On the sides of the glass slide layout two cover slips, slides between a drop of water goes from larva and everything I cover with a coverslip. The larva is not crushed but is stuck.
I understand. You are using coverslips as spacers to stop crushing the larva but putting enough pressure on it to keep it still. Are you using a gradient filter as well as the polarisation and retarders? There seems to be some oblique effects adding to the visual appeal, especially in the last two shots.