This fly is about 1/2 inch (13 mm) in length and is characterized by an unusually large head in relation to the size of the insect, thus the name. It has smoky wings and a long pedicel connecting the bulbous abdomen to the thorax. The fly is mostly black with yellow on the legs and abdomen.
The frequency of occurrence is not known, but the photographs of these individuals were taken in July in Fontenelle Forest.
This fly is distinguished from the other Thick-headed Fly in Nature Search by the uniformly thin legs and slightly thicker pedicel. This family of flies is a parasite of solitary bees and sometimes wasps. The female grabs the host while in flight and forces an egg between the bee’s abdominal segments. This genus includes 12 species in North America.
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