It’s amazing how things can change in just one week, especially if you are an insect. Last week I posted ‘Balancing Act’, which showed these caterpillars in an early stage of development, and after one week of almost continuous feasting on my rose-bush leaves how they have grown and changed.
These are Large Rose Sawfly (Arge pagana) larvae, and how bright yellow and distinctly marked they have become within just a short period of time. They can grow up to 25mm in length. By the end of this month they will have dropped from the rose leaves to bury themselves in the earth. Pupation will take place in a very short time, and at the start of August the brightly yellow coloured adults will emerge to begin the cycle over again.
Nature Journeys 
I saw a coincidence in the fact that the sawfly larvae are on leaves with sawtooth margins.
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It is the adult fly which saws plant tissue to lay the eggs from which the larvae hatch. They are feeding on rose leaves, yes, with sawtooth margins.
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Thanks for the clarification. The coincidence was more in the words (saw, sawfly, sawtooth) than in the biology.
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