Bug-Man? Is he a superhero or a villain? The facial expression is so nondescript it is difficult to tell. The mask always reminds me of the Hydra troops from the Nick Fury, Agent of S.H.I.E.L.D. comics in the 60's. The webbing looks spidery; but the scales have a reptilian texture.
I think this comical horse is one of the oddest masks I have in my collection . Maybe, it is because it doesn't look like a typical Halloween character that it seems so out of place. It would take a few moments to get the joke if a trick-or-treater came to my door wearing this Horse Fly face.
Thanks to the comment from Eddie Riff, you can see this mask on the cover of Steve Miller's 1973 album "The Joker." It is amazing how a 49 cent piece of plastic can look like a million bucks.