46 THE SAN JOSE SCALE. 
DESCRIPTIONS OF SCALE AND INSECT. 
Scale of female. — The scale of the female is circular, very slightly 
raised centrally, and varies in diameter from 1 to 2 mm , averaging about 
1.4 mm . The exuviae is central or nearly so. The large, well-developed 
scales are gray, excepting the central part covering the exuviae, which 
varies from pale to reddish yellow, although in some cases dark colored. 
The scale is usually smooth exteriorly or sometimes slightly annulated, 
and the limits of the larval scale are always plainly marked. The 
natural color of the scale is frequently obscured by the presence of the 
sooty fungus (Fumago salicina). 
Scale of male. — The mature male scale is oblong oval, nearly twice as 
long as wide, and averaging in length about half the diameter of the 
female scale. The position of the larval scale is marked by a nipple- 
like prominence located between the center and the anterior margin 
of the scale. The scale of the male is usually darker than of the 
female, sometimes black, but often gray, the larval scale covering the 
exuviae very frequently light yellow as with the female. Not uncom- 
monly the circular scale, formed prior to the first molt, is black, while 
the later additions, giving it its oblong shape, are gray. 
Egg. — The egg is never (or rarely) extruded as such by the female, 
and as it exists within the body of the mother is a mere amniotic mem- 
brane, and the forming embryo showing through gives it a yellowish- 
white color. The embryo with the envelope measures about 0.2 mm long 
by 0.1 mm wide. 
Newly hatched larva. — The young larvae of both sexes are alike, and 
are pale orange in color, with long oval bodies. They measure in length 
about 0.24 mm by 0.1 mm in width. The sucking bristles are normally 
doubled on themselves, but when unfolded are nearly three times the 
length of the body. The antennae are apparently five-jointed, the last 
two joints being much longer than the others, slender, subequal in 
length, and both finely and distinctly annulated. The last joint bears 
a small nipple-like projection near the tip. The head is somewhat con- 
cave in front, and the eyes are nearly transparent aud slightly purplish. 
The terminal segment of the abdomen foreshadows in structure the 
plates and spines of the adult female. The large central plates each 
terminate in a long hair. The tarsus is represented by apparently a 
single, strong, slightly curved claw. The tip of the tibia bears exteri- 
orly two rather long capitate hairs, and two similar hairs project also 
from the inner extremity. Other details of structure are shown in the 
illustration. 
Larva of the second stage. — After the first molt the difference in the 
sexes becomes apparent, although the covering scales are still identical. 
The female insects are somewhat smaller than the males at this stage. 
The eyes, legs, and antennae in this sex have entirely disappeared. The 
form is almost circular, flattened. The color is yellow with irregular 
transparent spots appearing in different parts of the body. 
