Hello Kees,
to help you in your problem, it would be important to know under which breeding terms you draw up the caterpillars!
Because you now 2. Thread has opened into which you have put at least a photo, your request seems to you to be important.
However, without further information one can badly help you.
At least it looks for me in such a way that the animals lack humidity. The caterpillar looks, as if it has peeled not right.
Moreover, you seem to hold them very aerial. Do you have all around aviation grid?
best regards
ute 
Hi Kees.
Could it possible, that the black dots are wounds based on attackes from other caterpillars?
It´s an sometimes seen phenomenon, when caterpillars haven´t enough place for undisturbed feeding.
Best regards.
Rudi
hello guys,
last year I had a similar problem with the caterpillars of A.mimosae, surely the problem is moisture or water stagnation.
I breed them on the tree and after a week of rain fell ill.
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