This is a catchy novelty tune and judging by the title and his alias, the composer seems to have had a sense of humour! I couldn't find a translation for the title other than that mate is a popular 'herbal' drink in South America, (hence the alliterative title perhaps) and Doncella is a Spanish word for a young lady. The piano score is in C but G works better on the banjo. The scoreand midi are in the library...Steve.