Thanks Dr Seow. For typical examples, the ID key that you've crafted works very well. However, there appears to be either intermediates or possible hybrids that make it hard to establish an ID for one or the other, unless the individual is captured and the brands examined in a collection. There are some field examples that are pretty hard to separate just via photos. But for the rest which have the typical diagnostic characteristics as you have described, they are quite easy to identify. I guess it's just one of those things in nature where there isn't always a single answer to everything. I am still hoping that we have somehow missed Mycalesis horsfieldi or Mycalesis intermedia due to the fact that most photographers tend to avoid chasing and shooting these Bush Browns. Perhaps one day someone will find them here in Singapore.