82 



maculated, the forms of the maculae differing with the species, 

 but also differing so much at different stages of growth in the 

 same species that it is very iiazardous to undertake to determ- 

 ine a species by the markings of the larva. No decided con- 

 necting link between the two groups has been discovered, but 

 the larvas of some of the species of the flat group seem to 

 undergo developmental changes, whereby they approach in 

 form those of the cylindrical group, without, however, ever 

 assuming the cylindrical form. The only species in Avhich I 

 have ever observed this approach to the characters of the cylin- 

 drical larva? are L. cincinjiatiella Cham, and L. coryliella Cham. 

 I will not undertake to say positively that none of the other 

 species of the flat group })ass through similar developmental 

 changes. It is possible that they all do so, and I can only say 

 that, if they do, I have failed to detect it. Even in L. gutti- 

 finitella Clem., which is so nearly allied to L. coryliella Cham, 

 that some entomologists might consider them varieties of only 

 one species, I have never met with the intermediate larval 

 stage, which I have sometimes found in L. coryliella. If these 

 species, which have not been found to assume the intermediate 

 form, do really assume it, they do so only after the last moult 

 before passing into the pupal state, and it is very strange that 

 it should never have been observed in them. It is, however, 

 a point somewhat difficult to determine, because the removal of 

 a larva from its mine ensures its speedy death, and one cannot 

 say certainly that it would not have undergone some further 

 development if it had remained in the mine. I can only sav 

 that I have removed them from the mine both before and after 

 they had retired into the little circular nidus or depression into 

 which they retire to pupate, but have never found any species 

 in the intermediate stage, except the two above named, L. cin- 

 cinnatiella and L. coryliella. Nevertheless it is still possible 

 that, in such cases, their retirement into the nidus was only for 

 some temporary purpose, and that if they had been permitted 

 to remain in the mine they would still have undergone some 

 farther change, and might have passed into the intermediate 

 stage. One thing, however, is certain : the larva? of the cylin- 

 drical group are always cylindrical, while those of the flat 



