Key to males of South-Eastern Asian species of Nala
1 Forceps in basal third to basal half conspicuously dilated internally (Fig. 8). Distribution: Pakistan, India, Nepal, Bhutan, Malaysia. .............................. N. nepalensis (Burr, 1907)
– Forceps long and slender, not dilated in basal half .......................................................... 2
2 Each branch of forceps with large, distally oriented hooked tooth near inner base (Fig. 7). Distribution: Timor. ............................................................... N. timorensis Brindle, 1967
– Forceps without prominent hooked teeth (Figs. 6, 9-12) ................................................. 3
3 Tegmina long, 1.5-2 times as long as pronotum. Wings visible or concealed .................. 4
– Tegmina short, approximately as long as pronotum. Wings entirely concealed. Distribution: Cambodia. ..................................................................................... N. alenae sp. nov.
4 Dark brown species, head black or blackish brown. ........................................................ 5
– Yellowish-brown to pale reddish-brown species (including head). .................................. 6
5 Slender species, forceps twice as long as width of ultimate tergite (Fig. 6). Distribution: Indonesia. ........................................................................ N. tenuicornis (Bormans, 1900)
– Stout species, forceps 1.1 to 1.4 times as long as width of ultimate tergite (Fig. 11). Distribution: Europe, Africa, Asia. ................................................... N. lividipes (Dufour, 1829)
6 Forceps with two pairs of small teeth on inner margin (Fig. 9).... N. ornata Borelli, 1932
– Each branch of forceps with cylindrical tooth (not hooked) on inner margin close to base (Fig. 10), entire inner margin sparsely serrated. Distribution: Afghanistan, Pakistan, Thailand. ...................................................................................... N. basalis Bey-Bienko, 1970