Hibernating Butterflies. 147 



They are laid in a cluster round the twig, and near the 

 petiole of a young leaf, upon which the newly-hatched larvae 

 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 larvae 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 



