The adult weevil is dark brown with a large, bulbous snout.

It is active throughout the summer when the female lays yellow eggs in the opened flower head.

The larva emerges and feeds on the developing seeds inside the head.

It was first introduced to the United States for the biocontrol of knapweeds in the Boulder, Colorado area in 1991.

[1] This weevil is quite similar to its relative, Larinus minutus, which is also a knapweed specialist used for biocontrol.