It's possible but hardly likely that the Trevelyan is Charles Edward Trevelyan who was Assistant Secretary to the Treasury at the time of the Famine in the 1840s. He set up a Famine Relief Scheme in 1847/48 and his main object was not so much relief as to minimise the cost to the Treasury. For example - "the able bodied only could get relief in a workhouse. Non-able bodied could get relief outside the workhouse and retain their homes." By February 1848 450,000 and by June 830,000 were receiving outdoor relief. However food was only distributed at workhouses and many people had to walk scores of miles to get to such a centre. Most were weak from hunger anyway. Another little twist was called the "quarter acre clause." People with a small-holding could only get relief if they gave up their land. For the period 1848/49 he went one better. There would be no Treasury grants to distressed Unions and the outdoor feeding of destitute children was to stop in order to encourage "independence." Indian meal or maize was also imported to Ireland as a substitute food source. I suppose it might be called "corn" but to the best of my knowledge it was known as "yellow meal" and was not popular. To get back to the original line, it is likely that the name "Trevelyan" had nothing to do with the monster above but was just a phrase to make the song flow along. In any case, transportation from the British Isles ceased in 1868. Trust the above is of some enlightenment albeit a bit long winded.