The mix of stars in the spiral arms is similar to that in other regions of these galaxies.
The spiral arms consist almost entirely of older stars but have occasional "blue stragglers" among them.
We cannot measure the mix of star types in such spiral arms due to absorption in the dust lanes that surround them.
A larger number of young, bright stars are found in the spiral arms than in other regions of these galaxies.
The spiral arms tend to be depleted in young, hot stars compared to other regions of these galaxies.