Found under an aluminum pan with about 30 "Pill Bugs" with a slight bit of moist soil remaining. The pan is a catch pan under a double cement set of sinks in the garden used to wash produce. The beetle acted dead & was folded up when first exposed, but it caught my eye & I checked it out & it wasn't crunchy....so I pocketed it & brought it in the house for photo session then released. Sorry, I for got to take a measurement, but think it to have been just under 20mm.