THE SHARP- HEADED GRAIN LEAFHOPPER. 13 
HATCHING OF THE EGGS. 
The emerging nymphs burst the end of the eggshell irregularly and 
emerge head first. Eggs deposited in the leaves hatch sooner than 
those in stems, as there is not so much plant tissue covering them. 
Those in stems appear to be inserted more deeply into the plant. 
The nymphs issue at about the same time, irrespective of the posi- 
tion of the eggs in the pocket. 
MOLTING OF THE NYMPHS. 
The fourth molting of a nymph was minutely observed, the whole 
operation taking 20 minutes. The old skin split dors ally along the 
head and thorax. The head of the nymph first came out, slowly fol- 
lowed by the thorax and abdomen. The abdomen was pulled for- 
ward through the old abdominal skin and put through the thoracic 
slit. As the nymph gradually emerged it leaned or threw its weight 
backward until the tip of its abdomen was nearly out; then it shifted 
and spread its legs, taking a firm hold on the leaf surface. After com- 
pleting the molt it remained still for several minutes. 
In examining the last-molt nymphal skin an indication of sex was 
discovered. Outlines of the ovipositor or genitalia were quite promi- 
nent and plain on this cast skin. Attention was then directed to the 
examination of the last-instar nymphs, and it was found that there is 
a sex indication with all nymphs of the fifth instar, as the distinction 
between the male and female genitalia could readily be recognized. 
(See fig. 1, i, j.) No sex indications appear in the nymphs of the 
fo'urth instar. 
ADAPTABILITY OF SPECIES TO CHANGE OF FOOD PLANT. 
Only the nymphs of the last two ins tars can adapt themselves to a 
change of food plants to any extent. This fact offers a suggestion in 
the control of the species, in that cutting or grazing their food at the 
time the nymphs are young will tend to starve them, and thus many 
will be destroyed. 
However, the adults find no difficulty at all in a change. If their 
food plants be destroyed or cut down, they immediately hunt for sub- 
stitutes. Starving the adults in the fields would be next to impossible. 
MIGRATION. 
The species does not spread itself throughout one field or into other 
fields by the dissemination of the young nymphs, but almost wholly 
by the flight of the adults. The latter migrate freely from one 
field to another in search of attractive areas for food and oviposition. 
Besides this, Prof. Osborn remarks: 1 "The insect shows at times a 
distinct habit of migration at night." They have been reported 
1 Op. cit., p. 59. 
