46 Annals Entomological Society of America [Vol. XV, 



developed into a large bivalved prominence (PI. X, Figs. 91-93), 

 which perhaps serves as a clasper* (of. Stagmomantis). Strong 

 muscles connect the upper valve with the apophysis, as in 

 Blattella, though their action is probably quite different, 

 appearing in the case of P. jiiliginosa to elevate the valve. 



In Periplaneta brunnea Burm. the two processes representing 

 the distal part of the shaft are modified into a pair of hooks, as 

 shown in Fig. 96, and the clasper is also of different form. 

 In P. americana L. the upper of the processes (the short one in 

 P. Jiiliginosa) is the well-known "bird's head" process, termed 

 by Crampton "fimbrilobus. " It is a broad, flat structure, 

 clearly belonging to the dorsal surface of .the paramere lobe, 

 and has the form shown in Fig. 99. The other process, so 

 strongly developed in P. Juliginosa and P. hrunnea, is reduced 

 to an insignificant hook. The parts representing the clasper 

 are of simpler structure and more easily recognized as the 

 chitinized walls of the pocket from which the apophysis is 

 formed. 



The sinistral paramere lobe (Figs. 94, 95) is apparently not 

 comparable in detail with the dextral. In P. Juliginosa it is 

 divided into three principal processes, a dorsal, a ventro- 

 lateral and a ventro-mesial. As seen from the left side (Fig. 95) 

 the dorsal and ventro-lateral processes appear separated by 

 a deep distal cleft. The dorsal process is chitinized along the 

 side, terminating in a sharp point, but is membranous above and 

 on the oblique inner surface. The ventro-lateral process is 

 well chitinized and is the long, slender titillator (pm) which 

 curves dextrad and dorsad, tapering to a pointed apex. The 

 ventro-mesial part is free from the dorsal process only distally, 

 where it terminates in a rounded lobe and a slender spur or 

 hook. The dorso-mesial surface also bears two smaller, sharp- 

 pointed processes and above these two membranous lobes. 



In Periplaneta brimnea Burm. the same parts are recognizable 

 but differ more or less in form, particularly the ventro-mesial 

 process, which terminates in a long, straight spine, and the 

 dorso-mesial sclerites, which, instead of bearing straight spines, 

 are low tubercles covered with minute spinules. 



In P. americana L. the ventro-lateral process is stouter and 

 tipped with a hook, the ventro-mesial process is somewhat 



* The "tuberculum" of Berlese. 



