Blue Dress "C"
The blue dress uniform with long-sleeve khaki shirt (without coat), and tie for male Marines and tab for female Marines, is designated as blue dress "C." Don't Confuse Blue C with "chucks"! "Chucks" are service Charlie's: green trousers and short sleeve khaki shirt.
COVER: you must wear the white "dress" cover. Do not wear the green service cover.
NECKTIES may be tied with any type of standard necktie knot which presents a neat military appearance. The necktie will be tied so that the tip of the bottom of the tie is between 1/2 inches above the belt buckle and 1/2 inches below the belt buckle. Approved hook-on (pre-tied) khaki neckties may be worn with the service and dress uniforms at the individual's option.
NECKTIE CLASP will be worn midway between the third and fourth button from the top. Officer's clasp with a silver EGA, enlisted with a gold EGA.
MARKSMANSHIP BADGES (optional) are centered above the left breast pocket with the bottom edge of the holding bar 1/8 inch above the pocket's top edge.
RIBBONS (optional) are centered 1/8 inch above and parallel to to top of the left pocket or 1/8 inch above the widest holding bar when marksmanship badges are worn.
BREAST INSIGNIA (optional) are centered 1/8 inch above the top row of ribbons.
ENLISTED GRADE INSIGNIA are centered on each sleeve, four inches below the shoulder seam (3 inches E8 and above)
OFFICER GRADE INSIGNIA are centered between the top and bottom edge of each collar, with the outer edge of the insignia once inch from the edge of the collar.
From The Order:
The blue dress uniform with long-sleeve khaki shirt (without coat), and tie for male Marines and tab for female Marines, is designated as blue dress "C." Commanders may prescribe blue dress "C" as the uniform of the day for specified occasions or duties. Commanders may prescribe this uniform for honors, parades, and ceremonies on and off the military activity. This uniform is authorized for leave and liberty. The blue dress sweater may be worn as part of the blue dress "C" uniform at the option of the individual except on those occasions when the wear of the blue coat would be more appropriate. The sweater may be worn as part of the duty uniform both on and off the military installation and for commuting to and from work. The sweater may be worn as the uniform of the day and on leave and liberty but will not be worn for inspections, ceremonial formations, or parades.