I don't know. Maybe Red-spotted purple butterfly egg. Maybe oak "worm" egg.

PUPATION - Butterfly caterpillars generally pupate on a branch or stick, seldom on the host plant. Monarchs and other species that make hanging chrysalides will often use the underside of the lid of their container. Most will make a silk button or other structure to attach to for pupation. Once attached, they will hang inactive for a day or so and may shrink and discolor before actually pupating. Moth caterpillars make cocoons in leaves, crevices or on sticks, depending on the species. Most Sphinx moth cats will burrow underground and excavate a chamber lined with a small amount of silk. Sphinx cats will readily pupate in leaf litter or paper towels in captivity. Sphinx cats severely shrink and discolor before pupation. Don't mistake them for dead or dying caterpillars. Over-wintering cocoons and chrysalides are best kept in an unheated outdoor shelter like a garage. Another option is to store them in the crisper drawer of your refrigerator. You can mist them with water occasionally to keep them from dehydrating, but avoid too much moisture; that can cause mold. ECLOSION - When a butterfly or moth emerges from its chrysalis or cocoon, it needs to hang to properly inflate its wings. Be sure it has something it can climb up or hang onto. Most butterflies will cling to their empty chrysalis case. Try not to disturb them after eclosion. If disturbed, they may prematurely eject the fluid used to inflate the wings and be crippled for life. After the wings are inflated they need to dry and harden. This usually takes about 6 hours. A butterfly or moth may be able to fly before then, but will be unable to go far because the wings will still be too heavy or soft. Before taking flight, butterflies and moths will eject the excess fluid in their bodies (called meconium). Place paper toweling under them if they are above an area you don't want to get stained. HAND FEEDING - Usually feeding isn't necessary, but in cases of extended bad weather there may be a need to feed your unreleased butterflies. In the wild, lack of sunshine and/or cool temperatures will make butterflies inactive, reducing their need for feeding. There has been quite a bit of discussion on what sugar/water ratio is appropriate for butterflies. It has been argued that butterflies require less sugar than there is in commercial hummingbird nectar mix, but it has also been argued that hummingbirds and butterflies feed from the same nectar sources in the wild. The most common formula seems to be 1 part sugar to 4 parts water. One tablespoon of sugar mixed with four tablespoons of water is a typical batch. Gatorade has also been recommended. Soak a small sponge with the liquid or place a few drops on a tabletop. Avoid large puddles; you don't want the butterfly's wings to get wet and sticky. Hold the butterfly by the upper wing tips and unroll the feeding tube with a toothpick, placing the tip in the mix. Butterflies are surprisingly cooperative once they get a taste and will often sit and drink unrestrained until they've had their fill. BREEDING - Butterflies are very difficult to breed in captivity. Your best bet is to release them. Female silk moths can be left outside overnight in a cage to attract males. The bars should be spaced wide enough to allow mating but close enough to prevent the female from escaping. Females emit a pheromone from a scent gland at the end of the abdomen, usually the first few nights after eclosing. This scent will attract males from miles away. Females rarely fly before mating. This is why females caught at lights are usually fertilized. Always breed moths in open cages and where there is some airflow. Closed containers and aquariums concentrate the phermone released by the females making them difficult for the males to locate. Males navigate by smell and touch, not sight, so a slight breeze is essential. After mating, the female moth can be placed in a brown grocery bag for egg-laying. Since the eggs are attached to surfaces with a strong adhesive, the bag makes it much easier to cut out the eggs later. Females will continue to lay eggs until they are nearly dead. Since silk moths have no mouthparts and don't feed, there is nothing you can do to prolong their lives. Typically silk moths live only about 10 days. INBREEDING - Inbreeding is not recommended. Inbred silkmoths have been known to produce a higher percentage of unviable eggs and entire broods of inbred caterpillars have been known to die for apparently no other reason. However, if no wild males are available, inbreeding is preferable to not breeding at all. Males that emerge before females can be stored in a refrigerator to prolong their lives until females are available. The recommended temperature is 55 degrees. Colder temperatures can cause behavior changes that will render them incapable of mating.

Looks like Eastern Comma Polygonia comma http://www.gardenswithwings.com/facts-info/ncommaquestionmark.html That little bright white mark on the underside looks like a comma on the "Eastern Comma" and a question mark on the "Question Mark".

I just hatched out 9 Luna moth caterpillars in a tupperware tub a few days ago. I did have 23 eggs but only 9 hatched so far lol. I happy I got some though. Hopefully some of them will make it to adult size. I can't wait to see them come out of their cocoons! They are eating Sweet Gum leaves and growing quickly.