Key to species groups of Trichadenotecnum from Peninsular Malaysia and Singapore

1. Forewing extensively covered by tiny spots (Fig. 1B–M)...................................................... 2

-. Forewing not extensively covered by tiny spots (Fig. 1A, N–U)................................................ 3

2. Anterior region of basal band around Rs-M fusion well developed (Fig. 1B–D)....................... corniculum group

-. Anterior region of basal band around Rs-M fusion obscure (Fig. 1E–M)........................... spiniserrulum group

3. Forewing Rs forking at right angle, third section of vein CuA1 (distal margin of areola postica) directed posteriorly to poster- obasally (Fig. 1N–U)................................................................................... 4

-. Forewing Rs forking at acute angle, third section of vein CuA1 directed posterodistally (Fig. 1A)....... circularoides group

4. Male hypandrium asymmetrical; phallosome lacking pseudoparamere (e.g., Figs 18, 27).................... majus group

-. Male hypandrium symmetrical; phallosome with pseudoparamere (Fig. 29). Female unknown........... krucilense group