Of Viper’s-bugloss (Echium vulgare), Richard Mabey writes in Flora Britannica:
[It] is a viperish plant in all its parts. The sprays of flowers that spiral up the stem are half-coiled; the long red stamens protrude from the mouths of the blue and purple flowers like tongues; the fruits resemble adders’ heads. Even the ‘speckled’ stem (it is hairy in fact) suggested snakes’ skins to early herbalists.
And like all members of the Echium family, this glorious plant is much loved and visited by insects, especially (from my own observations) bumblebees.