Other Common Names
Milkweeds, Tigers, Monarchs, Queens and Soldiers.
Explanation of Names
A name from Greek mythology. Danaus (Greek δαναος) was son of Belus, king of Egypt and twin brother to Aegyptus. Apparently Aegyptus ruled in Egypt and Danaus in Libya. Danaus was driven out of the area by his brother and went to Argos in Greece. His daughters were the Danaids. I can't see any particular connection of Danaus to the genus, other than the regal nature of the butterflies.
Numbers
Scott,
(1) pp. 228-232, lists three North American species: Monarch,
D. plexippus; Queen,
D. gilippus; Soldier,
D. eresimus.
12 species worldwide.
Range
D. plexippus, The Monarch, is widespread in North America, esp. in migration. D. gilippus, The Queen, is resident in south Texas, parts of the southwest, and southern Florida. It wanders north. D. eresimus, The Soldier, is resident in south Florida, and is a stray to south Texas and the southwest.
Habitat
Open areas with hostplants, flowers.
Life Cycle
Larvae feed on milkweed, Asclepias.