Microcercis

Foster, George A., 2024, Revision of Nearctic Microcercis Beschovski (Diptera: Chloropidae), with Synonymy of Incertella Sabrosky, Zootaxa 5481 (4), pp. 401-439 : 406

Key to the Nearctic species of Microcercis

1 Pleuron, postpronotal lobe and notopleuron entirely gray or brown; narrow dorsal margin of katepisternum rarely lighter brown to dark yellow....................................................................................... 2

- At least the postpronotal lobe yellowish and often propleuron yellow, with evenly gray pleuron, most species with pleuron and postpronotal lobe with bright to dark yellow areas, notopleuron usually with some yellow along the ventral margin but occasionally completely gray; katepisternum nearly always yellow on dorsal margin and quite dark ventrally or entirely yellow............................................................................................. 5

2 Ventral pleuron evenly polished from propleuron to the meron, posterior anepisternum and all of anepimeron tomentose; postpedicel entirely brown to black or brown dorsally, yellow ventrally; legs mostly brown or femora brown, tibiae yellow or legs entirely yellow................................................................................... 3

- Ventral pleuron incompletely polished, tomentose at least on the katepisternum; postpedicel consistently yellow ventrally, at least on medial surface; legs mostly brown or with foreleg mostly yellow........................................ 4

3 Scapular setae absent, postpedicel entirely black.......................................... M. albipalpis (Meigen)

- Scapular setae present between postpronotal lobes, one or two pairs; postpedicel usually yellow ventrally, occasionally all black.............................................................................. M. bispina (Malloch)

4 Prosternum yellow; pleuron gray, dorsally tomentose, ventral half from propleuron to but not including the meron polished except most of anterior katepisternum and meron tomentose; fore coxa, femur, tibia and basal two tarsomeres yellow, mid and hind legs variable; syntergite 1+2 usually yellow with small brown spots laterally and centrally, may vary from entirely gray to partially yellow, posterior margins of tergites three to five yellow, anterior portion brown to gray; epandrium black, contrasting sharply with yellow 5 th tergite; distal margin of surstylus smooth (fig. 30); salt marsh species.......... M. infesta (Becker)

- Prosternum gray; pleuron gray tomentose except small spot on propleuron just below the anterior spiracle, posterior third of katepisternum and the meron polished black; all coxae, femora and tibiae mostly gray to black; abdomen entirely gray to brown, tergites occasionally with narrow yellow hind margin; epandrium concolorous with abdomen; distal margin of surstylus with a medial projection (fig. 31); salt marsh species............................................ M. insularis (Malloch)

5 Postpronotal lobe mostly yellow; pleuron and notopleuron evenly gray, pleuron mostly tomentose except small, polished spot just below anterior spiracle, posterior surface of the katepisternum and central meron; legs mostly gray, distal tips of femora often yellow; salt marsh species....................................................... M. laytoni new species

- Postpronotal lobe and propleuron yellow, notopleuron and pleuron may be light gray to yellowish, pleuron more or less extensively polished; legs various........................................................................ 6

6 Ocellar triangle entirely gray; scapular setae absent.......................................................... 7

- Ocellar triangle gray to black only on tubercle or only in center with posterior corners yellow, if entirely gray, scapular setae present............................................................................................. 8

7 Anterior ¼ of pleuron grayish to dark yellow; ventral pleuron polished from propleuron to meron except anterior ventral katepisternum tomentose; fore coxa and femur gray, fore tibia and basal two tarsomeres yellow, 3 rd to 5 th fore tarsomeres darker; mid and hind coxae and femora gray, mid tibia yellow, hind tibia gray except distal tip, mid and hind tarsi yellow except 4 th and 5 th tarsomeres black; surstylus broadly spatulate, widening apically, without an apical point; found on inland grassy habitats usually with M. minor .............................................................. M. murphyi new species

- Anterior ¼ of pleuron yellow from postpronotal lobe to and including most of the foreleg; pleuron mostly tomentose except propleuron and posterior surface of katepisternum; legs yellow except hind femur and tibia often with grayish tint; surstylus with a slight, pointed projection distally; salt marsh species............................ M. trifeminarum new species

8 Ocellar tubercle largely gray with posterior corners yellow; scapular setae present between postpronotal lobes; scutum anteriorly only or entirely faintly yellow; legs mostly yellow............................................ M. dorsata (Loew)

- Ocellar tubercle gray to black only on the tubercle, the rest yellow; scapular setae absent; scutum mostly gray or with distinct yellow vittae anteriorly; legs mostly yellow................................................................ 9

9 Scutum with distinct yellowish vittae anteriorly.......................................... M. johanni new species

- Scutum evenly gray, rarely light yellow anteriorly, without distinct vittae........................... M. minor (Adams)