4 ARKIV FÖR ZOOLOGI. BAND 8. NIO 9. 



After the appearance of Dimmock's paper, I have only 

 fyeen able to find a few records of the dimorphism exhibited 

 by ma ny larvae of Tineidae and, moreover, the papers of the 

 two American entomologists seem to have been overlooked 

 by låter authors. 



Nowhere in the different textbooks of entomology have 

 I been able to find this singular dimorphism mentioned, or 

 even alluded to; only Tutt, in his great work, »British Lepido- 

 ptera» mentions Chambers' and Dimmock's papers [7, p. 43]. 



The dimorphism of Gracilaria and Phyllocnistis is, however, 

 known to some English and German [10, p. 40 — 54] lepido- 

 pterologists, although they have not ehtered into any minute 

 investigation of the morphology. Especially A. Sich has 

 given an excellent account of Phyllocnistis suffusella ZmjL 

 [8, p. 30 — 48] and of Chrysopora hermanella Fab. [10, p. 43 — 49, 

 pl. 13] but in his »Aid to the study of Lepidopterous Leaf- 

 miners» [9, p. 45 — 53] he does not call attention to the di- 

 morphism. 



Further, Dr. Chapman [12. p. 81—88, 138—142, 159— 

 184] in a paper »Notes on the Gracilariadce» , read March 18th, 

 1902, at the meeting of the City of London Entomological 

 and Natural History Soeiety pointed ont that in this group 

 the unusual phenomen occurred that while the earlier instars 

 were modified the låter ones were normal, and pointed out 

 the great value of the characters of the larvae and pupae for 

 systematic purposes. 



On the whole, however, this interesting subject is verv 

 little known; how little may perhaps be best illustrated by 

 a quotation from Fulmek [13. p. 1.] who in his paper on 

 Gracilaria syringella says: »Die jiingeren minierenden und 

 die älteren skelettierenden Raupen unterscheiden sieh in ihrem 

 Aaeusseren nicht wesentlich voneinander». 



It was in the summer of 1909, when staying in Båstad, 

 on the SW coast of Sweden, that the leaf- miners attracted 

 my interest. The leaves of Syringa vulgaris, as well as those 

 of Ligustrum vulgäre and Fraxinus excelsior were badly at- 

 tacked by the larvae of Gracilaria syringella. I was at first 

 very puzzled by the curious shape of the young larvae, which 

 did not at all correspond to my idea of what a tineid larva 



