This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:"
http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html
A quite naked cupid passes a valentines day card to a group of giggling and overly happy young girls. Really. Shouldn't they be quite worried that this angel boy is standing there naked in front of them?! Or maybe that is the source of their lecherous grins. Dear lord! (From a 1910 comics section, if you are curious! Over a 100 years ago! Time, time, time...)