Globally, there are twenty-four species of Apethymus distributed across the Palaearctic and oriental regions. In Britain and Ireland they are represented by two species.
The genus is characterised within the subfamily Allantinae by the following characteristics. The antennae are filiform and are more than twice as long as the head width. On the foreleg the inner tibial spur is forked at the tip. In the hindwing cell M is open apically, and the forewing has three cubital cells as cells 1R1 and 1Rs are merged. On the thorax the metapostnotum is broad and flattened. In common with other genera in the subfamily, the body is slender with the abdomen longer than the thorax and head combined.
The Apethymus are unusual in the Tentredinidae in that they fly late in the year and overwinter as an egg. The larvae feed in the spring on deciduous trees.
Apethymus filiformis (Klug, 1818)
Apethymus serotinus (O. F. Müller, 1776)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168
Park, B.; Lee, J.-W. 2018: First records of the monotypic genus Harpiphorus Hartig (Hymenoptera: Symphyta: Tenthredinidae: Allantinae) from the Eastern Palaearctic Region and northern Africa. - Journal of Asia-Pacific Biodiversity 11: 590-594.