126 GIANT SILK-WORMS. 
The caterpillar (Fig. 127) of this striking moth resembles 
somewhat that of the polyphemus. It is of a clear, pale 
bluish-green color, with a yellow stripe on each side of the 
body; the back is crossed between the segments by trans- 
verse lines of yellow. On each segment are about six minute, 
pearl-colored warts, tinged with purple or rosy color; from 
each arise a few hairs. At the extremity of the body are 
three brown spots edged with yellow. When full grown it 
draws together several leaves, fastens them with silken 
threads, and spins inside this hollow space a cocoon very 
much resembling that of the preceding species; it falls like it 
to the ground with the leaves in autumn. The cocoon is 
quite thin and papery and socompact thatit can not well be 
unwound. : 
The colors of the moths vary according to the food con- 
sumed by the caterpillars. lf fed on the foliage of hickory 
their color is yellowish-green, if on black walnut it is a much 
more vivid green, and the markings and_borders are much 
darker and more plainly marked. In fact, in some very 
brightly colored specimens there is a wavy band of purple 
parallel to the outer borders. 
This insect occurs in Minnesota wherever hickories and 
walnuts grow, but as the caterpillars are also much preyed 
upon by parasites it is not likely to become a serious pest. 
Still another species of native silk-worms has been 
reported from the state, but must be very uncommon, at 
least no specimens have been seen by the writer. It is the 
Prometheus Moth (Callosamia promethea Drury). The 
sexes of this moth differ greatly, both in shape of wings, in 
color, and in the pattern of their marking. 
THE 10 EMPEROR MOTH. 
(Hyperchiria Io Linn. ). 
This is also a very beautiful insect (Fig.129, Plate XVI), 
but it is not as common as the other silk-producing species. 
The sexes vary very greatly, both in size and color. The 
