Sphiximorpha or Ceriana perhaps? - Ceriana abbreviata

Moved

… Aaron Schusteff, 25 June, 2021 - 3:24am

Apologies, Pam...I erred here!

I had been looking & hoping for a Colorado sighting of C. ancoralis after reading the discussions under C. tridens and C. ancoralis in Curran(1924)...and focusing on the characters 1)-5) in the comments under my reference post here. That 'bias' caused me to jump the gun upon seeing what I thought was a good match here for C. ancoralis.

But there are two crictical characters I overlooked:

1) the 2nd abdominal segment here is significantly shorter than the 3rd. [Note: The actual 1st abdominal segment here lacks a posterior yellow band and has a very subtle & easy-to-overlook posterior edge in the photo above. One might easily mistake the initial two abdominal segments for a single faux "1st segment".];

2) there are no yellow supra-alar vitta here

Those two characters (especially "1)") indicate C. abbreviata here...as Bill had correctly suggested earlier. In C. tridens and C. ancoralis, the 2nd abdominal segment is nearly equal in length to the 3rd (whereas in C. abbreviata it's around 2/3 the length of the 3rd segment...which is the case here).

Colorado had seemed rather far west to me for C. abbreviata to me (but it now seems otherwise, see range given here)...and in my mind I had been framing the ID challenge here as one of C. tridens vs. C. ancoralis...overlooking the possibility of C. abbreviata (temporary blindness on my part!).

… Aaron Schusteff, 25 June, 2021 - 3:23am

Ceriana ancoralis

Thanks so much for taking this cool Diptera to species and explaining why. So much to learn! Pam

… Pamela Piombino, 12 June, 2021 - 10:04pm

Moved

Moved from Ceriana.

… Aaron Schusteff, 11 June, 2021 - 12:37am

Ceriana

Was there ever a definitive i.d. to species on this Dipter? Lynn and Gene Monroe would like to use it in their latest book. Many thanks, Pam

… Pamela Piombino, 7 August, 2019 - 2:50pm

Just recently became more confident of separating characters

...for Ceriana ancoralis and C. tridens.

I'm now convinced this is indeed C. ancoralis from:

1) Long, uninterrupted yellow band along upper-back edge of head;

2) The absence of a yellow spot on the pteropleuron;

3) The very narrow medial black stripe on the face between the base of the antennifer and the oral margin (see 5th image of series);

4) The only mildly forward-projecting medial portion of the posterior band on the 4th tergite, with gradually tapering lateral forward edge and little or no posterior "crimping" of the 4th tergite;

5) The apparent lack of any brown-to-yellow pollinose markings on T4 (or T3);

...and finally, the "east of the continental divide" CO locality.

All of the above points to C. ancoralis...see the discussion under the post below for more details & references:

… Aaron Schusteff, 11 June, 2021 - 12:37am

Moved

Moved from Syrphid Flies.

… Martin Hauser, 17 June, 2019 - 7:03pm

I think this is Ceriana abbre

I think this is Ceriana abbreviata ..... male.
I have sent it to Kevin.

… Bill Dean, 5 June, 2019 - 10:09pm

Moved

Moved from ID Request.

… Ken Wolgemuth, 5 June, 2019 - 5:59pm