172 
TRANSFORMATIONS OF INSECTS. 
and curiously enough it never attacks a second twig on the same 
tree. Day after day a new plant is chosen, and there is evidently 
a plan in this. Why should the insect avoid the tempting stems 
of the same bushes, and seek those of other rose trees ? Simply 
because were it to lay too many eggs on one tree there would 
not be leaves enough for the progeny. What a wonderful instinct 
is this, that causes the creature to think for the future, and to 
reason more wisely than many men ! The Hylotoma takes care 
of all its little ones in the most clever manner possible, and it 
leaves them enough to live on without starving each other — an 
example which might be followed by most of the creatures that 
consider themselves infinitely higher and more able than the 
tiny insects. 
About eight or ten days elapse after the eggs have been fixed 
into the twigs of the rose, and then the young larvae are hatched, 
and they immediately crawl on to the leaves, and begin to eat 
them. 
Their growth is rapid, and they change their skins time after 
time, but without the general shape of the body or its colours 
undergoing a decided alteration. The body of the larva is of a 
more or less dark yellow colour, and the sides are green. It is 
marked very generally with numerous black and shining tubercles, 
which are covered with hairs. The head is yellow, and the black 
eyes are surrounded with spots of the same colour. 
These larvae resemble true caterpillars exceedingly, especially 
when they move from place to place, but their characteristic atti- 
tude is very different from those of the Lepidoptera. They are very 
prone to adopt the curious and striking posture which has been 
noticed already. Holding on to the plant by their fore legs, they 
stick up the end of the body, and if they are feeding with the 
body in the usual horizontal position, and are disturbed suddenly, 
this threatening attitude is forthwith adopted. Under different 
circumstances, and when they are at rest, they simply twist the 
last segments of the body underneath, but do not roll themselves 
up in a spiral like many other larvae of saw-flies. 
By the end of the month of June the larvae of this interesting 
saw-fly have reached their full growth, and most of them walk 
off the leaves and twigs that have been so serviceable to them, 
