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Home » Guide » Arthropods (Arthropoda) » Hexapods (Hexapoda) » Insects (Insecta) » Flies (Diptera) » Orthorrhapha » Asiloidea » Robber Flies (Asilidae) » Asilinae » Polacantha » Polacantha grossa
Photo#114786
Polacantha species - Polacantha grossa - male
Copyright © 2007 John Cowsar Jr

Polacantha species - Polacantha grossa - Male
Garden Ridge/San Antonio, Comal County, Texas, USA
May 7, 2007
Size: approx 25mm
I believe this is an Efferia (Nerax), but what species? Thanks in advance!

edit: (3June07) IDed by Herschel Raney as a Polacantha species. See his comments.
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Contributed by John Cowsar Jr on 2 June, 2007 - 5:40pm
Last updated 15 October, 2009 - 3:42pm

Moved
Moved from Polacantha.
… Charley Eiseman, 15 October, 2009 - 3:42pm login or register to post comments

This is Polacantha grossa
This is Polacantha grossa
… Eric Fisher, 15 October, 2009 - 12:24pm login or register to post comments

Anatomical term for body part on thorax?
What is the anatomical term for the small projecting stalk-like body part which has a bulb on the end? It is located near the junction of the thorax and tail. Any idea of the function of this part?
Thank you Herschel for your genus ID!
… John Cowsar Jr, 3 June, 2007 - 11:28am login or register to post comments

 
Halteres
Modified from the second wing that flies lack.

Everyone on bugguide should check out this amazing fly anatomy site.

http://www.ento.csiro.au/biology/fly/flyGlossary.html
… Herschel Raney, 3 June, 2007 - 3:20pm login or register to post comments

Very fine image
Of a Polacantha species. Compare the Florida species here


Not the same species. There are three in robber-rich TX. P composita, grossa and sinuosa. Two of these were not defined until 1975 by Martin and I don't have that paper. Bromley, in his big TX study, caught only composita (then in Asilus) near Kerrville, as far as I can tell.
… Herschel Raney, 3 June, 2007 - 9:54am login or register to post comments

Or could it be?
Maybe an Ommatius instead of Efferia [Nerax] after further browsing in the Guide? Which species?
… John Cowsar Jr, 3 June, 2007 - 6:35am login or register to post comments

 
We think of Ommatius as being
much smaller, maybe 10 - 15 mm? Herschel Raney will likely visit your image soon and you will get your ID. Meanwhile visit his website to learn much more about Robbers.
… john and jane balaban, 3 June, 2007 - 7:57am login or register to post comments

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