Right, I had been trying to use that on my two sets of photos. I think I was misinterpreting a couple of things.
Pygidium with two lateral cretaceous spots not obscured by pubescence
--->OK, I was confused. I thought those two long hairy band hannging down were obscuring the cretaceous (chalky) spots. I guess the cretaceous spots on the pygidium are down along its side--I can just see one there--I think that's still the pygidium.

pubescence sparse
--->My lunulatus (above) looks more hairy in spots than my T. bibens (below). That had really confused me. I see what you mean now. The hairiness of the lunulatus is in local bunches, such as in the "armpits". The bibens has a more even coat. The lunulatus pronotum, for instance, has very little hair, while the T. bibens has a uniform coat. Thanks!


cretaceous bands on declivious portions of elytra usually present;
---> Yes, I see those on the lunulatus

elytra and pronotum shiny green in many specimens
--->Yes, definitely the lunulatus above is more green than the bibens.

I was going mostly on the pygidium. I thought those pesky cretaceous spots were being obscured by the big bands of pubescence.

Thanks for your help. I realize it takes a lot of experience to use such keys.

Patrick Coin
Durham, North Carolina