42 



segments deserve special mentioning. For them I cannot give any defi- 

 nite rules, as in some cases they are far more reduced than in others. 



Type I. This pattern consists of the following setae, tubercula 

 etc. (PI. I, fig. 19). 



Seta dorsalis on the oral and at the same time on the dorsal 

 edge of the segment. 



S. subdorsalis superior more caudal and also a little more ventral 

 than the former. 



S. suprastig mails lying over the stigma, abont in a line with 

 the stigma and s. dorsalis. 



S. prostigmalis is usually very short and stands right in front 

 of the stigma or has been shifted a little upwards. 



S. poststigmalis caudal and in most cases somewhat ventral of 

 the stigma. 



S. infrastigmalis under the stigma. 



S. basalts anterior and 



S. basalts posterior situated between s. infrastigmalis and the 

 place where the leg is implanted, or where this is wanting, 

 between s. infrastigmalis and s. pedalis. 



S. pedalis at the beginning of the leg and, if the leg is wanting, 

 on the place where we might expect it. 



In connection with the remarks in chapter IV the presence of 

 this seta seems to me a proof of the secondary disappearance of 

 the legs on the abdominal segments 1, 2, 7,8,9. 



S. propedalis on the ventral side, in front of the beginning of 

 the leg. 



S. ventralis between the inner side of the leg and the ventral 

 median line. 



We see that this Type I almost completely agrees with the 

 pattern chosen as the fundamental plan by W. Muller (1886), 

 Dyar (1894), 0. HoFMANN (1898) and Quail (1904). Where, 

 in my investigation independently of them, I was led to the same 

 type, I think I am justified in attaching great value to this result. 



As rather frequently occurring extensions of this type, there 

 also occur: 



