This is a large and impressive potter wasp, usually 20 to 30mm; males are smaller and thinner. Brilliantly marked with yellow, brown and black. The yellow colouring forms a distinctive pattern on the thorax.
This species is sometimes known under the synonyms of Delta pyriformis or Eumenes pyriformis. It is quite widely distributed; besides Hong Kong, its range includes Myanmar, India, Taiwan and Mainland China.
This is a common species; in Hong Kong, it is sometimes active even through the colder part of winter. It uses a variety of nesting sites, often in the open. Because of its large size, it often attracts considerable attention and also causes consternation. Despite its menacing appearance, it is totally harmless and has a surprisingly mild sting, and will not attack anyway. If you happen to catch sight of one and see it in the process of building its nest, I suggest you watch this fascinating process. Just don't get too close, not for fear of being attacked but to prevent scaring it away!