Last modified: April 15, 2021, 12:49 p.m.
Probably a rather rare species throughout Belgium, but due to the similarity with Horisme tersata it is unsufficiently known.
With worn individuals it's a good idea to check the genitalia because external characteristics are not enough to be sure at species level. Fresh specimens can be identified by the pale brown ground color, with reddish or warm chocolate brown tinge. Discal spot usually absent. Area between apical streak and costa often pale ochraceous colored.
The adults fly in two generations a year with a peak during May and August. They come to light. It has a preference to more termophilous habitats than its sibling species H. tersata, allthough they often fly together.
The larva feeds mainly on Clematis vitalba. It hibernates as pupa in a loose cocoon among debris or in the soil.