This is a beautiful and impressive potter wasp, ranging from 25 to 29mm; males are smaller and thinner. Brilliantly marked with yellow and black. The yellow pattern on the thorax distinguishes it from other species. The petiole (the “waist” joining thorax and abdomen) is also very long, even by potter wasp standards.
This species is sometimes listed as Phi flavopunctatum in Hong Kong and Mainland Chinese publications; this is an outdated name. I have also seen it featured on a stamp in Singapore, and referred to as “Delta arcuata“. I have no idea about the validity of this name, but since it appears to have structural characteristics distinguishing it from members of the genus Delta, I will stick with the current name. It can be found in Hong Kong, Taiwan and parts of China and Thailand. I did not expect to find it as far south as Singapore, but it is quite surprisingly common there. Source
Location: Choa Chu Kang – August 2021
Thanks Zestin Soh Bees & Wasps of Singapore for the ID
