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Species Arilus cristatus - Wheel Bug

Hatchlings - Arilus cristatus Wheel Bugs? - Arilus cristatus - male - female Squash Bug or Assassin Bug Nymph - Arilus cristatus Young Assassin Bug - Arilus cristatus Bug 0969 - Arilus cristatus Gray Insect - Arilus cristatus Florida WheelBug - Arilus cristatus Wheel Bug - Arilus cristatus - male Acanthocephala? - Arilus cristatus Wheel Bug - Arilus cristatus assasin bug? - Arilus cristatus Wheel Bug - Arilus cristatus
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies)
Suborder Heteroptera (True Bugs)
Infraorder Cimicomorpha
Family Reduviidae (Assassin Bugs)
Subfamily Harpactorinae
Genus Arilus
Species cristatus (Wheel Bug)
Synonyms and other taxonomic changes
Arilus cristatus (Linnaeus)
Orig. Comb: Cimex cristatus Linnaeus 1763
Explanation of Names
cristatus - Latin for "crested"
The common name derives from the cog-like projection on the back of the mature insect.
Numbers
1 sp. n. of Mex.
Size
at 28-36 mm (females larger than males), our largest assassin bug (1)
Identification
The "wheel" on the adult insect's back is unmistakable. Immature nymphs are mostly red. Adults are gray to brown.
Range
CA-FL-NJ-NE / Ont. / Mex. to C. Amer. (Hagerty & McPherson 2000)
Habitat
Found where prey is abundant: adults often lurk on composite (daisy-like) flowers attractive to insects, or prowl in trees where caterpillars are plentiful.
Season
Nymphs hatch in spring, adults are found late spring into fall and early winter.
Food
All stages prey upon other insects - caterpillars, aphids, bees, sawflies etc. - and are thus considered beneficial.
Life Cycle
One generation occurs per year. Adults mate in fall, the male then guards the female
since other males may try to move in .
Clusters of eggs (described as "brown bottles with fancy stoppers") are laid in hexagonal clusters of 42-182 on trees, shrubs or other structures, generally within 4 feet of the ground
.
Here's a great series from Jim Kramer on eggs and hatching (more in the guide):

After eggs hatch in spring , nymphs develop slowly. They must
watch out for predators including their own brethren!
and
(about 3 months to maturity): red/black
;
red/grey
;
grey/black
.

They hunt down their prey such as this one walking on a Hyphantria tent
and attack
They have a heavy beak for feeding ,
pierce their prey and eat
.
They need to molt in order to grow, described by one contributor as looking like an orange bug with a spider stuck on its tail!

.
Which can be fatal if they can't extricate themselves:

Adults are generally not seen until May even in warmest parts of US



Some are unfortunate victims of parasitoids .
Despite chemical defenses
Others thrive, sometimes even with deformed wheels ,
reproduce,and the cycle begins again. Adults may survive into December in warmest regions.
Remarks
CAUTION: The bug can inflict a very painful bite. Ammonia water and magnesium sulphate soaks can be helpful in relieving pain from the bite. Perhaps (like fire ant bites), quick treatment with an ammonia-based household cleaner may be effective if you have been bitten. More suggestions here.
Print References
Hagerty, A.M., & J.E. McPherson. 2000. Life History and Laboratory Rearing of Arilus cristatus (Heteroptera: Reduviidae) in Southern Illinois. The Florida Entomologist 83(1): 58-63. (PDF) (life history)
Internet References
Fact sheet: Featured Creatures - F.W. Mead, U. of Florida, 2008
Works Cited
1.How to Know the True Bugs
Slater, James A., and Baranowski, Richard M. 1978. Wm. C. Brown Company.