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Yes, Winnie Winkle's younger brother is named Perry Winkle. Perry was an orphan living on the streets who was adopted by Winnie's parents, and is therefore not well-versed in proper etiquette. The Spud Finnegan he mentions in the first panel is a member of the local kids' gang the Rinkydinks, who Perry hung around with and was shown with more and more as the strip continued.

I really like this particular strip, because although it shows a very stark contrast between Perry's behavior and the behavior of the other children, and although they do laugh at the end, Reggie and the Hyatt family are very kind and welcoming to Perry and are tolerant of his errant behavior. I can imagine many other strips that wouldn't be nearly as nice to their protagonists, and would most definitely end with the child being flung unceremoniously out the front door. Actually, I'm pretty sure I've read a few of those.