plum buds begin to burst, a stout female plant louse known as the stem mother, which differs from the summer individuals by having shorter legs and shorter honey tubes.

She gives birth without the intervention of the male to living young, and this method of propagation continues until the last generation of the season. The second generation grows to full size and gives birth to a third, which becomes winged (Fig. 7), and develops after the hops have made considerable growth in the yards. The winged lice then fly from the plums to the hops, deserting the plum tree entirely and settling upon the leaves of the hops, where they begin giving birth to another generation of wingless individ

The hop plant louse, third generation, on plum-the generation which flies to the hophead below at right-both enlarged.

uals. These multiply with astonishing rapidity. Each female is capable of producing on an average about one hundred young, at the rate of three per day, under favorable conditions. Each generation begins to breed about the eighth day after birth, so that the issue from a single individual runs up, in the course of a summer, to trillions. The issue from a single stem mother may thus, under favorable circumstances, blight hundreds of acres in the course of two or three months. From five to twelve generations are produced in the course of the summer, carrying us in point of time to the hop picking season. There then develope a generation of winged females (sexuparce), which fly back to the plum tree and give birth to the true sexual females (Fig. 8), which never acquire

wings and never leave the plum tree. By the time this generation has matured, which requires but a few days, varying according to the temperature, belated winged individuals, which are the true males (Fig. 9), fly in from the hop fields. These fertilize the wing

less true females upon the plum leaves, and these soon thereafter lay the winter eggs. Thus, there is but one generation of sexed individuals produced, and this at the close of the life round — the females, wingless on plum trees; the males, winged on hops. All

The hop plant louse, true, sexual female-enlarged.

intervening generations are composed of virgin females only (parthenogenetic). This is the invariable round of the insect's life.

REMEDIES.

From the life history just given, three important facts are obtained: (1) It will pay to make a preventive application of some of the mixtures mentioned further on, to all plum trees in the neighborhood of hop yards, either in the spring, before the appearance of the first winged generation and its consequent migration to hop, or in the fall, after hop picking and after the lice have once more returned to the plum and are making their preparations for · the laying of winter eggs. The latter time will, perhaps, be preferable, for the reason that in the fall the plum trees will be less susceptible to the action of the washes, and a stronger solution can be applied without danger to the trees. (2) All wild plum trees in the woods through a hop-growing country should be destroyed. (3) The hop vines should be either burned or thoroughly drenched

with kerosene emulsion as soon after the crop is harvested as possible, with a view of killing the males, and thus preventing the impregnation of the females. (4) If the above measures have been neglected and the lice have attacked the vines, the crop can still be protected by spraying with insecticide mixtures, which, if thoroughly applied, will prove quite effective, and there will be no danger of reinfestation from neighboring untreated yards, since during

the summer the lice cannot migrate except by crawling from one yard to another.

Of all the different substances experimented with in 1888, none gave more satisfaction than properly prepared kerosene emulsions and fish oil soaps.

Dissolve the soap in the water and add boiling hot to the kerosene. Churn the mixture by means of a force pump and spray nozzle for five or ten minutes. The emulsion, if perfect, forms a cream which thickens on cooling, and should adhere without oiliness to the surface of glass. Dilute one part of the emulsion with twenty

five parts of water. A common grade of kerosene, which is good enough for this work, can be bought in most localities at eight cents per gallon by the barrel, and the soap used can be made for one cent a pound. This would make the batch given above cost eight and one-half cents, and diluted with twenty-five gallons of water to one of the emulsion would make thirty-eight and one-half gallons of wash. At this rate one hundred gallons would cost twenty cents.

Crystal potash lye...
Fish oil......

Soft water.........

FORMULA FOR TWENTY-FIVE POUNDS FISH-OIL SOAP.

.pounds 1

..pints 2

.....

...gallons 3

A strong suds made at the rate of one pound of this soap to eight gallons of water will also be found a uniformly safe and satisfactory wash to use, killing the lice and not harming the vines. After standing three days, however, the suds will lose its efficacy.

The board also recommends the quassia chips solution which has been used with great efficiency in the hop yards of the Puyallup and White river valleys. Formula as follows:

Quassia chips........
Whale oil soap...

QUASSIA CHIPS SOLUTION.

.8 pounds.

.....7 pounds.

The quassia chips are boiled in about one gallon of water to each pound of chips, for one hour. The soap is added while hot and allowed to dissolve. This solution is then diluted with 100 gallons of water. Use with sprayer.

DURING THE SEASON OF 1891.

The pest shortened the hop crop considerably in some yards throughout the Puyallup and White river valleys last season. Several solutions were used for spraying the vines, but from a majority of the reports received, the quassia chips and whale oil soap seems to have given the best satisfaction. A number of the growers failed to prepare the kerosene emulsion properly, the mixture not forming a perfect emulsion. The formulas in any of these washes should be closely observed and carried out.

An insect found about the roots of the hop plants in early spring, when placed under a glass, appeared identical with the "stemmother." Samples of the lice were sent to Prof. Riley, Washington, D. C., who stated that they were not the hop lice, but belonged to the genus tychea.

Whether in this state, which differs so widely in climate and veg

etation from the middle or eastern states, the hop louse lays its winter eggs on "terminal twigs of wild and cultivated species of prunes" (plums, prunes and cherries) only, or whether the eggs are found elsewhere as well, there is no question but that spraying must be done in order to save crops. The work should begin very early, watching the outside rows, and as soon as any lice are detected, the work with spray pumps should begin.

EXPERIENCES DURING 1892.

The hop plant louse has worked greater disaster to the hop growers of Western Washington during the season just past (1892) than all previous seasons combined. The weather has been cool and favorable for its propagation, and most growers were slow to secure the material and appliances for spraying, as recommended in Bulletin No. 2 of October, '91, and Bulletin No. 3 of April, '92, which were duly distributed amongst the producers of this state.

In some instances the kerosene emulsion has been used, but has generally been discarded for the whale oil soap and quassia chips. It seems there are few growers who churn the mixture, after the kerosene has been added to the soap, long enough to form a persect emulsion, but apply the solution improperly emulsified on the foliage of the hop plant, which is more tender in Western Washington than where there is more hot sun, with the result of injuring the leaves. Then, again, it cannot be used after the bloom has set without injury.

Large quantities of the quassia wood have been ordered by various firms, so that it is estimated that the cost of combatting the lice and preventing injury to the crop will be under 1 cent per pound with the quassia solution.

In Eastern Washington it is found that the hot weather is obnoxious to the vermin. During certain hot days in July and August last year the hop lice were found dead underneath the leaves at North Yakima and Walla Walla, and the crop was uninjured at these places.

THE WOOLLY MAPLE BARK LOUSE.

(Pulvinaria innumerabilis.)

The presence of the woolly maple bark louse is manifested in the spring and early summer by the occurrence upon the twigs of maple trees, especially on the under side, of a brown, circular,