IDENTIFICATION KEY TO NEW WORLD SPECIES OF DISTICHLICOCCUS FERRIS, 1950 (adapted from descriptions by Cockerell [1902], Ehrhorn [1911], McKenzie [1967], and Williams & Granara de Willink [1992] and taxonomic keys by McKenzie [1967], and Williams & Granara de Willink [1992])
1. Circulus present .......................................................................................................................................... 2
— Circulus absent ........................................................................................................................................... 7
2. With fewer than 9 pairs of cerarii .................................. D. sinaloanus Williams & Granara de Willink, 1992
— With more than 9 pairs of cerarii ................................................................................................................ 3
3. Oral rim tubular ducts absent from venter .................. D. zacapuensis Williams & Granara de Willink, 1992
— Oral rim tubular ducts present on venter ..................................................................................................... 4
4. Hind tibia with fewer than 20 translucent pores............................................... D. arundinis McKenzie, 1967
— Hind tibia with more than 30 translucent pores .......................................................................................... 5
5. Oral collar tubular ducts present on abdominal segment IV ........................ D. megacirculus McKenzie, 1967
— Oral collar tubular ducts absent from abdominal segment IV ...................................................................... 6
6. Cerarii numbering 14 recognizable pairs; oral collar tubular ducts present on abdominal segment V ............. ....................................................................................... D. digitariae Williams & Granara de Willink, 1992
— Cerarii numbering 17 recognizable pairs; oral collar tubular ducts absent from abdominal segment V ........... ................................................................................... D. sahuayoensis Williams & Granara de Willink, 1992
7. Oral collar tubular ducts absent ................................................................................................................... 8
— Oral collar tubular ducts present ................................................................................................................. 9
8. Venter of abdomen with oral rim tubular ducts in a submarginal row 1 pore wide ......................................... ...................................................................................................................... D. californicus (Ehrhorn, 1911)
— Venter of abdomen with oral rim tubular ducts in a submarginal row 2 or 3 pores wide.................................. ................................................................................................................................. D. fontanus Ferris, 1950
9. Cerarii numbering more than 10 recognizable pairs .................................................................................. 10
— Cerarii numbering fewer than 10 recognizable pairs .................................................................................. 11
10. Dorsum with oral collar tubular ducts; cerarii numbering 12 to 14 recognizable pairs..................................... .......................................................................................... D. salazari Williams & Granara de Willink, 1992
— Dorsum without any oral collar tubular ducts; cerarii numbering 15 to 17 recognizable pairs ........................ ........................................................................................................................................ D. takumasae n. sp.
11. Anal ring situated on dorsum, separated from posterior apex of abdomen by about its own diameter; cerarii restricted to abdomen ...................................................................................... D. alkalinus (Cockerell, 1902)
— Anal ring situated at posterior apex of abdomen; cerarii present on head as well as abdomen ......................... ........................................................................................................................... D. salinus (Cockerell, 1902)