Thread subject: Diptera.info :: California pair (= Cyrtopogon)

Posted by John Carr on 07-10-2012 23:55
#1

In the mountains of northern California (USA), elevation 2300 meters, August 30, 2012.

farm9.staticflickr.com/8321/8041503854_06122d647f_z.jpg
(Click to enlarge, or view on Flickr.)

Edited by John Carr on 08-10-2012 17:27

Posted by ChrisR on 08-10-2012 08:29
#2

I might be wrong but could they be Therevidae?

Posted by John Carr on 08-10-2012 13:31
#3

I was wondering that too but convinced myself of Asilidae.

Posted by Eric Fisher on 08-10-2012 17:16
#4

John,

These are Cyrtopogon sp. (I puzzled over them when I first saw them in BugGuide!) The male, on the left, looks very much like C. rattus. However, the female does not fit that sp. (the abdomen should be nearly all whitish tomentose, with minimal shiny-black, at the edges of the terites). Close to C. sudator also (except the female doesn't quite fit either). So, it remains a puzzle as to which Cyrtopogon it is. Possibly the female has aberrant coloration?

Eric

Posted by John Carr on 08-10-2012 19:08
#5

I saw this similar fly a few miles away the next day:

farm9.staticflickr.com/8445/7903867972_60b892c7fd_z.jpg

Does the male of my original pair have a modified fore tibia? It appears to have a bulge.

Edited by John Carr on 08-10-2012 19:09

Posted by Eric Fisher on 09-10-2012 02:05
#6

This one is Cyrtopogon evidens, a female; quite similar to the previous pair, but with a slightly different design on the scutum and fewer white setae on the legs. These (along with about 25 other mainly California spp.) belong to a sub-group of the genus that share a flat, all tomentose scutellum, a face that is less gibbose, and overall are less setose and more tomentose. This sub-group all lack the striking, dimorphic ornamentation and modifications on the body that many other Cyrtopogon often have.