80 AECTIAD J?. 



Subfamily LITHOSIAN^E. 



Proboscis usually well developed, but often aborted ; palpi 

 usually short and porrect, sometimes reaching well beyond the 

 frons, often upturned, rarely reaching above vertex of head; antennae 

 of male usually with bristles and cilia, often bipectinate, sometimes 

 dilated or with tuft of scales on npperside of shaft ; ocelli absent ; 

 tibiae with the spurs usually moderate, sometimes long or absent. 

 Fore wing typically long and narrow, but in a large section short and 

 broad, the narrow-winged genera having vein 5, and often vein 4, 

 absent. Hind wing with vein 8 coincident with the cell from base 

 to one-third or to near end of cell. 



The more generalized forms of Lithosiance have a very sligltly 

 modified venation in the fore wing ; in Diduga all the veins arising 

 Irom the cell except 7, 8 ; and the subfamily probably has its 

 origin in an early Arctid form which was related to Acontia and its 

 allies in the ISIooiuidce. 



The normal evolution of the venation seems to have been that 7, 

 8 and 9, 10 should become stalked, that 9 should then anastomose 

 with 8 to form an areole, which in most of the genera has dis- 

 appeared by reduction, leaving vein 9 stalked with 7, 8 ; in the 

 genus Ileyna especially the areole being often either present or 

 absent in different specimens of the same species. 



The genus Bcenasa presents in the male a most extraordinary 

 modification of the hind wing, which is probably unique in the 

 Lepidoptera, the whole wing being reduced to a minute lobe below 

 the base of the fore wing, except the inner area, which is largely 

 developed, appearing at first sight like a normal hind wing, but in 

 reality rotated at base, the npperside becoming the functional 

 un^lerside and the inner margin the functional costa. 



The Lithosiance as a group present great variety of s ructure as 



Fig. 25.— Larva of Fhilayria entella. \. (From Moths Ind. vol. ii.) 



regards both venation and secondary sexual characters, so that the 

 genera and sections of genera are very numerous. 



Some of the most generalized forms seem to be Hemonia, Tro- 

 pacme, and the genera allied to Nudaria ; whilst another gene- 

 ralized form Castulo, with veins 7, 8 and 9, 10 stalked, seems 



