I think this is likely A. porosus. A. pallidicollis doesn't have the metallic green colouration on the underside of the abdomen like here, and often a larger extent of coverage of the abdominal sternites with white setae. See this picture for a typical appearance: https://inaturalist-open-data.s3.amazonaws.com/photos/351552667/original.jpeg A. porosus and A. pallidicollis look very similar in our area on the dorsal view. It's ideally best to get a view of the pygidium and look at the pattern of setae there (covered entirely in short, white setae for A. pallidicollis, and white setae only along the margins and through the centre line in A. porosus).