Eumenes dubius can reach a length of about 13 millimetres. The first metasomal segment is narrow and elongated, creating a "bulbous" appearance to the abdomen. Body is black with yellow markings. These wasps lack of standinghairs on the first tergum and show a very short general pilosity, with a short pubescence on head's rear. In malesclypeus is long, with smooth and bright yellow free margin. Mandibles are orange yellow, basally spotted. In the females scape is ventrally yellow, while dorsally it is orange-yellow, with a thin black line on flagellomeres 3–9. These flagellomeres are black dorsally, while the others are orange-yellow. The last flagellomere is recurved.
Biology
These potter wasp are predatory of caterpillars. They build cells which are complete spherical pots.