Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Information, insects and people from the 2019 BugGuide Gathering in Louisiana, July 25-27

Discussion, insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

small headed fly - Ocnaea - male - female

small headed fly - Ocnaea - Male Female
gainsville , Missouri, USA
last summer i collected a few tarantulas from caney mountain here in southern missouri. the tarantulas were Aphonopelma henzi. the slings i collected were 1 to 2 inches and the fist one had one of these flies emerge back in august and last week the last sling had the second one emerege. i belive i have a male and female pair de to size diffrence. im just wanting a possible I.D. if possible. i would appreciate any info as i have a few people wanting to write articals in tarantula keeping magazines about it. thanks

Images of this individual: tag all
small headed fly - Ocnaea - male - female small headed fly - Ocnaea - male - female small headed fly - Ocnaea - male - female small headed fly - Ocnaea - male - female

neat find! thanks cody & Dennis
Moved from ID Request.

Ocnaea sp.
Ocnaea are known to parasitize tarantulas, and there is no doubt in my mind that you managed to raise a male and female of this genus! They are extremely sensitive to movement while in the pupal stage, and so are very hard to raise out! Male on the left and female on the right. I really don't know of any described species from southern Missouri, so I'm at a loss to tell you what you have at the species level, but definite Ocnaea. They also don't have well developed mouth part, so don't go to flowers. These are exceedingly rare! And I pair at that. It will be interesting to see what Ev Schlinger will say! Plus you know the host.

Can you tell that I'm excited! ;-)

Based on Cole's key (1919) I
Based on Cole's key (1919) I believe this is Ocnaea loewi Cole 1919. The species was described from a single female specimen collected in "Texas". When compared with the type specimen your female has the dark areas arranged in more centralized spots rather than a basal band, so I'm not sure. It would be best to wait and see what Ev says.

small headed fly
yeah...i can tell lol.

they actually wasnt to hard to raise. the first one emerged from the tarantula, and i kept the substrate moist and it pretty much came out no problems. the weird thing is though. both specimen only lived for about 12 hours after pupating. both seemed weak and unable to fly.

the second one i had emerge, i actually did nothing for. i walked into my tarantula room and this was crawling on top on the substrate.

i actually froze both of them in hopes for someone to identify and possible study them.

interesting enough they seem to be some kind of honey bee mimic.

What's a "sling?"
I have never heard that term and can't tell from the context what you mean by it.

I think it is
an immature spider? as in spiderlings = Slings? It is a common term used among tarantula keepers I know that :- )

While most Ocnaea resemble Ho
While most Ocnaea resemble Honey Bees, its important to remember that Apis melifera is an introduced species in North America.

yeah a "sling" means spiderling. sorry should have been more specific. i am just used to the term from my tarantula hobby.

so is this a rare find? because i took 2 slings from the area i collected the tarantulas from and both were affected by this fly. i imagine i could get more of these flies this coming summer, as we host a bug hunt every year there. i am going to collect a few more baby tarantulas and see if i have more emerge from them.

anyway im hoping to get a positive I.D. so i can possible have a scientific note wrote up on them, and the process of the emerging from the tarantulas.

Typically you would expect th
Typically you would expect that the fly larva would consume the spider and pupate shortly after the young spider starts to moult into an adult. So the different times for the two specimens may be related to the amount of food and temperatures you had the spiders in under these artificial conditions.

how it happened.
the maggot actually came out of the spiders abdomen. leaving the sling dead. the maggot crawled around untill it made a sort of cocoon. both spiders where kept at the exact same temps(78 degrees F in my climate controlled tarantula room) once the maggot made a cocoon it basically didnt move for about 15 days, then it emerged as an adult fly. like i said though, both flies seemed weak, barely able to crawl, and not at all able to fly.

I would encourage you to try
I would encourage you to try again next year. So many Ocnaea species were described from only one specimen (male or female) that we often don't know much about the variation in size and pattern within each species. Having both male and female from the same site is remarkable, and the possibility of a series would be exciting.

I sent Ev an e-mail and hopefully we will hear back from him soon.

Wow! This is great biological biographical!
Interesting to learn a little about the life cycles of insects, especially unusual ones! I guess the news from the tarantula perspective was a little less rosy, but still I'm glad the story was documented!

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.