1909. ] LIFE-HISTORY OF THE LEAF=INSECT. 107 
ensure this, | sprayed them once a day with tepid water. It was 
most interesting to see the thirsty larve eagerly drinking the 
drops as they hung from the leaves and branches after the 
Spraying. 
As the autumn advanced the leaves of the oak became less 
nutritious, and it was necessary to find another substitute for the 
larve. Again following the advice of Mr. St. Quintin, I placed 
the larve on small binges of the evergreen oak (Quercus ilex) and 
on this they settled down very well. 
The rate of development, 7. e. the time occupied between the 
«leposition of the eggs and the appearance of the imago, depends 
very largely upon the temperature. TI have not yet been able to 
work out the exact length of the various larval stadia, but have 
‘determined their approximate lengths, and I should think that 
under favourable circumstances the whole development would be 
completed in ten or eleven months. 
The Leaf-Insect is Paurometabolous and corresponds to the 
general rule in the Orthoptera. The larve in all stages are on 
the whole similar to the adults and there is no very abrupt 
transition, development taking place by a gradual increase in size. 
In the newly- hatched larva neither joni nor wings are present, 
these being acquired during the later stages, but only attaining 
their full dimensions in the imago state. There is no pupal stage, 
the larva merely passing through a slight resting stage prior to its 
reaching the perfect condition. JI found that there are six or 
seven larval stadia, so that the number of ecdyses is six or 
seven. Murray gave three as the number of ecdyses in Phyllium 
scythe, and if this is correct it appears curious there should be 
such a discrepancy in the number of moults in the Phylliums. 
The larve moult for the first time when about six weeks 
old if kept in a mean temperature of 66° F., the succeeding 
moults following at intervals varying from five to six weeks. 
The colour of the newly-hatched larva is, as previously stated, 
reddish-brown streaked with dull red, but this soon changes and 
the larva passes through a regular series of colorations from brown 
to green during the first fortnight. In the first day or two of 
lereal life hardly any change is mene amie excepting the slightly 
paler colour ; but when the insect is a week old a yellowish-green 
colour is assumed which gives place in about a fortnight. to a 
beautiful pale green on the dorsal and to a rich glossy green on 
the ventral side. Later, as the larve increase in size, their colour 
becomes more varied and, although green predominates, many 
shades occur. Some individuals are beautifully marked with 
different shades of brown and yellow. These colours combined 
with the positions assumed by the larve render them most in- 
conspicuous on the leaves. 
Nor is the resemblance to plant-life confined to colour, for the 
larva has a very peculiar gait which imitates to a remarkable 
degree the shaking of the leaves rather than the movements of an 
insect. The larva of the second stadium is about 20 mm. in 
