These are galls of Melittia snowii on Cucurbita foetidissima, the buffalo gourd. They are formed along the stem and along leaf veins. The galls are first seen in mid to late June. The larvae mature in late July or early August. They chew their way out of the gall and enter the soil to pupate. Many other bugs enter the gall through the larval exit hole. I have seen tipulid larvae, isopods, cucumber beetles, mites, even lady bugs in these vacated galls. Here is an adult [thumb:#665169].