Flew indoors through open door. At first glance It looked like a smallish Elderberry Longhorn, but its antennae were banded and the elytral blue was more navy-to-black. Agrees with body shape, colors and pattern for female of species, Yanega, plate 6, however, it is 3mm longer than the upper limit given in that source (10-15mm). If ID is correct, the extrusion from the posterior must be an ovipositor.