Bay Checkerspot (Euphydryas editha bayensis)
The Bay Checkerspot is a threatened subspecies of Edith’s checkerspot butterfly found in a very small region of the United States. It is the black banding of this butterfly that gives it its unique appearance and its name.
Scientific Classification
- Family: Nymphalidae
- Genus: Euphydryas
- Scientific Name: Euphydryas editha bayensis
Description and Identification
Caterpillar
The mature larva of the bay checkerspot is black in color with numerous hairy growths all over the body in small tufts. There is also a dotted line in bright yellow or orange, running vertically through the middle of the dorsal side.
Pupa
The chrysalis is white in color with uneven markings in orange and black that gives the pupa an almost similar look like the adult stage.
Adult Butterfly
Sexual Dimorphism: Not present
Color and Appearance: When the wings are open, the dorsal side of the forewings show markings with black bands along the veins of the wing’s upper part contrasting sharply with bright red, yellow and white spots. When the wings are closed, the ventral part displays a mirror image of the upper side.
Average wingspan: Little more than 2 inches (51 mm)
Flight pattern: Medium to fast
Eggs
Females can lay up to five masses of eggs, with each containing 2 to 250, deposited at the base of the host plant
Quick Facts |
|
Distribution | San Francisco Bay region of the U.S. state of California |
Habitat | Ridge tops, open woodlands, alpine tundra, grasslands and rocky outcrops of the mountains |
Host plants | Plantago erecta, Castilleja exserta, Castilleja densiflora |
Adult diet | Flower nectar |
Did You Know?
- The male butterflies typically emerge four to eight days before the female.

Bay Checkerspot Butterfly Habitat
Scientific Classification
- Family: Nymphalidae
- Genus: Euphydryas
- Scientific Name: Euphydryas editha bayensis