"USMC "Blood Stripe" around 1900" Topic

I am painting some Boxer Rebellion era marines. Two of my figures seem to be officers--have revolvers, not rifles, straps for a scabbard, although not actually carrying a sword.

My understanding is as follows:

A) Officers and Noncoms were to wear a red stripe down the outside seam of their blue trousers, as was standardized around 1840 or so.

B)In modern usage, the red stripe is part of the dress uniform, and not worn into combat.

C) Back in the day the red stripe might appear in the field uniform. I have read descriptions of this being the case as recently as during the 1846- 1848 war between the US and Mexico.

At what point did U.S. Marine officers and noncoms stop wearing this as part of their combat ensemble? Thanks for your input.

According to my Osprey book on the Spanish American War, here are a few things to consider. This is regulation dress.

NCO's did wear the light blue trousers with a thin scarlet stripe. Officers wore the light blue trousers with a one inch wide scarlet welt.

However, the Marines were also issued gray trousers and during the summer months could wear white duck trousers.

My guys are definitely wearing light blue trousers. My Osprey book on the Boxer Rebellion shows an enlisted man in the color plate, and describes the blood stripe only in reference to officer and NCO dress uniforms. The Chinamarine.org site asserts that the marines in Peking had only one uniform with them, their undress blues.