If you have an aversion to pictures and discussion of beetles, slugs, and ravenous song sparrows, go on to the next post. Otherwise, here's some research I did on a beetle found on a routine plant-hunting expedition I was on recently. (Its nickname came from looking at it from the belly side. It uncannily resembles Darth Vader from that vantage point.)
First, a picture of the specimen (source):
Exhausting Googling gave me a tentative name: Pterostichus melanarius (Illiger). Given the name, I found out its habitat (native to Europe but spreading into the Midwest from the coasts - check, because my specimen was found in the heart of the Midwest), food (aphids, slugs), and what eats it (any insectivore in the area, basically). Its length is listed as Coincidentally, a colleague caught a song sparrow - listed in the field guide as a connoisseur of this carabid - a few days later in a live-animal trap that was only supposed to catch mammals.
Now share your beetle stories! Or correct my species identification.
Update: While walking on a wooded bluff the morning of 9/27/08, I spotted a juvenile individual of this species; it was about 12mm long and had yellowish legs. Leia, perhaps?