The grape vine (Vitis vinifera), which is a common fruit crop grown extensively in Mysore, has not been noticed till now to be subject to any very serious insect pests, though one occasionally comes across a Chrysomelid beetle (Scelodonta strigicoUis, Mot.), stray leaf-eating cockchafers (Adoretus spp.), twig-girdling Longicorn beetles (Sthenias grisator, F.), and stray scale-insects, which, however, have not done any very serious damage so far ; but recently substantial damage has been caused to the grape vine crop by an insect which appears to be quite a new record—at any rate for S. India. The insect concerned is a species of plume moth (Oxyptilus regulus, Meyr.), the larva of which bores into the ripening berries of the grape bunches and causes substantial injury. The grapes grown in the Mysore State belong to a local black variety, the fruits of which have a sub-acid taste and do not therefore fetch good prices at present because of the very large imports of sweet varieties from North India and elsewhere. The serious nature of the damage done by this new pest and the consequent menace to the grape crop, which is one of the oldest of the fruit plants to be raised in the State, and the likelihood of the insect extending its activities to the different varieties of this crop cultivated outside the State, prompted the author to attempt a fairly thorough study of the insect with a view to adopting control measures.