Great work on the skin! Smooth carapace highlighting as well!
The purple seems fairly strong for this scheme - it seemed more natural and blended with the bases better. Possibly go up to a pinkish hue? Eh I painted the wings on my Tyrant the same bone color.
I actually use the same scheme - for the life of me I cannot find a picture of my Hive Tyrant except the one below.
I apologize for a massive picture - here's a slideshow instead:
http://www.youtube.com/watch?v=fuiY5ggnIHU
Keep it up!