I. trägardh: höstminornas gröna färg. i 8g 



attains the size shown in fig. i. During the period of its 

 life when the larva accomplishes this work it is a sap-feeder 

 (comp. Trägardh 191 3, a) and does only consume the 

 spongeous parenchyma, forming a thin layer closely above 

 the lower epidermis (s, fig. 2). When the widening of the 

 area of the mine is finished the larva starts to increase the 

 height of it by folding the floor once or twice, thus com- 

 pelling the roof to rise, and subsequently it starts afresh 

 devouring what is left of the parenchyma on the »walls» of 

 the mine. 



It follows from the method employed by the larva that 

 during the first period of its construction the vascular bund- 

 les are not at all interfered with; as a matter of fact it de- 

 pends entirely on whether the larva when the leaves begin 

 to turn yellow has arrived so far with the mine that it has 

 started to feed on the rest of the parenchyma above the 

 spongeous parench}-ma or not if the mine shall remain 

 green or not. 



The mine of Nepticula siibbiDiaciilclla is constructed in 

 a quite different way. The egg is laid on the upper side 

 of the leaf, as a rule close to a nervule; (ä, fig. 3); the 

 larva at first makes a narrow gallery (gm, fig. 3) which 

 follows a nervule and later widens to a large blotch (bl, fig. 

 3) wherin already from the very first all paren- 

 chyma is consumed. In fig. 4 a section through a com- 

 pleted mine is delineated; we notice that there is in realty 

 nothing left but the upper and lower epidermis; the rounded 

 bodies (b) to be seen in the mine are clusters of fungi, ha- 

 ving penetrated the dead epidermis. 



It is evident that this type of mine interferes with the 

 vascular system at a much earlier period than the LitJio- 

 colletis-m\x\ç:\ moreover, it is almost invariably placed in the 

 angle between to nervailes, thus through its position at the 

 mouth of the vascular system of a part of the leaf inter- 

 fering more seriously with it than the other mine which ge- 

 nerally is placed in the middle between two side nervules, 

 thus at the sources of two vascular systems. 



And, as a matter of fact, the influence of the mine is, 

 in this instance far greater than in the former case, the por- 



