Nigma walckenaeri is a green, cribellate spider up to 5 millimetres long, the biggest of the family Dictynidae. While most of the body is a bit yellowish, the abdomen is a shining green, which makes it rather distinct and hard to confuse with other species. The green color makes it almost invisible. Males have an elevated head region. From August to October these spiders can be found in gardens or on walls - often on big leaves such as lilac or feral grapevine.