_Machine Gun Company, Infantry, Cavalry and Field Artillery_—The distinctive insignia of the regiment to which it belongs with the number of the regiment in the upper angle and the letters “M. G.” in the lower angle. _Supply Company, Infantry, Cavalry and Field Artillery_—The distinctive insignia of the regiment to which it belongs with the number of the regiment in the upper angle and the letter “S” in the lower angle. _U. S. Army Disciplinary Barracks Guard_—The letters “D. B. G.” in gothic design enclosed in a wreath with the letter of the company below. _Noncommissioned Officers of Disciplinary Battalions_—The letters “D. B.” in gothic design enclosed in a wreath with the letter of the company below. _Noncommissioned Staff Officers of Engineers_—The turretted castle device of the Engineer Corps with the number of the regiment above it. [Illustration: U. S. Army. Noncommissioned officers’ chevrons 1. Band Leader 2. Assistant Leader, West Point Band 3. Chief Trumpeter 4. Sergeant, Band] [Illustration: U. S. Army. Noncommissioned officers’ chevrons 1. Master Electrician, Quartermaster Corps 2. Master Signal Electrician 3. First Class Private, Signal Corps 4. Wagoner 5. First Class Private, Quartermaster Corps 6. Farrier 7. Chief Mechanic 8. Mechanic or Artificer] _For Service coats_ the collar insignia consist of bronze metal disks with a raised rim, worn on each side one inch from the neck opening. The disk on the right side bears the letters “U. S.” with the number of the regiment or, where there is no regimental organization, the number of the unit if there is one. To designate men of the Volunteers, Reserves, National Guard and National Army the letters “U. S.” have superimposed upon them the letters “V,” “R,” “N. G.” or “N. A.” respectively. The disk on the left side bears the special device of the corps, department or arm of the service with the letter of the company, battery or troop below it, except for the Engineers where the letter is above the device. The special devices referred to are the same as the gilt ones already described with the following exceptions: _Corps of Interpreters_—The letters “INT.” _Machine Gun Battalions or Squadrons_—The letters “M. G.” in the upper angles of the crossed rifles or sabers. _Corps of Intelligence Police_—The letters “I. P.” _Headquarters of Brigades and Higher Units_—The letter “H.” _Headquarters of Trains_—The letter “T.” _General Recruiting Service_—The letters “RS.” _Disciplinary Barracks Guard_—The letters “DBG.” _Trench Mortar Organizations_—Crossed cannon with the letters “TM” in the upper angle. _Anti-aircraft Artillery_—Crossed cannon with the letters “AA” in the upper angle. ARMY AVIATION SERVICE INSIGNIA For officers these insignia are worn on the left breast and are as follows: