| Scientific name | Arilus cristatus |
|---|---|
| Group | True Bugs |
| Size | 25–38 mm (up to about 1.5 in) |
| Colors | Gray and Brown |
| Legs | 6 legs |
| Wings | Yes |
| Where found | Garden or plants and Trees or shrubs |
| Most active | Summer and Fall |
| Bites | Yes |
| Stings | No |
| Risk level | Can bite or sting |
How to identify it
The wheel bug is a large member of the true bugs group. Piercing, straw-like beaks and wings that overlap in an X on the back. Check for these three features:
- Semicircular, cog-like crest on the thorax
- Long, narrow head with a curved beak
- Slow, deliberate movement on plants
About this bug
A large, gray assassin bug with a raised, toothed crest on its back that looks like half a gear wheel. It hunts caterpillars and beetles and is a garden ally.
You'll usually find wheel bugs in gardens and on plants and on trees and shrubs. They are most active in summer and fall.
Is it dangerous?
Its bite is extremely painful and can take days or weeks to heal, so avoid handling it.
Our rating: Can bite or sting, meaning it can bite or sting, usually with mild, local effects.
When you'll see wheel bugs
Wheel Bugs are most active in summer and fall. Summer heat speeds up development, so populations can grow quickly. In fall, many bugs look for shelter, and some move toward or into buildings.
Typical places to check: garden or plants and trees or shrubs.
About true bugs
The wheel bug is one of the true bugs. True bugs have piercing, straw-like mouthparts used to suck plant sap or, in a few species, blood. They develop through gradual metamorphosis: nymphs look like small, wingless adults and molt several times as they grow. Many release strong odors from scent glands when threatened.
Because nymphs look like adults, you'll often see mixed sizes of the same bug together, which is a good sign that a population is breeding nearby.
Should you get rid of it?
No control is needed. Wheel Bugs are not pests, and many help by eating other insects or pollinating plants. If one is indoors, move it outside with a cup and a sheet of paper.
Bugs that look similar
Size: Wheel Bugs are larger, reaching 38 mm, while kissing bugs top out around 25 mm.
Size: Wheel Bugs are larger, reaching 38 mm, while western conifer seed bugs top out around 20 mm.
Size: Wheel Bugs are larger, reaching 38 mm, while brown marmorated stink bugs top out around 17 mm.
Frequently asked questions
What does a wheel bug look like?
Semicircular, cog-like crest on the thorax. Adults measure 25–38 mm (up to about 1.5 in).
Does the wheel bug bite or sting?
It can bite. It does not sting. Its bite is extremely painful and can take days or weeks to heal, so avoid handling it.
Where do wheel bugs live?
Wheel Bugs live in gardens and on plants and on trees and shrubs.
When are wheel bugs most active?
Mostly in summer and fall.