444 
ANNUAL REPORT OF NEW YORK 
POTATO-BEETLE. ITS PUPA. 
another of these larva; may be seen with their skins dry and destitute of 
this coating', yet without manifesting any uneasiness or discomfort from 
the privation. These considerations induce us to regard this opinion as 
not being well founded. Another supposition of authors, namely, that this 
coating serves to protect these larvae from being devoured by birds, is prob¬ 
ably correct, as no bird will be apt to relish a worm which is thus covered 
with filth. 
The larva having attained its growth, it descends into the ground to 
repose during its pupa state, and there forms for itself a small oval cell, 
the walls of which are made firm and smooth by being wetted and plais- 
tered over with a'white frothy substance which the worm'ejects from its 
mouth. A full grown larva which I had inclosed in a small box was dis¬ 
covered the next day to have cast off its wet filthy coat, and to have com¬ 
menced inclosing itself in a cocoon, which it was forming upon the bottom 
of the box, from white froth which it was giving out copiously from its 
mouth. This froth was full of little air bubbles at the place where it had 
just then been emitted, but elsewhere it had become more dried and con¬ 
densed, resembling the pulp of paper. Herewith the worm had then built 
a wall around itself, in the form of an oval ring, about the tenth of art- 
inch in height. Two days after it was found to have completed its 
cocoon, which was of an oval shape, measuring 0.35 by 0.20, its external 
surface uneven, white, pliant and yielding, but afterwards becoming dry 
and hard. 
I have not fed and reared this insect to observe with accuracy the time 
it requires to pass through its several forms and complete its growth. Dr. 
Harris states that the eggs arc about a fortnight in hatching, that the 
larva gets its growth in about another fortnight, and that it remains a fort¬ 
night more in its pupa state. As these are the same periods which arc 
given in books as occupied bj'the European Crioceris merdigera in obtain¬ 
ing its growth, we are in doubt whether Dr. Harris’s statements arc made 
from actual observation or are inferences derived from the analogy furnished 
by that species. 
The insect at length emerges from the ground in its perfect form, a 
totally different creature in every respect from what it has previously 
been, save only that it still continues to subsist upon the potato leaves. It 
is now a bright shining, prettily colored beetle, so clean, so neat and tidy 
in its appearance that it would not be suspected of having been such a 
filthy, groveling, repulsive creature as it was in the days of its youth. On 
cloudy, cool days, these beetles remain at rest and concealed from view 
down among the foliage of the potato fields. It is on pleasant, sunshiny 
days that they are observed, standing here and there upon the leaves. 
They are shy and timorous, taking wing as you come near them, and 
flying a few yards away and again alighting. When annoyed or in dis¬ 
tress, they make a peculiar creaking sound, by rubbing the tip of the 
abdomen briskly up and down against the hind end of the closed wing- 
covers. , 
It has been reported that there are two generations of these insects 
annually, the beetles coining abroad early in June and again towards the 
