Summon Monster to summon variant monsters

[Cryptichorror]

Are there any rules in place for being able to summon some of the varient versions of monsters using Summon Monster? Specifically, I want my wizard to be able to summon a Giant Black Widow instead of a generic Giant Spider. Obviously, the CR and HD are different for the two, so I wouldn't expect it to be an even exchange. I just didn't know if there was any rule that addressed this.

[HaraldKlak]

Cryptichorror wrote:

Are there any rules in place for being able to summon some of the varient versions of monsters using Summon Monster? Specifically, I want my wizard to be able to summon a Giant Black Widow instead of a generic Giant Spider. Obviously, the CR and HD are different for the two, so I wouldn't expect it to be an even exchange. I just didn't know if there was any rule that addressed this.

Take at look at this feat.

It could easily be adapted for another race than drow (or perhaps allowed without the feat by the GM).

[darkwarriorkarg]

I cast <summon giant black widow>

Suddenly, a 6' tall 30ish noblewoman approaches you, having heard of your adventuring prowess. She is looking to for a powerful adventurer to comfort her as she lost her 6th husband while he was out hunting.

[Cryptichorror]

Yea, something like that.