Lygistorrhina (Probolaeus), Williston 1896

Blagoderov, Vladimir & Pollet, Marc, 2020, Diversity of Lygistorrhina (Probolaeus) Williston, 1896 (Diptera: Keroplatidae, Lygistorrhininae) of Mitaraka (French Guiana), with descriptions of three new species, Zoosystema 42 (30), pp. 593-606 : 604-605

KEY TO EXTANT AND FOSSIL SPECIES OF SUBGENUS LYGISTORRHINA (PROBOLAEUS ) WILLISTON 1896

1. Wing membrane entirely hyaline ................................................................................................................ 2

— Wing membrane with dark spots ................................................................................................................. 9

2. Sc ending free .............................................................................................................................................. 3

— Sc ending in C ............................................................................................................................................ 4

3. Antenna light brown; each flagellomere with two or more prominent dorsal setae; C extending to half distance between R₅ and M₁; coxa 1 pale with dark basal part; laterotergite with 13-14 setae; abdominal segments 2-5 (sometimes 2-4) with pale posterior band ............................. Lygistorrhina santaecatharinae Thompson, 1975 . [eastern USA: Alabama, Georgia, North Carolina, South Carolina, Tennessee, Virginia, West Virginia]

— Antenna with basal 4-5 flagellomeres pale yellow, remaining brown; each flagellomere with one prominent dorsal seta; fore coxa entirely yellow; laterotergite with 18-20 setae; abdominal segments 1-5 with pale posterior band ..................................................... Lygistorrhina brasiliensis Edwards, 1932 [ Brazil: São Paulo, Minas Gerais].

4. First abdominal tergite entirely dark (brown) (sometimes first sternite with narrow pale band) ................... 5

— First abdominal tergite pale or with pale posterior band ............................................................................. 6

5. Antenna light brown at base, gradually becoming yellow towards apex; M₁ bent anteriorly and slightly sinusoid; fore coxa entirely pale; abdominal segments 2-4 with pale posterior band ...................................................... .................................................................................................... Lygistorrhina conica n. sp. [ French Guiana].

— Antenna entirely dark; M₁ almost straight; fore coxa entirely dark; abdominal segments 2-5 with pale posterior band .................................... Lygistorrhina barrettoi Lane, 1947 [ Brazil: Goiás, Mato Grosso, Mato Grosso do Sul]

6. Abdominal segments 1-5 with pale posterior band ........................................................................................ 7

— First abdominal tergite entirely pale and segments 2-4 with pale posterior band ......................................... 8

7. Flagellomeres 1-5 reddish brown, the rest dark brown; fore coxa entirely yellow; fore basitarsus longer than fore tibia; laterotergite with 13-14 setae; M₁ bent posteriorly ................................................................................ .............................................................. Lygistorrhina edwardsi Lane, 1947 [ Brazil: São Paulo, Minas Gerais].

— Antenna unicolourous (true colour unknown, amber inclusion); fore coxa entirely dark; fore basitarsus shorter than fore tibia; laterotergite with 9-10 setae; M₁ bent anteriorly and sinusoid ................................................ ................................................... Lygistorrhina caribbiana Grund, 2012 [fossil, Miocene: Dominican amber].

8. Costa extending to more than half distance between R₅ and M₁; M3+4 curved posteriorly; fore basitarsus longer than fore tibia; abdominal segments 1-4 with pale posterior band .................................................................. ................................................................................... Lygistorrhina singularis ( Williston, 1896) [ St. Vincent].

— Costa extending to half distance between R₅ and M₁; M3+4 curved anteriorly; fore basitarsus shorter than fore tibia; abdominal segments 1-5 with pale posterior band .................................................................................. .......................................................................................... Lygistorrhina mitarakensis n. sp. [ French Guiana].

9. Sc ending free; segment 6 with pale posterior band (sometimes inconspicuous) ........................................ 10

— Sc ending in C; segment 6 entirely dark, without a pale posterior band ..................................................... 11

10. Wing with pigmented spots in the middle of the wing and along veins; M₁ bent anteriorly and sinusoid; C extending beyond half distance between R₅ and M₁ ........................................................................................ .................................................................................. Lygistorrhina cerqueirai Lane, 1958 [ Brazil: Amazonas].

— Wing with pigmented spot at wing tip only; M₁ bent posteriorly; C extending to half distance between R₅ and M₁ .......................................................................................... Lygistorrhina maculipennis n. sp. [ French Guiana].

11. Wing with triangular pigmented spot restricted to anterior part of cell R₅ only ......................................... 12

— Wing with pigmented spot extending between R₁ and M₂ ........................................................................ 13

12. Abdominal segment 1 and 5 completely dark, segments 2-4 with pale posterior band; M₁ and CuA bent posteriorly; laterotergite with 17 setae ................................................................................................................. ........................................................ Lygistorrhina borkenti Huerta & Ibanes-Bernal, 2008 [ Mexico: Morelos].

— Abdominal segments 2-5 (and at least sternite of segment 1, but often also tergite 1) with pale posterior band; M₁ almost straight, CuA conspicuously sinusoid; laterotergite with 18-20 setae ............................................ ................................................................................................ Lygistorrhina urichi Edwards, 1912 [ Trinidad].

13. Mediotergite with a pair of pre-apical setae; fore coxa pale yellow with dark brown spot in centre .................. ................................................................... Lygistorrhina acahuizotla Huerta et al., 2019 [ Mexico: Guerrero].

— Mediotergite without setae; fore coxa completely pale yellow .......................................................................... .................................. Lygistorrhina alexi Huerta & Ibanes-Bernal, 2008 [ Mexico: Jalisco, Guerrero, Yucatan].