Wasp mimic Flower Fly cleans its face

There were lots of various hoverflies and bees visiting a patch of flowering St. Andrew's Cross plants at Houston Arboretum & Nature Center in Houston, TX, USA. Among them was this big flower fly (Milesia virginiensis), stopping briefly on a Chamberbitter plant (Phyllanthus urinaria) to clean its face. Its bright yellow and black markings seem to help it to mimic a yellowjacket.