Darcy Clothing

Tie tacks are very useful devices for keeping ties from flapping about.
They were particularly popular in 1940's when presumably flapping ties did little to aid the war effort.

This is a link to a handy visual guide showing how they work. The idea is to stab them through the tie and then fasten the little chain through a buttonhole on the shirt.
http://hiwaay.net/~jimes/necktie/tietack.html