Ironclad beetles belong to a small family of beetles which contains only about 20 species. These beetles are found mostly in the western and southwestern United States. They venture down into Mexico and one species is found on shelf fungus in the New England states.
Ironclad beetles range in size from about ½ to 1 1/4 inches in length. Some of the species are entirely black but some are strikingly marked with white and black patterns, which can make it very difficult to locate them on the trunk of trees.
These beetles are unique in that they have no hind wings and their elytra (front wings) are fused together. Thus they do not fly but crawl from place to place.
The ironclads are indeed tough. Many a strong lad has lost a bet that he could crush a beetle by squeezing it between the thumb and forefinger.
This group of beetles have not been studied thoroughly and very little is known about their biology and habits.
Immature forms have been collected from dead wood of pecan and oak trees. The beetles have not been found to damage living trees, or any other plants. The adults may feed on lichens growing on dead wood.
Adults appear in midsummer. They may be found crawling slowly on tree trunks, posts, patio floors, sidewalks, and up walls.
Ironclads are very slow moving and will fane death (roll over and play dead) when disturbed.