GENERAL INTRODUCTION. 25 



strongly chitinized plate extending right to the apex. The 

 apex of the sternite is spinose. 



The eighth sternite of the male is modified ; it is always 

 without spines, deeply sinuate as a rule, and occasionally 

 incrassate mesially or produced into a process (figs. 21 J, 

 22 B, F, Oxyambulyx). The eighth tergite of the male is 

 spinose and varies in size and shape. 



The scaling of the posterior segments exhibits sometimes 

 striking features. The scales at the ventral apical angles 

 are occasionally prolonged to tufts. The expansible fan-tail 

 found in numerous Sesiin^ and Nephelini is generally 

 tripartite ; it occurs also in Cypa and allies of the subfamily 

 Ambulicinje. 



Genitalia. — <J. The copulatory apparatus of the male is 

 composed of the ninth and tenth segments. The accom- 

 panying diagram (fig. 7 A) will make clear the relative 

 position of the various elements of the clasping -organs. 



The ninth segment * is a strongly chitinized girdle, broadest 

 above, and here sinuate basally. This belt is ventro -laterally 

 dilated into a large flap (CI), the clasper or valve, and bears 

 the harpe (H). The pleurum is attached to a proximal strip 

 of chitin (pi) and to the sternite. The tenth segment f 

 (x. t and x. v) stands in very close connection with the ninth ; 

 there is no intersegmental membrane between them, except 

 occasionally a remnant on the upper side. The tenth tergite 

 is strongly chitinized and is movable in a vertical direction, 

 or, if completely divided, also mesiad. 



Between the sternite and tergite is the anus (A), and between 

 the tenth sternite and the ninth the penis-funnel (P-F), 

 from which protrudes the penis-sheath % (P) . 



The tenth tergite bears stiff hairs, which stand either singly 

 or form a more or less dense covering on the upper and lateral 

 surface. There are two principal forms of the tergite, it being 

 either divided mesially or simple. 



The tenth sternite is a belt running from the base of the 

 tergite ventrad, encircling a membranaceous area, from 

 which projects the anal cone, the end of the gut (A). The 

 ventral transverse part of the sternite is in by far the larger 

 proportion of Hawk-Moths as strongly chitinized as the vertical 

 side parts, and is produced into one or two processes or lobes 

 of various shapes and sizes §. 



The clasper is normally sole-shaped, with the dorsal and 

 ventral margins rounded. There are various modifications 

 by reduction and by division and the development of a special 



* Sometimes called the tegumen. 

 t Usually called, the uncus. 

 | Also called the aedeagus. 

 § Also called the scaphium. 



