404 
Journal of Agricultural Research 
Vol. XXIV, No. s 
A series of 50 larvae from eggs laid July 23 was reared for individual 
instar records. Each larva was confined in a half-ounce tin box floored 
with damp blotting paper and was fed blue grass. A record was made 
of each molt, and the results are condensed in Table III. 
Tabi^iS III .—Instar records of 50 Crambus mutabilis larvce from eggs laid July 2j, igiS 
Stage. 
Maximum. 
Minimum. 
Average. 
Number of 
individuals 
included in 
average. 
Days, 
Days. 
Days. 
Ege. 
7 
7 
7 
Larva: 
/ 
Instar I. 
5 
3 
3-2 
50 
II... 
5 
2 
3-3 
48 
Ill. 
4 
3 
3-3 
44 
IV. 
5 
3 
3-3 
41 
V. 
7 
3 
4.1 
36 
VI. 
7 
3 
4.8 
29 
VII. 
17 
9 
14.1 
19 
Pupa: 
^. 
II 
7 
9.9 
8 
9 . 
10 
7 
8.0 
8 
Total. 
56 
50 
52.6 
16 
THE MOTH 
HABITS 
The moths of this species (fig. 2) are essentially grass lovers and are 
seldom found among weeds or bushes. They are reluctant to leave tall 
grass for a mown field or closely grazed pasture and when driven out 
will at once circle back. 
They alight abruptly, 
usually on a grass stem, 
and instantly turn head 
downward and stand 
with the head pressed 
closely to the stem and 
the body elevated at a 
considerable angle. 
When at rest the dark 
costal margin of the fore¬ 
wing contrasts with the 
paler gray median por¬ 
tion and with the pale 
gray underbody, giving 
the moth an almost 
striped appearance when viewed from the side. This coloring and the 
characteristic attitude make this species one of the easiest to identify 
at a distance in the field. The moths are most often found in abund¬ 
ance in the lower and damper portions of the meadow, seemingly 
attracted by the greater luxuriance of the grass. They also occur in 
open woodland, especially if the ground is grass-covered. Their flight is 
erratic and awkward. 
Fig. 2.—Crambus mutabilis: Adult female. About three times 
natural size. 
