This larger female ichneumon wasp Stenarella domator [1] appeared in the afternoon on a sun warmed wall where she roamed for some time under the cover of the grape vines growing against it. She carries an impressive ovipositor that is almost twice the length of her body.
She is a parasitioid [2] on the Sphecidae, Sceliphron caementarium which is expected in the Netherlands [1]. Other host groups are probably potterwasps and mason bees [3].
Another female roamed the wall with bee hotels, but did not show a direct interest for them.
Literature
1 Nederlands Soortenregister2 SCARAMOZZNO, Pier Luigi; STRUMIA, Franco. Parassitoidi e inquilini di Sceliphron caementarium (Drury, 1773)(Hymenoptera: Sphecidae) in Romagna.
3 SAAKSJARVI, Ilari E. One Cryptinae genus (Hymenoptera, lchneumonidae) new to Finland. Entomologica Fennica, 1998, 9.1: 8-8.