Diomus insidiosus is a species of beetle of the family Coccinellidae. It is found in eastern Australia.
Description Adults reach a length of about . They are variable in colour, but the head, pronotum, antennae and legs are usually yellowish, while the elytra are dark brown to almost black with two yellowish markings. The dorsal surface is covered by yellowish pubescence, forming wavy patterns on the elytra.
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