22 
Journal of Agricultural Research 
Vol. II, No. i 
riddled even in the fields. Plate I, figure 4, illustrates this work in a 
leaf of millet as it occurs in the fields. In fact, in almost any place in the 
fields where eggs may be found there are usually one or more of these 
feeding punctures near by. Figure 2, a, b, c> represents the feeding punc¬ 
tures, eggs, and newly hatched larvae as one often finds them in the field. 
These spots or punctures finally dry out and turn almost white. 
Oviposition is, in all probability, accomplished during the day. Obser¬ 
vations were made several times at night, but the adults were almost 
always at rest upon the plant at the top of the cage. 
PERIOD OF INCUBATION OF THE EGG 
No exact incubation period can be given, since this depends mainly 
upon the temperature. It is quite short in the summer, being about 80 
hours in the latter part of July. In the latter part of September and the 
first part of October the eggs were not less than five days in hatching, and 
perhaps slightly longer. This would be nearly two days longer than the 
time required for hatching in July. 
length of larval stage 
The larval period, like the egg stage, varies considerably in length. In 
the middle of the summer larvae will attain full growth in four days, while 
in the cooler weather of spring or fall they will require 10 days or more. 
Some larvae hatched the first week in October and were overtaken by 
frosts. 
LARVAL HABITS 
When ready to hatch, the larva ruptures the eggshell at the cephalic 
extremity and begins to feed, gradually working its way out of the shell 
into its excavated burrow. It can not leave one leaf and enter another, 
and if removed from the leaf it will die. If a full-grown larva be taken 
from its burrow and placed upon a hard surface, it will bring each 
extremity beneath its body, then suddenly straighten to its full length, 
and thus skip about over the surface like a cheese maggot. Larvae will 
continue this skipping for a considerable time, often jumping an inch 
high, apparently hunting for a hiding place. They may remain entirely 
submerged in water for a day or more and still recover and pupate 
normally. Excrement is voided at intervals within the mine, but at no 
time has a cast skin been found or other evidence of molting. The larva 
apparently punctures one of the walls of the mine and drops to the ground 
to pupate, going down sometimes 2 inches if the soil be sandy; in ordinary 
soil it will go only from one-fourth to one-half inch below ground. 
Larvae will pupate on a solid surface in the open if they can not reach the 
ground or find cover. When ready to pupate the larva contracts in 
length, the segments becoming quite distinct. It then turns a cream 
color, gradually darkening until it becomes a reddish brown. 
