This is pretty cool, because we have almost the entire cycle (I just don’t have photos of the eggs). It’s a White-rayed Patch butterfly, Chlosyne ehrenbergii, and caterpillar, and chrysalis, all in Cuernavaca Mexico at an altitude of 1580 meters, in October 2014. They even picked the plant as Buddleja cordata, the genus of which is called Butterfly Bush. In Spanish the name is “Mariposa parche negra”. It grew out of a drain, and I tried to kill it for a few years fearing it would block the drain but I failed. So it grew to a few meters in diameter and these butterflies were over it for years, until a particularly heavy load of caterpillars ate enough of it that it didn’t recover.
This seems to be a caterpillar of a Coenonympha tullia, or Common Ringlet, based on a similarity to the photo on this page. There are some obvious differences – the head is white, the tail prongs are far longer, and the caterpillar in my photo has orange horns…but there are a great deal of sub-species and I can’t find any other caterpillars with similar body shape and colouringOpsiphanes cassina, identified by Keith Wolfe on the Insectos en Mexico page. The photo was taken on November 11, 2013 in Cuernavaca, at an altitude of 1580 metres.