Interesting that they used a precancelled stamp on one of the envelopes. The permit envelope (The block upper right saying paid) should have been all that was needed.
I'm thinking that they used the permit envelope for first class mail since it doesn't say anything different. The 1 1/2 cent precancel would have covered I think third class mail which might have been required to be sent unsealed.
So maybe the 33 premiums went first class, and the 34s went third to save a bit of money?
I'm not quite up to speed on my 1930's postal rates. I'm ok with the older stuff but have forgotten a lot of the different 30's stuff. All of which were just as confusing as todays rates. Collecting envelopes from unusual uses is a branch of the stamp hobby that's popular right now.
Steve B
PS If anyone works for an antivenom lab that does scorpion stuff I REALLY want a box used to mail live scorpions. Just the box, no contents required. As long as it has the "contains live scorpions" notation. I might even swap a prewar card for one
