This guide shall help you to paint any wings - not only for Scourges, but for any Tyranids or heavily mutated Chaos Space Marines. Special thanks for the guide to David Soper
It's necessary to use a white primer. Then apply Rakarth Flesh. Wash it with mixture of Seraphim Sepia + Reikland Fleshshade 1 to 1, and don't forget to use some lahmian medium.
Mix Carroburg Crimson with lahmian medium and make shades and veins. Be very careful.
Next technique is called Dotting - put some nice dots with the tip of a small brush near the shades. Again use Carroburg Crimson for this
Reach smooth edge between dark and light colors mixing dotting and Seraphim Sepia + Reikland Fleshshade wash
Highlight fingersand bones with mixture of Rakarth Flesh + White Scar and edge the veins. So - the inner part of the wing is done.
The other surface is done the same way, but with more intense colours. Improvise!
Beautiful models need beautiful table! And it can be bought here