Ludovic MacDonald was a younger son of Allan Roy MacDonald, 7th Laird of Morar. Burke's Landed Gentry (2001) does not include the dates but it shows "ksp in America". I believe dsp means died without issue.
What is the story with Ludovic? I have Lewis McDonald of Bedford township, Westchester county of New York whose gravemarker says: "Sacred to the memory of Col. Lewis McDonald Esq. and Sarah his wife being a native of North Britain borne at Strathspey 1709 and departed this life 24 July 1777".
Lewis McDonald is believed to have arrived in New York in 1730. We also have the following: “Bedford, Westchester County, New York Historical Records, 1689-1800. Land Records 3:52. on 12 Mar 1755. William & Sarah Woolsey, executor and executrix of the will of John Woolsey, late of Bedford, Westchester Co., NY, deceased, Sold to Lewis McDonald of Bedford for 400 pounds, in the 28th year of George II - A certain tract … of land … within … Bedford in quantity two hundred and thirty one acres, it being the farm where John Woolsey died possest of in the New Purchase…” Lewis was a justice of the peace, colonel of the militia, and one of the wealthiest farmers in the county. He left cash bequests of 4600 UK pounds as well as real estate and movable property.