Unknown Fly - Dasysyrphus venustus

Moved

… v belov, 11 December, 2013 - 1:39pm

I think this is Dasysyrphus v

I think this is Dasysyrphus venustus, but it could be a member of the D. intrudens species complex. I'm basing this on the new Locke and Skevington Key (Zootaxa 3660, 2013). D. venustus appears to have a fairly broad range, but may not come into CA as the intrudens complex does.

The maculae on tergies 3-4 appear to reach the edge of the abdomen, and the maculae on tergite 2 are large, so we reach the point in the key between venustus and the intrudens species complex. To me, the maculae on 3+4 fit the description of venustus better (transverse, constricted slightly medially, medial edge swollen slightly) than the intrudens complex (arcuate/lunulate, U/V shape on anterior edge, constricted in the middle, large swelling on medial edge) but this is somewhat of a judgment call.

… Kelsey J.R.P. Byers, 8 December, 2013 - 11:32pm

Thanks Kelsey, and...

...there does seem to be a very high degree of precision in the description of the shapes of the maculae is amazing I would tend to agree that D. venustus sounds closer. I'm not sure what is meant by either "medial edge swollen slightly", or "large swelling on medial edge". I would probably have thought that the medial edge was more constricted than swollen, but I may have gotten lost!

… Arthur Scott Macmillan, 9 December, 2013 - 3:27pm

The key terminology is a bit

The key terminology is a bit vague there, indeed! What I believe is being discussed is the appearance of the maculae at the medial part of the fly - in other words, the end of the spot in the middle of the fly, as opposed to the middle of the spot itself, if that makes sense. e.g. "at least slight swelling on medial edge, sometimes constricted medially" from the key would mean "the end of the spot in the middle of the fly is somewhat swollen, but the spot itself is sometimes constricted in the middle of the spot."

… Kelsey J.R.P. Byers, 9 December, 2013 - 3:30pm

I see what you mean...

It sounded to me like they were saying that the spots were constricted in the middle of the spots and that the spots did not constrict at all at the medial end, but that would not make sense at all! I think they mean that in one case the medial half of the spot, relative to the constriction is more noticeably wide than in the other. Or, as I have heard it put, "more blobby". Sorry about my difficulties with the terminology!

… Arthur Scott Macmillan, 9 December, 2013 - 3:52pm

I honestly think "more blobby

I honestly think "more blobby" is actually a bit easier to read! It took me a while of staring at the images of the flies and the key to figure out exactly what the authors meant. (among other things, they use the term "profemur" which took going through a book on Google Books on insect terminology to decipher - it just means the femur on the front pair of legs. a totally reasonable term, but one I hadn't run into before)

… Kelsey J.R.P. Byers, 9 December, 2013 - 4:09pm

profemur

the term is in BG glossary(1), no need to look for it elsewhere...

… v belov, 11 December, 2013 - 1:38pm

Thank you! For some reason w

Thank you! For some reason when I found the glossary I got directed to a list of BG resources starting with the arthropods, even when I clicked from P to Glossary and so on. Glad to have the actual link - hooray!

… Kelsey J.R.P. Byers, 11 December, 2013 - 1:41pm

navigate the makeshift Glossary using the Taxonomy tab...

...then click on the target term and switch to the Info tab to see the entry; the Glossary uses the tree structure designed for taxa, thus the stupid procedure

… v belov, 13 December, 2013 - 9:55am

GTK!

I suppose it is just a matter of time before we will be reading "retrofemur".

… Arthur Scott Macmillan, 9 December, 2013 - 4:16pm

Moved

Moved from Syrphid Flies.

… Martin Hauser, 11 April, 2012 - 3:14pm

Thanks for the ID!

Welcome back Ron! I guess we have both been out of circulation?

… Arthur Scott Macmillan, 14 April, 2012 - 2:30am

I think it's Eupeodes, Mac.

But I've been away from these for some time and have lost my edge. See comments here:

ID to Tribe Syrphini is solid.

… Ron Hemberger, 6 April, 2012 - 12:12am

Moved

Moved from ID Request.

… v belov, 15 March, 2012 - 10:39pm