304 



In dependence on the phylogenetic hypothesis in 7.4. the following view results: A far 

 anterior position of the hla-base and a narrow membrane 30 (and a non-retractable hla) 

 are present in the subgroups 2.1. and 2.2.2.2. Thus, the more posterior position of the hla- 

 base and the expansion of membrane 30 (and the retractility of hla) can be regarded as 

 apomorphic states developed in the Blattarian subgroups 2.2.1. and 2.2.3. (These are 

 possibly synapomorphies of these two subgroups: (35) and (36) in 7.4.) The more posterior 

 position of the hla-base in subgroup 2.2.2.1. {Cryptocercus, fig. 151), which is, however, 

 not accompanied by an expansion of membrane 30 and by a retractility of hla, is also 

 derived. 



There are some functional intercorrelations between the various characters of hla and 

 between these and some other elements of the left complex. Consequently, the species 

 with a completely retractable hla (subgroup 2.2.3.) show some concomitant morphological 

 and functional differences to the species with a non-retractable hla. Since for some of 

 these correlated elements or properties an outgroup comparison with Mantodea and hence 

 a polarisation of the respective character states is possible, these intercorrelations permit 

 assessing the polarity of the characters of hla independently of the phylogenetic hypothesis 

 in 7.4. The following intercorrelations and evolutionary changes are assumed: 



- The extension of membrane 30, the retractility of hla, and the position of the hla-base 

 are intercorrelated: If membrane 30 is more extensive, hla can be retracted more deeply, 

 and then its base can be more posteriorly without having hla exceeding the subgenital 

 plate or protruding from the genital pouch during its inactive state. From a functional 

 point of view, the more posterior position of the hla-base and the retractility of hla 

 might have the advantage that in its active state (during copulation) hla protrudes farther 

 from the genital pouch and is more flexible. In Cryptocercus the more posterior position 

 of the hla-base is not accompanied by an extension of membrane 30 but by a shortening 

 of hla (fig. 151). 



- The retractility of hla, the length of 114, and the positions of the 114-insertions are 

 intercorrelated: In the species with a non-retractable hla, muscle 114 has only the 

 function to move hla; to accomphsh this function 114 has to be contracted for a short 

 distance only and can be rather short (fig.72). In the species retracting hla (subgroup 

 2.2.3.) the contraction distance of 114 has to be much longer, and thus 114 itself has to 

 be longer. This requirement is in part fulfilled by the posteriad shift of the posterior 

 114-insertion together with the hla-base. Additionally, the anterior insertion of 114 has 

 shifted anteriad. At a first stage, this latter shift has evidently been achieved by an 

 anteriad shift of the L4n-region and of the nla-process, the primary anterior insertion 

 area of 114; this stage is represented by Anaplecta (fig.222; compare Eurycotis, fig.68, 

 72, where nla and the 114-insertion are by far more posteriorly). At a later stage, in 

 subgroup 2.2.3.2., the anterior 114-insertion has been translocated to the top of the Ive- 

 pouch (Ive-apodeme), and the 114-insertion is shifted further anteriad by a lengthening 

 of this Ive-apodeme (compare Anaplecta, fig.222, and Nahublattella and Parcoblatta, 

 fig.249, 276). 



- The position of the anterior 114-insertion and the condition of the swe- and Ive-apodemes 

 and of the nla-process are intercorrelated: A lot of force seems to be needed in operating 



