can all ages of instars be in the same enclosure?

[dlakows]

I am new at this I am keeping the eggs separate from the cats. However while I was checking the garden for new eggs I found some small cats that had their stripes. Is it OK to put them into the same enclosure as my new born cats?
Debb
Northern IL

[Mona Miller]

The new first instar (caterpillars) are still pretty small. I'd put the almost second instars (caterpillars) into their own container.

http://www.monarchwatch.org/biology/cycle1.htm
Monarchs go through five instars (see photo). Approximate length of body at each stage: 1st instar, 2-6mm; 2nd instar, 6-9mm; 3rd instar, 10-14mm; 4th instar, 13-25mm; 5th instar, 25-45mm.