We return to the beetles again this week and focus on the family Brentidae. Specifically, the beetle Arrhenodes minutus. Common name is oak timberworm. Larvae often tunnel in oak and elm trees and this species can be a pest. This insect is a known vector of the fungus which causes oak wilt. This species ranges throughout the eastern United States. 

As adults, males and females show dimorphism in their mouthparts. Male mouthparts are flattened and broad. They use these manbibles in combat with other males. A male is shown in the photo. Yes, I collected this insect over 2 decades ago in central Illinois.