782 
Journal o f Agricultural Research 
Vol. XXX, No. 8 
on the leaves of Rumex crispus (curled 
dock) and Fagopyrum fagopyrum 
(buckwheat). 4 These workers have 
found the larvae in the following 
plants, which they assume to be purely 
shelter plants: Zea mays (corn), Am¬ 
brosia trifida and A. artemisiaefolia 
(ragweeds) Xanthium communis , cock- 
lebur) Solidago spp. (goldenrod), Aster 
spp. (aster), Phleum pratense (timothy), 
Typha latifolia (cat-tail), Bidens bi- 
pinnata and B. frondosa (beggar- 
ticks), Brassica arvensis (wild mustard) 
(recorded by Felt), Eupatorium sp.? 
(Joe-pye weed) (recorded by Chitten¬ 
den). Since both nubilalis and ains- 
liei possess this migratory habit, the 
former perhaps to a less degree, it will 
not be surprising if the larvae are taken 
in many plants and in other situations 
affording suitable quarters in which to 
pass the winter. Flint and Malloch 
(< 8 , p. 293) published a substantial list 
of plants in which the larvae of ainsliei 
have been taken in the fall. 
It is amazing that a species so abun¬ 
dant and so widely distributed as 
ainsliei should have remained undis¬ 
covered until so recent a time. It oc¬ 
curs abundantly wherever it has been 
reported as present, from Quebec, south 
through New England, New York, 
New Jersey, Pennsylvania, Maryland, 
Virginia, the Carolinas, and Tennessee, 
to Florida, west through Mississippi to 
Louisiana, and north through Kansas 
and Iowa to Michigan. It doubtless 
has a range even greater than we know 
of at present. 
In Massachusetts the insect has a 
single brood (very often a partial 
second), in New York apparently 
one generation (Bartley and Hofer 5 ); 
in Northern Ohio apparently two 
generations (Poos 5 ); in Iowa two 
generations (20) ; in Tennessee two 
generations ( 1 ); and in Mississippi three 
generations (Allen 5 ). In New England 
the moths appeared in 1921 the first 
week in June, emergence continuing 
through July 10, on which date the 
last pupa was observed in the field. 
Larvae were full grown by September 
1, although many immature were also 
present in the field. On September 12, 
1921, the writer first observed the 
larvae in corn for the season and from 
this date until October 5 their num¬ 
bers appeared to increase constantly in 
corn plantations and in other places of 
shelter. In confinement, pupae re¬ 
mained as such for an average period 
of 15.3 days. 6 Egg masses hatched on 
the average in 6.5 days. 
Small holes in the stalks of Polygo¬ 
num and other plants with frass extrud¬ 
ing and suspended somewhat beneath 
the openings indicate where the borers 
are at work in the plant. The tissue 
about the opening is usually slightly 
sunken and discolored. Since a large 
number of borers can be found at work 
in a single plant it is common to find 
the Polygonums on dumps and at way- 
side places in a state of utter collapse. 
On opening such infested plants one 
finds in place of the customary pith 
and fleshy medulla, a mass of castings, 
larvae, and larval exuviae. Prior to 
pupation, the larvae cut exits in the 
stalk for the convenience of the moths, 
covering these openings with tympana 
of silk. The larvae rarely mine through 
the septa of the nodes of Polygonum 
but confine their feeding almost exclu¬ 
sively to the internodes. The larvae 
are much less active than the larvae of 
Pyrausta nubilalis; in fact, they are 
comparatively sluggish. Corn borers, 
on the slightest disturbance or provo¬ 
cation, move out of their quarters; 
ainsliei larvae remain to be prodded 
out or summarily removed by hand. 
Observations made by the writer in 
New England on the developing larvae 
do not completely coincide with those 
made by Ainslie and Cartwright in 
Tennessee (1, p. 84-0). The young 
larvae, for the most part, do not at once 
enter the stems of Polygonum, but in¬ 
variably on emergence from the eggs 
they freely pit the midrib and feed on 
the epidermis of the under surface of 
the leaves which hold the egg masses. 
During the time the larvae are thus 
engaged the chitin of the mandibles 
fully hardens and the head capsule 
assumes its normal pigmentation. It is 
true that immediately following their 
escape from the eggs the young larvae 
remain assembled in gregarious fashion, 
but in the course of a day they disperse, 
4 In this connection Ainslie and Cartwright also state (1, p. 838): “Leaves of all common weeds and 
plants were offered to the larvae, but in every case except the two mentioned above they were either re¬ 
fused or only slightly gnawed.” This general statement implies that all common weeds and plants from 
various sections of the country were offered to the larvae. These investigators probably mean that the 
most common weeds and plants in the vicinity of Knoxville, Tenn., w T ere utilized in experimentation. 
5 Unpublished. 
6 Win. B. Turner, of the Sacramento Entomological Laboratory of Cereal and Forage Insect Investiga¬ 
tions, was connected with the European Corn Borer Laboratory and directly associated with the work in 
1920 and 1921. He secured the pupation records, devised cages, and contributed other important data to 
our knowledge of P. ainsliei. Air. Turner died June 12, 1924. 
