396 Dr. T. A. Chapman on the 



especially the dorsal line or band and the median line on the slope 

 noted in second instar, which to a great extent breaks up the white 

 diagonal line. 



There are a good many larvae intermediate between these two. 

 One for instance has the brown most pronounced on the fourth, fifth 

 and sixth abdominal segments and paler behind and fading to green 

 only on the prothorax ; the pale green forms are, however, the most 

 numerous. 



One of these larvae observed feeding presented a rather 

 astonishing and weird object. The larva was absolutely 

 at rest and immovable on a leaf, a little over 4 mm. long 

 and 1"5 ram. broad; round its prothorax was on the leaf 

 a halo consisting of the pale area of the mine the larva 

 had nearly completed. Through the transparent leaf 

 cuticle was seen the " neck " of the larva stretching from 

 the margin of the prothorax to the black head, the neck 

 looking Tike a transparent hose. The weird item was to 

 have, in connection with the immobile larva and the ap- 

 parently structureless and water-like hose, the head, at 

 the end of the latter, and quite at a distance from the 

 larva, moving rapidly to and fro and from side to side, the 

 jaws actively at work devouring the parenchyma and ex- 

 tending the mine. As the latter was nearly completed, 

 the larva left it a minute later. The neck was fully 

 stretched, and the contrast between the robust thickset 

 larva and the structureless neck, flattened to an almost 

 invisible nothing in the mine, and the black active head 

 working strenuously in the most purposeful way with so 

 vague a connection with the larva, was quite uncanny. Not- 

 withstanding the hundreds of mines, I happened to see 

 this curious spectacle only on one occasion, yet it must 

 occur as the normal process in the making of each mine. 



In the third instar there is a great variation in colouring, 

 several with the markings most pronounced are shown 

 on Plate XX ; fig. 4 presents the most highly-coloured 

 specimen ; others are simply green, much as in figures of 

 fourth and fifth instar, but with the yellow lateral line 

 still undeveloped. In the second instar a few specimens 

 show traces of the darker markings seen in the third, and 

 in the fourth they are present still more rarely and faintly. 

 The few last instar examples seen showed no trace of dark 

 marking ; they are, however, possibly present in rare 

 instances. 



