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the hia-hook, and there are various supporting mechanisms present to give the 

 contraction of 114 the proper effect, which is the movement or retraction of hla, and to 

 prevent a distortion of the areas (1) between the anterior 114-insertion and the hla-base 

 and (2) immediately around the anterior 114-insertion. (1) In Archiblatta and Eurycotis 

 the swe-apodeme might fulfil the former function (fig. 53, 65), and since the morphology 

 of the L41-region and swe is the same in Mantoida (6.3.1.), this mechanism is certainly 

 the most primitive within Blattaria. In subgroup 2.2.3. swe is missing, and the anterior 

 part of the Ive-pouch has been elaborated as a long and stiff Ive-apodeme. In Anaplecta 

 (subgroup 2.2.3.1.) the anterior 114-insertion on nla is stabihsed by nla being firmly 

 rested upon the top of the Ive-apodeme (fig. 209, 210). The stabilisation of nla might 

 be the primary function of the Ive-apodeme. In the further evolution (in subgroup 

 2.2.3.2.) the anterior 114-insertion has shifted even further anteriad, and it has apparently 

 been preferred to make more directly use of the supporting function of the Ive-apodeme 

 and to translocate the 114-insertion to the top of Ive. (2) The nla-process itself assumedly 

 has the function to stiffen the immediate vicinity of the anterior 114-insertion - as long 

 as this insertion is on the L4n-region - and is therefore bulge-like {Archiblatta, 

 Eurycotis, Anaplecta). In species having this insertion translocated to the Ive-apodeme, 

 nla is either modified in its shape (Nahublattella: whip-like) or has been lost 

 (Parcoblatta, Blaberus). 

 - The position of the anterior 114-insertion and the condition of the phallomero-stemal 

 muscles si and s7 are intercorrelated: Additional stabilisation preventing a distortion of 

 the area around the anterior 114-insertion is probably achieved by muscles conducting 

 much of the force which 114 exerts to this area to the left apophysis of the subgenital 

 plate. These phallomero-sternal muscles insert immediately anterior to the anterior 114- 

 insertion. In Eurycotis this function is accomplished by muscle si, which inserts 

 between nla and the anterior end of swe (fig. 70). In the species of subgroup 2.2.3., 

 where the supporting function has been transferred from swe to Ive and where, except 

 for Anaplecta, the muscle-insertion for which the support is needed (114) has been 

 transferred from nla to Ive, the function of the "conductor"-muscle has consequently 

 been transferred from si to s7, which inserts anteriorly on the Ive-apodeme. Muscle si 

 has been lost in all species using a Ive-apodeme for support (subgroup 2.2.3.; 6.9.). 

 The reciprocal outgroup comparison between Blattaria and Mantodea clearly suggests that 

 swe (6.3.1.) and si (6.9.) are ground-plan elements, that the primitive position of the L4n- 

 region is like in Eurycotis (6.3.1.; compare fig. 325c and e), and that there is no tube- 

 shaped Ive-apodeme. The lack of swe and si, the extremely far anterior position of the 

 L4n-region (or its lack), and the Ive-apodeme - the features of subgroup 2.2.3. - are 

 certainly derivations within Blattaria. Especially the assumedly primitive position of the 

 L4n-region (like in Eurycotis) is clearly correlated with a short 114 inserted on L4n, with 

 the non-retractility of hla, and with a narrow basal membrane 30, and a non-retractable 

 hla can be expected to have its base far anteriorly. Thus, the non-retractable hla with its 

 base in the anterior ventral wall can be assumed to represent the plesiomorphic condition 

 within Blattaria. A bulge-shaped nla-process can also be regarded as a ground-plan element 

 of Blattaria, since it is present in all species showing the primitive condition that the 

 anterior 114-insertion is on a well-developed L4n-region. 



