E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Yellow-bellies.
Frogs, fenmen. The Mexicans are so called.
1
When the Queens Prize was won at Wimbledon, July 21st, 1885, by Sergeant Bulmer, 2nd Lincoln, his victory was hailed with Well done, yellow-belly! in allusion to his being a Lincolnshire man.Notes and Queries, August 22nd, 1885, p. 146.
Ah, then, agin, it kin scarce be Mexikins neyther. It ur too fur noth for any o them yellow-bellies.Coptain Mayne Reid: The War Trail, chap. lxxi.