Caterpillar of the split tail butterfly un-edited

These two caterpillars are eating a dill plant. These caterpillars absorb toxins from the host plants, and therefore tastes poorly to bird predators. The Black Swallowtail caterpillar has an orange "forked gland", called the osmeteriun. When in danger, the osmeterium, which looks like a snake's tongue, everts and releases a foul smell to repel predators.
The pupae may be green or brown, but not depending on surroundings or the background on which they have pupated. The color of the chrysalis is determined by a local genetic balance that ensures the majority of pupae will blend in. Note that a section of the green pupae will turns a much darker green at the very end of the pupae stage. This color change occurs a few hours to a full day before hatching.
Winter is spent in the chrysalis stage, and adults will emerge in the spring to seek out host plants. Adults will emerge in the mornings on a daily basis. First brood adults will fly from mid May until late June, second brood adults will fly from early July until late August, and occasionally a partial third brood will occur that will emerge later in the season. Members of the Black Swallowtail are long-lived compared to other butterflies that inhabit temperate zones. They encounter little predation and are quick and agile if they are disturbed.
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