Caloptilia semifascia (Haworth, 1828)
maple slender

Acer campestre, Britain © Rob Edmunds
mine
The mine begins as an inconspicuous, short, lower-surface epidermal gallery. This widens into a small triangular blotch, usually in a vein axil. The mine in this stage is rather transparent. Older larvae live free in a leaf cone, made by folding down a leaf segment. In the course of its free life the larva makes three cones, of increasing size, either on the same leaf or not. Pupation in a flat, parchement-like, shining, yellowish white cocoon on either side of the leaf, generally near the margin (Emmet ao, 1985a).
hostplants
Sapindaceae, narrowly monophagous
Acer
campestre.
Rarely transgressing to Acer pseudoplatanus (Emmet ao, 1985a).
phenology
Larvae in two generations, May-June and June-July (Emmet ea, 1985a, Langmaid ea, 2011a)
BENELUX
BE recorded (de Prins & Spronck).
NE recorded (Huisman & Muus).
LUX not recorded (Fauna Europaea, 2011).
distribution within Europe
From Fennoscandia to the Pyrenees, Italy, and Bulgaria, and from Britain to South Russia.
larva
Pale green, head capsule light brown.
synonyms
Caloptilia onustella (Hübner, 1813) (cf De Prins & De Prins, Global Taxonomic Database of Gracillariidae (Lepidoptera), 2011); Caloptilia hauderi of British authors (cf Langmaid ao, 2011a).
notes
Mines mainly in the higher parts of the crown (2-4) of trees growing in forests; not in hedgerows (Emmet ao, 1985a).
references
Ahr (1966a), Bengtsson & Johansson (2011a), Biesenbaum (2010a), Bengtsson (2011b), Brown (1947a), Buszko (1992b), Corver, Muus & Ellis (2011a), Emmet, Watkinson & Wilson (1985a), Hering (1924b, 1934b, 1957a), Huemer (2012a), Huemer & Erlebach (2003a), Huisman & Muus (2020a), Kasy (1983a, 1987a), Klimesch (1950c), Langmaid, Sattler & Lopez-Vaamonde (2011a), Maček (1999a), Opheim (1977a), De Prins (2010b, 2011a), De Prins & Spronck, 2004a, Robbins (1991a), Sefrová (2005a), Skala & Zavřel (1945a), Sønderup (1949a), Stolnicu (2007a), Szőcs (1977a).