This is the first appearance of George du Maurier's aesthetic poet named Jellaby Postlethwaite, whose name suggests a soft and effeminate nature. Postlethwaite is described as having a sad smile, flowerlike eyes, and a grand head. Our Gallant Colonel is presented as an outsider who is curious about the Postlethwaite's importance. Du Maurier's other aesthetic character, Maudle, is also referenced in this cartoon. Both Postlethwaite and Maudle are reminiscent of Wilde's aesthetic philosophy and are both reoccurring characters.

Source:
Du Maurier, George. "Nincompoopiana. -- The Mutual Admiration Society". Punch. 14 February 1880.