I justed tested my Chryssalid in the arena. A no skill chryssalid, can easily kill a no skill dwarf in full iron armor. The chryssalid more or less opens the dwarf like a can of meat, then snip off body parts. Or it just injects venom into the dwarf, killing him almost instantly. I'm thinking instead of using the standard chitin, I should make it as strong as copper.
Also, at 20 tiles, 20 dwarves with crossbows and iron bolts couldn't bring a single one down, out of 20. When I tested a grandmaster crossbowdwarf, he ALMOST killed one, but the chryssalid closed the distance far to quickly, and lopped his head off. To be somewhat fair, I'm not letting the chryssalids have weapons or armor, because that would be crazy.