422 
Journal of Agricultural Research 
Vol. XXIV, No s 
molt had occurred. The only sure proof was to find the cast of the 
head, but in this species the first act of the newly molted larva was in 
most cases to eat the head cast, often leaving nothing but the mandibles 
as evidence that ecdysis had really occurred. 
The first food of the larva consists of the fragment of eggshell con¬ 
sumed m effecting escape from the egg. This particle becomes bright 
pmk or salmon color in the intestinal tract. As soon as it is free from 
the egg the tiny caterpillar is ready for green food. When placed on 
a blue-grass leaf it begins operations by cutting a narrow pit lengthwise 
of the leaf, at first avoiding the veins. This pit soon becomes large 
enough to contain the entire body of its maker and then a few threads 
of silk are spun across above it. The excrement is placed on or among 
th^e strands and in a few hours the larva is practically concealed from 
sight by this filthy roof. After the first day or two the larva eats the 
small veins as well as the tissue between them down to the lower epider¬ 
mis of the leaf, but not until it reaches the third instar does it consume 
the entire l^f blade. By this time it has become too large effectually 
to conceal itself on a blue-grass leaf, and thenceforth seeks the earth, 
where, for protection, it constructs a tubular retreat of mingled silk 
and earth particles. From this vantage ground it comes out, usually 
at night, to cut off and consume one by one the blue-grass leaves. 
As stated above, the larvae of this species do not spend any time in 
a resting period, but pupate as soon as fully fed, weather conditions 
permitting. Of course during the cool weather of spring and fall, and 
in the winter, their activities are much retarded or cease altogether, but 
as soon as warmer temperatures prevail feeding is resumed and the 
•transformations completed. 
The following tables give figures showing the maximum, minimum^ 
and average periods required for the various instars and for the com¬ 
plete life history. 
Tabi.^ III .—Length in days of various stages and instars of Crambus praefectellus 
A. EGGS HATcmNG MAY 13 
Ksrgs. 
I. 
u. 
m. 
IV. 
V. 
VI nor- 
maL 
Vlpre- 
PUpaL 
vn 
pre- 
pupaL 
Pupa. 
Maximum. 
o 
5 
3 
3 - 46 
5 
A 
A 
A 
IS 
8 
00 00 od 
12 
Minimum. 
y 
Q 
4 
0 
U 
A 
0 
Average. 
y 
o 
3-83 
3 
3 - 92 
4 
5- 20 
4 
5.00 
7 
9 
9. Sjf 
Number of rec¬ 
y 
o* 
9*30 
ords averaged. 
.6 
20 
27 
^7 
25 
. 
19 
15 
■^y 
2 
I 
B. EGGS HATCmNG JUNE 25 
Maximum. 
5 
5 
5 
2 
A 
A 
A 
ft 
18 
II 
13-14 
12 
II 
Minimum. 
2 
3 
3 - 50 
12 
4 
4 
5 
5 
Average. 
2 
6 
3 - 17 
12 
3 
3.82 
II 
z 
4.25 
8 
5 
5. 00 
T 
12 
10 
Number of rec¬ 
ords averaged. 
14 
12 
10.33: 
6 
X 
7 
I 
