Last modified: Jan. 20, 2020, 11:54 a.m.
Very local and very rare in Belgium.
Head brown; forewing ground colour golden brown; white pattern consisting of a basal line edged with a thin brown line, a small basal patch on the dorsum; four costal (rarely three) and three dorsal striae, the first pair merged in the center to form a transversal band.
At first a rather small tentiform mine on the underside of a leaf, only covering part of the leaf, but later on the mine becomes strongly inflated and covered completely by the leaflet, though the caterpillar does not use the entire leaflet surface.
See also gracillariidae.net and bladmineerders.be.
Pupa light brown, strongly resembling the one of Ph. medicaginella, which has the 10th abdominal segment as wide as long, while in Ph. insignitella it is clearly wider than long.
Pupation inside the mine. The species hibernates in the pupal stage among leaf litter on the ground.
Two generations a year: May–June and August.