flawless gems yield more spiders. also hoard salt piles to make cloaked versions, and dwarven oil makes a spider that em. secretes. flamable oil, which also makes it worth noting flame cloak spiders are immune to fire.
damaged pod+gem=trap spider. a dead spider that explodes like a rune spell. deals roughly 100 damage from what i've experienced. need more testing with the damages of these spiders though.
normal pod+gem=jumping spider.
normal pod+salt pile+gem=cloaked spider.
that is the basics of them there are also these two additional ones others have discovered:
Soul gem+normal pod=mind control spider. takes control of target for 30 seconds. or a minute. i've heard varying things but havent tested myself.
Dwarven oil+normal pod=oil secreting spider.
i plan on making a character that using only these spiders for weapons. except against dragons i'll also use thralls. these spiders, honestly trump all my want for spell creation, spears, etc etc. especially since you can have a small army of them out at once. (most i've used at one time is 7).