For the last few weeks, I have created myself a garden pond in a large plastic pot about 80cm across and similar height. Today, I noticed a large population of mosquito and other larvae.
I sacrificed one of these larvae today to view its structure under crossed polarisation on my LOMO Polam P-113 polarising microscope.
I had read online that muscle shows up on crossed polarisation. Certainly, the photos below show birefringence which might be muscle.
I am particularly pleased with the photo at the bottom. I managed to work out how to use layers in GIMP2 and change relative transparency between the layers and consequently combine the bright field and crossed polarisation images so that you can see where the colourful polarised tissue is located.
Bright field view of larva, x3.5 objective:
Crossed polarisation views x3.5 objective mosquito larva:
Combined bright field and crossed polar image:
The strips of birefringence follows down the side of the larval body. The photo above this one shows this follows the organism around. From http://www.sciencephoto.com/media/74993/view/mosquito-larva-light-micrograph, it would appear that this represents muscle bundles down the side of the insect.