THE UNICORN WORM. 269 
this line and the outer margin is a faint band. Between the two principal lines are 
some black scales ; a few black scales mark the obsolete discal spot. Towards the 
apex on tLe costa are four dark spots. Hind wings smoky, a little discolored at the 
internal angle, beneath concolorous. The female wants the few black scales between 
the two principal lines. Length of body, male, .70 ; female, .75; expanse of wings, 
male, 1.50; female, 1.50 inch. 
THE UNICORN WORM. 
39. Schizura unicornis (Abbot and Smith). 
The caterpillar of this moth, more commonly met with on the apple 
tree, we have found September 6 on the elm at Brunswick, Me. At 
about this date, Harris says, it makes its cocoon, which is thin and al- 
most transparent, resembling parchment in texture, and covered gen- 
erally with bits of leaves on the outside. The caterpillars remain in 
their cocoons a long time previous to changing to chrysalids, and the 
moth appears the following May and June. 
This and the other species of the genus are doubtless protected from 
the attacks of birds by their close resemblance to a dead, dry portion 
or blotch on the edge of the leaf, as they usually feed on the edge. 
The following observations have been made by Professor Riley : 
The larva of the above species is found feeding on quite a number of different 
plants, such as oak, elm, plum, apple, dogwood, alder, winterberry, rose, and black- 
berry, also on hickory. 
It is a very singularly shaped caterpillar. General color in sound specimens, rich 
reddish-brown, in others grayish-brown, shaded with very minute spots of a darker 
color, which give it a shagreened appearance. A faint line of a darker color runs 
along each side from the third segment. It is variegated on the back with a lighter 
color, somewhat in the shape of a letter W as oue looks from the head, and two lines 
forming a V start. 
Larvie found on blackberry were mostly very pale, with the white Y niark on 
joints 9 and 10 very plain, with much glaucous color about the back, and with the 
other shades of purple-brown, flesh-brown, olive and pale green, which are found on 
the withering blackberry bushes, all present. The glaucous and brown colors are 
especially noticed on the canes of this plant. 
The insect is evidently two-brooded, those of the first brood spinning up at the 
commencement of July, while larvie of a second brood, often only about one -fourth 
grown, are found as late as October 10. 
The cocoon is very thin and looks much like parchment. It frequently draws a 
few leaves together for this purpose, and changes to a chrysalis in about four days, 
which is at first of the same color as was the caterpillar, the green segments being 
■distinctly visible, but soon changes to a shiny brown, with two points at the tail, and 
one blunter one at the head. There are also slight elevations on the under part of 
the abdomen where the prolegs of the caterpillar were. 
The mimicry of the larva when on the blackberry, either stem or leaf, is perfect, 
-and the imitative resemblance of the moth, when at rest, to the bark of a tree is still 
more striking. The moth always rests head downwards with the legs all drawn to- 
gether and its wings folded round the body, which is stretched out at an angle of 
about 45 degrees, the dull gray coloring of the wings with the lichen-green and flesh 
■color giving the whole such a perfect appearance to a piece of rough bark that the 
deception is perfect. 
Some of the larvae are, however, infested with Tachinids aud with Ophion purgator 
Say. (Riley's unpublished notes.) 
