13 



- The boundaries of the insertion areas of muscles are also shown by continuous black 

 lines if they are directly visible. Parts of these boundary lines which are covered by 

 the muscle itself or by other structures are drawn as broken lines. In some cases the 

 insertion areas alone are drawn without the respective muscles (mainly in the figures 

 showing the subgenital plates, e.g. fig. 5); the boundary of the insertion area is again 

 shown by a continuous black line. 



- Undulate lines are cutting lines (through cuticle of normal thickness) or bound cut 

 surfaces (of muscles or strongly thickened cuticle cut through). 



- The series of figures pertaining to a certain species has as a whole been worked out 

 with the intention of showing all relative positions of all elements of the phallomeres, 

 including all the membranous foldings. 



- The series of figures for the various species are designed for the best possible 

 comparability. For example, in the overall views of the postabdomdna (compare fig.l, 

 2, 3 and fig. 58, 59, 60) the cutting hnes have the same course in each species (their 

 courses are, so to speak, homologous), and, if present, the same muscles are shown. 

 Or, the right phallomeres of Blattaria are always shown in the same four aspects. 



Remarks on homology 



As a principle, elements regarded as homologous will be given the same name, and 

 elements given the same name are regarded as homologous. Minor exceptions to this rule, 

 mainly due to a not very high probability of homology, will be explicitly mentioned in 

 the text. 



Mainly the criteria of the relative position and of the special structure (1. and 2. major 

 criteria of Remane 1952) will be used in this paper. These will be applied to the following 

 kinds of structures, whose relative position and special structure will be comprehensively 

 discussed in the homology analysis: 



- Sclerotised areas of the cuticle (sclerites). 



- Articulations or other special relations between sclerites. 



- Formative elements: more or less distinct evaginations or invaginations of the cuticular 

 surface of the phallomere complex (processes, ridges, pouches, tendons, apodemes, 

 lobes, etc.). 



- Insertion areas of muscles. 



- The opening of the ejaculatory duct or genital opening. 



- The opening of the phallomere-gland (a gland within the left part of the phallomere 

 complex). 



The sclerotisations of the phallomeres will be divided into areas which are strictly 

 homologous in the different species. These areas are the main sclerites (or sclerite groups, 

 if these main sclerites have split into several isolated sclerites) and - as their subunits - 

 the sclerite regions. Some difficulties arise in this demarcation of homologous areas within 

 the cuticular surface of different species and in the standardisation of this procedure. The 

 following example shall illustrate these problems: Provided: In two compared species A 

 and B homology is certain (as much as it can be) for a sclerite as well as for a muscle. 

 In species A the muscle inserts on the sclerite, in species B the muscle inserts on the 



