THE ALFALFA LOOPER IN PACIFIC NORTHWEST. . 111 
Early in June the young larve become numerous in the fields, 
walking very much as do geometrid larve or “measuring worms.” 
This is due to the fact that the larvee have prolegs on only the fifth, 
sixth, and ninth abdominal segments. If disturbed they curl up 
and drop to the ground, the older larve lying there tightly curled 
up and refusing to move when irritated, but larvee of the second and 
third instars when touched alternately straighten out and curl up 
very suddenly, thus jumping about spasmodically. The larvee while 
young feed upon the epidermis of the leaves, skeletonizing them and 
giving to the attacked plant a brownish appearance. The older 
larvee—that is, after the third molt—eat from the edge of the leaf 
toward the midrib, entirely consuming the leaves. The larval period 
lasts about two weeks, there being five molts with periods of about 
three days elapsing between each. When ready to pupate the larva 
spins a loose white silken cocoon (PI. XI, fig. 2) among a number of 
leaves, usually well up in the plants, incorporating two or three 
leaves in its structure. The larva completes the cocoon in about half 
a day and, at least in the case of specimens reared in our insectary, 
pupates the day following that on which the cocoon is completed. 
The length of the pupal stage of specimens reared in our laboratory 
was very uniformly 10 or 11 days. Dr. H. G. Dyar* gives 12 days 
as the length of this period, and Mr. Koebele? records the length of 
the pupal stage as from 10 to 15 days. He gives an exact rearing 
record*® wherein he mentions a larva collected at Piedmont, Cal., 
February 24, 1888, which pupated on March 5, the moth emerging 
March 22, making a pupal period of 17 days. Dr. F. H. Chittenden, 
of this bureau, gives from 6 to 22 days as the pupal period of a 
closely related species, Autographa brassice. 
Thus the time elapsing from egg laying until the adult emerges 
covers a period of from 26 to 48 days, probably being about 30 days 
in the Palouse country of Washington. 
The first adults of the second generation appear in early July, 
and adults continue quite numerous throughout this month, belated 
individuals having been collected as late as August 3. There are 
two generations, and probably three in the case of the earlier ap- 
pearing individuals, and larve in all instars are to be found in the 
field as late as the end of August, but these very late larve probably 
succumb during the winter. 
Mr. T. H. Parks, of this office, records finding the larve of this 
species about half grown in the alfalfa fields about Salt Lake City, 
Utah, as early as May 22, in 1911. Larve were found throughout 
June. The first pupa found in this locality was obtained on June 5 
1Entomologica Americana, vol. 6, p. 14, 1890. 
2 Bureau of Entomology Notes, No. 95 K. 
8 Bureau of Entomology Notes, No. 389 K. 
