What Are These Bugs on My Cactus?! Cactus coreids or cactus bugs, Chelinidea vittiger, are shield-shaped insects with piercing-sucking mouthparts. They are most commonly red but can vary in color. They have distinctive antennae; if you look at the antennae in cross section, they are triangular in shape. Adults have fully developed wings while immatures, or nymphs, do not and are sometimes mistaken for weevils. Cactus coreids feed in groups on prickly pear cactus. Often the first indication of damage is round, yellowish spots on the cactus pads…. Read More →