Adelpha bredowi, the Sisters butterfly, is a species of the southwestern U.S. and Mexico. By 1981, Ferris and Brown had recorded specimens from eight Colorado counties, mostly in the southwestern corner of the state, but including El Paso and Douglas.
Although the foodplant is oak, which is abundant here, the species does not appear to thrive this far north. I never found it in my early years (1959-1983), but it has shown up four times since 2001. One of these records was a dead specimen on a street in Broadmoor (29 August 2003), where it was killed by a passing car. Two others are from Bear Creek Canyon (2 June 2001 and today, 25 August 2017), and the fourth is from an ephemeral pond immediately west of the large, disused landfill northwest of Bear Creek Road (26 June 2005). The June and August dates might suggest a double brooded species, or it might have a very long flight period. My suspicion is that as the autumns get longer and the springs get earlier, this species might be more often encountered here. I paid for this spectacular find, however, by stepping in a yellow jacket nest. They got me five times before I could escape. Here it is on my forearm, twenty-four hours later, even after aloe vera and benadryl cream. Geez.