California Root Borer, male and female (Prionus californicus):  This rather large species of long-horned beetle can grow to over 2 inches. The way to quickly determine male from female is by the antennae. The antennae of males are very saw-toothed (and about 2/3 the length of the body). Females have more slender and shorter antennae. They can be found throughout western North America and feed primarily on living deciduous trees (cottonwood). Their lifecycle takes between 3 to 5 years to complete. Photo of male by Siren Ambush on 8/10/18 in western, MT. Photo of female by Erin Mills on 8/12/18 in Lolo, MT.