Favoritos de nikirob

HFDF! This syrphid fly was hovering around a single dock (Rumex) along a ditch in suburban Durham, NC (USA) on 26 April 2012. (I recently processed the images more carefully.) It perched occasionally, but briefly, to oviposit. The larvae are carnivorous, and in one of these images you can see the prey--aphids.
Ocyptamus fuscipennis (female, ~10 mm length)
Identification references:
bugguide.net/node/view/43727
Skevington, Field Guide to the Flower Flies of Northeastern North America, pp. 376-7.

There is much confusion in this group, in the NE we have B. auriporus which has a equal stipe tapered at base with white mycelium, B. innixus has a swollen bottom with a tapered base and yellow mycelium and B. tenax which has a rock hard stalk base and large reticulation

I saw this crawling across the outside of my kitchen window, and something did not appear right with the "ant". For one thing, it had eight legs. Clearly a male with those big pedipalps.
Synemosyna formica (male), length 5 mm
bugguide.net/node/view/53128
This photo at:
bugguide.net/node/view/385233
I thought this was a similar ant-mimic, Peckhamia, but experts on BugGuide corrected me.

This little long-legged fly must be 1/100 the mass or less of the mydas fly in the adjacent frame (on Flickr). They are very flighty, and will usually take off when a flash is fired. When using a TTL (through-the-lens) flash system that fires a pre-flash to gauge exposure, they will often take off after the pre-flash, and the shutter and main flash burst will come after they are gone. I finally learned to avoid this by using manual flash settings, which do not fire a pre-flash.
Condylostylus species
bugguide.net/node/view/42317
Perhaps one of
Condylostylus sipho group
bugguide.net/node/view/479158
Edit. Detail shots added--see comments. This is a female and cannot be identified to species, but it seems to be a member of the C. sipho group. Many thanks to commenters for educating me about these flies!