338 Mr. G. C. Champion o?i various 



tip (A. correptus) ; the margins of the distal portion of this 

 organ are usually clothed with long curled hairs. The very 

 elongate penis-sheath exhibits a variety of forms : (1) almost 

 straight from near the base and simply pointed at the tip 

 (A. antis and many other species) ; (2) broad, compressed, 

 and obliquely truncate at the tip (J., sexmaculatus) ; 

 (3) constricted distally, and obliquely truncate and sub- 

 securiform at the tip (^4. vittaticollis) ; (4) flattened and 

 strongly bisinuate as seen in profile (A. trifasciatus and 

 gayi). The long membranous sac, containing the true 

 intromittent organ, has not been examined : the distal portion 

 of it is usually seen protruding from the dorsal surface of 

 the penis-sheath at some distance before the apex of the 

 latter, and in tome cases the exposed part appears to be 

 studded with asperities or short bristles *. The terminal 

 abdominal segment of the $ is separated from the preceding 

 segment, on both the ventral and dorsal aspects, by a mem- 

 branous space, extending broadly forward along the entire 

 length of the fifth ventral segment in A. trifasciatus, sex- 

 maculatus, &c, allowing great freedom o£ movement of this 

 portion of the body during copulation. In several species a 

 thickened hook-like process has been noticed on the front of 

 the first ventral segment in £ ; but as this structure is almost 

 covered by the posterior coxae, and cannot be seen till the 

 abdomen is detached, no use has been made of it in the 

 present paper. 



The genus Astylus extends over the greater part of South 

 America, and is particularly well represented at high eleva- 

 tions in the Ecuadorean Andes, two species occurring as far 

 north as Panama, and two in the Lesser Antilles. The large 

 Chilean forms have been placed under a separate genus, 

 Mecoglossa, by Solier, a name that might conveniently be 

 retained for them, on account of the extraordinary genital 

 armature of the $ , and the cleft terminal ventral segment of 

 the ? . Since the publication of the " Munich " Catalogue 

 of Malacodermata, in 1869, numerous species of Astylus 

 have been described or named by Kirsch, Berg, Steinheil, 

 Gorham, Bourgeois, and Pic. It is questionable whether 

 one of the papers by the last-named author, entitled " Sur le 

 genre Astylus, Cast." (L'Echange, xvii. pp. 34-36, 1902), 

 containing many proposed new names for JS. American forms, 

 unaccompanied by definite descriptions or measurements, and 

 issued solely — as the author states — to secure priority, should 



* The genitalia examined have been dissected by Mr. A. Cant. To 

 extract these pieces without injury, it has been found necessary to boil 

 the detached abdomen in caustic potash. 



