☛ Mafalda 2 by Quino, comic strip no. 379, Buenos Aires: Ediciones de la Flor, 1972 [my translation]. Also reproduced in Toda Malfada, Buenos Aires: Ediciones de la Flor, 1993. © Joaquín Salvador Lavado (Quino).

Mafalda was very popular in Latin America and Europe while the strip was running. It was translated in many different languages. Since 2004, English editions are slowly being made available as well (see Amazon.com: Mafalda & Friends). I couldn’t find an English version for the strip shown above and translate it myself with the help of Google Translate (the last panel was the most difficult: I choose to use “the most enthusiastic” to translate the idiom “al más pintado”).
One other interesting thing to notice: “Cowboy” is the term chosen to translate the Spanish word “Llanero” meaning plainsman (from the name of the transnational geographical region Llanos). See Wikipedia for more information: “Llanero”.
[UPDATE–Dec. 30, 2017] A reader from Uruguay generously wrote to share this useful information: “Although not a literal translation, ‘el llanero solitario‘ is the Spanish translation for the character ‘the Lone Ranger’, whom Felipe is dressed as. So Susanita’s reaction would be to call him ‘the Single Ranger’. Thank you Gabriel.
As a means for comparison between translations, one will find bellow the original Spanish version as well as one of the official French translation (click for higher resolution). For more information about Mafalda, visit Quino official website.