Is the great black wasp dangerous to kids or pets?

No. The great black wasp is solitary — no colony to defend — and it stings only if physically grabbed or trapped, which almost never happens accidentally. University of Minnesota Extension states it is 'not aggressive toward humans' and 'will only sting if directly threatened or handled.' Males, which are frequently seen near burrows, have no stinger at all. Children and pets who walk past a foraging great black wasp are in no danger. The actual sting threat in your yard comes from social species — paper wasps and yellowjackets — that defend colonies numbering in the hundreds or thousands.

Is the great black wasp in New Hampshire?

Yes, but uncommon and near the northern edge of its range. Reference range maps list New Hampshire, and the species expanded northward into New York, Quebec, Ontario, and Nova Scotia during the late twentieth century. NH-specific photo records in citizen-science databases are sparse, so 'present but uncommon' is the honest verdict — not a common backyard fixture. Where it does occur in southern NH, adults are active mid-July through early September in sunny, open areas with bare or sandy soil. The NH range-edge status draws on Wikipedia's range expansion data and the insectidentification.org NH state listing as corroboration.

Should I kill a great black wasp?

No — there is no reason to. The great black wasp is a solitary, docile, beneficial insect that poses no sting risk under normal circumstances and delivers genuine ecological value. It hunts katydids and grasshoppers to provision its underground nest cells, acting as a natural population control for these crop and garden pests. It is also a significant late-summer pollinator of milkweed, mountain mint, and goldenrod. University of Minnesota Extension describes it as beneficial and non-aggressive. Killing it removes a useful predator and pollinator in exchange for protection from a threat that effectively does not exist for people walking past.

What is a great black wasp good for?

Two clear benefits: predator and pollinator. As a predator, it hunts katydids and grasshoppers — two to six per nest cell — acting as a natural check on those garden and crop pests. As a pollinator, it is a documented late-summer visitor on milkweed, mountain mint, and goldenrod at a time when many bee pollinators are winding down. Illinois DNR and University of Minnesota Extension both cite its beneficial role. It was also the subject of the first published scientific paper on a New World insect, presented to the Royal Society in 1749 by William Bartram — a historical footnote that reflects how long naturalists have recognized its ecological value.

How do I tell a great black wasp from a steel-blue cricket hunter?

Color quality is the key. The great black wasp (Sphex pensylvanicus) is matte-to-glossy flat black with smoky, dark wings. The steel-blue cricket hunter (Chlorion aerarium) shows a vivid metallic steel-blue or blue-green sheen across its body in daylight, and its wings have an oil-slick iridescence that is distinctly brighter than the great black wasp's smoky wings. Both species run 20–25 mm at the smaller end, so size alone does not separate them — look for the blue metallic sheen on Chlorion. Both are solitary, harmless, and beneficial; if you cannot determine which you have, the correct action is the same: leave it alone.

Does the great black wasp sting?

Technically yes, but practically almost never. Only females have stingers, and they sting only if physically handled or pressed against skin — not when foraging, flying over soil, or entering a burrow. Males, which are frequently seen near burrows and flowers, have no stinger at all. University of Minnesota Extension confirms: 'Only the female has a stinger, and she will only sting if directly threatened or handled.' The sting is mild relative to social wasps, and because this is a solitary species there is no alarm pheromone and no recruitable nestmates — a disturbance ends with one wasp, not a swarm.

Where does the great black wasp nest?

The great black wasp digs solitary underground burrows — typically about 30 cm (roughly a foot) deep — in compact but penetrable soil in open, sunny areas. Common sites include garden borders, unpaved paths, the edges of landscaped beds, and flat areas with sparse vegetation. Unlike a yellowjacket or cicada-killer aggregation, each great black wasp female has her own separate burrow. There is no shared entrance, no colony, and no defensive perimeter around the nest. A single female may dig several burrow cells in the same general area over the course of a season, visiting each to provision it with paralyzed katydids before sealing it with an egg inside.

How big is a great black wasp?

The great black wasp ranges from 20 to 35 mm in length, with females (25–34 mm) noticeably larger than males (19–28 mm). At the upper end, a female great black wasp is roughly 1.4 times the width of a US quarter (which is 24.26 mm in diameter, per US Mint specifications). That makes it a genuinely large insect — larger than a yellowjacket or paper wasp and comparable to some cicada killers at the smaller end — which is why it triggers alarm. Size alone, however, does not indicate danger in a solitary wasp. Wikipedia and insectidentification.org both document the 20–35 mm size range.

Why is there a big black wasp digging in my garden?

A female great black wasp is provisioning her underground burrow. She excavates a cell, hunts a katydid or grasshopper, paralyzes it with venom, and seals it in with an egg. The larva hatches and feeds on the paralyzed prey. Each cell holds two to six prey items. This digging looks alarming but is directed entirely at prey capture and nest construction — not at people. No intervention is needed. If you spot a solitary female making repeated trips to and from a hole in bare or sandy soil, watch for a few minutes and leave her to it.

Is a black wasp the same as a murder hornet?

No — entirely different insects. The northern giant hornet (Vespa mandarinia), called the 'murder hornet,' was declared eradicated from the US on December 18, 2024, by WSDA and USDA after three years without confirmed detections. It was found only in Washington State — never in New Hampshire or New England. The great black wasp is a native North American Sphecidae; the northern giant hornet is an Asian Vespa with no established presence in the eastern US. A large dark wasp digging in a NH lawn in midsummer is almost certainly a great black wasp or cicada killer — both solitary and harmless.

Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

|Reviewed by Daniel Brady

Great Black Wasp — What It Is & Whether It Stings in NH

Identification

The 'black wasp' people search is almost always the great black wasp (Sphex pensylvanicus) — a large (20–35 mm), glossy-black solitary digger wasp with smoky blue-iridescent wings. It is genuinely docile: it has no colony to defend, stings only if physically handled, and males have no stinger at all. In New Hampshire it occurs near the northern edge of its range — uncommon but harmless — and almost never warrants treatment. The metallic-blue lookalike is the steel-blue cricket hunter (Chlorion aerarium), a separate harmless species.

Quick facts

Size: 20–35 mm (females 25–34 mm; males 19–28 mm)Wikipedia — Sphex pensylvanicus; insectidentification.org
Sociality: Solitary — no colony, no nest to defendUMN Extension; Illinois DNR
Sting risk: Only if handled; males have no stingerUniversity of Minnesota Extension
Diet (prey): 2–6 katydids or grasshoppers per nest cellWikipedia — Sphex pensylvanicus

Size
20–35 mm (females 25–34 mm; males 19–28 mm)
Wikipedia — Sphex pensylvanicus; insectidentification.org
Sociality
Solitary — no colony, no nest to defend
UMN Extension; Illinois DNR
Sting risk
Only if handled; males have no stinger
University of Minnesota Extension
Diet (prey)
2–6 katydids or grasshoppers per nest cell
Wikipedia — Sphex pensylvanicus

Overview

Big, black, and buzzing — but not the threat it looks like

If a large, glossy-black wasp has stopped you mid-step in a garden or along a sunny path, you are almost certainly looking at a great black wasp (Sphex pensylvanicus) — and you can relax. At up to 35 mm long, it is one of the most visually striking insects in the Northeast, but it is also one of the most docile. Entomologists routinely describe it as a 'gentle giant': it is solitary, which means it has no colony and no defended nest, and it will not sting unless you physically grab or pin it. Males, which you see as often as females, have no stinger whatsoever.

The great black wasp's reputation suffers from a simple equation — big plus black plus buzzing equals dangerous — that does not hold up. Size correlates with social-wasp colony populations, not with aggression in solitary species. The wasps that actually sting people are the social ones (paper wasps, yellowjackets, hornets) defending hundreds or thousands of nestmates. A solitary wasp has no alarm pheromone cascade, no workers to recruit, and no evolutionary reason to waste its venom on a person.

In New Hampshire the great black wasp occurs near the northern edge of its range — listed for the state, but photo records are sparse and it should be treated as present-but-uncommon rather than a common backyard fixture. Where it does occur, adults are active from mid-July through September, when females are digging soil burrows and hunting katydids and grasshoppers to provision them, and when both sexes are important pollinators of late-summer flowers.

This page covers how to identify the great black wasp, how to tell it from its metallic-blue lookalike (the steel-blue cricket hunter), what its sting risk actually is, and what — if anything — you should do about it.

New Hampshire context

Great black wasp in southern and central New Hampshire

The great black wasp reaches the northern edge of its range in New England, and New Hampshire sits at that edge. The species is listed for NH on reference range maps, and its documented range expanded northward into New York, Quebec, Ontario, and Nova Scotia during the late twentieth century. However, NH-specific photo records in citizen-science databases remain sparse, and the species should be understood as present-but-uncommon rather than a common sight across Anchor's service area of Manchester, Nashua, Concord, and surrounding communities. Where great black wasps do occur in southern NH, adults are active from roughly mid-July through early September — the same window as late-summer pollinators and katydid/grasshopper season. Females excavate individual soil burrows in compact, sunny, often sandy ground (garden edges, unpaved paths, landscaped beds); each burrow is solitary and undefended. The presence of one or two large black wasps visiting flowers or patrolling the ground near a burrow entrance is a harmless event that requires no action. If what you are seeing instead is a steady stream of wasps flying in and out of a single hole with any sign of defensive behavior, that is not a great black wasp — it is almost certainly a ground-nesting yellowjacket colony, which is a very different situation.

Peak activity · Mid-July through early September

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Field identification

How to identify the great black wasp — and tell it from its lookalikes

The great black wasp looks formidable — it is one of the largest wasps a New Hampshire resident is likely to encounter — but three field marks confirm its identity and its harmlessness instantly.

Great black wasp

Also called: Katydid hunter, Black digger wasp

Rare in New HampshireSolitaryLow aggression

Scientific name: Sphex pensylvanicus
Family: Sphecidae
Sociality: Solitary
Size: 20–35 mm (females 25–34 mm; males 19–28 mm)
Coloration: Entirely matte-to-glossy black body; smoky blue-iridescent wings; narrow, thread-like waist (petiole); spiny hind legs. No yellow markings, no banding. In direct sunlight the wings show a faint blue-violet tint, but the body reads as flat black — not metallic blue like the steel-blue cricket hunter.
Range: Present in NH near the northern range edge — listed for the state and documented via range expansion into NY, Quebec, Ontario, and Nova Scotia in the late 20th century, but NH-specific photo records are sparse. Treat as present-but-uncommon. Active July–September where it occurs.
Nest style: Solitary underground burrow ~30 cm deep in compact, sunny soil (garden borders, unpaved paths, bare ground); each burrow is a single female's nest with no shared entrance and no colony
Sting: Mild and rare — stings only if physically handled; males have no stinger
Beneficial role: Provisions nest cells with 2–6 paralyzed katydids or grasshoppers per cell (natural pest control); significant late-summer pollinator of milkweed, mountain mint, and goldenrod

Colony?

None — each female nests alone

No nest to defend = no sting risk under normal circumstances

Active season

Mid-July through early September in NH

Timed to katydid and grasshopper peak; late-summer flower bloom

Historical note

Subject of the first scientific paper on a New World insect (Bartram, Royal Society 1749)

University of Minnesota Extension

Body color

Uniformly matte-to-glossy black with no yellow, brown, or banding of any kind. This immediately separates it from paper wasps (banded), yellowjackets (bright yellow markings), and cicada killers (rusty-red and yellow). The metallic blue-green sheen of the steel-blue cricket hunter is also absent — great black wasp reads as flat black.

Wings

Smoky and slightly blue-violet when viewed in direct sunlight — translucent with a dark tint. Held flat over the body at rest. Noticeably darker and less iridescent than the oil-slick wings of the steel-blue cricket hunter.

Waist (petiole)

Long and conspicuously narrow — a thread-like connection between thorax and abdomen typical of the Sphecidae family. This 'thread waist' is even more pronounced than on paper wasps and is a useful confirming mark when the wasp is at rest.

Legs

Black, slender, and spiny. Females use their strong hind legs together with their mandibles to excavate burrows in soil. In flight, legs do not dangle as prominently as paper wasps but are slender rather than tucked.

Size

Females 25–34 mm; males 19–28 mm. Noticeably larger than a yellowjacket (12 mm worker) or paper wasp (15–21 mm). A large female at ~35 mm is roughly 1.4 times the diameter of a US quarter (24.26 mm) — the size that triggers alarm but signals nothing dangerous in a solitary species.

Common look-alikes

Steel-blue cricket hunter (Chlorion aerarium)
How to tell: The most common great-black-wasp lookalike. The steel-blue cricket hunter is similarly sized (20–25 mm) and also has a slender black body — but its defining feature is a vivid metallic steel-blue or blue-green sheen across the body and oil-slick iridescent wings. In good daylight, Chlorion aerarium looks blue, not black. The great black wasp's body is matte-to-glossy flat black; its wings are smoky and dark but not oil-slick blue. Both are solitary, harmless, and beneficial — if you cannot determine which you have, the correct action is the same: leave it alone.
Eastern cicada killer (Sphecius speciosus)
How to tell: Also a large solitary digger wasp, but the cicada killer is dramatically different in color: rusty-red or orange head and thorax, black abdomen banded with bright yellow markings, and amber-tinted wings. It is also typically larger (30–50 mm). If the big wasp in your yard has any rusty-red or yellow on it, it is a cicada killer — not a great black wasp. Both are harmless solitary species.
European hornet (Vespa crabro)
How to tell: The European hornet is NH's only true hornet — brown and yellow, not all-black, and significantly bulkier. Workers are ~25 mm and queens reach 35 mm. The European hornet is a social species that flies at night and is attracted to lights, which the great black wasp is not. If you see a large brown-and-yellow wasp at a porch light after dark, that is a European hornet. See /bald-faced-hornet/ for hornet depth.

Common Questions

Frequently asked

References

Sources & further reading (10)

[1]
University of Minnesota Extension — Great Black Wasp
extension · Docility; 'not aggressive toward humans'; females sting only if handled; males have no stinger; beneficial predator and pollinator; Bartram 1749 first scientific paper · verified Jun 2026
[2]
Illinois DNR — Great Black Wasp
gov · Size (males ~0.7–1.1 in; females ~1.0–1.3 in); late-summer pollinator role; katydid/grasshopper prey; active July–September · verified Jun 2026
[3]
Wikipedia — Sphex pensylvanicus (Great Black Wasp)
encyclopedia · Size range 20–35 mm; females 25–34 mm vs males 19–28 mm; 2–6 katydids per cell; range expansion to NY/Quebec/Ontario/Nova Scotia; males lack stinger · verified Jun 2026
[4]
insectidentification.org — Great Black Wasp
encyclopedia · NH state listing (corroborative); size range confirmation · verified Jun 2026
[5]
insectidentification.org — Steel-Blue Cricket Hunter
encyclopedia · Steel-blue cricket hunter (Chlorion aerarium) metallic-blue coloration and size (20–25 mm); lookalike disambiguation · verified Jun 2026
[6]
USFWS — Steel-Blue Cricket Hunter (Chlorion aerarium)
gov · Chlorion aerarium taxonomy; metallic steel-blue sheen; harmless solitary behavior; lookalike disambiguation from great black wasp · verified Jun 2026
[7]
US Mint — Quarter Coin Specifications
gov · US quarter diameter = 24.26 mm (0.955 in) — true-to-scale size reference · verified Jun 2026
[8]
WSDA / USDA — Northern Giant Hornet Eradication (December 18, 2024)
gov · Vespa mandarinia declared eradicated from the US on Dec 18, 2024; only ever found in Washington State; never in NH or New England · verified Jun 2026
[9]
UMD Extension — Solitary and Social Wasps
extension · Solitary wasps sting only to capture prey, not in defense; field-test sorter (one hole + defensive stream = social; scattered holes + calm wasps = solitary) · verified Jun 2026
[10]
Northern New England Poison Center
medical · 24/7 poison control for NH/ME/VT; 1-800-222-1222 · verified Jun 2026

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

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Last updated Jun 2026

Anchor Pest Services

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Keep Exploring

Great Black Wasp — What It Is & Whether It Stings in NH

Big, black, and buzzing — but not the threat it looks like

Great black wasp in southern and central New Hampshire

How to identify the great black wasp — and tell it from its lookalikes

Great black wasp

Body color

Wings

Waist (petiole)

Legs

Size

Common look-alikes

Steel-blue cricket hunter (Chlorion aerarium)

Eastern cicada killer (Sphecius speciosus)

European hornet (Vespa crabro)

Frequently asked

Sources & further reading (10)

Wasps gone — and they stay gone.

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