266 Prof. L. C. Miall and Mr. T. H. Taylor on the 
been described in several particulars. There are now two 
oral plates, one on either side of the mouth-opening, the 
right plate being larger than the left. Each bears two 
hooks, which are probably used in dividing the food. The 
anterior hook of the right plate is the largest of the four, 
and the distortion which regularly occurs brings it exactly 
in front of the mouth-opening (fig. 5). The asymmetry 
of the oral plates may be connected with the circumstance 
Fie. 5. 
Head and prothorax of larva of 3rd stage, ventral 
view. lp, rp, left and right oral plates ; 7, oblique 
sunk rods; x, chitinous rings. (x 360.) 
that the larva lies on its side while feeding on the cells of 
the leaf. The endocranium is stronger and of darker 
colour, almost black. The anterior median piece has 
become distinct from the forked part (fig. 6) A new 
structure, the tentacle, now appears on the exposed surface 
of the head; what seems to be the labrum is produced 
into two pairs of lobes; there are also for the first time 
chitinous rings on the head and prothorax which resemble 
the bases of setze and are perhaps sensory (no true setz 
have been seen on any part of the cuticle); the oblique 
sunk rods are more conspicuous. The segmental bands of 
