PROC. ENTOMOL. SOC. WASH. 96(4), 1994, pp. 599-606 VACCINIDIPLOSIS, A NEW GENUS FOR CECIDOMYIA VACCINII OSTEN SACKEN (DIPTERA: CECIDOMYIIDAE) Raymond J. Gagne and Jerry A. Payne (RJG) Systematic Entomology Laboratory, PSI, Agricultural Research Service, USDA, % U.S. National Museum NHB 168, Washington, D.C. 20560; (JAP) Southeastern Fruit and Tree Nut Research Laboratory, Agricultural Research Service, USDA, 1 1 1 Dunbar Road, Byron, Georgia 31008. Abstract. —The adult and pupal stages ofCecidomyia vaccinii Osten Sacken are described for the first time and the larva is redescribed. Vaccinidiplosis Gagne, a new genus in the supertribe Cecidomyiidi, is expressly erected for C. vaccinii. ( 'accinidiplosis vaccinii forms a scallop-shaped leaf gall on deerberry, Vaccinium stamineum (Ericaceae). Past records of this gall midge on other hosts are discussed. Key Words: Gall midge, Nearctic, deerberry, Vaccinium, Ericaceae Osten Sacken (1862) named Cecidomyia vaccinii for a larva from leaf galls on a Vac-cinium from Washington, D.C. His full description of the larva consisted of "a red-dish larva." Osten Sacken's description of the gall was more diagnostic, which has made it possible to associate his species with a particular gall on ]'acciniiin}(¥\g. 1). Galls are usually green and scallop-shaped with a serrate distal margin. Galls may turn orange to red in the fall or after leaves are picked. They are attached to the main veins on the under surface of leaves, which makes them inconspicuous from above. Galls may be found from July to October along the At-lantic United States from Massachusetts to Georgia. Each gall contains one to several larvae. Larvae remain in the first instar for most of the summer, usually until late Au-gust, when growth proceeds quickly through the second instar to the mature third and last instar. When larvae become fully de-veloped in autumn, the galls split lengthwise into two equal halves. The larvae then drop to the ground, burrow under the surface. and form cocoons. Adults emerge the fol-lowing spring. We have found the galls only on deer-berr>', \'accinium stamineum L., in Georgia and Maryland, never on other blueberries or huckleberries. Galls have been found also on r. stamineum from Pennsylvania (J. Plakidas, personal communication, speci-mens in the National Museum of Natural History), North Carolina (Beutenmiiller 1907), and Massachusetts (Stebbins 1910). Osten Sacken's original gall specimens, col-lected in Washington, D.C. and preserved in the National Museum of Natural History, were probably also from deerberry. He re-ported the host as ""Vaccinium (or Gaylus-sacia?)." but the under surface of his galled leaves do not have the glandular surface of a Gaylussacia. The leaves otherwise agree in shape with those of I '. stamineum. Proc-ter (1946) listed a "blueberry leaf gall" as common on Vaccinium sp. on Mount De-sert Island, Maine. The gall was not specified further and I '. stamineum is not known from Maine ( Vander KJoet 1 988), so it is possible
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