Taiwan is endowed with a thriving population of butterflies. Among the numerous varieties are quite a few rare or brilliantly colored species that have earned Taiwan the name “Butterfly Kingdom.” To promote conservation of natural ecology, Chunghwa Post is issuing a set of four stamps on Taiwanese butterflies (Issue of 2004). The designs of the stamps follow:(1) Parantica sita niphonica (NT$5): This is a large and elegant looking Danaidae. The upper side of its forewings and hindwings are dark brown and reddish-brown respectively with semi-transparent rectangular bluish-white markings. The colors on the underside of its wings are relatively lighter (reddish-brown except the outer parts of its forewings) with semi-transparent bluish-white markings as well as submarginal rows of small bluish-white spots. Adults are slow in flight. They love to feed on the nectar of Eupatorium shimadai and like to rest on tree branches in the woods. They appear during March and April and disappear in the fall in the middle and northern Taiwan. They are capable of making long distance migrations; some are found to migrate from Taiwan to Japan in the spring and from Japan to Taiwan in the fall. (2) Choaspes benjaminii formosanus (NT$5): A medium large Hesperiidae. The upper side of its wings is dark bluish-purple and the undersides green with dark brown wing veins. There is a leaf like protrusion and a patch of orange marking with some black spots at the anal angle area on each of its hindwings. It is one of the most beautiful Hesperiidae in Taiwan. Adults are fast and agile in flight and can be seen anytime besides winter.(3) Junonia almana (NT$17): A medium Nymphalidae frequently seen in fields. The middle section of the outer margin of each of its forewings arches inward while the outer margin of each of its hindwings is shaped like waves with a protruded anal angle. The upper side of its wings is orange with several eyespots of different sizes. The patterns of the underside of its wings are distinctly different from season to season. When the weather is hot, they are the color of mud with obvious eyespots. When it is cool, they are brown without any eyespots. Adults are nimble in flight and usually appear in sunny and open areas. In the past when pesticides were rarely applied, one could often spot them flying in farmers’ fields anytime except winter.(4) Artipe eryx horiella (NT$20): A medium large Lycaenidae frequently seen in mid and low altitude areas. There is a pair of slender tails and oval shaped leaf like protrusions in its hindwings. The upper side of the male’s wings are dark brown with metallic dark purple shimmer in the basal area of the forewings and in the hindwings. The upper side of the female’s wings are brown with a row of white markings on the outer margins of the hindwings, whereas the undersides are light green with a broken row of white markings on the outer margin of each of its wings. There is a small black spot beside each tail that mimics the eye and antenna. Among all the Lycaenidae found in Taiwan, this is the only species that is green on the underside. Demure and lovely, adults are agile and fast in flight.