Here comes another Harpy, this time from the pages of the Dungeons & Dragons Monster & Treasure Assortment, Sets One-Three: Levels One-Nine, published in 1977.
Looking at the M&TA, I came across another Harpy illustration. Perhaps someone can tell me, who is the artist?
According to the tables in the M&TA, Harpies do not appear until Dungeon level 4. That gives players lots of time to find an antidote or protection from the charm ability of Harpies.
Edit: James Chevski and Spielmeister opine that this may be a David A. Trampier piece. I am inclined to agree, although the drooping fingers and the nail on the thumb of the free hand, the over-long arms, the elbows, the dagger hand with its awkward flexion, the wavy dagger ... they all contribute to an unsettling Erol Otus feel to the art.