Have not heard of the "blood red hash mark" but would like to. Please ask your correspondents tell me about it.
It seems to me that USMC NCO's wear scarlet chevrons and trouser stripes in commemoration of service in Mexico, perhaps Chapultepec (the halls of Montezuma).
I looked at "The Horse Soldier, 1776-1943" by Randy Steffen (University of Oklahoma Press, Norman, 1978), Volume 2, p. 11, in which he quotes US Army Regulations regarding the Uniform and Dress of the Army of the United States (GO No. 31 AGO 1851), para. 131.
It states "all NCO's, musicians and privates who have served faithfully for a period of five years...will wear...a diagonal half chevron...to be the same color as the cord on the trousers....Service in war will be indicated by a light or Saxony blue stripe on each side of the chevron for Artillery, and a red stripe for all other corps, the stripe to one-eigth of an inch wide.
Also, James A. Sawicki in "Infantry Regiments of the US Army", (Wyvern, Dumfries, 1981), p. 56, mentions the Distinctive Trimming of the 4th Infantry. He says, "Subsequent to the Mexican War and until the blue uniform was abolished, the band of the 4th Infantry was authorized to wear scarlet piping on the chevrons and trouser stripes in commemoration of distinguished service in the Battle of Monterey....
The regiment still wears a scarlet and green loop on the shoulder strap of the uniform to commmemorate service in Mexico. My uncle served in the 4th in the 1950's. I have a photo of him in Class A uniform wearing this insignia.
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