Brachypogon (Isohelea)

Spinelli, Gustavo R. & Cazorla, Carla G., 2004, A new species of Brachypogon (Isohelea) from arid zones of Argentina (Diptera: Ceratopogonidae), Zootaxa 570, pp. 1-6 : 2-3

Key to the extant Neotropical species of Brachypogon (Isohelea)

1. Females.......................................................................................................................... 2

— Males ........................................................................................................................... 7

2. One spermatheca .......................................................................................................... 3

— Two spermathecae ....................................................................................................... 4

3. Large species, wing length 0.97–1.03 mm; wing membrane infuscated with two well developed radial cells, macrotrichia present in margin of cell cua1 and anal cell; halter whitish; spermatheca with conical neck ............................ B. hugoi Spinelli & Grogan

— Smaller species, wing length 0.74 mm; wing membrane hyaline, 2nd radial cell minute, macrotrichia absent in margin of cell cua1 and anal cell; halter dark brown; spermatheca with narrow neck ...................................................... B. mapuche Spinelli

4. Wing membrane infuscated; antennal ratio 1.15–1.25 ................................................ 5

— Wing membrane whitish hyaline; antennal ratio 0.93–0.98 ........................................ 6

5. Anterior margin of wing without a significant dip; vein M2 present; veins M1, CuA1, CuA2 abutting wing margin; macrotrichia absent in margin of cells cua1 and anal cell .................................................................................................... B. misionensis Spinelli

— Anterior margin of wing with a significant dip; Vein M2 obsolete; veins M1, CuA1, CuA2 not abutting wing margin; macrotrichia present in margin of cells cua1and anal cell .............................................................................................................. B . borkenti n. sp.

6. Radial cells equal sized, stigma yellowish; spermatheca equal sized, ovoid ................. .............................................................................................................. B . wirthi Spinelli

— Second radial cell minute, stigma pale brown; spermatheca unequal, obliquely ovoid. ................................................................................ B. pallidipennis Spinelli & Grogan

7. Tergite 9 with posterior projection with heavily sclerotized margins ......................... 8

— Tergite 9 without posterior projection ........................................................................ 10

8. Posterior projection of tergite 9 circular or quadrangular; apex of aedeagus bilobed. 9

— Posterior projection of tergite 9 heptagonal; apex of aedeagus not bilobed ..................

.............................................................................................................. B . borkenti n. sp. 9. Posterior projection of tergite 9 quadrangular; basal arm of aedeagus short ................. ............................................................................................ B. hugoi Spinelli & Grogan

— Posterior projection of tergite 9 circular; basal arm of aedeagus long ........................... ..................................................................................................... B . misionensis Spinelli

10. Gonocoxite 1.5 times longer than wide without stout distal setae; gonostylus slender with pointed apex, surface smooth; parameres elongate, 2.5 times longer than wide, distal portion divided with slender abruptly recurved extensions; apex of aedeagus truncate, without additional processes .......................................... B . mapuche Spinelli

— Gonocoxite stout with 12 strong distal setae; gonostylus stout with bilobed apex, surface irregular; parameres shorter than wide, distal portion with truncate apex; aedeagus with a pair of sublateral, distal processes and a single distomedian one, the latter extending beyond tip of aedeagus ......................... B. pallidipennis Spinelli & Grogan