TRAGARDH: NOTES ON THE EARLIER STAGES OF ORCHESTES FAGI L. 7671 
edge of the leaf. This gallery widens only very little as it 
approaches the edge of the leaf, and, to judge from the 
size of the larvæ found at the edge of the leaf, at the end 
of the gallery, this is made by the larvæ during the 15t and 
and instar. Arrived at the edge, 
the larva follows that for a 
short distance and then com- 
mences constructing a blotch 
mine, which widens gradually 
towards the middle of the leaf. 
It is obvious that the con- | 
ditions in a tunnel mine differ | 
form those of a blotch mine. 
In the former the upper and 
under cuticle of the leaf is pres- 
sed very_ closely to the body, 
and dorsal or ventral spinulæ 
would to all appearance be of 
little use, as there is very little 
room for contracting and extend- 
ing the body; the only room whe- 
re locomotorial structures can be 
Nat. 
left side a normal 
Leaf of beech-tree. 
the 
Fig. 4. 
size. On 
applied to the walls are at the 
sides of the body, since at least 
a small interspace is bound to 
arise there. In the blotch mine 
on the other band there is ample 
room between the roof and the 
floor, and here locomotorial struc- 
tures of the later instars can be 
brought into action. 
gallery is delineated. On the right 
a gallery made partly after the 
leaf has been picked. We notice 
that the gallery runs straight 
for ?/3 of the distance between 
the median nervule and the edge: 
this part was made before the leaf 
was picked; afterwards the gallery 
doubles back on itself and winds 
both to the left and to the right; 
the holes are caten by the adult 
beetles. 
Tropism of larva. 
An interesting feature in connection with the formation 
of the gallery of the larvæ is that the galleries on the leaves, 
as long as they are on the trees, always run straight towards 
the edge, but as soon as the leaves are picked, the larve 
appear to lose their capacity of taking their bearings. 
