larval & pupal exuviae

[ernst neering]

Yes!
I always keep exuvia and pupal cases together with the adult I rear from 
caterpillars. I do the same for those where parasitoids emerged from. If you 
collect series of caterpillars and some develop into parasitic wasps or 
Tachinids, you can compare the remains of immature stages and proove which 
species was the host. For instance, the subfamilies of Tortricidae can be 
identified on whether there is a second row of teeth on the inside of the 
mandidula and whether this row is parallel or under an angle to the main 
teeth. For some species the identification could be 100 % certain.

Hairs (setae), colours, etc. on/of the softer bodyparts are not suitable. 
Identification marks should be on the chitinized parts.

Lots of work remains to be done!