I love insects with definitive identifications. When I type “big green katydid” into Google, this bad boy pops right up (along with suggestions that I search for “Florida giant grasshopper”, “Florida giant centipede”, and “Florida giant mosquito”, making me wonder why I moved to this state). And it’s exactly like it says on the tin — this is a Florida giant katydid, all right. The largest katydid in the US, with adults being up to 65mm long.
This particular Stilpnochlora couloniana is actually a late-instar nymph, still wingless but almost full size (its body was about 40mm long, not including the legs). As an adult, its wings will extend beyond its body (out into the space between its hind “knees”, giving it a long, flattened body that resembles a leaf. As you might expect, they can both fly and jump, much like a grasshopper. Here’s some photos of an adult:
Giant katydids are nocturnal. Males, which are slightly smaller than the females, can “sing” like crickets do, by rubbing their legs and wings together, making a short, chirping call to attract females. They eat only the leaves of plants, preferring those of trees.
First-instar nymphs are brightly colored, with black and white striped antennae, striped legs, and a neon yellow and green body. They look like Beetlejuice! 🙂
At what instar of a giant Florida katydid can you see the genders start to show?
Man, I wish I knew! If I had to guess, I’d say it would be a pretty late instar.
This late instar one on bugguide has been identified as female: https://bugguide.net/node/view/1967871/bgimage
Here’s another one: https://bugguide.net/node/view/420247/bgimage
This image on Flickr has a female (left) and a male (right), you can see the female’s ovipositor (which of course the male does not have): https://www.flickr.com/photos/106357585@N07/17154451588 (Flickr is not a reliable source of information/insect ID, I could be terribly wrong about everything, etc.)