THE GRAPE PHYLLOXERA IN CALIFORNIA. 
65 
period. Toward the period of hatching the egg becomes darker and 
the eyespots of the embryo become visible. 
The larva. — In hatching, the young larva (PL IX, </, h) splits 
the eggshell from the micropyle lengthwise to about three-fourths 
of its length. This splitting is more or less gradual and is caused 
by the thorax and head of the young phylloxera bursting the shell 
and then gradually enlarging the crack. The larva poises itself at 
an angle of 45°, with legs and antennae appressed to the body, and 
slowly eases its way out. It seems to rely simply on a slow side- 
wise body movement to free itself of the shell. When freed, it 
spreads the appendages and is then able to walk off. The newly 
hatched larva is of a pale lemon yellow, with dark claret-colored 
eyes, composed each of three circular facets and placed in the form 
of the angles of an equilateral triangle. The body segmentation is 
quite distinct, more so than in later instars. The shape is oval and 
very flat. The antennae, as in all forms of the grape phylloxera, are 
three-j ointed. The terminal joint is twice as long as the two basal 
combined. Near the apex of the third joint occurs a circular sen- 
sorium. The beak in early generations reaches to the penultimate 
or antipenultimate body segment, and in later generations protrudes 
beyond the caudal segment of the abdomen. The legs and antennae 
bear hairs. Table XV gives measurements for five newly hatched 
individuals. 
Table XV. — Measurements of newly hatched radicicoles of the grape phylloxera. 
Walnut Creek, Calif., Oct. 23, 19V h 
Individual No. 
Length 
of body. 
Maxi- 
mum 
width 
of body. 
Length 
of beak. 
Length 
of hind 
femur. 
Length 
of hind 
tibia. 
Length of antennal joints. 
Length 
of sen- 
sorium. 
1 
2 
3 
Mm. 
0.359 
.327 
Mm. 
0.176 
.179 
Mm. 
0. 1964 
.2036 
Mm. 
0. 0679 
Mm. 
0.0571 
Mm. 
Mm. 
0. 0161 
.0143 
.0196 
.0180 
.0188 
.0152 
Mm. 
0. 0705 
.0625 
.0680 
.0705 
.0634 
.0670 
Mm. 
2 
6. 0169 
.0214 
.0232 
.0188 
.0179 
3 
.0562 
. 0580 
.0566 
.0554 
.0429 
.0491 
. 0455 
.0491 
4 
.359 
.341 
.189 
.190 
.2152 
.2107 
0. 0231 
6.. . 
. 02'^ 
The young phylloxerae hatching in spring have shorter beaks than 
those which hatch in the fall, the beaks in spring averaging in length 
about 0.155 mm. 
The first molt does not take place until more than half of the grow- 
ing period is passed. The molting of the radicicoles is a procedure 
quite similar in detail to the hatching from the egg. After each molt 
the individual for about 24 hours is brighter in color than at any 
other time during the instar. After the first molt the phylloxera 
changes from oval or suboval to pyriform in shape (PL IX, i, j). 
1000°— 21 5 
