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 Avithout 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 Lepidoptcra. 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 difterent 

 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 larvne of saw-flies. 



By the end of the month of June the larv^^e 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, 



