221 



been lost. The nla-process is well-developed. The L4v-region is a plate in the ventral wall 

 of the vla-lobe, the L4G-sclerite. 



From this situation the morphology of the five species in the heading and the remaining 

 Blattellidae and Blaberidae can be derived. In all these species, however, L4K and L4N 

 are no longer articulated but far away from each other. In some species L4K or L4N 

 undergo further divisions. In Cryptocercus, Polyphaga, Ergaula, and Lamproblatta the 

 anterior sclerite L4K has been strongly reduced (fig. 150, 124, 177). The sclerotisations 

 of paa and pda remain in most species connected, and this connection often becomes 

 very close. The L4v-region may retain its shape and position, or it becomes enlarged 

 (Lamproblatta, Polyphaga, Ergaula) or lost (Nahublattella, Parcoblatta, Blaberus). 

 As a first point, the evolution of the L4N-sclerite and the processes pda and paa of the 

 species in the heading will be discussed; then the L4K-sclerite with the nla-process and, 

 at last, the sclerite in the ventral vla-wall will be considered, paa, pda, and via have in 

 part already been discussed in 6.2.4, but a discussion of these elements is only complete 

 by considering them in context with the other L4-sclerotisations. This will be done in this 

 section. 



L4N-sclerite, processes pda and paa The homology of L4N of Tryonicus 

 (fig.94-97), Polyphaga (fig.117, 118), Ergaula, Cryptocercus (fig. 150, 151), and Anaplecta 

 (fig.210-215) - and of its derivatives L4S and L4T in Lamproblatta (fig. 177-180) - can 

 best be deduced from a comparison of the prominent substructures. In Tryonicus these 

 are: (1) The pda-sclerotisation (posteriormost L41-region), including its close vicinity to 

 and connection with the paa-sclerotisation (L2d-region). (2) The dorsal extension to the 

 anterior (L4d-region). 



Further evidence comes from the musculature, which, however, has not been studied in 

 Tryonicus. The homology relations and the resulting regioning of these sclerotisations into 

 L41 and L4d are shown in fig.325g,h,i,k,l. 



The pda and paa of Tryonicus, Lamproblatta, Polyphaga, Ergaula, and Anaplecta have 

 some features in common, none of which, however, is realised in all these species. But 

 the whole of the similarities is sufficient to regard the pda and paa of all species as 

 homologous. 



- pda and paa are two processes with their sclerotisations firmly connected. (The 

 sclerotisation of pda is designated as L4N or L4T, that of paa as L2 or L2C). Ergaula, 

 however, has lost the right process paa. 



- The position of pda and paa on the left complex is dorsal, far posterior, and far to the 

 left - near the left end of the Ive-pouch. In Lamproblatta, however, their position relative 

 to Ive is more to the right (fig. 179, 180). 



- The common sclerotisation of paa and pda is, to the right (Anaplecta, fig.211) or to 

 the ventral side (Polyphaga, fig. 11 8, 122; Ergaula; Tryonicus, fig. 97), firmly connected 

 with the left end of the L2-sclerotisation in the Ive-pouch. Lamproblatta, however, has 

 lost this connection (fig. 178, 179). 



- On the common sclerotisation of paa and pda there inserts a muscle coming from the 

 left part of the Ive-pouch (110 in fig. 129, 186, 222; compare in 6.2.4.; not analysed in 

 Tryonicus). 



