Julia – Dryas iulia

Julia – Dryas iulia

Julia butterflies are found (in the US) primarily in the southernmost parts of Florida and Texas.


The host plant for Julia butterflies is passionvine. They only use a few species of passionvine. In south Florida, their primary host is Corky Stem passion vine; Passiflora suberosa.  They also eat Passiflora biflora, lutea, and multiflora.

Roosting (resting with wings closed, upside down, under a leaf) resemble dead leaves.


When courted by a male, a female rejects his advances by lifting her abdomen into the air. To pair, he must move beside her and reach her abdomen by reaching his abdomen under her wings. With her abdomen in the air, it is impossible for him to pair.


Eggs are laid singly on or off the host plant. Upon hatching, the young caterpillar must locate the plant if the egg was laid off the leaf. Once the caterpillar is on a leaf, it often cuts a tiny curl of the side of the leaf. It often stays on the curl when it is not eating.


Caterpillars are black and white with orange and black heads. When a caterpillar has eaten so much of the host plant that it cannot find shade and is in full sun, it will be much lighter in appearance.


Caterpillars have long bristles. Although they cannot sting, touching them can be much like touching a stiff bristled hairbrush. It can be uncomfortable if one is not very gentle.


When ready to pupate, a caterpillar hangs in a J position.


The next day it pupates into a chrysalis by shedding its skin/cuticle. Chrysalises are brown. Chrysalises in darker areas, away from light, are darker brown than those that pupate in lighter areas or bright sunlight.