I think, Chainweb Aracnir would fit here. It can shoot down some flyers for you, and can come out of the graveyard by itself. You may want to run a few fetchlands then, to fuel the escape a bit better.
Spider Spawning may also fit, but is at odds with the Chainweb Aracnir, so you probably don't want to play both. Arachnogenesis is a card I consider as too situational. It may do next to nothing, or it may decide out the game. If that uncertainty is your thing, no issue there, but I prefer predictability. The Spawning more consistently makes spiders.
11 Forest
3 Swamp
4 Blooming Marsh
4 Woodland Cemetery
Creatures
1 Arachnus Spinner
2 Arasta of the Endless Web
4 Deadly Recluse
2 Ishkanah, Grafwidow
3 Rotwidow Pack
4 Twin-Silk Spider
4 Arachnogenesis
4 Cultivate
4 Putrefy
4 Rampant Growth
Enchantments
4 Arachnus Web
Artifacts
2 Bow of Nylea
2 Silklash Spider
Spider Spawning may also fit, but is at odds with the Chainweb Aracnir, so you probably don't want to play both. Arachnogenesis is a card I consider as too situational. It may do next to nothing, or it may decide out the game. If that uncertainty is your thing, no issue there, but I prefer predictability. The Spawning more consistently makes spiders.
How hard set on only spiders are you? Because Rampant Growth with legs is better than just Rampant Growth and also fuels your Rotwidow Pack. Yes, it cuts down on sorceries for delirium, but adding some fetchlands (even the common ones: Terramorphic Expanse and Evolving Wilds, Jund Panorama) gives you another card type altogether.
Maybe some selfmilling with an enchantment spider?
Former Rules Advisor
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(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
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