Easterling1982, 148supposes a three-stage corruption: “ταν- must have fallen out of the text, leaving αϋφῆ which was ʻcorrectedʼ to εὐϋφῆ, with γ᾽ added to make metre”. Davies 1991, 164 takes a similar line, adding that the sequence of the letters ΤΟΝΔΕΤΑΝΑΥΦΗ would have made it easy for ΤΑΝ to slip out. Davies does not explain this and there is no obvious reason for the sequence to have induced the omission.
Jackson1955, 228. If the text were in genuine need of alteration as opposed to re-ordering, then a more obvious solution than Wunderʼs would be to read Reiskeʼs τόνδε νεοϋφῆ πέπλον, anticipating Deianeiraʼs vow that Heracles should φανεῖν θεοῖϲ θυτῆρα καινῷ καινὸν ἐν πεπλώµατι (612-613). Blaydes 1871, 132 thought that this solution would appeal to some, pointing out that it was customary to use new robes at sacrifices (referring to Poll. 1.25; Pollux actually says that one must approach the gods ὑπὸ νεουργῷ ϲτολῇ, ὑπὸ νεοπλυνεῖ ἐϲθῆτι, i.e. with a new robe or at least a newly washed one). However, νεοϋφῆ is, like ταναϋφῆ, unattested in ancient sources.