PROC. BIOL. SOC. WASH. 96(3), 1983, pp. 489-523 » THE NEARCTIC SPECIES OF THE BEZZIA BIVITTATA GROUP (DIPTERA: CERATOPOGONIDAE) Willis W. Wirth and William L. Grogan, Jr. Abstract. — The bivittata Group of the genus Bezzia Kieffer, subgenus Bezzici, is comprised in North America of at least 15 species, of which the following 12 are described as new: aklavakensis from Canadian Northern Territory, ander-sonorum from Maryland, capitata from Honduras and Arizona, chelistyla from Arizona, gibberella from Maryland, luteiventris from Virginia, mohave from Cal-ifornia, nigripes from Utah, sandersoni from Arizona, setosinotum and spathida from Maryland, and texensis from Texas. Diagnoses are given of all taxa, a key is presented, and all species are illustrated. This review is one of a series in which additions and corrections are made to the "Revision of the Nearctic Species of the Genus Bezzia'' by Dow and Turner (1976). In the present series six groups have already been studied in depth since 1976: Grogan and Wirth (1981) on the genus Amerohelea Grogan and Wirth; Wirth and Grogan (1982) on the genus Phaenobezzia Haeselbarth; Wirth (in press) on the bicolor Group, Wirth (in press) on the cockerelli and dorsasetula Groups, and Wirth et al. (in press) on the annulipes Group oi Bezzia, subgenus Hoino-bezzia; and Wirth (in press) on the nobilis Group of the subgenus Bezzia s.s. The present paper deals with a second group of Bezzia s.s., here named the bivittata Group. In addition to the revision by Dow and Turner, we urge that users of our Bezzia papers also refer closely to the excellent revisions of the Soviet species by Remm (1974a, 1974b). We beheve that Remm reached a sound basic understanding of the characters useful in recognition of natural groups within the genus Bezzia, although we would disagree in one or two instances whether certain groups should be given generic or subgeneric status. Starting with the characters used by Remm, we will offer short diagnoses that should explain the basis of our group classifi-cation. We wish to stress that our present treatment is to be considered provi-sional and for this reason we will try to be as conservative as possible. In addition to Remm's important papers, we have drawn on several other recent works on Bezzia for an evaluation of group characters. Clastrier (1962) presented excellent descriptions and figures of a large number of Palaearctic species but made very little attempt to place them in systematic groups or to take into account the species poorly described by eariier authors. Haeselbarth (1965a, 1965b, 1975) treated three groups of African species in similar detail, but added excellent diagnoses and taxonomic discussions of the africana and nicator groups, and the group which he separated off as the genus Phaenobezzia Haeselbarth. Tokunaga (1966) made no attempt at group classification when he offered excellent descrip-tions and figures of the New Guinea species. Taxonomic characters employed for identification of adult ceratopogonids were described by Wirth (1952), Dow and Turner (1976), and Wirth et al. (1977). Wing
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