Evoxysoma vitis Saunders

The seeds of the wild grape in the eastern United States and Canada are commonly infested by a milk-white larva about 1/8 of an inch in length which eats out the kernel. The insect passes the winter as a larva within the seed. Pupation takes place in June, and in early July the adult gnaws its way out of the seed, leaving a small, round hole. The adult is a small four-winged fly about 1/8 inch in length and black in color. The female is provided with a sharp needle-like ovipositor which she inserts through the skin and pulp of the grape and deposits her minute whitish egg in the kernel of the seed. Most of the egg-laying takes place in July. Cultivated varieties are rarely infested, but we have occasionally seen Delawares badly injured by the punctures made by the female in ovipositing. The injured berries color prematurely and sometimes shrivel and drop. Infestation by the grape-seed chalcis may be prevented by destroying all wild grape-vines in the vicinity of the vine- yard, and by not allowing any of the infested fruit to remain in the vineyard after picking time.

- Mark Slingerland, Cyrus Crosby: (1915) Manual of fruit insects^©

Reference: https://www.biodiversitylibrary.org/page/30873865#page/464/mode/1up