Page 463 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Sphingidae
TRIBUTION
DISTRIBUTION Western areas of North America
DIS
DISTRIBUTION
HABITAT
A
HABITAT T Wet woodlands, riparian forest, parks, and gardens
HABIT
HOST PLANTS S Poplar (Populus spp.) and willow (Salix spp.)
T PLANT
HOST PLANTS
HOS
NOTE
NOTE
NO TE Large, green caterpillar that has distinctive oblique stripes
CONSERVATION STATUS
CONSERVATION STATUS
CONSERV A TION S T A TUS Not evaluated
ADULT WINGSPAN
5–6½ in (130–165 mm)
CATERPILLAR LENGTH
3½ in (90 mm)
PACHYSPHINX OCCIDENTALIS
WESTERN POPLAR SPHINX 461

(HY. EDWARDS, 1875)

The caterpillars of the Western Poplar Sphinx moth hatch from
large, pale green eggs laid in small groups on the leaves of the

host plant. The larvae feed on leaves for about ve weeks before
crawling to the ground, where they dig a shallow burrow in
loose soil in which to pupate. The resulting pupa is brown. The
species then overwinters in the burrow and ecloses in spring.

Pachysphinx occidentalis is a nocturnal moth, on the wing from
June to August in the northern part of the range with a single
generation, while in the south of the range the moths are seen
from May to September and there are two generations. The adult
moths live for about six to ten days and do not feed, instead
surviving on fats stored in the body. There are two known
subspecies, one found in the south of the United States and
the other in Mexico.

The Western Poplar Sphinx caterpillar is light
green dotted with white. There are six oblique
white stripes and an oblique white band that
extends to the short caudal horn. The spiracles
are ringed in red, and the legs and the tips of
the prolegs are brown.

Actual size