LIBRARY

494
COLLEGE ENTOMOLOGY
In the history of sericulture in the north temperate regions, many attempts
have been made in various parts of the world to find new sources of silk and
especially to utilize the wild species which can be gathered in the forests.
Particula.rly in Europe and North America wild silkworms have been utilized,
but in all cases with only temporary success. In Europe the native emperor
moth, S(lturnia pavonia Linn., expanse 30-45 mm., is the only representative
in Great Britain while S. pyri Schiffenmul1er, expanse 60-75 mm., is the largest
lepidopteran in Europe. The caterpillars feed on a wide variety of deciduous
forest trees.
In North America a number of species have been tested for silk production
but none has proved satisfactory. The cecropia or emperor moth, Samia
cecropia (Linn.), the largest lepidopteran on the continent north of Mexico,
has a wing expanse of 125-165 mm., is reddish with white lines and dusky
wings, and occurs in the eastern areas. The caterpillars, 75-100 mm. long,
bear six rows of spiny dorsal tubercles, and feed on a variety of deciduous
trees and shrubs. The cocoons are very large and open at one end. The silk
is very difficult to reel. Glover's silkworm, S. gloveri Strecker, is common in
the Great Basin and the Rocky Mountain region, and the ceanothus silkworm,
S. eurya[us (Bdv.) (= rubra Behr), expanse 125-160 mm., and common on
ceanothus, is the western representative. They are both univoltine and general
feeders. The spicebush silkworm or promethea moth, Callosamia promethea
(Drury), is the commonest large moth in eastern North America. The adults
are black and dull red with pinkish markings and have an expanse of 75 mm.
The caterpillars feed on a variety of deciduous trees and shrubs, especially
spicebush, sassafras, sweet gum, and tulip. The cocoons are suspended. The
polyphemus moth, Telea polYPhemus Cramer, is a beautiful ocherous or buff
and pink species with a wing expanse of 110-120 mm. which occurs throughout
North America and is polyphagous on deciduous trees and shrubs. The closed
cocoons are suspended and usually incorporate leaves and at least one stem.
The silk is reelable but was never commercialized. One of the reasons no
doubt is the presence of dipterous and hymenopterous parasites which very
effectively reduce the number of aU these large wild species. The io or corn
emperor, Automeris £0 (Fab.), a large pinkish-brown and yellowish species,
60-80 mm. expanse, is also a general feeder which occurs east of the Rocky
Mountains plains area [rom Canada into Florida. This genus is considered by
some to be the most primitive in the family.
Other interesting members of the family are not classed as silkworms. The
luna moth, Troprea luna (Linn.), expanse 125-150 mm., is considered by many
to be the most beautiful insect in North America. Its soft light-green color,
purple-brown markings, eye spots, and long tails make it an object of great
beauty and one desired by collectors the world over. The caterpillars feed
chiefly on deciduous trees. The species inhabits the hardwood forests east of
the Rocky Mountains from southern Canada to the Gulf of Mexico and is
especially noted in the Ohio and Mississippi River valleys. The buck moth,
Hemileuca maia Drury, a smoky-blaCk species with markings of pale yellow.