Tenthredo colon
Tenthredo colon measures some 10 to 13 mm. The animal is entirely black, however the hind tip and the legs are reddish. The antennea are black, except for the tips which are white. There are some look-a-likes, but Tenthredo colon has one distinguising feature: the pterostigma is black. Adults are usually seen on cow parsley.
The larvae are greyish brown or light brown with a striking number of upside down v's on the back in a darker kind of brown. They have a dark spot on the head. They resemble caterpillars a lot. The larvae eat many plants, but among the favourites are: Great Willowherb (Epilobium hirsutum), Fireweed (Chamerion angustifolium), Bracken Fern (Pteridium aquilinum), Cinquefoil (Potentilla) and Willows (Salix).
Adults are active from May to the end of August. The larvae are seen in september mainly. Tenthredo colon occupies a vast area: from Europe through Asia and Siberia all the way to Kamchatka. Strangely enough in Britain a rather uncommon species in the South, and rare elsewhere.
