281 



7.3. The evolution of the phallomere complex and the phylogeny in Blattaria 



(= subgroup 2.) 



The ground-plan of the phallomere complex of Blattaria 



The features listed subsequently can be ascribed to the ground-plan of Blattaria since they 

 are true either of all investigated species or at least of representatives of the two basal 

 sister-groups (subgroups 2.1. and 2.2., see below). For all these features, except for the 

 last-mentioned (reduction of muscle s2), it is not clear whether they belong to the common 

 ground-plan of Blattaria and Mantodea or whether they are autapomorphic for Blattaria. 

 The following elements or properties are assumed to be present in the ground-plan since 

 they are found in all Blattaria: sclerotisations L3, R2; formative element hla-hook. The 

 L4v-region (in close connection with the L4c-region, if L4c is present) is separated from 

 the regions L41 and L4ii. The regions Rid and Rlv are connected with each other 

 (narrowly in the primitive case) posterior to the membranous area 17. 

 The following elements or properties occur only in part of the investigated species but are 

 assumed to be present in the ground-plan since they are found in representatives of the 

 two basal sister- groups: formative elements dca-processes, nla-process, tre-tendon, rge- 

 groove; articulations A6, A7, A8, A9; muscles 114, r6, s7, and s8. The right parts of L2 

 and of the Ive-pouch curve dorsad and back to the left. The base of the hla-hook is in the 

 left anterior ventral wall of the left complex, and the introversible membranous basal part 

 30 of hla is narrow. The dca are two membranous cushions posterior to LI. 

 Another ground-plan feature of Blattaria might be that muscle s2 is distinctly thinner than 

 its left counterpart si (6.9.); this situation is distinct in Eurycotis (fig. 62: s2 weak), 

 Polyphaga, and Lamproblatta (fig. 113, 173: s2 lost). In Cryptocercus the condition of s2 

 is not assessable; in Anaplecta, Nahublattella, Parcoblatta, and Blabenis s2 is also weak 

 or absent, but, in addition, si has been completely lost. The situation in the Mantodean 

 ground-plan, with si and s2 of similar stoutness (Mantoida, fig. 37, 40), is regarded as 

 more primitive than in all Blattaria since both muscles as well as their symmetry are 

 preserved. An asymmetry in the stoutness of si and s2 is assumed to be an autapomorphy 

 of Blattaria. 



Subgroup 2.1.: Archiblatta + Eurycotis (and Periplaneta, Blatta, Deropeltis) 

 Periplaneta, Deropeltis, and Blatta have been studied only in part, but at least all the 

 derived features listed subsequently are also present in these species. The muscles have 

 not been studied in Archiblatta. 



Most of the autapomorphies are on the left complex: The anteroventral part of the Ive- 

 pouch is, like a tongue, deeply invaginated to the left (6.2.1.). The posteroventral part of 

 the Ive-pouch has strongly receded to the right (or is even more reduced: Eurycotis; 6.2.1.). 

 Correlated with the latter feature is that the paa-process has shifted far to the right and 

 is far away from the pda-process (6.2.1.). The sclerotisations of pda (L41-region) and paa 

 (L2d-region) have, possibly again in correlation with the previous feature, been separated 

 from each other (hke in some other subgroups: compare (A) in 7.5.; 6.2.1.). The L4c- 

 region is highly elaborated (or L4c is as a whole an autapomorphy of this subgroup), and 



