270 LEP1DOPTEHA. 
foregoing characters. It is the Pontia oleracea 6 (Fig. 99), 
potherb Pontia, or white 
butterfly, and was first de- 
scribed by me in the year 
1829, in the seventh vol- 
ume of the “ New England 
Farmer.” * About the last 
of May, and the beginning 
of June, it is seen flutter- 
ing over cabbage, radish, 
and turnip beds, and patches of mustard, for the purpose of 
depositing its eggs. These are fastened to the under sides 
of the leaves, and but seldom more than three or four are 
left upon one leaf. The eggs are yellowish, nearly pear- 
shaped, longitudinally ribbed, and are one fifteenth of an 
inch in length. They are hatched in a week or ten days 
after they are laid, and the caterpillars produced from them 
attain their full size when three weeks old, and then measure 
about one inch and a half in length. Being of a pale green 
color, they are not readily distinguished from the ribs of the 
leaves beneath which they live. They do not devour the 
leaf at its edge, but begin indiscriminately upon any part of 
its under side, through which they eat irregular holes. 
When they have completed the feeding stage, they quit 
the plants, and retire beneath palings, or the edges of stones, 
or into the interstices of walls, where they spin a little tuft 
of silk, entangle the hooks of their hindmost feet in it, and 
then proceed to form a loop to sustain the fore part of the 
body in a horizontal or vertical position. Bending its head 
on one side, the caterpillar fastens to the surface, beneath the 
middle of its body, a silken thread, which it carries across 
[ 0 Pontia oleracea belongs to the genus Pieris Schrk. (Morris’s Catalogue). 
The P. casta of Kirby, in Faun. Bor., IV. 288, is only a variety of Harris’s P- 
oleracea ; and Kirby’s casta is the cruciferarum of Boisd. Spec. Gen., I. 519.— 
Morris] 
* Page 402. For a figure of it, see “ Lake Superior,” by Agassiz and Cabo‘, 
ph 7, fig. 1. 
