. Ontario Sessional Papers, 1919, . r surface. They commenceto hatch when the fruit buds are beginninof to break, and nearly all have hatched 1919 ENTOMOLOGICAL SOCIETY 83 by the time the petals drop. The period of incubation varies, according to thetemperature, from 8 to 33 days, the average being about three weeks. The newlyhatched nymphs migrate to the opening buds where they feed chiefly on thepetioles and blossom stems. They grow rapidly and after moulting five timesreach the adult stage in about one month. This first brood is then succeededby three other broods, and the life cyc
. Ontario Sessional Papers, 1919, . r surface. They commenceto hatch when the fruit buds are beginninof to break, and nearly all have hatched 1919 ENTOMOLOGICAL SOCIETY 83 by the time the petals drop. The period of incubation varies, according to thetemperature, from 8 to 33 days, the average being about three weeks. The newlyhatched nymphs migrate to the opening buds where they feed chiefly on thepetioles and blossom stems. They grow rapidly and after moulting five timesreach the adult stage in about one month. This first brood is then succeededby three other broods, and the life cycle is finally completed in the fall by theappearance of the winter adults—the hibernating forms. The Egg. Description: The egg (Fig. 18) is sub-oval, blunt at the base and pointed atthe apex. In colour it is creamy or pale yellowish with orange at the base. Inlength it varies from .315 mm. to .340 mm. The egg is attached to leaf or bark by a short stalk projecting from nearthe basal end, and at the apex there is a long hair-like Fig. 16.—^Showing eggs alongmidrib of leaf. (Much enlarged.) Fig. 17.—First generation eggs laid on bark.(Much enlarged.) Location of Eggs,: The overwintering females deposit their eggs on the twigs,fruit spurs and smaller branches, chiefly on the under surface. (Fig. 16). Afterthe buds have burst, belated females may be found laying their eggs on the youngleaves. The eggs of the summer forms are laid principally on the leaves, singly orin clusters, along the midrib (Fig. 17). They also may be found on the leafpetioles and shoots. Period of Incubation: In the case of first generation eggs, , eggs laid byoverwintering females, the period of incubation was determined in 1917 from astudy of 21 batches of eggs deposited at various dates from April 14th to June average period was about 20 days, the maximum and minimum being respec-tively 32 and 8 days. The average duration of the egg stage in April was 26 days,in May 19 days, and
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