32 



atrophid. ^Edceagus large. Cornuti fairly long, numerous. 

 Cristae absent. Saccus pointed. 



Ostium wide, with small operculum. Bursa large, 

 pyriform, spined longitudinally. 



AGNATHOI. 



Gnathos reduced to a mere thickening of chitine, or absent. 

 Anus generally long, with spiny subscaphium. Central 

 area with labides, anellus lobes, or calcar. Manica well 

 developed, often spiny. 



Acidaliinae. 



This natural genus has peculiarities which we have not 

 found in any other group of Geometridce. The male features 

 are found in the extreme fusion of the genitalia; the 

 separation of the hard chitinous sacculus, from the con- 

 siderably reduced valvula; the absence of uncus; the great 

 development of the socii; the hard chitinous anellus; the 

 large saccus; and the pencil of long, curved, plumed scales, 

 springing from a circular base, at the articulation of the 

 sacculus with the tegumen. This group also, is peculiar 

 owing to the presence of a special development of the eighth 

 sternite, consisting of a chitinous plate, internal for half 

 its length, then coming to the surface, where it is con- 

 tinued in two pointed arms termed cerata. Covering these 

 cerata is a loose, semi-circular flap, clothed with long, 

 narrow scales, termed the mappa. 



In the female, the mappa is represented by a loose 

 flap, which in repose, covers the ostium. This we term the 

 instita. Throughout the genus the signum is composed of 

 a number of " pip " like spines, arranged in a patch. 



Acidalia strigilaria, Hb. ii 



Valvula fused; costa long, curved; saccnli asymmetrical, 

 left, tapered, pointed; right, tip broad, pointed, protruding 

 from which is a large lobe. Uncus obsolete; socii spined 

 lobes. /Edoeagus stout, tip pointed. Cornuti elaborate, 

 large, curved, with long base, thickened in parts. Anellus 



