Adult: This small beetle is predominately a secondary pest but may be a primary pest in some situations. It is reddish brown and up to 4.5 mm long. The last three segments of the 11 segmented antennae are
abruptly enlarged to form a club. This beetle is capable of flight, but seldom flies.
Larvae: The immature stage is approximately 4-5 mm long, white to yellowish in colour, and wiry in appearance. The last abdominal segment ends with two prominent points called urogomphi. Heavy infestations of flour by this insect may cause the product to turn greyish or mould prematurely. This insect can also impart a nauseous smell and taste from its scent glands to the material infested. Both adults and larvae cause damage. This beetle is an extremely important pest of flour, but also feeds on moist milled grain products, grain dust and broken kernels, processed beans, nuts, spices, chocolate, and pharmaceuticals especially once these products are damaged by primary stored food products. Female beetles will deposit 400-500 eggs in food or food sacks during a 2 or more year life span. Eggs hatch in 5-12 days; the larvae can mature within 22 days or can take as long as 120 days depending on surrounding temperature, type of foodstuff and relative humidity. The life cycle for one generation is 20 days.