Efferia species robber flies

This page will have images of unknown Efferia species robber flies. Even with collected specimens, identification is often problematical. I am posting various Efferia species with information about where and when they were photographed. Perhaps at some future time these will be identified. The Efferia species shown at right was photographed in western Travis Co, Texas in May, 2004, with a Canon EOS 10D and EF 70-200 mm F2.8L IS lens with a 2X extender and 550 EX flash. It is preying on a Common Buckeye (Junonia coenia).
The Efferia shown here was photographed in Uvalde Co, Texas in August, 2005, with a Canon EOS 1D Mark II and EF 300 mm F/4L IS lens with a 2X extender and 580 EX flash. After this one image the fly left and thus will probably not be identified to species based on this single image and no specimen.
The Efferia species pair in copula shown here and the image just below it were shot in April, 2005, in Travis Co., Texas, with a Canon EOS 1D Mark II and EF 300mm F/4 L IS lens and 2X extender and 580 flash.

The Efferia shown here was shot in April, 2006, in Hidalgo Co., Texas, near Edinburg. The photo was taken with a Canon EOS 1D Mark II and EF 300mm F/4 L IS lens and 2X extender and 580 flash.
The Efferia shown here was shot in May, 2006, also in Hidalgo Co., Texas.
The next 2 images of unknown Efferia robbers were taken in the Chinati Mountains, Presidio Co., Texas, in September, 2005, with a Canon EOS 1D Mark II and EF 300mm F/4 L IS lens and 2X extender.

The robber fly shown here, apparently another Efferia species, was in Madera Canyon, Davis Mountains, Jeff Davis Co., Texas, in June, 2005.
The Efferia species robber fly shown here was at Bentsen State Park, Hidalgo Co., Texas, in June, 2008.
The next two images of an unknown Efferia species were taken in Starr Co., Texas, in May, 2010.

The male Efferia species shown here was in western Travis Co., Texas, in October, 2010.
Efferia species Charo Ranch Park, Dripping Springs, Hays Co., Texas 28 May 2013