Cupid By SARA VANDEN BERGE One of this week’s featured pets up for adoption at the Erath County Humane Society is Cupid, a five to six-year-old pit mix.   “He is one of our longest stay pups, and he's more than ready to find his forever home,” ECHS executive director Serena Wright told Beneath the Surface News .     “Cupid is a wiggly, lovable goofball who lives for attention, belly rubs and playtime.   “He's a friendly, excitable boy who may get a little jumpy with greeting