May St ^ 9^3 
Silver-Striped Webworm 
421 
several other species, it is found that the variations among the eggs of 
different individuals, especially in size, were greater than those existing 
between this and other species, thus rendering interspecific measurements 
of very little value. In fact, it holds true throughout the genus that the 
eggs of the various species are so similar as to render them practically 
indistinguishable. 
To indicate the variation in size of the eggs of this species, the following 
measurements of two lots of 10 eggs each were made at different times: 
TabI/]® II .-—Egg measurements of Crambus praefectellus 
l^ength. 
Width. 
Maximum. 
Minimum. 
Average. 
Maximum. 
Minimum. 
Average. 
Mm. 
Mm. 
Mm. 
Mm. 
ATm. 
Mm. 
0. 5471 
a 5118 
0. 5207 
0.3353 
0. 3000 
0. 3106 
• 5736 
• 4633 
.5018 
•3442 
. 2692 
•3149 
The color is of interest because it has been found that the maximum 
color attained during the incubation period is very similar in the various 
subgeneric groups of closely related species, and differs between these 
groups from a pale straw-yellow to a deep coral-red. Thus the egg 
colors as well as the head colors of the newly hatched larvae help to 
indicate the affinities of the various species. 
The chorion is ornamented with acute longitudinal ribs, usually 21 
in number, which become obsolete before reaching the poles. The polar* 
areas are covered with scattered oval tubercles of variable size (PI. i, 
H). Between the ribs there are also less prominent cross carinae, about 
17 of these in the length of the egg. The egg is suboval in outline, one 
end slightly larger and more flattened than the other. 
THE EARVA 
The writer has never taken larvae in the field, and the only notes on 
their normal behavior are those contained in Britton's account (2) of 
the attack on com in Connecticut. Even here the conditions were not 
strictly normal, for the grass sod in which the larvae were living was 
plowed under in the spring and the field planted to com, forcing the 
larvae onto the young com plants as the only available food. The 
larvae fed in the manner usual to most of the species under similar con¬ 
ditions, cutting a hole into the tender stalk below the ground level and 
living in a fragile tube of silk and earth particles attached to the stalk 
and leading off iiito the ground. Except when actually at work the 
larva does not remain in the stalk, but in this tube, so that when the 
plant is pulled the author of the injury, together with most of its domicile, 
is likely to be left behind in the earth. 
In the cages used the larvae were reared without especial difficulty. 
Eor the most part i-ounce or 2-ounce tin salve boxes floored with damp 
blotting paper were used and the food was supplied in the form of short 
sections of the leaves of various grasses, usually blue grass (Poa pra- 
tensis). Under these conditions the progress through the instars was 
easily watched. It was not always easy, however, to be sure that a 
