28 



structures. These more or less distinct invaginations (or infoldings) and evaginations (or 

 outfoldings) of the cuticle are responsible for the shape of the phallomere complex, and 

 I will designate them as the formative elements. These will receive special names serving 

 for a clear and practicable reference and for a clear presentation of homology relations. 

 The terms are composed of three small letters. The first two letters are the individual name 

 of the respective formative element, the third letter stands for one of the two possible 

 categories (a = evagination, German "Ausstülpung"; e = invagination, German "Einstül- 

 pung"). A certain area of the cuticle can belong to two or more neighboring formative 

 elements, and, in such a case, the respective terms "overlap" each other. For example, a 

 certain area of the cuticle can be e.g. the dorsal wall of a specific evagination and the 

 ventral wall of an immediately adjacent invagination at the same time, or a large 

 evagination can fork into smaller ones in its distal part. 



The first two letters are essentially selected arbitrarily but are mostly abbreviations for 

 characteristic attitudes (e.g. via = ventral lobe, evagination). In other cases the 

 abbreviations of the terms of LaGreca (1954) have been used (e.g. Ive = lamina ventrale, 

 invagination; LaGreca's name for sclerite L2 and for the pouch containing L2; compare 

 fig.321g). The formative elements of the phallomere complex termed in this paper are 

 Hsted in 4.7. 



Similar terms are used for formative elements outside the phallomere complex (e.g. sbl = 

 subanal lobe), but the letter in third position is part of the abbreviation and does not stand 

 for a category. 



4.4. The terminology for the muscles 



Muscles are named by a small letter determining the category, followed by a number for 



the individual muscle. Numbering is arbitrary. The categories are as follows: 



1 Intrinsic muscles of the left complex (left) 



r Intrinsic muscles of the right phallomere (right) 



b Muscles connecting the left complex and the right phallomere (between) 



s Phallomero-sternal muscles (sternal) 



p Muscles not inserted on the phallomere complex but taken 



into account (some ventral, dorsal, dorsoventral, and rectal muscles) (peripheral) 

 In some cases it can be reliably assumed that a muscle has divided. In other cases 

 homology can be assumed for groups of muscles of different species, without the 

 possibility to ascertain the homology relations for the single muscles of the group. In both 

 these situations all muscles of the group get the same number, and the single muscles are 

 distinguished by adding a small letter in the third position. In these cases equal letters do 

 not mean homology of the respective muscles by principle; which homologies are assumed 

 will be explicitly mentioned in the text. 



For the muscles of the categories 1 and r it is not clear which of them have originally 

 been pairs or if there are pairs at all. The muscles of category b are probably unpaired 

 transverse muscles. The phallomero-sternal muscles s will be separately numbered on the 



