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Great Black Wasp

Sphex pensylvanicus[4]

The great black wasp is a large, solitary, satiny black wasp, about 1 to 1 1/4 inches long, with smoky black wings that shine blue or violet; it visits garden flowers in late summer and is not aggressive.[1][2][3]

Group
Insect
Order
Hymenoptera
Family
Sphecidae
US records
40 states
Sources
4 cited
Updated
2026-10-16
Great black wasp with smoky blue-black wings on a flower
Great black wasp with smoky blue-black wings on a flower. (c) DiegoH, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Females are about 1 to 1.3 inches long and males 0.7 to 1.1 inches.[2][3]
  • The body is black and the smoky black wings have a blue or violet iridescence and are usually folded lengthwise down the back.[1][2][3]

Look-alikes

Look-alikeHow to tell them apart
Great golden digger waspA very close relative in the same genus with orange on the body.[1]
Mud daubersRelatives in the same family of thread-waisted digger wasps.[1]
Cicada killerAnother large solitary ground-nesting wasp that hunts cicadas rather than katydids.[1]

Where it lives

Common across the eastern and central United States, including Missouri, Minnesota and Illinois.[1][2][3]

US map: public records from 40 states since 1990 (GBIF).

Biology and life cycle

Adults are seen on flowers in open areas from July through September.[1][2][3]

Females hunt grasshoppers, katydids and crickets, sting each to paralyze it, and fly it back to an underground nest, placing two to six in each cell with one egg; a single female can catch 16 hoppers a day.[1][3]

The larva feeds on the paralyzed prey for about 10 days; birds such as catbirds and sparrows sometimes steal the prey.[1][3]

Damage and signs

  • It does not harm plants; adults drink nectar and pollinate milkweeds and plants in the carrot and bean families, and the larvae help control grasshoppers.[1][2][3]

Health risk

It can sting if disturbed and the sting is reportedly painful, but it is not aggressive, rarely stings and is dangerous only to people allergic to stings.[1][2]

Control

Prevention

No control is needed; it is a gardener's friend that helps control grasshoppers and katydids.[1][2]

Common questions

What is the huge black wasp with blue wings on my flowers?
Likely a great black wasp.[1][2]
Will it sting me?
Rarely; it is not aggressive, though it can sting if disturbed.[1][2]
What does it eat?
Adults drink nectar; larvae eat paralyzed grasshoppers and katydids.[1][3]

Sources

  1. Missouri Department of Conservation, “Great Black Wasp (Field Guide).” mdc.mo.gov/discover-nature/field-guide/great-black-wasp (accessed 2026-10-16)
  2. University of Minnesota Extension, “Great black wasp (What insect is this? diagnostic pages).” apps.extension.umn.edu/garden/diagnose/insect/garden/flies/large/greatblackwasp.html (accessed 2026-10-16)
  3. Illinois Department of Natural Resources, “great black wasp, Sphex pensylvanicus (Biodiversity of Illinois).” dnr.illinois.gov/education/wildaboutpages/wildaboutinvertebrates/wildaboutwasps/wabwgreatblackwasp.html (accessed 2026-10-16)
  4. iNaturalist, “Sphex pensylvanicus taxon page (order and family).” www.inaturalist.org/taxa/48738 (accessed 2026-10-06)

Updated 2026-10-16. Built from sourced records. Spot an error? Tell us.