[Illustration: Chrysalis showing butterfly ready to emerge The empty chrysalis Butterfly just out of chrysalis Side view a little later THE MONARCH BUTTERFLY: THE CHANGE FROM CHRYSALIS TO ADULT. Photographs from life (_See pages 10-13, 235_)] [Illustration: _See page 30_ THE CAROLINA LOCUST Above, with wings expanded as in flight] SELECTIVE COLOR SENSE One who collects the Underwing moths soon discovers that the light colored species which resemble the bark of birch trees are likely to be found upon the trunks of those trees, and that the dark colored kinds which resemble the bark of maple trees are likely to be found upon the trunks of these. Obviously, were this not true the protective coloring would avail but little and it is evident that these moths are able to select a background which is of advantage in helping to conceal them. There is much evidence to show that in a similar way the butterflies are able by means of a well-developed color sense to select the places where they alight. One of the most notable examples is that of a South American species, _Peridromia feronia_. This is a silvery gray butterfly which alights head downward upon the bark of certain palm trees that have silvery gray stems and remains there with its wings fully expanded so that it utilizes the background in much the same way that the Underwing moths do. "When disturbed they will return to the same tree again and again." One who will observe the habits of our Angle-wings and other butterflies which have obliterative coloring of the under wing surface can easily learn that these insects select rather carefully the places where they alight. It will be found that as a rule each species utilizes a background that blends with its own coloring. It is probable that this habit is much more common in other groups of butterflies than has been realized. Much evidence of this sort has been collected regarding the butterflies of Europe and other countries, as well as near our own borders in America. WARNING COLORATION AND MIMICRY The colors of a great many animals, including a considerable percentage of American butterflies and their larvae, have been commonly explained by the theory of _warning colors_. According to this theory animals which were for any reason not edible by birds and mammals have developed various striking combinations of color such as black and yellow, red and black, or black and white, in order to advertise to their foes their inedible qualities. This theory has been very generally accepted by naturalists and will be found expounded at length in many books published during the last quarter century.