1a lobed, yellow-green blotch mine, centre often pinkish: Phytomyza ilicis

1b long, initially quite narrow, later broad gallery => 2

1c galls, etc => Tables for all parasites per species

2a frass line broad, brown; the pupa does not protrude from the mine: Metriochroa latifoliella

2b frass line narrow, black; front spiracula of the puparium protrude through the epidermis: Phytomyza jucunda.