Antiproton-nucleon annihilations into three pions

New data are presented for antiproton capture in deuterium for the reactions (a) $\overline{p}d\to 2{\pi }^{-}{\pi }^{+}{p}_s$ at rest with spectator proton, (b)$\overline{p}d\to 2{\pi }^{-}{\pi }^{+}{p}_s$ with the antiproton in flight (∼0.35 GeV/c momentum), and (c)$\overline{p}d\to 2{\pi }^{-}{\pi }^{+}p$ at rest but with nonspectator protons. The striking features of the $2{\pi }^{-}{\pi }^{+}$ Dalitz plot for (a) are compared with $\overline{p}p\to 3{\pi }^0$, ${\pi }^{+}{\pi }^{-}{\pi }^0$ at rest, with $\overline{p}d\to 2{\pi }^{-}{\pi }^{+}{p}_s$ at other energies, and with predictions of dual models. No consistent and satisfactory interpretation has been found. The possible quantum numbers of the $2{\pi }^{-}{\pi }^{+}$ final state are discussed.