The last thing I associate with picnics is "pancakes," and I really don't think about watermelons as a pancake accompanyment, but I never really experienced picnic culture as deeply as they did in the 40s.

 

 
   

Wow, kids! A cheap reflective surface! Can be seen for ten miles, if anyone's likely to notice! Which they aren't!

More on the character of Aunt Jemima:

The R. T. Davis Milling Company hired former slave Nancy Green as a spokesperson for the Aunt Jemima pancake mix in 1890. Nancy Green was born in Montgomery County, Kentucky, and played the Jemima character from 1890 until her death on September 23, 1923. As Jemima, Green operated a pancake-cooking display at the World's Columbian Exposition in Chicago, Illinois, USA in 1893, appearing beside the "world's largest flour barrel".

From this point on, marketing materials for the line of products centered around the stereotypical mammy archetype, including the Aunt Jemima marketing slogan first used at the World Fair: "I's in Town, Honey".  Anna Julia Cooper used the World's Columbian Exposition as an opportunity to address how young African American women were being exploited by white men.  She predicted the appeal of Aunt Jemima and the southern domestic ideal and went on to describe the north's fascination with southern traditions as part of America’s “unwritten history”.