Fiibernating Butterfiics. 147 
They are laid in a cluster round the twig, and near the 
petiole of a young leaf, upon which the newly-hatched larvee 
are to feed. The eggs hatch inside of a week into small 
black spiny caterpillars which, in their early stages, are very 
social in their habits. Just before the final skin-moulting 
they separate, each caterpillar living alone, the necessity for 
food, which their very vigorous appetites now demand, being 
the impelling motive. In a state of maturity the larve are 
two inches in length. They are black, and minutely dotted 
with white, which gives them a greyish look. A row of 
brick-red spots are found down the back, and their body is 
armed with many black, rather long and slightly branching 
spines. The head is black, and roughened with small black 
tubercles. 
Having completed their period of feeding, which they do 
in about four weeks, the caterpillars attach themselves by 
means of their tails to a fence-rail, a window-ledge, or some 
such place, and pass into the chrysalis state, which is accom- 
plished in about four days. In this condition they present 
an odd-looking appearance. The head will be found to be 
deeply notched, or furnished with two ear-like prominences. 
The sides are very angular. In the middle of the thorax 
there is a thin projection, somewhat like a Roman nose in 
profile, while on the back are two rows of very sharp tuber- 
cles of a tawny color, which contrast very markedly in 
coloration with the dark-brown of the rest of the chrysalis. 
Fifteen days, when the weather is favorable, are sufficient for 
the development of the imago, or butterfly. As maturity 
approaches, the chrysalis-shell becomes quite soft, and the 
efforts of the imago to free itself from this covering are facili- 
tated by the ejection of a blood-red fluid, which rots the case, 
while it acts, at the same time, as a lubricant to the emerging 
butterfly. 
When these caterpillars are very abundant, as was the 
case in the vicinity of Germantown some twenty-five years 
ago, every fence-rail was hung with chrysalids, as many as 
