Galactic longitude-velocity diagram of tracers of star formation in the Dragonfish complex that are listed in Table 6, as well as Mercer 30. The black thin horizontal lines show the average (continuous line) and standard deviation (dotted) of tracers with ν_LSR> 10 km s^-1. The thick gray curves are the Hou & Han (2014) fit for the Sagittarius-Carina spiral arm, which crosses the diagram twice, at ~−20 km s^-1 (near part) and at ~+ 22 km s^-1 (far part).