448 
The Moths and Butterflies 
species with more translucent fore wings, is found only on the Pacific coast 
and in the Wyoming mountains. I have seen P. smintheus in great numbers 
in the beautiful flower-dotted glacial parks of Colorado from an altitude 
of 6000 feet upward. The wings are so thinly scaled that they are nearly 
translucent, and the scales themselves are narrow and club-like, so different 
indeed from those of other butterflies that they probably have some special 
function not yet understood. The larvae are “flattened,” having a some¬ 
what leech-like appearance; they are black or dark brown in color, marked 
with numerous light spots. The chrysalis is short and rounded at the head, 
and pupation takes place on the surface of the ground, among leaves and 
rubbish, a few loose threads of silk being spun about the spot in which trans¬ 
formation occurs. 
The swallowtails (Fig. 639), all except five of which belong to the genus 
Papilio (a name given them a century and a half ago by Linnaeus, the first great 
classifier of animals and plants), are readily 
distinguished by the longer or shorter “tails,” 
one to three, which project backward from 
the hind wings. The ground color is black, 
sometimes suffused with metallic bluish or 
greenish, and the markings consist of yellow 
or greenish-white bands and blotches together 
with a few red, orange, and blue eye-spots on 
the upper and under sides of the hind wings. 
The larvae are large, cylindrical, fleshy, naked 
caterpillars usually conspicuously banded or 
spotted with green, black, yellow, orange, 
and white. They are provided with a pair 
of fleshy and flexible colored “horns” (osmateria) which can be protruded 
from, or withdrawn into, the front thoracic segment and which give off a 
strong musky scent sufficiently disagreeable to repel many threatening 
enemies of the caterpillar. The chrysalids (Fig. 640) are naked, sus¬ 
pended by the tail from a silken button and supported by a silken girdle 
or “bridle.” They often mimic very closely the coloration and surface 
configuration of the tree-trunk or other object to which they are attached 
(Fig. 640). Poulton, an English naturalist, has been able to obtain chrys¬ 
alids of a single swallowtail species of many different colors by enclosing 
the larvae just before pupation in separate boxes lined with paper of different 
colors. The color-tone of the chrysalid tended strongly toward that of the 
environing paper. Such a color plasticity is certainly of much advantage 
to the insect in rendering the exposed and defenceless chrysalid indistin¬ 
guishable. (See Chapter XVII for a discussion of “color and its uses.”) 
One of the best-known butterflies of the east is the zebra swallowtail, 
r J v Vw- 
Fig. 640.—Chrysalid of a swal¬ 
low-tailed butterfly, Papilio sp 
(Natural size.) 
