Butterflies of the San Francisco Bay Area
(a very incomplete list)

Cabbage Butterfly
(Pieris rapae)

Food plants include all kinds of cultivated and weedy plants of the mustard family. Also called the Imported Cabbageworm. It was introduced to North America more than a century ago and is now a pest in gardens throughout the United States. This is one of the urban area's commonest butterflies. Adults are a chalky white. The hindwing has a costal spot in outer 2/3, which is unique to A. rapae. The forewing has dark tips and no cell bar.


Anise Swallowtail Butterfly
(Papilio zelicaon)

In the SF Bay Area these butterflies and their large caterpillars occur commonly on Fennel (Foeniculum vulgaris). In other parts of the State they are pests on citrus.


Red Admiral Butterfly
(Vanessa atalanta)

Wingspan 45-50. Upper surface very dark brown with lightly shaded areas bright orange and apical spots; undersurface of the hindwings is marbled and marked with wavy lines of intricate pattern and by a green-dusted submarginal series of obscure eyespots. Larvae feed on nettle and hops. Distributed throughout North America. Five species in this genus. All are distinctively marked and very widely distributed.


Peacock or Buckeye Butterfly
(Junonia coenia)

Wingspan 50-55. Dorsally dark brown with a conspicuous peacocklike eyespot located on the front wing and a large and smaller one on each hind wing; front wings have small orange spots and a dull, whitish band; hind wings have a narrow but conspicuous band of yellow-orange; ventrally, much the same markings except that the eyespots are greatly reduced. Larvae feed on plantain, snapdragon, and other plants. Throughout the entire United States.


Monarch Butterfly
(Danaus plexippus L.)

Wingspan: 93 to 105 mm.
Danaus plexippus (Identification: Monarchs are easily recognized by their characteristic markings with a bold pattern of orange, black and some white. The queen butterfly is sometimes found in southern California and is smaller and browner than the Monarch. Biology: The larvae of monarch butterflies feed on milkweeds. They are able to sequester the cardiac glycosides from these plant and this makes them highly unpalatable to other animals.)


Pine White Butterfly
(Neophasia menapia)

Wingspan: 44-50 mm. Upperside of forewing is nearly all white, with a black margin along leading edge and heavy black markings on wing tip. Underside of hindwing shows a consistent pattern of black veins. The female has black markings along the margin of upper hindwing. Underside of female's hindwing shows tinges of yellow and often has red spots outlined in black along the edge. Similar Species: Only White with a black band along leading edge of forewing. Range: Western North America south through Rocky Mountain States to Mexico. In British Columbia found on Vancouver Island east to the Rockies, north to the Chilcotin in the Fraser drainage and the Bella Coola Valley on the coast. Early Stages: Tiny green eggs laid in rows on a conifer needle (e.g. Ponderosa Pine, Douglas-Fir, and true firs (Abies spp.). Dark green caterpillar with white back and side stripes and two short tails. Flight Season: One flight June to September; most abundant in late summer. Habitat: Pine and fir forests from sea-level to mid-montane. Remarks: A close relative of the South American whites in the genus Catasticta. This butterfly normally flutters weakly high among conifers, and only occasionally comes to the ground to take nectar.


Mourning Cloak Butterfly
(Nymphalis antiopa)

Wingspan 55-85 mm. This butterfly cannot be confused with any other species because of its uniformly brown, nearly black wings and the series of submarginal blue spots with the straw-yellow marginal bands on both pairs of wings; underside is similar but without blue spots. Larvae feed on willow, poplar, elm and hackberry. Adults overwinter and fly on any warm day of the year. Common throughout North America. Four species of Nymphalis occur in the United States. The other three species are known as tortoise shells because of the marking on the underside of the wings which resembles that of certain tortoises.


California Tortoise Shell
(Nymphalis californica)


Oreas Comma
(Polygonia oreas)


Chalcedon Checkerspot
(Euphydryas chalcedona)


Bibliography
A Field Guide to the Insects of America North of Mexico. Borror, Donald J. and Richard E. White. Houghton Mifflin Co. Boston, MA. 1970.
California Insects. Powell, Jerry A. and Charles Hogue. University Press. University of California. 1979.
Introduction to Insect Biology and Diversity. Daly, Howell V., John T. Doyen, and Alexander H. Purcell, III. Second Edition. Oxford University Press. New York, NY. 1998.