Colorado has a combination of big and small beetles, the ten-lined june beetle, 22-30 mm long being the largest, and the 9-13 mm long emerald ash borer beetle the smallest. The Colorado potato beetle mainly infesting potatoes is not just found in Colorado but other states as well.

Another pest worth mentioning, that mostly attacks the several pine tree species found in Colorado is the mountain pine beetle. While species of the skin beetle family found in most Colorado homes are notable house pests.

Large Beetles: Ten-lined June Beetle, Colorado Potato Beetle, Black Blister Beetle

Small Beetles: Emerald Ash Borer Beetle, Black Carpet Beetle

Common Beetles: Colorado Potato Beetle, Golden Tortoise Beetle

Leaf Beetles

• Colorado Potato Beetle (Leptinotarsa decemlineata)
• Apple Flea Beetle (Altica foliaceae)
• Sumac Flea Beetle (Blepharida rhois)
• Golden Tortoise Beetle (Charidotella sexpunctata)
• Checkered Melon Beetle (Paranapiacaba tricincta)
• Rubber Rabbitbrush Beetle (Ericameria nauseosa)
• Spotted Cucumber Beetle (Diabrotica undecimpunctata)
• Elm Leaf Beetle (Xanthogaleruca luteola)

Click Beetles

• Eastern Eyed Click Beetle (Alaus oculatus)

Ground Beetles

• Punctured Tiger Beetle (Cicindela punctulata)

Longhorn Beetles

• New House Borer Beetle (Arhopalus asperatus)
• Locust Borer Beetle (Megacyllene robiniae)
• Pine Sawyer Beetle (Monochamus galloprovincialis)
• Pole Borer Beetle (Neandra brunnea)
• California Root Borer Beetle (Prionus californicus)
• Red Milkweed Beetle (Tetraopes tetrophthalmus)

True Weevils

• Cherry Curculio Beetle (Anthonomus consors)
• Plum Curculio Beetle (Conotrachelus nenuphar)
• European Elm Flea Weevil (Orchestes alni)
• Black Vine Weevil Beetle (Otiorhynchus sulcatus)

Bark Beetles

• Mountain Pine Beetle (Dendroctonus ponderosae)
• Spruce Beetle (Dendroctonus rufipennis)

Water Scavenger Beetles

• Giant Black Water Beetle (Hydrophilus triangularis)

Scarab Beetles

• Ten-lined June Beetle (Polyphylla decemlineata)
• Japanese Beetle (Popillia japonica)

Jewel Beetles

• Emerald Ash Borer Beetle (Agrilus planipennis)

Skin Beetles

• Black Carpet Beetle ( Attagenus unicolor)
• Varied Carpet Beetle (Anthrenus verbasci)
• Furniture Carpet Beetle (Anthrenus flavipes)

Ptinidae Beetles

• Common Furniture Beetle (Anobium punctatum)

Pleasing Fungus Beetles

• Blue Fungus Beetle (Cypherotylus californicus)

Soldier Beetles

• Colorado Soldier Beetle (Chauliognathus basalis)

Ladybird Beetles

• Convergent Lady Beetle (Hippodamia convergens)

Fire-colored Beetles

• Cardinal Beetle (Pyrochroa coccinea)

Blister Beetles

• Margined Blister Beetle (Epicauta funebris)
• Black Blister Beetle (Epicauta pensylvanica)