3 1 4 LEPIDOPTERA CHAP. 



less extent to the inside of the body, and modified to form part of 

 a copulatory apparatus ; its dorsal portion bears a process called the 

 " uncus " ; the anal orifice opens on the inner face of this process, 

 and below it there is another process developed to a greater or 

 less extent called the " scaphium." The ventral portion of the 

 ninth segment bears a lobe, the " saccus " (Peytoureau, I.e."). On 

 each side of the ninth abdominal segment there is a process called 

 the " valve," the internal wall of which bears some hook-like or 

 other processes called " harpes " ; it is continued as a membrane 

 surrounding the " oedeagus," or penis, and bearing more or 

 less distinct prominences connects with the scaphium. In many 

 forms the parts alluded to, other than the valves, are concealed 



by the latter, which 

 sc come together when 

 closed, and may lie 

 covered externally with 

 _, scales like the rest of 



the abdomen. Peytou- 

 reau considers that the 

 uncus is really the dorsal 

 plate of a tenth segment, 

 c and that the scaphium 



FIG. 160. AcJierontia atropos. The termination of jg iliQ tenth Ventral 



body, one side removed. 7A, Ninth dorsal plate ; 1 , . 



/A", ninth ventral ; s, lobe, saccus, of ninth plate. IhllS, according 



ventral plate ; A", tenth dorsal plate, or nncus ; ^ Q ^his view the ninth 

 sc, scaphium, or tenth ventral plate ; , position of 



anus ; b, chitinised band of scaphium ; V, valve or segment IS extensive and 

 clasper : c, hooks, or harpes, of clasper ; _/>, penis Complex beilio 1 VCl'V 

 (or oedeagus). (After Peytoureau.) 



highly modified in all 



its parts : while the tenth segment is greatly reduced. The 

 structure of the male organs is simpler in Lepidoptera, and less 

 varied than it is in the other great Orders of Insects. There 

 are seven pairs of abdominal spiracles on the upper parts of the 

 membranous pleurae. 



LEGS. The legs are long, slender, covered with scales, and 

 chiefly remarkable from the fact that the tibiae sometimes bear 

 articulated spurs on their middle as well as at the tip. The 

 front tibia usually possesses on its inner aspect a peculiar 

 mobile pad ; this seems to be in some cases a combing organ ; 

 it also often acts as a cover to peculiar scales. The tarsi 

 are five-jointed, with two small claws and a small apparatus, 



