214 



Tryonicus. Features of Periplaneta will also be discussed (no figures). In Mantoida L4 is 

 one large sclerite, in the Blattarian species L4 is a group of sclerites. 

 L4 of Archiblatta (fig.53-57) and L4 of Periplaneta are very similar: 5 sclerites L4C, 

 L4D, L4E, L4F, and L4G in the same arrangement. Euiycotis (fig.65-69) has three 

 sclerites L4H, L4F, and L4G. 



That both L4F and L4G are homologous in the three species is evident from the identical 

 positions and similar outlines of the sclerites and from the fact that in Eurycotis as well 

 as in Periplaneta the muscles 15 (fig. 72) and 16b (fig. 70, 71) insert on them. A special 

 feature of Eurycotis is the mla-lobe (fig. 63, 68, 69). 



L4H of Eurycotis (fig. 65-68, 325e) is composed of three parts which are homologous with 

 L4C, L4D, and L4E of Archiblatta (fig.53, 57, 325 f) and Periplaneta: (1) The left, 

 crescent-shaped part of L4H corresponds to L4C. It lies in the left edge and in the 

 anteriormost ventral wall, an apodeme swe runs along it, and its posteriormost part 

 occupies a process pda. In Eurycotis and Periplaneta the muscles 12 and 14 (fig.70, 71) 

 insert on the posterior part of swe and run to the pouches pne and Ive. (2) The left part 

 of the L4H-plate in the anterior ventral wall is homologous with L4D. It takes a position 

 left-posterior to the right-anterior end of swe and bears a node-like process nla. Eurycotis 

 and Periplaneta have a stout muscle from this sclerotisation to the hla-hook (114c in 

 fig. 72). (3) The right part of the L4H-plate in the anterior ventral wall is homologous with 

 L4E. It takes a position in between the right-anterior end of swe and L4F. Eurycotis and 

 Periplaneta have a muscle from this sclerotisation to the anterior part of the Ive-pouch 

 (16a in fig.73). 



The definition of the regions of main sclerite L4 is mainly based on the condition of L4 



- as several isolated sclerites - in Archiblatta (compare fig.53-57 and fig.325f). The choice 

 of Archiblatta as the type of reference is made for practical reasons and has nothing to 

 do with an assumption of a primitive state. The positions of muscle insertions on the 

 various L4-regions (not studied in Archiblatta) are taken from Periplaneta and Eurycotis 



- in accordance with the homology relations to Archiblatta discussed above. For 

 Archiblatta and Eurycotis the regioning is shown in fig.325e,f. 



- L41 (lateral): The sclerotisation homologous with sclerite L4C of Archiblatta, minus its 

 dorsal extension to the right (L4d, see below). L41 bears the swe-apodeme and 

 sclerotises the pda-process posteriorly. On L41 there are the left insertions of the 

 muscles 12 and 14, which run to the pouches pne and Ive. 



- L4d (dorsal): The sclerotisation homologous with the dorsal, rightward directed 

 extension of sclerite L4C of Archiblatta. 



- L4n (node): The sclerotisation homologous with sclerite L4D of Archiblatta. L4n bears 

 the evagination nla. On L4n there is the anterior insertion of muscle 114, which runs 

 to the hla-hook. 



- L4c (central): The sclerotisation homologous with the sclerites L4E and L4F of 

 Archiblatta. 



- L4v (ventral): The sclerotisation homologous with sclerite L4G in the ventral wall of 

 the vla-lobe of Archiblatta. On L4v there is the ventral insertion of muscle 16b, which 

 runs to the Ive-pouch. 



