I. TRAGARDH, LEPIDOPTEROUS LEAF-MINERS. 3 



flat group», but he believes that Frey bas mentioned it 

 somewhere. 



Furthermore, Chambers points out tbat Stainton, in 

 vol. 2 of his work, has delineated some apodous larvae wbich, 

 however, belong to the cylindrical group. 



Tbe following year, Chambers discovers that bis »inter- 

 mediate» form represents the last instar of the flattened type, 

 and forms a connecting link between his two groups. 



In 1880, Ch. continues his studies [5. p. 63—68, 133—137, 

 147 — 149], and ascertains, amongst other things that the larva 

 of Ornix prunivorella Cham. assumes »the secondary form of 

 larval trophi» at the' second moult, and tbat the trophi of 

 Phyllocnistis are very similar to those of the earlier instars 

 of Lithocolletis . 



Chambers' papers inspired G. Dimmock [6. p 99—103] to 

 study further tbe mouth-parts of the larva? of Tineina, espe- 

 cially in their earlier stages ; and he selected Gracilaria syrin- 

 gella for that purpose, on account of the abundance of that 

 species in the leaves of tbe lilac trees round about Leipzig, 

 where he pursued his studies under the direetion of Letjckart. 

 He gives an interpretion, correct in all essential parts, of the 

 mouth-parts of the earlier instars on comparison with those 

 of the last instars, and points out that the two different types 

 coordinate with the two different periods of the development 

 of the larva, as is also aecording to him the case with Litho- 

 colletis and Phyllocnistis, and possibly in other Tineina, in 

 which the earlier form of the larva is so different from its låter. 



He concludes: »In Gracilaria syringella, so long as the 

 larva? feed only in a plane surface, and do not spin, no great 

 difference is visible between the mouth-parts above the man- 

 dibles and those below them. 



Both labrum and labium exeroise their simplest functions 

 of pushing the food between, and keeping it subject to the 

 action of the mandibles, and, perhaps, of sawing it out of 

 the parenchyma by a lateral motion. 



But contemporaneous with the appearance of the låter 

 form of larval trophi — the labium capable of turning under, 

 and the better developed maxilla? — the larva, now having 

 its mandibles directed slightly ventrally to the surface of the 

 leaf, and of spinning threads in all directions.» 



