Misumessus
Misumessus is a small genus of New World crab spiders, and almost everything the public knows about it comes from a single species: the American green crab spider, Misumessus oblongus. These are tiny, translucent green ambush hunters that build no capture web at all. They wait on a leaf or a blossom with their long front legs cocked open like tongs, and kill insects several times their own weight.
By Dr Richard J. Pearce (PhD)Published September 9, 2019Updated September 13, 2026✓ Reviewed by Dr. James Watuwa
In this guide
Physical description and identification
Misumessus is a genus of small crab spiders in the family Thomisidae, erected by the American arachnologist Nathan Banks in 1904. It is a strictly New World group, confined to North America and the Caribbean, and a small one: only a handful of species are recognised, and the count has shifted as revisions shuffled species between Misumessus, Misumenops and Mecaphesa. To most people the genus means one spider — the American green crab spider (Misumessus oblongus), common in gardens and old fields across the United States.
The body plan is pure thomisid: flat and broad, the front two leg pairs much longer and heavier than the rear two and all eight held sideways in the laterigrade posture, so the spider walks forwards, backwards and sideways equally well.
Adults
- Size: mature females of M. oblongus run roughly 4–6 mm in body length and males 3–4 mm. Older accounts put the female at 3 mm and the male at half that; a 1.5 mm adult crab spider would be extraordinary, and males are nearer two thirds the female's length.
- Colour: pale translucent green, sometimes shading to yellowish white. The green shows through a thin cuticle rather than sitting on it, so it fades within days in preserved specimens. Many individuals carry faint reddish stripes along the sides of the abdomen, and M. oblongus often shows a pale kite-shaped figure on top.
- Eyes: eight small eyes in two strongly recurved rows of four, the side eyes raised on tubercles. Resolution is poor; these spiders react to movement and to vibration through the leaf. See our guide to spider eyes.
- Distinctive features: carapace, abdomen and legs carry scattered stiff erect bristles, giving Misumessus a slightly spiny look that separates it from the smooth-bodied Misumena and Misumenoides. Males are browner and longer-legged, with swollen palp tips.
Eggs and egg sacs
The female builds a flattened white sac inside a folded leaf, or between two leaves stitched together with silk, then stands over it and stops hunting. In M. oblongus she usually dies before the spiderlings break out, so the young get no care beyond the sac itself.
Spiderlings
Hatchlings are nearly colourless and stay inside the sac for their first moult, then disperse by ballooning — how a spider that never leaves its plant reaches new ground. Juveniles feed through the summer, overwinter part-grown in litter or evergreen foliage, and mature the following late spring; the life cycle takes about a year.
The hunt, not the web
No Misumessus spins a capture web. Silk still matters — dragline, egg sac, moulting pad, sperm web, ballooning thread — but nothing is built to trap food. A green spider sitting in an orb or a sheet is something else; compare the structures in our overview of spider webs.
Where Misumessus spiders live
The genus is American and nothing else, covering North America and the Caribbean with no established populations elsewhere. Misumessus oblongus is the widespread member, recorded from New England and southern Canada south to the Gulf states, west to California and on into Mexico. The remaining species are far more restricted, concentrated in the subtropical south — Florida in particular — and on Cuba, Hispaniola, Jamaica, Puerto Rico and the Bahamas.
The habitat is low green vegetation in good light: old fields, meadows, woodland edge, hedgerows, garden borders, orchards and crop margins. Dark closed forest holds almost none. The spider sits on the upper surface of leaves, on stems and on flower heads, usually within a metre or two of the ground. This is where Misumessus parts company with the flower specialists: Misumena vatia and Misumenoides formosipes post themselves inside a bloom and wait for pollinators, while Misumessus is more a foliage spider, green on green. A beating tray worked through a shrub layer in early summer turns up far more than searching flowers does.
Are Misumessus spiders venomous?
Yes, and usefully so. Like almost all spiders, Misumessus injects venom to subdue prey, and crab spider venom is unusually effective for the size of the animal: a 5 mm spider can stop a bee heavier than itself within seconds. None of that translates into risk for people. The genus has no medical significance anywhere in its range, no antivenom exists or is needed, and there are no credible reports of necrotic lesions or systemic illness from a bite. The word "poisonous" is worth retiring here: these spiders are venomous, and nothing about them is harmful to touch.
Can Misumessus spiders bite?
They can, in the sense that any spider with working fangs can, but bites are close to non-existent. The spider's first response to a hand is to drop off the leaf on a dragline; it has no defensive display, and the fangs are so small that they struggle to grip adult human skin at all.
If a bite does happen, expect a sharp pinprick, a small red mark and perhaps an hour of mild itching — many people would not notice it. Wash the spot with soap and water, apply a cold pack if it is sore, and leave it alone. The realistic complication is ordinary skin infection rather than venom, so see a doctor if redness spreads, the area turns hot and swollen, or pus appears.
The identification that matters: two very different animals get called "green spiders" in North America. A Misumessus is 4–6 mm, flat and pale translucent green, with short rear legs and long crab-like front legs held sideways. The green lynx spider is a bright green hunter three or four times that size, with long black-spined legs and eyes arranged in a hexagon; it guards its egg sac and can eject venom as a spray when harassed. Neither is dangerous, but only one of them stands its ground.
Ecological importance and behavior of Misumessus spiders
Misumessus spiders are pure sit-and-wait predators. The spider settles on a leaf or petal, folds its body low and holds the two long front leg pairs apart and slightly raised, a pose it can keep for hours. When an insect lands within reach the legs snap shut, the spider bites at the neck membrane or wing base where the cuticle is thin, and holds on while the venom works. There is no wrapping and no hauling of prey to a retreat, because there is no retreat.
Diet: flies and hoverflies, small bees and wasps, leafhoppers, aphids, thrips, small moths and beetles, and occasionally other small spiders. One correction to the older account of this genus is worth making: centipedes and millipedes are not part of the diet. Those are ground-dwelling animals with chemical defences that a 5 mm spider perched on foliage never meets.
Natural predators: mud-dauber and spider wasps matter most, since they hunt spiders to provision their nests, and parasitoid wasps attack the egg sacs. Birds, ants, assassin bugs, mantises and larger spiders take them too.
Prey-predator dynamics: camouflage does double duty — the green that hides the spider from a fly also hides it from a foraging warbler. The cost is opportunity: pick the wrong plant and you go days without a meal.
Seasonal behaviour: adults are on the vegetation from late spring into early autumn, mature males appearing first and wandering in search of females. Males live only weeks. Females persist into late summer, produce their sac and die; the genus overwinters as half-grown juveniles.
Relationship with humans: benign and quietly useful. Generalist predators like these help suppress aphids, leafhoppers and small caterpillars in orchards and vegetable plots, which is why pest management programmes try to keep them alive rather than spray them out.
Species in the genus and similar spiders
| Spider | What sets it apart |
|---|---|
| American green crab spider (Misumessus oblongus) | The type species and the only one most people see. Pale translucent green, females 4–6 mm, with a faint kite-shaped mark on the abdomen. Widespread from Canada to Mexico. |
| Other Misumessus species | A small set of southern and Caribbean spiders, several known from very little material. They are separated on adult genitalia, so photographs alone will not name them. |
| Goldenrod crab spider (Misumena vatia) | Much larger, females to about 10 mm, smooth-bodied rather than bristly, and able to switch slowly between white and yellow. It sits in the bloom, not on the leaf. |
| Misumenoides and the white-banded crab spider | Recognised at once by the white ridge, or carina, across the face below the eyes. Bulkier than Misumessus. |
| Mecaphesa species | The genuinely difficult confusion: also small, also bristly, historically shuffled between the same genera. More heavily spined, and separation is a microscope job. |
| Green lynx spider (Peucetia viridans) | Bright green and far bigger at 12–22 mm, with long black-spined legs and eyes set in a hexagon. An active hunter. |
Quick facts
| Rank and authority | Genus Misumessus Banks, 1904; family Thomisidae. |
|---|---|
| Species | A handful, all American; Misumessus oblongus is the type and the only widespread one. |
| Distribution | Southern Canada to Mexico, plus the Caribbean islands. Not introduced elsewhere. |
| Habitat | Meadows, woodland edge, hedgerows, gardens and crop margins. |
| Web type | None. Silk is used for draglines, egg sacs, moulting pads and ballooning. |
| Diet | Flies, small bees and wasps, leafhoppers, aphids, thrips, moths, beetles. |
| Lifespan | About one year; juveniles overwinter, adults appear from late spring. |
| Predators | Mud-dauber and spider wasps, birds, ants, mantises, larger spiders. |
| IUCN status | Not evaluated; M. oblongus is common and shows no sign of decline. |
Did you know?
- Nathan Banks, who named the genus in 1904, was one of the most prolific describers of North American arachnids, and his material still underpins identification work.
- For much of the twentieth century these spiders sat in Misumenops. Later revisions of the Thomisidae restored Misumessus and moved many former Misumenops species to Mecaphesa, which is why species counts differ between sources.
- The green colouring is not a surface pigment layer, so a Misumessus preserved in alcohol turns a disappointing cream within days.
- A spider that never leaves its plant still travels: ballooning spiderlings can be carried for kilometres on rising air.
In summary, Misumessus is a small, entirely American genus of crab spiders best represented by the green crab spider of gardens and old fields. They spin no capture web, hunt by ambush from foliage, are venomous to insects and irrelevant to people, and they earn their keep as unpaid pest control in almost every hedgerow they occupy.
Frequently asked questions about the misumessus
What does a Misumessus spider look like?
Small, flat and pale translucent green, sometimes shading to yellowish white, with faint reddish stripes along the sides of the abdomen. The two front pairs of legs are long and held out sideways like a crab's claws, and the body carries scattered stiff bristles. Females reach about 4 to 6 mm; males are smaller, darker and browner.
How big do Misumessus spiders get?
Adult females of the common green crab spider measure roughly 4 to 6 mm in body length, about a quarter of an inch, with the legs adding more. Males are around 3 to 4 mm. Older accounts claiming 3 mm females and 1.5 mm males understate the genus; males are about two thirds the female's length.
How do Misumessus spiders catch their food?
By ambush. The spider settles motionless on a leaf or flower with its long front legs held open, relying on its green colouring to hide it. When an insect lands within reach the legs snap shut and the spider bites through thin cuticle at the neck or wing base, holding on while the venom takes effect.
Are Misumessus spiders dangerous to humans?
No. They are venomous to insects but have no medical significance for people, and there is no antivenom because none is needed. Bites are very rare, since the spider's instinct is to drop off the leaf rather than defend itself, and the fangs are tiny. A bite feels like a brief pinprick.
Where are Misumessus spiders found?
Only in the Americas. The genus occurs across North America from southern Canada to Mexico and through the Caribbean islands. The green crab spider is the widespread species; the rest are largely confined to Florida and the islands. Look for them in meadows, hedgerows, gardens, orchards and woodland edges.
Why don't Misumessus spiders build webs?
Because their hunting strategy does not need one. They are ambush predators that let insects come to them, using camouflage and patience rather than a snare. They still produce silk constantly, but for safety draglines, egg sacs, a pad to grip during moulting, the male's sperm web and the spiderlings' ballooning threads.
What happens to the female after she lays her eggs?
She spins a flat white sac inside a folded leaf or between two leaves stitched together, then stands guard and stops hunting. In the green crab spider the female normally dies at or before the moment the spiderlings emerge, so the young receive no care beyond the protection of the sac itself.
What is the ecological role of Misumessus spiders?
They are generalist predators of small insects on low vegetation, taking flies, leafhoppers, aphids, thrips, small bees and moths. In gardens, orchards and field margins they form part of the natural enemy community that suppresses plant pests, and they are themselves food for wasps, birds, mantises and larger spiders.
How can I tell Misumessus from a goldenrod crab spider?
Size and texture. The goldenrod crab spider reaches about 10 mm and has a smooth, almost polished body that can switch slowly between white and yellow. Misumessus stays under 6 mm, is green rather than white or yellow, cannot change colour, and its body and legs carry scattered stiff bristles.
Do Misumessus spiders come into houses?
Not deliberately. They are outdoor foliage spiders and cannot breed indoors, so the ones found in homes have almost always arrived on cut flowers, garden produce or potted plants. Put the spider back on vegetation outside rather than killing it; indoors it will simply starve within a few days.
References
- World Spider Catalog (2026). Misumessus Banks, 1904. Natural History Museum Bern. wsc.nmbe.ch/genus-detail/3842/taxon
- Nyffeler, M. & Birkhofer, K. (2017). An estimated 400–800 million tons of prey are annually killed by the global spider community. The Science of Nature 104: 30. doi.org/10.1007/s00114-017-1440-1
