Scinax ruber Two-striped Treefrog
Some other names for this species:
Common Scinax, Red-snouted Treefrog, Allen’s Snouted Treefrog
About half the references I've found for this species call it Scinax rubra, and the others call it Scinax ruber. S. ruber seems to be the current leader in this latin adjective gender competition.
Nauta Road, Iquitos, Loreto, PeruJanuary 12, 2013
Two-striped Treefrog (Scinax ruber)
This common frog was another of the few teasers we saw on a night of road-cruising near Iquitos prior to our proper Amazonian adventure.

Here is a complete list of the herps I saw in the wild on my 2013 MT Amazon Expeditions trip.

Santa Cruz Forest Reserve, Loreto, PeruJanuary 20, 2013
Two-striped Treefrog (Scinax ruber) Two-striped Treefrog (Scinax ruber)
Scinax ruber comes in a wide assortment of patterns and colors, just to make identification more interesting.
Yanamano Distillery along Rio Amazonas, Loreto, PeruJanuary 12, 2014
Two-striped Treefrog (Scinax ruber) Two-striped Treefrog (Scinax ruber) Two-striped Treefrog (Scinax ruber)
While most of our group was still enjoying the fine home-made rum at this tiny distillery along the river, Matt Cage, Kevin Messenger, and I were poking around for miscellaneous herps. Either Matt or Kevin uncovered this little treefrog, which Matt identified as Scinax ruber based on the faint traces of stripes down its back.

Here is a complete list of the herps I saw in the wild on my 2014 MT Amazon Expeditions trip.

Santa Cruz Forest Reserve, Loreto, PeruJanuary 21, 2014
Two-striped Treefrog (Scinax ruber) Two-striped Treefrog (Scinax ruber)
I believe that the larger, darker frog is an adult female Scinax ruber and the smaller, yellower frog a couple of plants away is an adult male Scinax ruber. I didn't wait around long enough to see whether they would ever meet.
Santa Cruz Forest Reserve, Loreto, PeruFebruary 7, 2016
Two-striped Treefrog (Scinax ruber)
This is quite probably the least interesting treefrog I saw in 2016. Also, my camera lens was fogged up at the time, so the colors and contrast are all off. Still, any treefrog is better than no treefrog at all.
Printed references: