Omalodes grossus
Nogales, Santa Cruz County, Arizona
Coordinates: 31.335112, -110.937919
Elevation: 3,931 ft
September 2, 2019
Size: 11.5 mm
Found on very wet kitchen compost bin teeming with soldier fly larvae
It only had three legs
Determined by Alexey Tishechkin, via these images, who said: “Locality and size definitely call for O. grossus Marseul (= texanus Marseul). O. ruficlavis Marseul (= klugii Marseul, laevigatus Erichson, vitreolucens Casey) is smaller and known in the US only in Florida.”