Acrocera orbiculus

Acrocera orbiculus, also known as the top-horned hunchback, is a species of fly belonging to the family Acroceridae. The species has a holarctic distribution, ranging from North America to the Palaearctic.

Etymology
The specific name is the Latin diminutive noun, meaning 'a small disk'. As a noun in apposition, the suffix does not alter to reflect the gender of the genus.

Description
"Antennae placed at the extreme top of the head, ending in a long thin arista. Venation very much reduced. Proboscis absent, or very short and stumpy"

Biology
The larvae are endoparasites of spiders in the families Amaurobiidae, Clubionidae and Lycosidae.