White Banded Crab (Misumenoides formosipes)
A small spider that sits motionless in the centre of a flower with its long front legs held open like a pair of tongs, waiting for a bee. The white banded crab spider is named for the pale ridge across its face, and the females can slowly repaint themselves from white to yellow to match the bloom they are hunting from.
By Dr Richard J. Pearce (PhD)Published July 3, 2020Updated September 13, 2026✓ Reviewed by Dr. James Watuwa
In this guide
- Physical description and identification
- Where the white banded crab spider lives
- Are white banded crab spiders venomous?
- Can white banded crab spiders bite?
- Ecological importance and behavior of the white banded crab spider
- Similar spiders and how to tell them apart
- Quick facts
- Did you know?
- Frequently asked questions
Physical description and identification
The white banded crab spider is a member of the crab spider family, Thomisidae, and it looks the part: a squat, wide-bodied spider that holds its long front legs out to the sides and walks sideways and backwards as readily as forwards. It builds no snare and chases nothing. It simply sits in a flower and waits, and the whole animal is built around that one tactic.
Adults
- Size: the sexes are startlingly different. Females measure 5.0–11.3 mm in body length; males only 2.5–3.2 mm, so a large female can be several times the mass of her mate. This is among the more extreme size gaps in North American spiders.
- Colour: females are white, cream, pale yellow or light brown, sometimes with reddish, brown or black markings down the sides of the abdomen and sometimes with none at all. Males are quite different — a shiny red, green or yellow carapace, a golden abdomen, dark brown or black front legs and pale yellow or green hind legs.
- Eyes: eight small eyes in two strongly curved rows, the side eyes raised on small bumps. Vision is good enough to judge an approaching insect but the spider relies heavily on touch. Our guide to spider eyes explains the arrangement.
- Distinctive features: the white band, a raised pale ridge running across the face between the eyes and the jaws, is the diagnostic character and the origin of the alternative name ridge-faced flower spider. The abdomen is broad and roughly triangular seen from above, and the first two pairs of legs are much longer and heavier than the back two.
Eggs and egg sac
In late summer the female builds a white, lens-shaped egg sac 10–14 mm across, usually folded into a leaf that she binds with silk. It holds roughly 80 to 180 tan eggs. She stands guard over it, feeds little or not at all afterwards, and dies in autumn.
Spiderlings
Hatchlings look like miniature adults rather than the translucent specks produced by many families. They disperse by ballooning on silk threads, overwinter as juveniles in leaf litter and grass tussocks, and mature the following summer. There is one generation a year across most of the range.
Hunting instead of a web
No crab spider spins a web to catch prey, and this species is a pure ambush hunter. It uses silk only for a dragline, for the egg sac and for a light mating thread. The spider selects a flower head, settles among the florets with the front legs spread, and stays put for days. When an insect lands within reach the legs snap shut and the spider bites, usually at the head or thorax. The venom works fast on insects, which is how a spider under a centimetre long can safely take a honeybee.
Where the white banded crab spider lives
Misumenoides formosipes is a North American species, found across most of the United States and into southern Canada, with the densest records in the east and the midwest and scattered populations west to the Pacific states. It is a spider of open, sunny, flowery ground: old fields, meadows, prairie remnants, roadside verges, hedgerows, waste ground and gardens.
Habitat choice is really flower choice. The spider favours flat or clustered blooms that give it a platform and cover — goldenrod, asters, daisies, yarrow, milkweed, Queen Anne's lace and garden composites — and it moves between flower heads as they open and fade. Females often stay on one inflorescence for several days at a time, which is long enough for colour change to be worth the effort. Populations shift through the season as the local flowering sequence changes, and by late summer the spiders concentrate on goldenrod, which is why that is where most people find them.
Are white banded crab spiders venomous?
Yes, and their venom is genuinely impressive — for an insect. An ambush hunter with no web has to stop prey instantly, and this species regularly kills honeybees, bumblebees, butterflies, wasps and flies that outweigh it. The venom acts quickly on the insect nervous system, which is what allows a spider of a few millimetres to hold onto a struggling bee without being stung or shaken off.
None of that translates into risk for people. The venom has no components known to be medically significant to humans, the fangs are tiny, and the volume delivered is minute. There is no antivenom because there is nothing to treat. Crab spiders are not related to the cellar spiders they are sometimes listed with, nor to the recluses or widows, and they carry none of their venom chemistry.
Not a cellar spider: the white banded crab spider belongs to Thomisidae, not to the pholcid cellar spider family. It is easy to tell them apart: a cellar spider such as the long-bodied cellar spider has a narrow body, hair-thin legs of roughly equal length and hangs upside down in a tangled indoor web. A crab spider is squat and wide, has two pairs of thick, much longer front legs, sits on flowers in the open and spins no snare at all.
Can white banded crab spiders bite?
They can, but it takes real effort to provoke one. The spider's instinct when a hand approaches is to sidle around the back of the flower head or drop on a dragline into the vegetation below. Bites happen only when a spider is picked up and squeezed, or trapped against skin while flowers are being cut.
The effect is a sharp pinprick with a little local redness, sometimes a brief itch, and nothing more. There is no swelling of consequence, no systemic reaction and no tissue damage. Wash the site and use a cold pack if it is sore. Seek medical advice only in the event of spreading redness or an allergic response, both of which would be unrelated to the venom's potency. Wearing gloves when cutting garden flowers in late summer is the only realistic precaution, and it is more about the bees than the spiders.
Ecological importance and behavior of the white banded crab spider
Colour change: adult females can shift between white and yellow to match the flower they are sitting on. The change is chemical, not optical — the spider moves pigment into or out of the outer layer of the body wall — and it takes days to a couple of weeks in each direction, not seconds like a chameleon. Males do not change colour at all, and neither sex can produce the pinks, blues or purples of some blooms.
Ambush and prey: a female may hold one flower head for days, front legs open, and take nothing for a week before catching a bee that feeds her for several more. The diet is dominated by flower visitors: honeybees, bumblebees, solitary bees, syrphid flies, butterflies, moths, wasps and beetles. The spider does not wrap prey; it holds on and feeds in place.
Males: the tiny males abandon hunting almost entirely once mature. They wander between flowers searching for females, wrestle rival males with their front legs, and often guard a subadult female by sitting on her until she moults into maturity so they can mate first. Their dark front legs are used in these contests.
Natural predators: birds, wasps — especially mud-daubers, which provision nests with crab spiders — ants, lizards, assassin bugs and other spiders including jumping spiders. The camouflage that hides the spider from prey works against predators too.
Relationship with humans: mixed but harmless. The species eats pollinators as well as pest insects, so it is not the unambiguous ally that a web-building garden spider is, but its numbers are never high enough to affect pollination on a meaningful scale, and it is an excellent indicator of a flower-rich, unsprayed garden.
Similar spiders and how to tell them apart
| Spider | How it differs from the white banded crab spider |
|---|---|
| Goldenrod crab spider (Misumena vatia) | The closest look-alike and the one most often confused. It has no raised white ridge across the face, and females usually show a pair of red stripes on the sides of the abdomen. |
| Misumenoides | The genus itself. The facial ridge is the shared genus character; M. formosipes is the common North American member people actually meet. |
| Flower crab spiders (Misumena) | Same build and same flower-sitting habit, separated by the face and the abdominal markings rather than by behaviour. |
| Green crab spider (Misumessus oblongus) | Clear translucent green rather than white or yellow, with a slimmer, more elongate abdomen; it hunts on foliage as much as on flowers. |
| Long-bodied cellar spider and Pholcus | Not related. Narrow bodies, uniformly hair-thin legs, permanent indoor tangle webs and an upside-down resting posture. |
| Marbled cellar spider (Holocnemus pluchei) | Another pholcid, grey and mottled, living communally in sheet webs in sheds and basements — a completely different family and lifestyle. |
Quick facts
| Other names | Ridge-faced flower spider, whitebanded crab spider. |
|---|---|
| Family | Thomisidae — the crab spiders — not Pholcidae. |
| Distribution | Most of the United States and southern Canada, commonest in the east and midwest. |
| Habitat | Open sunny flowery ground: meadows, old fields, prairie, roadsides, hedgerows and gardens. |
| Hunting method | Sit-and-wait ambush on flower heads; no prey-capture web. |
| Diet | Honeybees, bumblebees, solitary bees, hoverflies, butterflies, moths, wasps and beetles. |
| Lifespan | About one year; one generation per season. |
| Predators | Birds, mud-dauber wasps, ants, lizards, assassin bugs and other spiders. |
| IUCN status | Not evaluated. Common and widespread. |
Did you know?
- The species name formosipes means beautiful-footed, a reference to the long, pale, elegantly proportioned front legs.
- The white facial ridge is not decoration: it is a structural feature of the head used by arachnologists to separate Misumenoides from the otherwise similar Misumena.
- Colour change costs the spider something. Pigment has to be produced and moved, so a female that picks the wrong flower and keeps switching pays a real metabolic price.
- Males are so much smaller than females that early naturalists repeatedly described the two sexes as separate species.
- Because it takes honeybees regularly, this spider is one of the few small predators capable of killing an insect with a sting that could, in principle, kill it first.
In summary, the white banded crab spider is a patient, beautifully camouflaged ambush hunter of open flowery ground. Despite being filed alongside them in some listings, it is a crab spider and not a cellar spider, and it is no threat to anybody — unless you happen to be a bee.
Frequently asked questions about the white banded crab spider
How do you identify a white banded crab spider?
Look for the raised white band running across the face between the eyes and the jaws, a broad triangular abdomen, and first and second pairs of legs that are much longer and thicker than the back two. The spider sits openly on flower heads with its front legs spread and builds no web.
Is the white banded crab spider actually a cellar spider?
No. It belongs to Thomisidae, the crab spiders, and is unrelated to the pholcid cellar spiders it is sometimes listed beside. Cellar spiders are narrow-bodied, hang upside down in tangled indoor webs and have uniformly thin legs. Crab spiders are squat, sit on flowers in daylight and spin no prey-capture web.
Why are females so much bigger than males?
Females reach 5.0 to 11.3 mm in body length while males are only 2.5 to 3.2 mm. The female's size is tied to egg production and to subduing large prey such as bees, while males abandon hunting on maturity and specialise in finding and guarding females, for which small and mobile is an advantage.
Can white banded crab spiders change colour?
Adult females can shift between white and yellow to match the flower they are hunting from. The change is pigment-based and takes days to a couple of weeks in each direction, not seconds. Males cannot change colour, and neither sex can match pink, blue or purple blooms.
Do white banded crab spiders spin webs?
Not for catching prey. They are ambush hunters that sit motionless in flowers with their front legs open and grab insects that land within reach. Silk is used only for a safety dragline, for the egg sac and for a light thread during mating.
Are white banded crab spiders dangerous to humans?
No. Their venom is powerful against insects but has no components known to be medically significant to people, and the fangs are tiny. A defensive bite feels like a pinprick with brief redness. No antivenom exists because none is needed.
What do white banded crab spiders eat?
Flower visitors, above all: honeybees, bumblebees, solitary bees, hoverflies, butterflies, moths, wasps and beetles. Fast-acting venom lets the spider kill insects far heavier than itself, and a single bee can sustain a female for several days on the same flower head.
What does the egg sac look like and how many eggs does it hold?
It is a white, lens-shaped sac 10 to 14 mm across, usually built inside a leaf that the female folds and binds with silk. It contains roughly 80 to 180 tan-coloured eggs. The female guards it, eats little afterwards and dies in autumn.
Where and when are white banded crab spiders found?
Across most of the United States and into southern Canada, in meadows, old fields, roadsides, hedgerows and gardens. Adults are most obvious in mid to late summer, especially on goldenrod, asters, daisies and Queen Anne's lace. Juveniles overwinter in leaf litter and mature the next year.
What eats white banded crab spiders?
Birds, mud-dauber wasps that stock their nests with crab spiders, ants, lizards, assassin bugs and other spiders such as jumping spiders. The camouflage that conceals the spider from its prey also helps hide it from predators, but wandering males are especially exposed.
References
- World Spider Catalog (2026). Misumenoides formosipes (Walckenaer, 1837). Natural History Museum Bern. wsc.nmbe.ch/spec-data/47684/taxon
