A cockroach who cannot face the road: in one refrain because she is broke, in the older one because she is missing her two little back legs. That is the whole premise, and Mexico has been hanging new verses on it since before 1819, when a novelist could already name the song and expect readers to know it. During the Revolution every faction wrote verses about the others; a century earlier Spain sang its own. The refrain outlives them all.
Grammatically this is a porque machine: no , no - the stall before the reason lands is built into the tune. And the pair of refrains is a neat minimal pair for two verbs you must not mix: no (she no longer wants to) against no (she no longer can). Same tune, different verb, whole different tragedy.
The rendition we link sings this first refrain - the lame-cockroach version its title names - and then wanders into further traditional verses beyond the two we print, as every singer of this song has done for two centuries; read along with ours and enjoy the detours. - the little back legs - shows the diminutive -ita softening a word mid-sentence, and de atrás doing "rear" the way Spanish actually says it. The 1915 broadside we cite was printed in Mexico City with an engraving by José Guadalupe Posada, the great skeleton artist, which is about as Mexican as provenance gets.