44 Annals Entomological Society of America [Vol. XV, 



apophysis. The projecting blade appears to be the primary 

 part of the paramere. whose base has been invaginated for the 

 insertion of muscles, while the folded edges of the invagination 

 have become chitinized for muscular attachment. 



The sinistral paramere* is a large hook, which, when not in 

 use, is completely retracted into a membranous sheath. Muscles 

 are inserted directly into the inner end of the hook. When 

 protruded this is a very conspicuous structure, extending 

 beyond the edge of the ninth sternum. 



Parcoblatta pensyhanica DeGeer (Figs. 84-8Sj. The geni- 

 talia of this species are essentially smiliar to those of Blattella 

 germanica. The ninth sternum is but slightly asymmetrical, 

 but the paraprocts are strongly so. Each is divided into an 

 outer hook and an inner lobe. The dextral hook is a large, 

 heavil}^ chitinized structure, whose base meets the edge of the 

 tenth tergite. The sinistral hook is much feebler and is 

 scarcely chitinized. The relative sizes of the lobes is reversed, 

 the sinistral being much the larger. The penis is similar to 

 that of Blattella, the ejaculatory duct very slender and opening 

 near the apex of the slender, slightly curved virga. 



The sinistral paramere resembles that of Blattella except in 

 the lack of a prominent shaft, which is reduced to a mere 

 angular flap, overhanging the opening of the pocket. The 

 sinistral paramere is a retractile hook, like that of Blattella, but 

 much shorter and stouter. When retracted the curved end 

 of the hook is generally slightly exposed, as in Fig. 84. 



Blaberiis atropos Serv. In this large roach the ninth sternum 

 is somewhat asymmetrical, the styli of similar size and widely 

 separated. The paraprocts are less sharply divided into 

 outer chitinized and inner flexible parts, and only the dextral 

 hook is present, this being short, blunt and strongly curved. 

 The penis is very diflerent from that of the two preceding types, 

 being a large, fleshy outgrowth, deeply channeled above and 

 bearing numerous spinules on the inner surface of the channel 

 near its extremity. Ikying in the channel is an irregularly 

 chitinized process, probably a modification of the virga, but 

 the ejaculatory duct does not open upon it, but at the base of 

 the aedeagus and is a much wider passage than in Blattella and 

 Parcoblatta. The dextral paramere is much like the sinistral 



* Chopard ('20) identifies this process incorrectly with the penis (p. 98, 

 Fig. 15). 



