Calaveras’ symphony concert

Two calaveras sitting in the balcony of a theater full of calaveras are listening to an orchestral concert. Their skulls have "IV INTERNACIONAL "and "PNR" inscribed on them. In the lower part of the print there are 3 smaller calaveras, one in military uniform, one dressed as a workman and the third as a woman of humble class. Beside them are the words: "TODAY ‘EL SOL’ SPECIAL WORKERS’ TICKETS 25 pesos"