Oh and btw, anyone with dungeoneering or a 12+ intelligence score would know of the  vermin (http://www.d20pfsrd.com/bestiary/rules-for-monsters/creature-types#TOC-Vermin) and swarm traits (http://www.d20pfsrd.com/bestiary/rules-for-monsters/creature-types#subtype-swarm) for the spiders.