Gnu, is it possible you are seeing one of the several hundred species of Ichneumon Wasps? Some of them are huge, they usually have long skinny bodies and long legs, and in quite a few species the females have two very long thin ovipositors off their rear ends. They come in a variety of colours, yellow, black, orange, red, solid, striped, etc.

The poor things look really alien and scary, but in fact they are a beneficial insect that lays eggs in other insects' larva, sometimes drilling into treebark to get at larva underneath. They are utterly harmless to humans.

There are seven pages of pics here, and more if you delve deeper in the species-stack at the page top.

http://bugguide.net/node/view/4158/bgimage?from=0