender, brownish black, bivalved sheath case of 7-8 mm. The oral half is tubular, the rear part strongly laterally compressed. Mouth angle 30°.
Actually the case only looks like a sheath case. The larva cuts off mined leaves, after having removed the complete leaf margin: what is left is an upper and a lower epidermis, connected by the stub of the petiole. Leaves treated in this way are placed in front of the old case, the stub dorsally, and pointing forwards. The stubs together form a low dorsal keel. The case in fact is a composite leaf case. However, the larva adds so much silk (also because the leaves are too small to form a complete tube) that the leaf fragments are obliterated (Emmet ao, 1996a).
Thymus praecox, pulegioides, serpyllum.
Szőcs (1977a) adds Sarothamnus; that must concern a stray individual.
Larvae are full fed in mid-June (Emmet ao, 1996a).
BE recorded (Phegea, 2010).
NE recorded (Kuchlein & de Vos, 1999a; Microlepidoptera.nl, 2010).
LUX not recorded (Fauna Europaea, 2010).
distribution within Europe
From Sweden and Latvia to Spain, Italy, and Greece, and from Britain to Romania (Fauna Europaea, 2010).
Sometimes the cases are difficult to distinguish from those of the much more common C. albitarsella. A differential character is that the larva of niveicostella has the metanotum unicolorous with remainder of the pale greenish, while in albitarsella the metanotum bears two oval black sclerites. See Suire (1961a) and Emmet ao (1996a) for descriptions of the larva.
The small mined leaves remain green and/or are dropped soon; this makes the cases extremely difficult to find (Emmet ao, 1996a).
Baldizzone (1979a, 1983c, 2004a), Biesenbaum & van der Wolf (1999a), Buhr (1937a), Emmet, Langmaid, Bland ao (1996a), Hering (1957a), Huisman & Koster (2000a), Kuchlein & Donner (1993a), Kuchlein & de Vos (1999a), Patzak (1974a,b), De Prins (1998a), Razowski (1990a), Robbins (1991a), Suire (1961a), Šulcs (1996a), Szőcs (1977a), Toll (1952a, 1962a), Wullaert (2018a).