What Makes Us Itch? - A Science Lesson

Last weekend we had our first really nice summer-like day of the year. There was lots of sunshine, it was warm, and there was little wind. That little wind is a curse and a blessing in Maine at this time of year. It's nice because it makes for easier bike riding. It's bad because it's easier for the mosquitos and blackflies (gnats) to swarm you. I stopped on my bike to take this picture and got swarmed. And for a few days afterward my arms were covered in itchy bug bites.  Scratching...