Key to world species of Neurosystasis

1 Wing membrane unpatterned. M3 originating from M-fork, i.e. M1, M2 and M3 originating from same point..............2

- Wing membrane infuscate with white spots between vein apices. M3 originating near base of wing.....................3

2 Right gonostylus with two branches, left gonostylus one-branched. Hypopod with branches of equal length. (Jamaica).................................................................................... N. terminalis (Satchell, 1955)

- Gonostyli with one branch. Hypopod with epandrial branch less than half the length of cercal branch. (Florida, USA)............................................................................ N. bromeliphila Wagner & Hribar, 2010

3 Wing with vein R2+3 attached to vein R4. Hypopod unbranched. (Argentina).... N. saltenia (Omad, Mangudo & Gleiser, 2015)

- Wing with vein R2+3 not attached to vein R4, Hypopod divided into lateral epandrial branch and mesal cercal branch. (Cuba). 4

4 Eyes separated by distance of 1.4 facet diameters. Hypopod with epandrial branch as long as cercal branch............................................................................................. N. amplipenna (Knab, 1914)

- Eyes separated by distance of 2 facet diameters. Hypopod with epandrial branch shorter than cercal branch..............5

5 Interocular suture V-shaped. Sc connected to R1. Faint crossvein present between the bases of M1+2 and M3. Right gonocoxite with mesal branch straight, lateral branch recurved laterad. Lobes of gonocoxite smooth. Apex of gonostyli without setae............................................................................................ N. mira sp. nov.

- Interocular suture widely U-shaped. Sc not connected to R1. Bases of M1+2 and M3 without crossvein. Gonocoxite with both branches weakly curved towards median, lateral lobe of gonocoxite serrated laterally. Apex of gonostyli with 4-5 setae............................................................................................ .. N. starki sp. nov.