Small World Discoveries

HYMENOPTERA > SYMPHYTA > Tenthredinidae > Tenthredininae > Tenthredinini

Another medium-sized (9-11mm body length) Tenthredo wasp-like species where the females have a brown blotch beyond the stigma of the forewings. The yellow-banded tergites do not broaden at the sides. The tegulae are entirely black, the underside of the abdomen mostly black, the antennae are also black but with yellow scapes. The hind tibiae are yellow on the upper portion and reddish towards the apex in the female, and black in the slimmer male. The tarsi are dark brown or blackish.

Tenthredo thompsoni is a localised species across southern counties occurring both on calcareous grasslands and marshy areas where the larvae have different food sources. Adults fly from July to September and like to visit umbellifer flowers, particularly favouring marjoram, which has given rise to the common name of Marjoram Wasp-Sawfly that has been adopted by at least one well-known author.

Internet searches for information regarding this species may refer to Tenthredo marginella, Tenthredo marginella (cf.thompsoni) or Tenthredo marginella-thompsoni as they are two species that cannot be separated but, as far as I understand, Tenthredo thompsoni is the recognised British species.