1a small blotch mine,, usually several together, each one ultimately with an oval excision: Antispilina ludwigi

1b gallery, abruptly changing into an elongated blotch => 2

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

2a blotch oriented over the midrib; larva: front spiraculum with 13-14 papillae: Agromyza pittodes

2b blotch not associated with the midrib; larva: front spiraculum with ± 10 papillae: Agromyza polygoni