The Painted Lady is a medium to large butterfly, with a wing span of two to three-and-a-half inches. They are identified by the black and white corners of their mainly deep orange, black-spotted wings. They sport five white spots in the black forewing tips and while the orange areas may be pale here and there, there are no clean white dots in them. The hindwings carry four small submarginal eyespots on dorsal and ventral sides. Those on the dorsal side are black, but in the summer sometimes manifest small blue pupils. There are different types of Painted Ladies, but in California the  West Coast Lady (Vanessa annabella) is the most prolific. West Coast Painted Ladies do  not have obvious ventral eyespots. On the dorsal side, annabella lacks a white dot in the subapical orange found in other butterflies, and is a purer orange color. Vanessa annabella has a fully orange subapical band and leading edge on the forewing. The submarginal row of hindwing spots in annabella features three or four blue pupils. The two larger pupils in annabella are the inner spots, rather than the outer spots as in other butterflies
The lifespan of a Painted Lady Butterfly is 2–4 weeks.
The life of a Painted Lady  begins when the female oviposits (lays an egg) onto a host plant. Eggs are laid, usually, singularly on the tops of the host plant leaves¸ though on occasion eggs will be laid  one on top of another or, more rarely, in clusters. Eggs are a light green color and somewhat barrel-shaped. They have horizontal lines that go from tip to bottom. After four days or so, a caterpillar will hatch from the egg. After it has emerged, it will turn around and go back to eat the chorion or outer eggshell. This first meal provides the larva with protein. It will then feast upon the leaf upon which the egg had been laid.
First instar Painted Ladies are extremely small. They soon sprout bristles and the head shrinks a bit to become more proportional to the rest of the body. Soon little white ‘dots’  form at the base of some of the bristles in the next instar. Molting, or the shedding of skin takes place in several stages. With each successive molt, it grows larger and the larval features become distinctly different. the larval period lasts ten to thirteen days. By the fourth instar, the caterpillars grow very bristley and thicken. A white  stripe is visible  along its side and spiracles, which appear as little spots on the caterpillar’s sides, form. They are part of its respiratory or breathing system.
Soon, the larva will be ready to pupate. As do most brush-foot butterflies, the Painted Lady to deter predators will find a spot usually a distance away from its host plant upon which to pupate.
A silken button will be made and the caterpillar will suspend from its last prolegs in a ‘j’ position with its head hanging downward. It can take upwards of 24 hours for this final larval molt. A little black blob will attached to the chrysalis or on the ground nearby. This is the remaining exuvia, the final ‘molt’ from the caterpillar stage. It will include the head capsule of the caterpillar. The chrysalis or pupa is a non-descript brownish or tan colour with gold flecks. Close inspection will show  the spiracles and other features of the soon-to-be butterfly.
To stand off predators, the pupa may begin to rapidly jiggle.
In about ten days, the pupa will begin to change color and then a butterfly will eclose. It will take about an hour for the butterfly to fully expand its wings. The wings are very soft and unsupportive. They will require time to ‘harden.’
An orange-red liquid will often be found either in the exuvia (chrysalis ‘shell’) or on the ground. This is called meconium and is the waste material from the pupa. It is not blood as butterflies do not have blood; they have what is called hemolymph.
During the time the wings are drying, the proboscis (tongue tubes) will uncoil and recoil, as the imago (adult butterfly) readies itself to go out into the world to begin its 2-week or so life to procreate.
Each Spring, Painted Lady butterflies begin migrating northward, much like the ‘famous’ Monarchs. In California, every few years, particularly after an El Niño, there is a massive migration of Painted Ladies that will come up from Mexico. The rains from the El Niño help to increase the growth and number of host plants, and the Painted Ladies will then have a large number of options upon which to oviposit eggs as they travel. Although they migrate annually, it is during these El Nino seasons where they become highly noticeable, with hundreds of them traveling together, en masse.
The adult Painted Lady nectars on many plants, especially the composite flowers of the Asteraceae plant family. Favored nectar sources include thistle, aster, cosmos, blazing star, ironweed, and joe-pye weed. Painted Lady caterpillars feed on a variety of host plants, particularly thistle, mallow, and hollyhock.
The Painted Lady’s mottled colors look much like military camouflage, and provide effective cover from potential predators. The small caterpillars hide in their silk nests.
The Painted Lady inhabits open meadows and fields, disturbed areas and roadsides, and generally any sunny place that provides appropriate nectar and host plants.
Painted Ladies can cover a lot of ground, up to 100 miles per day during their migration. A painted lady is capable of reaching a speed of nearly 30 miles per hour. Painted ladies reach northern areas well ahead of some of their more famous migrating cousins, like the monarch butterflies.
Male painted ladies actively patrol their territory for receptive females in the afternoon. Should he find a mate, he will usually retreat with his partner to a treetop, where they will mate overnight.