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3. Reason: McKittrick names certain parts of her main sclerites with small letters in the 

 third position, no matter whether these parts are (1) products of a complete division or 

 (2) only certain regions of a main sclerite. However, these two situations represent two 

 different aspects of a sclerotisation and its evolution: (1) On the one hand, a main sclerite 

 is composed of one or more separate individual sclerites. Since divisions or fusions of 

 sclerites can take place, the state of subdivision of a main sclerite is subjected to 

 evolutionary changes. (2) On the other hand, a main sclerite, irrespective of its state of 

 subdivision, consists of several regions each of which is characterised by taking a certain 

 position, by having a certain shape, by occupying certain in- or evaginations of the cuticle, 

 or by bearing certain muscle insertions or articulations. The properties of these regions 

 undergo evolutionary changes, too. The special state of subdivision (1) and the special 

 properties of the regions (2) of a main sclerite are largely independent of each other, and 

 evolution works on both these aspects and has to be considered from both viewpoints. 

 3. Procedure: I strictly separate these two aspects (1) and (2) in my terminology, and for 

 the designation of different parts of main sclerites two terminologies completely 

 independent of each other will be used: 



The first terminology serves to designate individual sclerites having originated by a 

 division of a main sclerite: If any main sclerite is divided into two or more sclerites 

 completely separated from each other by membrane, each of the sclerites will get one 

 capital letter in the third position of its name (e.g. L2D, RIC). (The main sclerite has 

 become a sclerite group. An individual sclerite as defined here may, however, be connected 

 with parts of another main sclerite). If any of these individual sclerites undergoes a further 

 division or a fusion, all resulting sclerites involved in this process will get a new capital 

 letter. Equal designation of sclerites of different species means the assumption of 

 homology. Different designation, however, does not always mean complete non-homology: 

 Some small sclerites of one species can as a whole be homologous with one large sclerite 

 of another species, and none of the sclerites will have the same letter. In the third position 

 of these terms, I, O, and Q will not be used (danger of confusion with "1" and "0" in the 

 figures); R will not be used on the right side, L on the left side. Among other things, this 

 terminology serves for a clear reference between the text and the figures. 



The meaning of a term designating a certain individual sclerite, e.g. L2D, is hence as 

 follows: 



L 2 D 



a sclerotisation belonging to being the indi- 



of the Left side, main sclerite 2, vidual sclerite D 



The second terminology serves to designate certain regions of the main sclerites or 

 sclerite groups: This regioning is essentially independent of any natural sub-division of 

 the respective sclerotisations. To name these regions one small letter will be added in the 

 third position (e.g. L2d, Rlc). Equal designation of sclerotisations of different species 

 means the assumption of homology. Different designation means complete non-homology. 

 These names mainly serve for the demarcation of homologous areas on the main sclerites 

 / sclerite groups of different species and for a description of their evolution as regards the 

 properties listed above in 3. problem (2). Therefore, this dividing into regions, or 



