Ants in your pants

Hi, my phrase of the day is "ants in one's pants." I know it means antsy or restless (my Mom said so), but where does the phrase come from? Thank you,
Sax
PS: we saw the entry re: fissle/fistle, but that didn't answer the question. Thanx...

If I find anything else, I'll post again. But the phrase is quite literal. If a person sits on the ground, like during a picnic, he or she probably will get ants in his/her pants. And that makes a person fidget.

Here's a slightly different meaning and a possible source. Although I think the phrase is a lot older than the 1930s.

ANTS IN HIS PANTS - "Excessively restless or eager. Hugh S. Johnson, the colorful former Army general who headed the National Recovery Administration in 1933-34, may have originated this phrase but certainly made it popular. 'Full of beans' and 'full of red ants' convey the same idea." From The Dictionary of Cliches by James Rogers (Wings Books, Originally New York: Facts on File Publications, 1985).