It looks like you have squash bugs and they do indeed have several life stages such as nymphs but all hide on the underside of the leaves. There are many different types of hemiptera or True Bugs but all overwinter near host plants in the soil so good winter cleanup and removing infected plants in the fall is the practical way to make sure this problem does not visit you again next year. You can try handpicking in early morning when they feed and searching under the leaves for the egg masses and destroying them. This group of insect is difficult to control with insecticides and underside of leaves must be sprayed and then resprayed two weeks after the first application. Rotate your crops and avoid planting the infected plant for a year to discourage this pest. Keep growing, Marianne Binetti