More from Switzerland

These two caterpillars (Hostilian, on the right, and Quintillus on the left) were sitting near the top of a young, isolated sapling, about 6 feet tall. 

Sextus, at least an instar younger, was on a similar sapling some distance away:

This season I have located 6 caterpillars, all on isolated saplings, some considerable distance from more mature sallows.

Guy