Packard.] 
516 
[Feb. 19, 
tivorous birds. At the same time the bright colors, spots and 
stripes, the very peculiar Y-shaped silver or yellowish-white mark 
characteristic of the species of Schizura, — these are perhaps dan- 
ger-signals, though later in life the brown shades and green tints, 
so like the green leaf with its serrated, blotched, sere-patched 
edges, would often deceive the most observant of birds. 
In regard to the nutant or movable tubercles, it may be observed 
that a slight motion of these appendages may suffice to scare off 
an approaching ichneumon or Tacliina. If most insects have, as 
supposed by Exner and by Plateau, "'more imperfect vision than has 
formerly been attributed to them, so that they are extremely near- 
sighted and only clearly perceive bodies when in motion, then even 
slight movements of these tubercles, while the caterpillar itself was 
immobile, would probably be sufficient to frighten a parasitic in- 
sect and deter it from laying its eggs on the caterpillar. 
PARTIAL LIFE-HISTORY OF ICHTHYURA INCLUSA HUBN. 
(CLOSTERA AMERICANA HARRIS). 
For the opportunity of examining five alcoholic examples of the 
first stage of this larva, I am indebted to Professor Riley ; those of 
the last stage I have collected from the poplar. Mr. H. Edwards 
(Papilio, iii, 24) briefly describes the second stage, and adds that it 
“feeds in companies until after the second moult; the Jarvse then 
separate and act independently of each other.” 
First stage. — Length, 3-4 mm. The head is blackish brown, 
rounded, but little wider than the body, and provided with scattered, 
long, stiff, tapering bristles. The body is regularly cylindrical, 
and does not differ essentially in shape from the full-fed larva. 
There is a well developed prothoracic or cervical shield, on the 
front edge of which are four piliferous warts, and the bristles aris- 
ing from them are longer than the body is thick ; the warts on the 
hinder edge bear much shorter hairs. The shield is not large, but 
is very distinct, forming a blackish, chitinous plate. On each side 
of the same segment are two distinct piliferous w r arts. On the sec- 
ond and third thoracic segments is a transverse straight row of 
ten piliferous warts which, like all the others are dark, and con- 
trast with the pale flesh ground-color of the body. Of the ten pi- 
liferous warts, the two median dorsal ones are much smaller than 
the others, the two subdorsal ones on each side being twice as 
large, and those on the second segment bearing each a single long 
