Great picture!

That fly there looks like one of the sterile release flies that are bred in McAllen, TX by USDA. The pink dot on the frons is from the fluorescent powdered die they put all over the pupae. When the pupae emerge, the wet ptilinum gets covered by the powder so when the ptilinum is retracted into the head, the fluorescent die is trapped there, too. In some specimens, the die is so faint that you need an ultraviolet light to verify the presence of the die which fluoresces green.