Of hornets and humans: the etymology of *anthropos*

ἄνθρωπος, like μέροψ, is of unknown etymology; it is considered a classic case of an important Greek word of pre-hellenic origin. So why does it resemble φαιδρωπός ☺ and σκυθρωπός ☹, both readily explicable? Comparison with a word for ‘hornet’ (ἀνθρηδών, suffixed with ἔδω ‘eat’) shows that it came from *arthr- dissimilated into *anthr- (cf. *δέρ-δρεϝον > δένδρεον ‘tree’).