323 



- The whole phallomere complex is bilaterally symmetrical (p. 256). Consequently, all 

 side-homologous subregions would have to be regarded as completely symmetrical, too. 

 The procedure and the argumentation of Mizukubo & Hirashima have some weak points, 

 and many of their statements are in contradiction to my results. My critique concerns the 

 topics discussed subsequently. 



The negligence of the musculature as a reference frame for the homology analysis 



Mizukubo & Hirashima base their homology analysis on the relative positions of the 

 cuticular subregions to each other but largely neglect the musculature. Regarding their 

 results, the courses of most muscles are inconsistent with the homology assumptions 

 deduced from cuticular morphology. Referring to Matsuda (1976), they assume that, since 

 the muscles develop independently of the exoskeleton, the insertions of muscles generally 

 have a too large shifting potential in their evolution to be reliable landmarks in the analysis 

 of homology relations. Matsuda (1976) regards the musculature as a valuable 

 supplementary criterion only "when the structures within a relatively narrow range of 

 species - within a family, or perhaps an order - are under study" (p. 36). The question 

 arises, therefore, how valuable the muscles are in homologising the phallomere elements 

 of Blattaria and Mantodea and to what extent they deserve to be considered. 

 In Eurycotis and Mantoida, which are only distantly related, the cuticular elements of the 

 phallomeres are quite similar in their principal arrangement. The arrangement of the 

 musculature is to a large extent consistent with the homology relations resulting from the 

 relative positions and special features of the cuticular elements: The main muscles of the 

 phallomere complex have the same course (12, 13, 14, 16, rl, r2, r3). In many cases the 

 musculature can help in confirming homology assumptions. This is not inconsistent with 

 the views of Mizukubo & Hirashima, but in my opinion it also suggests that one should 

 not a priori regard the musculature as highly variable as these authors do. 

 In my view, (1) to regard the insertions a priori as conservative and (2) to assume shifts 

 of insertions only if inconsistencies arise is the better approach. (1) In the comparison 

 between Mantoida and Sphodromantis, the evolution of some sclerotisations could be 

 reconstructed in detail, because the musculature was taken as an integral instrument of the 

 homology analysis (compare L4 in 6.3.3.). In the comparison of distantly related species 

 in which homologous cuticular elements show, apart from a somewhat similar position, 

 hardly any similarities, the insertions of muscles can in my opinion be extremely valuable 

 landmarks. For example, the insertions of 14, 12, and 114 suggest that sclerite L4K of 

 Cryptocercus is homologous with a part of sclerite L4H of Eurycotis (L4n-region and 

 anterior L41-region). The insertion of 14 suggests (partial) homology for L4K of Ergaiila 

 and L4K of Cryptocercus, though L4K of Ergaula has shifted to the ventral hla-base and 

 fused to sclerite L3 (compare in 6.3.4.). (2) On the other hand, of course, the muscle 

 insertions have a certain shifting potential. By studying enough species, however, these 

 shifts can often be "observed" step by step, and in many cases it becomes obvious whether 

 the insertions of the muscles or the similarities in cuticular morphology are the better basis 

 for homology assumptions. Drastic shifts of muscle insertions are e.g. that of 114 from 

 the L4n-region {Eurycotis) to the L2a-region (Nahublattella) and that of 12 from sclerite 



