Metallic Longhorns

Cerambycidae, Prioninae, Prionini,

Psalidognathus and Callichroma.

Longhorns in the genus Psalidognathus (fig. 9.14a) are large (BL 5-7 cm) and beautifully colored in metallic tones of blue, green, and purple. The jaws of the males are long and the elytra somewhat thin and flexible. The females are without flight wings, some even with shortened elytra as well. They never fly, remaining on the ground or at the foot of the host trees, which are true cedars (Cedrus) (Duffy 1960: 69). The males of some fly at dusk or at night and are readily attracted to lights. Other males (e.g., P. modestas) have been seen during the day flying in the Costa Rican cloud forest (Giesbert pers. comm.).

The closely related genera Callichroma, Plinthocoelium (fig. 9.14e), and Schwarzerion are smaller (BL 2—3 cm) and much more streamlined, compact longhorns but also brilliantly colored in metallic greens and blues and also characterized by a strongly flattened hind femur and tibia. Both sexes are fully winged and fly readily. They are unusual in the possession of scent glands that give off a pungent odor, described as pleasing and vanillalike (Robertson pers. comm.). According to Welling (pers. comm., via Chemsak), the natives on the Yucatán Peninsula eat these beetles as an aphrodisiac.

The larva of one common species in Trinidad, Callichroma velutinum, attacks dead logs of the balata tree (Manilkara bidentata). It feeds under the bark when young but at maturity, burrows deeply through the sapwood and heartwood where it matures and pupates. Because the wood of this tree is used for railroad ties, the beetle is considered a pest (Duffy 1960: 162-167).


Duffy, E. A. J. 1960. A monograph of the immature stages of the Neotropical timber beetles (Cerambycidae). Brit. Mus. Nat. Hist., London.

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