I found this insect in my own courtyard in the city of Pamplona, Navarre, Spain; during mid-February. My courtyard is never directly exposed to sunlight and is always cold, poorly lit and humid. It was 15 millimeters (0.6 inches) long when it kept its body still and straight, without counting the antennae which were 3 millimeters long each (0.1 inches). Its abdomen covered 2/3rds of its body length, and it constantly curled up and down. It also had a pair of wings, with the beginning of each partially covered by a shorter, brown, wing-like structure. To the exception of those brown coverings, its entire body was jet black and was slightly shiny.
I kept it in a test tube and put it with a spider that was almost its size. It was undisturbed by the spider and even approached it often.
Update: It dismembered the spider in less than a day.