Pine bark beetle to scale.
Adults: reddish-brown to black, about the size of a grain of rice. They breed from April until late summer, producing two to three generations each year. Adults can be found making egg-laying tunnels, called galleries, in the inner bark. Mounds of reddish boring dust on the trunks of pines are evidence of pine bark beetle attack.
Larvae: small, cream-colored grubs. Larvae can be found feeding in galleries in the inner bark.
Galleries: Y- or X-shaped tunnels beneath the bark. Larvae, pupae, and adults can be found in the galleries during the growing season. Galleries are empty during the late fall, winter, and early spring.
Exit holes: small, round holes in the outer bark created by adults exiting the tree. Due to an abundance of exit holes, a tree that has died from bark beetle attack looks as if someone shot it with a shotgun.