Arge ochropus

Length 7-10 mm. The head and thorax are black, and the abdomen is orange. The wings have a dark mark along the border, but no wing stigma. The legs are banded and look like its wearing football socks.

Larvae of Arge ochropus and Arge pagana are tricky to separate, especially from photos. The best feature to check is the black mark on the last dorsal segment (supra-anal mark) – this is a simple spot in pagana but more-or-less divided with a pale middle in ochropus. In the field the best way is to look for the egg scars on the main stem near where the larvae are feeding – two parallel rows in pagana and just a single row in ochropus. See ID Aids below.

Athalia species also have 'stripy socks' but these lack the fused antennae.

• antennae with fused segments - appearing as a single filament
• yellow sides to the thorax
• stripy 'socks' (tibiae)

Adults may be seen near to hedgerows, and feeding on nectar and pollen from Hogweed and Tansy.

May to September

The larvae are bristly with yellow and black markings. There are two generations a year, the female laying 16 to 18 eggs at a time on the upper, succulent rose stems. The larvae eat the leaves of cultivated and wild roses.

Widely distributed in Britain, although most records come from south-eastern England

Fairly common in Leicestershire and Rutland.

https://www.sawflies.org.uk/arge-ochropus/