208 EXPERIMENTAL FARMS. 
Life History.—The winter 
is passed by the partially 
grown insects beneath their 
scales. With the return of 
warm weather the nextspring, 
growth is resumed, and the 
males reach maturity a few 
days before the females. They 
are extremely small two- 
‘winged flies (Fig. 17) and 
when examined under a mag- 
nifying glass are found to 
have orange yellow bodies, 
iridescent dusky wings and 
black eyes. ‘Lhese minute 
creatures have no mouths, so 
| A can takeno food; consequently 
A} after having fertilized the fe- 
ns x males they very soon die. 
Fig. 17.—San José Scale, male—much enlarged. The natural size is Lhe date when the femalex 
shown by the line in the circle below the right wing. become full-grown and begin 
to produce young varies with locality and climate. In Arizona the young larve 
are recorded as appearing in March. At Washington it is by the middle of May; in 
New Jersey during the last days of May; in the state of New York, early in June. At 
Amherst, Mass., they were first noticed 12th June, and, as far as I can learn, in our 
Niagara district between the middle of June and Ist of July. Most careful observations 
have been made under direction of the UnitedStates Entomologist, by Mr. Theo. Pergande. 
The following condensed life-history is -ompiled chiefly from United States Division of 
Entomology, Bulletin No. 8, N.S., in which Mr. Pergande’s observations are recorded. 
The adult female gives birth to living young, instead of laying eggs like most other 
scale insects. Ordinarily, as with the Oyster-shell Bark-louse, eggs laid beneath the 
seales, in the course of a longer or shorter time, hatch, and the young larve migrate to 
different parts of the plant; but in the case of the San José Scale living young are pro- 
duced day and night for a period of nearly six weeks before the exhausted female 
perishes, and this at the rate of about nine or ten every twenty-four hours. After birth, 
the young larva remains mctionless for a short time beneath the scale of the mother, it 
then forces its way out and runs over the plant, seeking a suitable place to settle. It isa 
microscopic creature, pale orange in colour with an oval body, six legs and two feelers. 
The long thread-like proboscis, with which it sucks the sap of the plant, is doubled on 
-itself and lies in a groove of the body wall. After crawling about for a few hours, the 
larva settles down and works its bristle-like sucking tube through the bark and remains 
fixed, if it be a female, for life, and if a male, until fully developed, when it will have a 
few hours more active life, during which it can fly about. 
The development of the scale begins even before the larva becomes fixed. The 
secretion of the scale starts in the form of very minute white waxy filaments, which 
spring from all parts of the body and rapidly become more numerous until, within two 
days, the insect is entirely concealed by a whitish shell or scale, which has a prominent 
central nipple. The scale is formed by the matting and melting together of the waxy 
filaments. As in the development of most insects, there are also with these sca‘e-insects 
distinct periods of the larval life, divided by moults of the skin, and, in the case of the maies, 
marked by important structural changes. The first moult takes place when the larva 
is twelve daysold. Up te this time, the male and female scales are exactly similar 
in size, colour and shape; but after the moult the insects beneath the scales bear no 
resemblance te each other; the males are larger than the females and have large purple 
eyes ; while the females have lost their eyes entirely. The legs and feelers have dis- 
appeared in both sexes. Eighteen days after birth the second moult occurs and the 
males change to the first pupal condition (pro-pupa). The male scales now assume an 
