4 
the Pacific, in most localities between the thirtieth and sixtieth 
degrees of latitude. In Switzerland it occurs on the level of perpetual 
snow, and in this country it has been taken on the barren subalpine 
heights of the White Mountains. 
FOOD AND OTHER HABITS. 
The imported cabbage worm feeds on the foliage of nearly all cru- 
ciferous plants, is particularly fond of cabbage and cauliflower, and 
somewhat less destructive to turnip, radish, mustard, and horseradish. 
It also does considerable injury to ornamental plants, such as nastur- 
tium, mignonette, sweet alyssum, and spider plant (Cleome).¢ 
The butterflies sip the nectar of flowers of many kinds and are to be 
seen any time hovering over them. They are especially fond of the 
white blossoms of crucifers, also of such plants as white aster, lavender, 
and thistle. Like other butterflies, this species is diurnal, and is on 
the wing from early morning until near dusk. It is a comparatively 
slow flyer, but capable of extended flight for long distances. The 
butterflies sometimes congregate in immense swarms, as has frequently 
occurred where the insect has emigrated from the continent of 
Europe to England. Its occurrence in mid-ocean has been recorded. 
LIFE HISTORY. 
The butterflies appear as early as March, even in the Northern 
States, and thereafter can usually be seen flying about cabbage fields 
and elsewhere throughout the year, until after several severe frosts in 
October. In the Gulf States they occur throughout the season. 
Egg deposit commences soon after the butterflies appear; in fact, 
pairing and egg-laying may begin within a day or two after the adult 
issues from the chrysalis. The duration of the different stages varies 
according to temperature. The observed egg period is from four to 
eight days. 
The larva eats voraciously and grows with greatrapidity, attaining 
full maturity in from ten days to two weeks after hatching. It molts 
four times; hence there are five distinct stages, the first molt taking 
place (in warm weather) in about two days from the hour of hatching, 
the second stage lasting two or three days; the third and fourth, one or 
two_days each, and the fifth, four or five days.? The duration of the 
chrysalis stage is from seven days to a fortnight during the summer 
time, but the last chrysalides formed in the more northern States 
remain undeveloped during the winter until the following spring. 
The life cycle occupies periods varying between twenty-two days 
and five weeks. Even in New England this species is credited with 
being triple-brooded, but in the District of Columbia and vicinity there 

at isa decided pest on this plant in the District of Columbia. 
6 Technical descriptions of the different larval stages with particular reference to wing 
development are given by W. F. Mercer (Jour. N. Y. Ent. Soc., Vol. VIII, pp. 1-20, March, 
1900). 
