Posted by John Carr on 02-05-2012 02:54
#1
Massachusetts, USA April 30, 2012 next to fresh water marsh.
I think this is
Chaetopsis massyla. I hope somebody who knows these flies can confirm. There has been some confusion in the literature. Old papers use the name
massyla for a species with black femora. Some recent papers use
massyla for a corn pest with all-red legs.
I took a video of the fly showing off its wings:
http://www.flickr...129819751/.
Profile (click for much larger size, or view
on Flickr):
It has a little comb of black hairs on the vertex, visible in the large size.
Thorax (click to enlarge):
Apical extension of CuP:
Edited by John Carr on 17-07-2012 16:45
Posted by Nosferatumyia on 09-05-2012 18:50
#2
Certainly a
Chaetopsis. Sorry, I do not have any US keys at the moment with me (mostly old papers)
Posted by John Carr on 17-07-2012 16:42
#3
I have just seen an unpublished key by Steyskal (1990) in which he treated
Chaetopsis fulvifrons (Macq.) and
C. debilis Loew as synonyms of
C. massyla Walker. Apparently this synonymy was never published. He also keyed some undescribed tropical species.
Following Steyskal, there is only one species associated with freshwater habitats in the Northeast.
The earlier key by Curran (1928),
Scientific Survey of Porto Rico, had distinguished
fulvifrons and
massyla in part by presence or absence of "cruciate frontals." I would have thought that a good species character, but Steyskal's key indicates he based his opinion on genital characters.
