37 
mine. In appearance it is very much changed. It forms a link be* 
ween the first and second instars, resembling the young larva in the 
form of the anterior segments, and the older larva in that of the 
posterior, lhe head remains practically the same in appearance, 
ine thorax is not quite so wide in comparison with the rest of the 
o y, as it is in the first stage. Certain of the abdominal segments, 
1 think from the second to the seventh, have on each side a papilla 
directed upwards and backwards. The eighth abdominal has, instead, 
a fleshy coneon each side, if not two ; the ninth, which is very narrow, 
is similarly furnished ; the tenth is very remarkable, being flat, very 
narrow, very long, and terminating in two points. In this stage, also, 
the prothoracic shield first appears. After feeding for two and a half 
or three days, the larva again rests in the mine to undergo the second 
mou . he process is accomplished in a similar manner to that 
above described, except that we notice that the prothorax, with dark 
shield, comes off attached to the head. The larva now enters upon 
a very important stage in its life-history, for it is in this third stage 
that by far the greatest amount of material is assimilated by the larva, 
and any deficiency of vigour during this stage cannot afterwards he 
made good. Almost at the commencement of this period the larva 
causes the mine to assume its wide, ribband-like, glistening, charac¬ 
teristic appearance. Hitherto the slender mine might easily’be mis¬ 
taken for that of a young Gracilaria, but now the hungry larva mines 
right and left on each side as well as directly forward,'keeping, how¬ 
ever, always on the surface of the parenchyma, and the results that 
it leaves behind it the special type of mine peculiar to Phyllmmti*. 
As the larva only consumes the fluid contents of certain cells, never, 
when quite healthy, any of the more solid portions of the leaf, it re¬ 
quires to mine over a considerable area before obtaining sufficient 
nourishment to bring it to perfection. The slender portion of the 
mine formed during the first and second stadia is usually about four 
to five inches in length, but the wider part, cut during the third stage, 
runs to a length of sixteen inches or more, so that a healthy normal 
mine is, when completed, usually not less than twenty inches in length. 
Yet the small creature that traverses this distance at the rate of three 
inches a day has no feet. The duration of the third stage is about 
five days, at the end of which period the larva has generally mined its 
way to the edge of the leaf. It now continues the mine parallel with 
the leaf edge for a space equal to its own length, and of an elongate 
oval form. In this space it subsequently forms its cocoon. In this, 
the last feeding stage, the larva attains the length of over 5mm! 
The wide, flat head, with its prominent wheel-like jaws, bears the 
same characteristics as in the two previous stages, but is larger. The 
prothorax now bears a distinct dark brown or blackish mark placed 
transversely on the dorsal posterior portion. This mark is, however, 
entirely wanting, as regards the colour, in those lame which mine on 
the underside of the leaf, except in very rare instances when the under 
side is exposed to the light. When present it forms, together with the 
amber mouth-parts, by far the most conspicuous parts of the larva. 
The dorsal vessel is yellowish, often becoming greenish towards the 
posterior half. The rest of the body might almost be described as 
colourless. It shows, however, a pale bluish grey when placed against 
a white background. The segmental incisions are very well marked, 
