Insect guide > Bugs > Wheel Bugs

Wheel Bugs

Life History of the Wheel Bug
(Arilus cristatus L.)
This is a large predatory bug common all through our southern states and Mexico and which extends up into southern Illinois and New Jersey and even to Long Island and Rhode Island. It is popularly known as the "wheel bug" and sometimes as the "devil's riding horse" and is referred to in the older books as Reduvius novenarius and Prionotus or Prionidus cristatus.

The eggs of the wheel bug look like miniature leather bottles standing on end and in hexagonal clusters, seventy or more in a
group, and attached to the bark of trees, on fence rails, or whereever the female chances to be. In this stage the insect passes the winter. In the late spring the cap of the bottle is pushed off and the young bug emerges. The young insect has a blood-red abdomen and its thorax is marked with black. In walking it frequently elevates the abdomen, curving it over forwards. It feeds upon soft-bodied insects, its attacks, while young, being confined mainly to such weak, delicate species as plant-lice. As they grow larger they attack larger insects and when full-grown destroy large caterpillars. They seem to inject a poison into the wound made by the beak and Glover tells of a bite on his thumb which was severely poisoned and gave him great trouble. After four molts the peculiar crest on the thorax appears which has given this insect its specific scientific name cristatus (crested) and its popular name "wheel bug". This is a semicircular longitudinal crest bearing nine teeth, prongs or cogs like a cog-wheel.

The full grown bug is sordid black in color. It captures its prey not by agility but by stealth. Its coloration is protective
and it slowly crawls up to some caterpillar or other insect, advancing one leg after another with a movement so slow as almost to be imperceptible. When once within striking distance, however, the beak is thrust into the victim which is at the same time grasped with the front legs with a movement which is quite the reverse of slow.

The wheel bug is a beneficial insect. It is a common inhabitant of southern cities and in such places as Baltimore and
Washington is an important factor in the destruction of the numerous caterpillars which defoliate shade trees.