Numbers
One of three species in the genus.
Size
10-13 mm including the horn.
Identification
Grayish spotted with yellow, or turquoise with red stripes and red eyes. With or without a thorn-like horn.
Range
Its Nearctic range is in a horseshoe shape, taking in the mid-Atlantic states, the southeastern states, the Deep South, Arizona, California, and Oregon. Present in some midwestern states such as Ohio, but lacking in the Plains states and Rockies. The species has been reported from Vancouver Island in Canada. It has also been reported from Mexico and Brazil.
Habitat
Forests and forest edges, parks, and anywhere Oak trees are found. Occasionally found on other trees, but these individuals were probably just resting on those non-Oak trees.
Season
Can be found at almost any time. Active in the South during winter, but probably not active then in the Northern states.
Life Cycle
Hatching occurs in Spring in the South, and in late Spring in the North. Larva pass through five instars, and adults and larva form aggregations along oak twigs of up to 100 individuals. Females seem to exhibit protective behavior, keeping predators away from the young.
Remarks
Does almost no damage to the host trees—leaves only a few twig scars from oviposition.
There are four named varieties and several other color variations, and some individuals lack the pronotal horn.
