Key to European Allomacrus species (females only)

1 Face and mesoscutum granulate (fig. 3). Fore wing with vein 3rs-m usually present. Hind coxa and femur fuscous (fig. 4). ............................................................................................................. A. longecaudatus

– Face and mesoscutum smooth (fig. 2). Fore wing with vein 3rs-m absent. ............................................... 2

2 Ovipositor at most weakly longer than the hind tibia length. Hind femur fuscous. ................... A. subtilis

– Ovipositor at least 1.8 times as long as the hind tibia length. Hind femur orange (fig. 1). ....... A. arcticus