Watt. — Leaf-mining Insects of New Zealand. 



451 



freedom from attachment to the surface of the leaf, and faint frass 

 lines. The only evidence on the upper surface of the leaf is an unusual 

 crinkled appearance, and sometimes short lengths of the later stages 

 of the mine where the larva has eaten deeper into the substance of 

 the leaf and reached the upper cuticle ; the pale-green portion of the mine 

 so exposed is readily noticed. Frass is finely granular, very scanty, and 

 offers no characteristic features. Very rarely, and then only in the larger 

 leaves, were two larvae found working in the same leaf. 



The Cocoon. 



The cocoon is constructed within the terminal part of the gallery, and 

 invariably close against the outer margin of the leaf, and usually on that 

 side opposite the one in which the mine commenced. Shape ovoid, slightly 

 broader at head end, 7 mm. by 3 mm. ; its long axis parallel to the leaf- 

 margin. It consists only of a very thin covering of white silk. Its presence 

 is quite conspicuous, due to the infolding and puckering-up of the leaf 

 round about it, and the small area of white transparent cuticle at the head 

 end prepared for the pupal dehiscence. The pupa thrusts the fore part 

 of its body through this window (vv^hich is, of course, on the under-surface 

 of the leaf) at dehiscence. 



In the North Island variety the cocoon is a small, flattened, oval structure 

 of white silk within the mine, generally found near the base of the leaf. It 

 can best be detected by holding the leaf up against the light, when the 

 pupa may be seen within. Externally its presence may be detected on the 

 upper surface by a slightly elevated portion of the leaf. Size, 6 mm. by 

 2*5 mm. There appears to be no prepared outlet for the pupa. 



The Pupa. 



The head as seen from the side is somewhat pointed, but rounded as 

 seen ventrally, with a slight incision at base of antennae. Cephalic plate 

 long and slender, three-bladed, sharply pointed, twice as long as broad 



II 



Fig. 10. — Ventral view of head of pupa of P. panacitorsens. 

 Fig. 11. — Lateral view. 



at its base, slightly longer than length of eye. Lateral cornua well deve- 

 loped, incurved, in length about three-quarters that of the plate. Frontal 

 tubercules and setae long and slender, situated just caudally to the base 

 of the cephalic plate ; bottom of labrum about the same level as base of 



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