Black hairstreak forewings. The most conclusive way to distinguish the two is by the row of black spots accompanying the orange band which the white-letter hairstreak never has. They spend most of their lives in the canopy or in dense scrub, feeding on honeydew, and very rarely come down to ground level. Eggs are laid singly on young blackthorn "Prunus spinosa" growth and it is this stage which hibernates. Although blackthorn is the main foodplant, wild plum "Prunus domestica" and other "Prunus" spp are occasionally used. The caterpillar hatches the following spring, at the end of April, just before the buds open
Prunus fruticosa the pun are "fructus" or "frux", from "fruor", "enjoy" - a fruit is a result enjoyed - and "frutex", "shrub", adjective "fruticosus", "bushy", from a totally different root. "Prunus" is a grammatical feminine, so "Prunus fruticosa" agrees in gender. However, Pallas says "Haec mihi tantum fructibus suis innotuit, qui distinctam itidem speciem indicare videntur", "It came to my attention at last because of its fruit, which repeatedly seemed to indicate a distinct species." The fruit seemed "fere Pruni forma", "nearly in the form of "Prunus"", especially because "praedita oblongo nucleo", "furnished with an oblong seed." So, Pallas moved it from