268 



fig. 200; Blaberus, fig.293), or they are completely missing (Lamproblatta, Nahublattella, 

 Parcoblatta). In Polyphaga, Anaplecta, and some specimens of Eurycotis the pi are 

 divided into two bundles on one or on both sides. 



In Blaberus the pi are also divided into two bundles on each side; the one bundle shows 

 the usual insertion on the anterior margin of the paraproct, but the other bundle inserts on 

 its posterior margin (fig.293), and this is certainly a derived feature. According to 

 McKittrick (1964), the posterior insertions of the ventral muscles of segment 9 take the 

 same positions in the females of most Blaberidae, too. 



In Cryptocercus the pi (fig. 143a) are extremely broad. This is unlikely to be a primitive 

 state since the pi are by far narrower in all other Blattaria as well as in Mantoida and 

 Sphodromantis . In last-instar nymphs of Blaberus and Eurycotis the pi are by far broader 

 than in the respective adults (though not as broad as in Cryptocercus). Hence, the 

 broadness of pi of Cryptocercus might be a neotenic trait. 



The p2-muscles are dorsoventral muscles of segment 9. They are either very delicate 

 {Eurycotis, fig. 58; Polyphaga, fig. 109; Cryptocercus, fig. 143a; Blaberus, fig.293) or 

 completely missing (Mantoida, Sphodromantis, Lamproblatta, Anaplecta, Nahublattella, 

 Parcoblatta). 



A special feature of Eurycotis is that the p2 as well as the serially homologous muscles 

 of abdominal segment 8 pass through two pairs of eyelets in the vasa deferentia (as shown 

 in fig. 58: Vd, p2, and p2(8)). Snodgrass (1937) finds such eyelets, in the same 

 arrangement, also in Blatta orientalis (Blattinae); Pipa (1988), fig. 7, describes eyelets for 

 Periplaneta americana. I have additionally investigated the vasa deferentia of Deropeltis, 

 Periplaneta, Parcoblatta, and Blaberus: There are no traces of eyelets in Blaberus. Eyelets 

 or vestiges of them have been found in Periplaneta, Deropeltis, and Parcoblatta, but either 

 the passage is more or less narrowed, or there is only a thickening of the vas deferens 

 without any passage. The degree of eyelet reduction can be rather different in the four 

 places (often asymmetrical; this was also the case in some specimens of Eurycotis) and 

 in different specimens of a species. If passages were present in these species, these were 

 never passed through by muscles (though very thin p2 were often present). Pipa (1988), 

 however, finds the p2 passing through the eyelets in Periplaneta (S-9 in his fig. 7). 



In last-instar nymphs of Eurycotis and Blaberus p2 and p2(8) are by far stronger than in 

 the adults of the same species, and they all run through eyelets in the vasa deferentia. The 

 eyelets and their penetration by p2 and p2(8) are assumed to be nymphal features, which 

 in the adults can be retained to rather various extents (even within a single species). The 

 same seems to be true of the muscles themselves. A far-reaching retention of these 

 structures in the adult is thus regarded as a neotenic trait. 



The p3-muscles (rectal muscles) are present in all species and have a similar fan-shape 

 throughout. In Cryptocercus they are divided into two fans on each side. 



The p4-muscles have their anterior insertions always far laterally on the anterior margin 

 of tergite 9 T9. In many species they additionally extend onto the paratergites T9p 

 (Mantoida, fig. 36, 37; Cryptocercus, fig. 143a; Lamproblatta, fig. 169, 170; Anaplecta, 

 fig.200, 201; Parcoblatta, fig.262, 263; Blaberus, fig.293, 294). In the latter case, except 



