37 



2. The alphabetical order is not so fixed in the mind as to 

 prejudice one in regard to homology. 



He distinguishes: 

 Pi-imary setae on the newly hatched larvae. 

 Subprimnry,, appearing after one moult, but fairly constant (/t«, &). 

 Secondary^ no constant position but scattered, very rare in the 

 first instar. 



PI. I fig. 15 shows Frackeu's indication best. 



The above-mentioned writer thinks it justifiable to conclude 

 from the setae on the prothorax of the Tortncidae (1. c. fig. 39), 

 Aegeriidae and Yponomeutidae (1. c. fig. 35), that e remains in its 

 place and ; moves forward towards it, whilst in the Macrolepi- 

 doptera the opposite movement is to be noted. In the latter e has 

 migrated back to ; on the fullgrown larva, whilst they are far 

 away from each other on the newly hatched larva (1. c. p. 34). 



He therefore thinks that, for instance, in instar / the first seta 

 over the stigma of Feltia ylandaria^ is not y or f but p (see PI, 

 I, fig. 17). 



On the mesothorax and the metathorax also he arrives at con- 

 clusions, which differ from those of former writers. 



These differences have been expressed in his figures, which 

 are kept very diagrammatic. Seta p as well as seta /3 is always 

 turned caudally, whilst x and e point in an oral direction. These 

 figures already suggest the hypothesis proposed by Fracker. 

 For the formation of an unprejudiced opinion it is therefore pre- 

 ferable to pay exclusive attention to the points of implantation 

 of the setae on the skin. 



I also wish to draw attention to PI. I, fig. 16 which agrees 

 with Fracker's PI. V fig. 36, the mesothorax of Atteva aurea 

 ( Yponomeiitidae). 



Fracker sometimes unites the setae into several groups: 



B = x + (3. K = ^-\-x-\->;. P = s-\- p. 



n ^ y + r (on thorax), y + tt + r (on abdomen). 



T = T + ^ -f «. 



Before proceeding to the nomenclatures I should like to 



