The Transvolcanic Range in Mexico or the Pacific coast of California. All images courtesy of Monarch Watch T he Monarch butterfly is one the most readily recognized and beloved insects in North America. With its vivid orange and black markings and often bold behavior around people, it seldom fails to create a smile on the face of an those who see it. In the images above it is easy to see the distinguishing characteristics of the species. Notice that the adult males have thinner veins in the wings and a large dot on one of the inner veins of the hind wing.
Females have thicker veins and no dots.
The dot is a scent gland. Males use the pheromones produced by this gland to make themselves attractive to females. As a butterfly caterpillar grows it must molt its skin. Each stage between molts is called an instar. All five instars of the Monarch are shown in the caterpillar photo.