The butterflies of each species commonly appear twice during the season, firs: in May and

b

(Fig. 10.) Pieris rapæ. (2) Larva.

(b) Chrysalis.

α

last in July or early in August.
The winter is passed in the
chrysalis or pupa stage, and the
motionle-s little insects may be
found in coldest weather care-
fully hung in sheltered fence-
corners and out-buildings. These
send forth the perfect insects in
spring-time; they copulate and
egg-laying begins at once. Two
broods are credited to each spe-
cies and my own observations
show this to be correct in the
case of protodice. Rapæ, how-
ever, is sometimes three brooded
-a last brood appearing some
time in September. In rare instances they pass the winter in the perfect
state. Of this I am well assured for I have upon two occasions caught
males of this species in January, both times in a barn loft. They seemed
dead, but upon being brought near the fire soon revived. I have also
reared three broods artificially, during the summer of 1885. Eggs were
taken from cabbage in May, and from these imagines were reared, appear-
ing the middle of July, and from this second brood other imagines
appeared in September. I have also seen fresh insects in September, indi-
cating that this is natural in our climate.

As a rule, however, I am inclined to think that the two-brood habit is universal. Such variations as I have noted are probably due to favorable springs and warm summers.

In neither species are the butterflies very active. My own experience teaches me that the protodice is the more wary and quick of flight and this can be interestingly explained when we remember that the rape has been accustomed for centuries, in its European home, to the sight of men and movements, while the protodice, having passed its life upon the plains and in the western part of North America, retains more of its original wild

ness.

Pieris rapæ is an immigrant from England, having been introduced in 1856 or '57 by way of Canada, whence it made its way into the United States in '65 or '66. Since that time it has spread rapidly, crowding native species to the wall.

I have been unable to find when it first made its appearance in Nebraska. In 1881 it was rare and protodice was our more abundant form. In 1883, by referring to my notes. I find that it had become common in the vicinity of Lincoln and last year it appeared in enormous numbers, so that it was a day's work to catch a pair of protodice for cabinet specimens. This year the butterflies have been less abundant, owing to the long dry spell, and I have seen fewer swarms than before, since 1883.

In Western Nebraska, the protodice seems still to hold its own. I observed it abundantly in 1885, at McCook and Indianola, and at Valentine later in the summer.

From my observations I conclude that the practical disappearance of protodice is to be looked for, since it is more delicate and the rape has introduced a parasite which preys upon it most. effectively. Having the field to itself rape is showing signs of extending its number of annual broods to three, and is clearly doing infinitely more mischief than the native species.

There is a north-eastern cabbage butterfly-Pieris oleracea, which is not indigenous in Nebraska, though very destructive in New England and New York. I have found one solitary imago in the vicinity of Lincoln, but am certain that it came upon some imported cabbage, or possibly, attached as a chrysalis to some railway car.*

*I once found a pupa of Melitoea photon, not an indigenous species, thus attached to a N. Y. C. & H R. R. freight car, standing in the B. & M. yards at Lincoln.

Under (1) much work can be done, but it is laborious and from the nature of the case cannot be complete. Boys set at it can render efficient service when nothing more important is on hand.

(2) Poisoning the worms is evidently not so simple an affair as in the case of the potatobeetle, where Paris green and London purple may be freely applied without fear of injury to the vegetable. The cabbage has its edible portion above ground and mineral poisons are in no case to be recommended. Kerosene emulsions, salt, or carbolic acid in weak solution are preferable. Prof. Riley recommends the "saponaceous compounds of cresylic acid." A correspondent advises the use of air-slacked lime, but I cannot see how the cabbages themselves could escape great injury under such treatment.

(3) To trap the chrysalis, boards should be set up edgeways between the rows. If each board has a piece nailed over the top, T fashion, so much the better. The "worms or larvæ, will, when ready to pupate, retire to these boards kindly prepared for them and they may then be removed and destroyed. Many will be found to have within them a little grub-the larva of a Pteromalus fly-and such chrysalides should not be destroyed, for the parasite is a most valuable ally, having followed Pieris rape across the ocean with the ruthlessness of a Pinkerton detective.

(4) The butterflies may be caught in a common ring net and thus exterminated. This remedy should be put in prac ice as soon as the butterflies appear in the spring, and, to make it effective, concerted action is important.

Losses by cabbage butterflies in Nebraska are very considerable, but relatively less than in eastern states. Where the wind has full sweep a great deal of dust is blown across the plants and this is very distasteful to insect foes, causing them to decline in numbers where they would otherwise perhaps be abundant. In parts of Nebraska this condition of things prevails, and, I imagine, has its effect upon the insects.

GRAPE VINE LOUSE-(Phylloxera vastatrix Planchon.)

ORDER HEMIPTERA, SUB ORDER HOMOPTERA.

Riley's Mo. Reports, 2, 4. 5, 6, 7, 8; Eugene Hilgard, Bull. Univ. of California, 1875; 8th Ills. Report. Cyrus Thomas; Inj. Insects of Mich., A. J. Cook; Insects of the Garden, A. S. Packard, Jr.; Naphthaline as an Insecticide, Thomas Taylor; Io. Hort. Reps., 1874, 1885; Am. Eutomologist, vols. 1, 2, and 3.

DESCRIPTION AND HABITS.

Economically and entomologically the Phylloxera is of the greatest interest and few insects present more remarkable habits than does this tiny plant-louse. It was first observed in Amer

ica by Asa Fitch, in 1856, and later its life-history was worked out by Prof. Riley, forming one of the most valuable of his contributions to American entomology. In this country the insect is indigenous, feeding upon wildgrapes and certain of the cultivated varieties, but its damage here has been slight compared to that done in France where it was introduced about 1865.

The grape-vine louse has two different forms, one living upon the leaves and producing the little excresences upon their under sides, called galls, and the other living upon the root and causing Pourridie or root rot. It is as if certain members of a human family should follow mining for a profession while others pursued carpentry.

We have then the two types-the gall louse and the root louse. Remembering that these are but different forms of the same species, the gallproducing form may first be noticed.

On vines one may often see certain leaves with warty outgrowths upon the under side, usually green but sometimes faintly reddish. In each of them, as in a chamber, lives a plantlouse, about one-twenty-fifth of an inch in length. It is wingless and has the remarkable knack of laying from

two to five hundred eggs without previous impregnation. This method of reproduction is called agamogenesis, or birth without marriage. The eggs are laid in the galls and in seven days the young larvæ hatch; they leave the galls, go to the surface of tender leaves and insert their little beaks, there to form new galls by the irritation of their presence. Each louse proceeds to lay eggs as before and so on through the summer. Prof. Hilgard says that at this rate of increase the sixth generation of descendants from a single louse would, if placed end to end, extend around the earth thirty times. He adds, reassuringly, that most of them die. Those which do not perish leave the galls late in September and go into the ground to hibernate.

The root-louse has a more complex history. Newly hatched larvæ, at first like the gall-louse, become tuberculous and exhibit two slightly different forms-one oval and the other somewhat pear-shaped in out

varieties of grape are favorable to the development of one form, and others to the development of the other. On the Vitis cordifolia and its descendants-notably the Clinton grape-galls seem to be formed with ease, but the root louse is absent. The reverse is true of all European grapes and such species as the Catawba and Delaware in our own country; on these the root louse is common, but the leaves are rarely infested.

The Clinton vine, then, has no lice upon its roots save those harmless ones which attach themselves to hibernate, having descended in autumn from the leaves. On the other hand the Delaware and Catawba rarely exhibit gall-disfigured leaves. but frequently the vines seem weak, the leaves turn yellow and wither, and the fruit does not form. These are the symptoms which indicate the work of root-lice, working silently, but fatally, under ground.

THE SPREADING OF THE INSECTS.

Gall-lice, being wingless, can spread only by crawling, or by means of the leaves being blown from place to place. Root-lice crawl from vine to vine by means of the interlacing roots under ground; but it is not until the winged form appears that the greatest spreading occurs. These winged females do not fly strongly, but their large wings enable the wind to carry them indefinite distances.

VARIETIES OF GRAPES AND THEIR SUSCEPTIBILITY.

According to Prof. Cook, the following are exempt from the root-louse: Concord. Hartford, Prolific, and Isabella; the following liable to attack: Delaware, Crevelling, Rebecca, Diana, Eumelan, and Allen's Hybrid; the following very delicate and liable to great damage: Catawba and Iona. To the latter class I would add the Salem.

NATURAL ENEMIES.

The name of these is legion, including lady-bird, soldier-bugs, mites, lace-winged flies, a species of Thrips, and several others. Together with changes in temperature, rains, dry weather, hard winters, etc., they keep the pest in a certain degree of subjection.

REMEDIES.

Gall-infested leaves should be gathered and burned, and the grape vines should be given high culture. This strengthens them and helps them to withstand attack. The gall louse form is, however, not nearly so destructive as the root-louse form, and remedies for the later are of the deepest importance. They may be enumerated and discussed in order.

(1.) Selecting hardy varieties. This is the course commonly pursued in America, and especially in the West. The Concord grape is found to be so hardy and generally satisfactory a form that it is, in many parts of the country, grown to the exclusion of more delicate, but finely-flavored varieties. Nebraska viticulturists, however, often desire to grow the choicer forms, and it is important to know how to defend them.

(2.) Grafting on a hardy stock. This is the next thing to growing the hardy variety itself, and is deemed very efficacious. A Delaware or Catawba grafted upon Clinton or Concord root will enjoy greater immunity from root-lice than could be brought about by any number of prophylactic remedies. In grafting, the split graft is not to be recommended, and most viticulturists use the arch or crown grait with better success.

(3.) Submersion. Where practicable, thirty days under water will be found to settle the phylloxera. This may be done in the late fall or early spring, and in France, where it has been extensively tried, it has been found that it must not be practiced during the growing season, for that would be disastrous to the vines themselves.

(4.) Sanding and salting the soil. In neither of these devices is there a practicable remedy, for so much sand and salt are necessary that the expense and trouble are far too great. The phylloxera does not like sand, and where plenty of it is applied vines are comparatively safe. The trouble is in applying enough. Moreover, no barrier is opposed to the winged form, and the wingless form working under ground is scarcely inconvenienced.

(5.) Tarred cloths, plaster, etc., around the vine. These applications are made in hopes of shutting off the emergence of the lice when about to migrate. They will easily find, however, some other way to leave the ground than by the part immediately around the main stem. Furthermore, the underground form is unrestrained.

(6.) Insecticides. Of these, coal-tar and crude carbolic acid have been highly recommended. The best way of applying is to sprinkle the ground with sawdust, previously saturated with the insecticide. This process may be repeated from time to time as the odor evaporates. Soot used in the same way is of some value, and does not injure the vines.

(7.) The best of insecticides for phylloxera is carbon bi-sulphide, made in chemical works by passing the vapor of sulphur over red-hot charcoal and condensing into liquid the gas thus formed. It is an exceedingly volatile and poisonous fluid, the fumes being disastrous if inhaled. Therefore, it must be handled with care. The originrl method of applying with a syringe which punched a hole in the ground, is not to be recommended. Flooding a vineyard with the material is excessively expensive, and a modified manner of application has been devised which meets all requirements. The carbon bi-sulphide is mixed with potash or soda, thus rendering it soluble in water, and it is then diluted in the proportion of one part of the dry powder to about eight thousand of water.

According to Prof. Hilgard, to whom I am indebted for most of the facts concerning this insecticide, about one pound of the mixture (dry) to seven vines is found effective. The expense will amount to from ten to fifteen dollars per acre.

In applying carbon bi-sulphide, the French commission mentions the following necessary precautions:

(a) Application in early spring, or late autumn. This minimizes possible bad effects upon the delicate rootlets which are most abundant in the rapidly growing season.

b. Application in sufficient quantity at one and the same time. This is so that it shall penetrate the ground as far as possible.

(c) The co-operation of manures. Wood ashes, containing, as they do, plenty of potash, are cheap and valuable.

To these Prof. Hilgard adds the consideration of thorough tillage, which is certainly of importance.

I have observed great numbers of wild grapes-Vitis cordifolia-covered with galls in Lancaster county; in Saline county, near Crete, and near Beatrice, in Gage county. This summer, 1887, while rowing on Oak creek, near Valparaiso, in Saunders county, I, in company with Mr. Charles S. Allen, noticed that hundreds of vines, drooping from trees along the bank, were affected.

In the vicinity of Lincoln I have seen occasional vines troubled with root-rot, and farmers from the southern part of the state occasionally complain that their vines are yellowing and lying from no appreciable cause. In a majority of cases this is due to the presence of phylloxera, though a species of root-borer may be also present.

The presence of the lice upon our wild grapes indicates to the thoughtful horticulturist that they will be ready for him if he attempts the cultivation of choice varieties. To be sure, vineyards of Delaware, Salem, or Catawba grapes are rare in Nebraska, but with vigilance and care they might be made a source of great profit. Energetic farmers would do well to make occasional experiments, and it is probable, if they do not fail in watchfulness, that they will be well repaid.