Order:Lepidoptera(Butterflies)
Subfamily: Danainae (The Milkweed Butterflies)

Danainae: The Milkweed Butterflies

Family Facts:

• The family is known as the Milkweed butterflies because the caterpillars of most of its members feed on some variety of milkweed (Family Asclepiadaceae).  When feeding on these plants, the caterpillars obtain certain chemicals which remain in their bodies.  The chemicals cause them to be distasteful to predators, both as caterpillars and later as adults, and through experience, potential predators learn to avoid these species.
• Some authors consider this group of butterflies to be a subfamily of the Nymphalidae, the Brush-footed butterflies, because the Danaidae, like the Nymphalidae, have forelegs that are reduced in size.  However, unlike the Nymphalidae and most of the other butterflies in our region, the Danaidae are unique in that their antennae are not covered with scales. 
• Most members of this family occur in Asia; only four species occur in North America, one of which is the well-known Monarch.  Two species occur in Idaho, and both belong to the Subfamily Danainae.
• In additon to the traits described above, this family is also characterized by: 1) large size, with a wingspan typically of three inches or more; 2) orange, brown, or black coloration in North American species; and 3) a hair pencil, a brushy extension from the rear of the abdomen in males, which is used to direct pheromones towards a female during courship.
• Eggs are typically elongated and ribbed.  Caterpillars are typically brightly colored and without hair or spines but bearing a pair of long filaments at each end.   Pupae form no cocoon, have a cremaster but no silk girdle, and may be spotted.

Genus: Danaus
Danaus gilippus- Queen
Danaus plexippus- Monarch