Subject: Very Odd Looking Cocoon
Location: San Diego
April 22, 2013 12:09 am
I found this cocoon on our fence. It is really weird, kind of creepy but also quite fascinating.
It is supported to the fence by two anchor lines. It is about 1.5 inches long. When I tap on the fence, its lower body flexes a little (I have video). I think it tries to disguise itself as a branch. I’m not sure if the face-like figure was actually a face or just a clever way to scare off predators. It has been there for over a month. Maybe two. Pictures were taken on the 7th and it was there for at least a week and it is now the 22nd and its still there.
A cocoon is spun, often of silk, and it protects the pupa of generally moths. This is a bare pupa of a butterfly, known as a chrysalis. The two anchor lines you mention are a silken girdle to support the chrysalis in an upright position, and this girdle is characteristic of a Swallowtail Chrysalis from the family Papilionidae. We suspect there might be a citrus tree near your fence and that this is the Chrysalis of a Giant Swallowtail, though it might be another species in the family. Here is a BugGuide photo of the Chrysalis of a Giant Swallowtail for comparison.
Thank you for the quick response. We do have a nectarine tree within 6 feet of the cocoon. I guess butterfly will emerge very soon based on this link: http://en.wikipedia.org/wiki/Papilio_cresphontes I hope to see it in action. What time of day do butterflies normally hatch?
Our guess is that butterflies are most likely to emerge in the morning, but we are not certain.