6 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
THE NYMPHAL STAGES. 
The young “ hoppers,” or nymphs, commence to appear about the 
middle of June, and a close examination of the underside of infested 
leaves at this time is likely to reveal a number of recently hatched 
nymphs, at about the stage shown in figure 2, running actively over 
the surface. In hatching from the egg the young “ hopper ” has to 
force its way through the pubescence on the underside of the leaf, 
and in doing so appears as a minute, whitish object, which, when 
examined under a lens, is seen to possess a pair of red eyes. After 
a few minutes of laborious struggling it forces itself to the surface 
of the pubescence, where its legs and antenne spread and become 
disengaged and the tiny creature is ready to commence its destructive 
operations. This it does by thrusting its tiny beaklike mouthparts 
into the tissue of the leaf and extracting the juices. As the season 
advances it is not uncommon to find individual leaves supporting 
from 200 to 300 of these nymphs in the various stages of nymphal 
development. 
As the nymph increases in size it casts or molts its old skin for a 
larger one. There are five of these molts before the nymph reaches 
the adult stage. The first four require a period of 5 days for each 
molt, and between the fourth and fifth molts there is a period of 12 
days. Hence about a month is required in which to complete the 
nymphal period. Figure 3 represents a nymph after the fourth 
molt with fully Geveloped wing pads. 
The term “hopper” applied to this form of the insect is a mis- 
nomer and is likely to create an erroneous impression concerning the 
movements of the insect at this period of its life history. The 
nymphs do not hop or leap, as the term “ hopper” would imply, and 
although they run about very actively on the underside of the leaf 
and sometimes a few of them may be seen running down the stem of 
the leaf and also upon its upper surface, it is doubtful if the journeys 
of more than a very small percentage of them extend beyond the con- 
fines of the leaf upon which the eggs from which they were hatched 
were deposited. This limited area of movement of the insect during 
this period of its life is exceedingly important from an economic 
point of view, since it admits of its destruction during the more rapid 
erowing season of the vine and at a period when there is slight 
possibility of reinfestation of treated areas. 
THE ADULT. 
With the final molt and the full development and use of its wings 
the adult leafhopper becomes an extremely agile and active creature, 
leaping and darting rapidly from leaf to leaf at the slightest dis- 
turbance, being much more active during the warm weather than on 
cold, windy days, when it can be dislodged from its shelter under the 
