Arizona Blister Beetles (Meloidae) among the few beetles that can be harmful to humans: eat 20 Blister Beetles and you might die 0-:
But they show their colors as a warning, and that makes them very pretty. Their poison cantharidin, only released as a defense, was used in former times in medicin.
See more at http://www.margarethebrummermann.com/beetlecollages.html
or at the upcoming ART IN THE PARK in Sierra Vista, Saturday and Sunday, Veterans' Memorial Park