BY E. MEYRICK. 595 



I5-IJ, in ^ serrate, shortly ciliated (|), basal joint moderate, with 

 strong pecten. Labial palpi moderate, rather drooping, slender, 

 with appressed scales, terminal joint longer than second, pointed. 

 Maxillary palpi rudimentary. Posterior tibiae rough-haired. 

 Fore wings with vein 1 furcate, 7 and 8 sometimes stalked, 7 to 

 costa, 11 from middle. Hindwings 1, elongate-ovate, cilia 1 ; cilia 

 of inner margin in ^ sometimes forming a long expansile pencil ; 

 vein 4 absent. 



Apparently a very eai'ly form, indicating a possible origin for 

 some of the preceding genera. 



1. Forewings with white costal streak 2. 



Forewings without white costal streak 3. 



2. White streak becoming subcostal posteriorly 177. schismatica. 

 White streak remaining costal throughout... 178. chionozyga. 



3. Hindwings in ^ with long inner-marginal 



pencil of cilia 175. arcana. 



Hindwings in (J without inner-marginal pencil 176. insidiosa. 



175. Ther. arcana, n.sp. 



^. 14 mm. Head ferruginous-fuscous, sides of crown whitish, 

 face grey mixed with blackish and whitish. Palpi whitish, 

 terminal joint fuscous-tinged. Antennte light fuscous. Thorax 

 fuscous mixed with whitish. Abdomen grey. Legs dark fuscons, 

 posterior pair ochreous-whitish. Forewings elongate, narrow, 

 costa moderately arched, apex roundpointed, hindmargin very 

 obliquely rounded ; 7 and 8 stalked ; fuscous, irrorated with dark 

 fuscous ; dorsal area beneath fold irrorated with whitish ; a short 

 oblique whitish mark resting on fold before middle, preceded and 

 followed by suffused blackish spots somewhat mixed with ferru- 

 ginous : cilia pale fuscous, with indications of a dark fuscous line. 

 Hindwings with cilia of inner margin enlarged to form a long 

 expansile whitish-ochreous pencil ; dark fuscous-grey ; cilia light 

 ochreous-grey. 



Albany, West Australia; in October, one specimen. 



