314 ENTOMOLOGICAL NEWS. [July, '08 



The Life-History of Pontia castoria Reakirt. 



BY KARL R. COOLIDGE AND ERVAL J. NEWCOMER. 

 Pontia castoria ranges from Central California to British 

 Columbia. It is common in the vicinity of San Francisco Bay 

 and we have also taken it very abundantly at Pacific Grove, 

 in Monterey County. It flies only in the open woods and the 

 clearings near them and is on the wing, in Central California at 

 least, from the end of January until the end of April. The 

 larvae feed upon the leaves of Dentaria integrifolia var. cali- 

 fornica Nutt., a cruciferous plant having both cauline and radi- 

 cal leaves. This plant is practically the only crucifer growing in 

 the woods where castoria flies so the larvae probably do not feed 

 upon any other. They will, however, eat leaves of Brassica 

 nigra Linn, when nothing else is at hand. The egg is laid erect 

 on the under side of both the cauline and radical leaves. As 

 many as five or six have been found on a single leaf but whether 

 or not they were laid by the same individual is uncertain. In 

 one instance an egg was found on a young flower-bud. As 

 soon as the young larva hatches, it eats most of the shell of 

 the egg. It remains on the lower side of the leaf eating through 

 it, not, as a rule, beginning at the edge. The larvae do not 

 usually eat all of the leaf tout move to a fresh one when the 

 first is eaten. They can easily be found by the holes eaten in the 

 leaves and by the frass in the leaves below. 



Egg. Tall fusiform, with the usual raised vertical ridges, about 

 fifteen in number, and numerous cross-veins. When first laid the egg 

 is of a pale greenish white color; about 1.5 mm. in heighth. 



Young Larva. Length almost 2 mm. ; at first of a glassy whitish 

 color, but becoming more and more greenish tinged as the larva feeds ; 

 sparsely clothed with fine short hairs. 



After First Moult. There is little or no change in the appearance 

 of the larva now except a more pronounced yellowish-green tinge ; 

 length, 6.5 mm. 



After Second Moult. Length about 10 mm. ; of a uniform grassy- 

 greenish color; head hemispherical, slightly larger in diameter than the 

 rest of the body. 



After Third Moult. Much as in preceding stage, but larger. 



Full Grown Larva. Length, 29 mm. ; uniform grassy-greenish, with 



