The Life-History and Anatomy of Butterflies 
within comparatively recent years been discovered in connection 
with the larval stage of certain small butterflies belonging to 
the family Lyccenidce. The caterpillars are carnivorous, or rather 
aphidivorous; they live upon aphids, or plant-lice, and scale- 
insects, and cover 
themselves with the 
white exudations or 
mealy secretions of 
the latter. This trait 
is characteristic of 
only one of our North 
American species, the 
Harvester (Feniseca 
tarquinius). 
In addition to 
being protected from 
enemies by having 
colors which enable 
them to elude obser¬ 
vation, as has been 
already stated, some 
caterpillars are pro¬ 
vided with other 
means of defense. 
The caterpillars of the 
swallowtail butter¬ 
flies are provided with a bifurcate or forked organ, generally 
yellow in color, which is protruded from an opening in the skin 
back of the head, and which emits a powerful 
odor (Fig. 22) „ This protrusive organ evidently 
exists only for purposes of defense, and the secre¬ 
tion of the odor is analogous to the secretion 
of evil odors by some of the vertebrate ani¬ 
mals, as the skunk. The majority of caterpil¬ 
lars, when attacked by insect or other enemies, 
defend themselves by quickly hurling the an¬ 
terior part of the body from side to side. 
Moults .—Caterpillars in the process of growth and develop¬ 
ment from time to time shed their skins. This process is called 
moulting. Moulting takes place, as a rule, at regular intervals, 
9 
Fig. 21.— Early stages of the goatweed butterfly: a, 
caterpillar; b, chrysalis; c, leaf drawn together at edges 
to form a nest. (Natural size.) (Riley.) 
§| 
Fig. 22. —Head 
of caterpillar of Pa- 
pilio troilus, with 
scent-organs, or os r 
materia , protruded. 
