Small Headed Fly

Subject: Flybee?
Location: Southern New Hampshire
July 30, 2017 12:53 am
Location: southern New, Hampshire USA
I’d just like to know what this is.
Signature: K. Stone

Small Headed Fly

Dear K. Stone,
This unusual creature is a Small Headed Fly in the family Acroceridae, possibly
Turbopsebius sulphuripes which is pictured on BugGuide.  Of the entire family, BugGuide notes:  “Humpbacked flies with thorax and abdomen balloon-like; small heads with holoptic eyes (covering most of the head); and large, conspicuous calypters (membranous disk-like structures) tucked-in at the base of the wings. Many species mimic bees/wasps or even beetles.”  The complex life cycle is described on BugGuide as:  “The first instar larva (‘planidium’) seeks out spiders. When a spider contacts a planidium, the larva grabs hold of the spider, crawls up the spider’s legs to its body, and forces its way through the body wall, often lodging near the book lung, where it may remain for years before completing its development.
Adult longevity is usually rather short (3 days to ~1 month). Mating usually takes place in flight; female begin to lay up to 5000 eggs soon after mating and may continue during the following 2-10 days. The tiny, pear-shaped, black, microtype eggs are deposited either in flight upon the ground (Eulonchus), upon dead branches (Ogcodes), upon tree trunks (Pterodontia), or upon grass stems (Acrocera). Eggs hatch in 3-6 weeks giving rise to small planidial larvae. Most 1st instar planidia must seek out their spider hosts and can crawl or jump with ‘inchworm-like’ movements. There is only one generation per year with the acrocerines (Acrocera, Ogcodes, Turbopsebius) on their araneomorph hosts; but many panopines (Eulonchus, Lasia, Ocnaea, Pterodontia) seem to have only one generation every 5-10 years due to the longer immature stages of their mygalomorph hosts.”

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