They do come bigger in Texas - this is the largest Robber fly I have encountered - it was about 3 cm long. It was also dead - found it early in the morning after a visit from the "bug guys" the previous afternoon.
I'm not sure if this one is S, M or L but it was certainly doing its best to look as large as possible (I'd estimate it's body was about 6 cm).
Lastly, something small and tricky - the best I have been able to get so far from the occasional humming bird visitor (from 4 sessions):