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Fly Seeks ID, #2 - Odontoloxozus longicornis

Fly Seeks ID, #2 - Odontoloxozus longicornis
Saguaro National Park near Tucson, Arizona, USA
March 7, 2004
This fly was on a fallen Saguaro cactus in Saguaro National Park. My Field Guide to Insects (Borror and White) suggests this is a Neriidae, or cactus fly, and says there are only two species in the U.S. I wish they said what the two species were and how to tell them apart. Can anyone help?

Odontoloxozus longicornis
Swan and Papp, p. 624, fig. 1337, (1) have two detailed illustrations of Odontoloxozus longicornis, one from a dorsal view, and one from a lateral. They seem to match this photo perfectly. Features of their detailed description also match this photo. Length is given as 0.3-0.5 inches (7-12 mm).

Patrick Coin
Durham, North Carolina

Thanks, Patrick, That is most
Thanks, Patrick, That is most helpful! Glad to get it identified to species rather than just family.


Stephen Cresswell
Buckhannon, WV

references on cactus flies
For what this is worth, Carl Olson, in Insects and the Saguaro, a chapter in A Natural History of the Sonoran Desert, (1) mentions only Odontoloxozus longicornis on Saguaros in Arionza. (There's an excerpt on the web.) That's a popular work, of course, not a systematic survey. The article in the printed book has a brief table of both "Insects of the Living Saguaro" and "Some Arthropods Associated with the Dead Saguaro".

John Acorn, "The Nature Nut" did a show where they hacked open a saguaro and looked at the decomposers--I can't recall if they looked at the flies. We should get Acorn to join BugGuide.

The photo does show long horns, I guess antennae? Sounds like it could be a longicornis? I can't find any images on the web of either genus. Ah, Arizona, so neat. On my list of places I wish I could spend a year looking at stuff.

Patrick Coin
Durham, North Carolina

Nature Nut on DVD
Hey Patrick - did you see that Acorn the Nature Nut is out on DVD now, 88 episodes' worth?

Nature Nut DVDs

Airlie bought me the whole set for Chanukah! Kinda pricey, but am loving watching them with the kids, forgot how great some of those were. I'll have to dig through and find that episode where he hacked open the saguaro...

Joshua S. Rose, Ph.D.
Natural Resource Specialist
World Birding Center
Bentsen-Rio Grande Valley State Park

Use provides a useful list of all Nearctic insects. If you drill down you can find that family and see the two species on this page, namely Glyphidops flavifrons and Odontoloxozus longicornis.
I'll leave it to you to research those further.

BTW, glad you found us and I'm enjoying your posts.

Cactus fly
Hey, I am very impressed you got the family ID! Nice work. Next time you are in Tucson, please look me up, Stephen.