399 



This case exceptocl, it secins to me tliat we eau [)i'()ve that the fea- 

 ture of plumose setae has been obtained later than tliat of verrueae. 



If this observation shoiild also be oonfirmed for other species 

 tliaii those I had at my disposal or for those of which I was 

 able to collect data from the literature, this might add to a more 

 accurate insight into the phylogeny of the Lepidoptera. 



Scudder's opinion that a homogeneous spreading of the setae 

 over the segment is a primitive quality, is decidedly wrong. Na- 

 ked forms and species with a dense covering of setae have always 

 arisen from species with a definite setal pattern. (Chapter VI 

 i. a. Boinhijx., Spliinx^ Pkrls napi). 



The verrueae of some families are reduced again to setae. Now" 

 in palaeontology the law of irreversibility liolds, which Dollo (1893) 

 formulates in the folio wing few words: "The development goes 

 on with leaps, ffe irreversible and limited." 



In discussing the families I have drawn attention to the fact 

 that it can sometimes be seen from the w^hole pattern, but often 

 not from the separate setae, whether they have arisen primitively 

 or by reduction of the verrueae. 



In any case therefore for the separate organs we have to do 

 with a reversible development, a fact which deserves our atten- 

 tion in connection w4th the interest which from the palaeontolo- 

 gical side especially is paid to this problem [compare for instance 

 the exceedingly clever expositions by Dépéiret (1908) and by his 

 critic HoERXEs (1911)]. 



The objections which Fracker (1915) makes to my opinion 

 explained above, do not appear to me to be quite convincing. 

 For particulars I refer to the Noctuidae^ Chapter YI. 



Concerning the separate series of development I can sum up 

 my results in the following way (Chapter VI) : 



The Hepialidae differ rather from the FKENATAE, but at the 

 same time present such important differences from the other 

 JUGATAE and even amongst themselves, that it is impossible to 

 fix a definite, strictly circumscribed pattern for this sub-order. 

 Verrueae occur on the Eriocephalidm. 



