Oy.... let's see...

Both genes (pastel and spider) are visible in their heterozygous forms...meaning they are either co-dominant or dominant. Pastels can produce a homozygous form, (super pastel) but so far as we can tell, spiders can not. All spiders are currently understood to be heterozygous...so you'll never be certain of getting a clutch that is 100% spiders. But with a super pastel, you can count on all its babies being at least pastel (+ whatever it might inherit from its other parent)

SO....if you bred two bumblebees together....you could get some pastels, some spiders, some bumblebees, some killerbees (super-pastel-spider), and maybe even some normals.

If you bred a killer bee to a spider, you'd get all pastels and bumbles in the clutch.

If you bred a killer to a bumble, you'd have a chance at pastels, bumbles and killers.

Hope that makes sense....I'm really too sleepy to be trying to type all this out!