Lets see..

Bumble-bee x Normal

...[S][P]
[n]Sn Pn
[n]Sn Pn

You should get 50% spiders, and 50% Pastels. ;]

Correct me anyone if I'm wrong.
Let me try one more too.

Bumble-bee x Pastel

...[S][P]
[P]SP PP
[n]Sn Pn

25% Spider, 25% Pastel, 25% Super Pastel, 25% Bumble Bee

I think I'm getting this..