The 0.20B stamp was issued in 2007 commemorating 150 years of Panama Canal Railway Company.
The Panama Canal Railway Company is a railway line that links the Atlantic Ocean to the Pacific Ocean across Panama in Central America. The route stretches 47.6 miles (76.6 km) across the Isthmus of Panama from Colón to Panama City.
The infrastructure of this still functioning railroad was of vital importance for construction of the Panama Canal over a parallel route half a century later. The principal incentive for the building of the rail line was the vast increase in traffic to California owing to the 1849 California Gold Rush.
The other 2 stamps are from 1997 Frog issue depicting Red Webbed Tree Frog (Hyla rufitela )and Nelsonophryne aterrima.
The Red Webbed Tree Frog is from genus Hyla,which is one of approximately 38 genera in the New World family of tree frogs (Hylidae). The word Hyla translates to "tree," and tree frogs are indeed arboreal. They have a very broad distribution; species can be found in Europe, Asia, Africa, and across the Americas.
Nelsonophryne aterrima occurs in lowland and premontane zones from Costa Rica and Panama to montane Colombia and northwestern Ecuador.It is a secretive, nocturnal leaf-litter species of humid lowland, montane forest, including secondary forest and areas close to these forests. Adults are generally found under fallen logs and other surface debris. Breeding takes place in swamps and shallow water-filled depressions on the forest floor.