...to continue:

According to J. Telfer Dunbar, the earliest definitive image of the "little kilt" is in a portrait of Alasdair Ruadh MacDonnell of Glengarry, dated to the early 1740's. In the painting, Glengarry himself is wearing a belted plaid, but his henchman to the rear has on a philabeg:



It's a bit hard to see, but those who have seen the original describe that kilt as being pleated in its entire circumference, common to the period. Now, that all-round neat pleating would be rather hard to achieve by throwing 4 yards of fabric out on the ground, hand-pleating it, and belting it on - the way modern reenactors don their "great kilts." A drawstring or pleats stitched into place seems more likely.

But, I'm just speculating (gasp!)....