Botany Bay Diamond Weevil

The body of Chrysolopus spectabilis is an elongated oval 15–25 millimetres (0.6–1.0 in) long. The elytra are black, with irregular spots of bright metallic green. The underside of the body is shaded in matt green, and a white or green line runs the length of the animal's sides. The head, thorax and legs are black with occasional metallic green markings. The colouration varies across the year, with animals emerging later in the season having a bluer colour. The snout is about as long as the bell-shaped pronotum, and strongly curved. The geniculate antennae arise from halfway along the snout, and end in a small club. The compound eyes protrude slightly. The elytra display a row of furrows with slight depressions, and the animal's ventral side is also covered with scales. The powerful legs have a thick covering of hair on the tarsi, which have no claws.

The larvae are 40–50 mm (1.6–2.0 in) long; they are white, round and wrinkled, with a few hairs on their sides, and a red–brown head with black mandibles. To date, the pupa has not been described.

Chrysolopus spectabilis occurs in the eastern and southern states of Australia, with a range stretching from the coastal region of Queensland to Victoria and eastern parts of South Australia. It is most common in eastern parts of New South Wales, particularly the surroundings of Sydney, and out to the foothills of the Great Dividing Range.

Adults are active both in daytime and at night, mostly during the warmer months (November–March). During this period, C. spectabilis is often seen in built-up areas and woodlands in areas with moderate precipitation, particularly around Acacia plants. In open areas, such as northern New South Wales, Acacia species with phyllodia (flattened leaf petioles) are preferred, but in more wooded areas, such as the Blue Mountains, species with paripinnate leaves are preferred. Adult beetles have been recorded on 28 Acacia species, out of the 1000 species present in Australia; the larvae, on the other hand, have only been recorded on seven species. The larvae are, however, thought to feed on the same species as the adults.

Development of the beetles to the adult state usually takes less than a year. Females bore up to 20 small holes close to each other in the stem of the Acacia plant, immediately above the soil level, and lay a single egg into each hole. After hatching, the grubs bore deeper into one of the plant's main roots. The imagines (adults) emerge in the spring in the more southerly latitudes, but can emerge throughout the year in the subtropical parts. They bore their way out of the plant, leaving the empty pupal case behind.