Positions of UCH II regions (De Pree et al. 1997) in the W49 field are shown with magenta diamonds on the IRAC 3.6 μm image with the associated YSOs. Red circles show the YSOs in subcluster 1a, and blue circles show the YSOs in subcluster 1d. The cyan circle marks the location of the O-type star discovered by Wu. et al. (2014). Green crosses mark the massive YSO candidates, cyan crosses 89, 90, 91, and 92 mark the massive dust clumps from Matthews et al. (2009), and blue crosses mark the methanol masers identified by Breen et al. (2015).