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DESCRIPTION.

The egg is very small, a fiftieth of an inch in length, cylindrical, pointed at each end, and pale red in color.

The larva is about a tenth of an inch long, with the body smooth and shining, and a little flattened beneath.

The "flaxseed state."-This is a name gived to the stage when the pupa is forming. Unlike many insects the pupa remains for a time inside the dried larva-skin, At this period the larvaskin with enclosed pupa resembles a flaxseed and thus the name came to be given. In this

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condition the insect passes the winter. In spring the pupa emerges, by breaking the dried larvaskin which has served it as a sort of a cocoon. Then, according to the observations of Dr. Fitch, it ascends the wheat straw, finds some cleft in it and crowds its way out. The crack closes behind it and is allowed to nip the end of the abdomen. The pupa-skin now dries and splits and the perfect insect appears. For a few moments the fly is quiet, waiting for its wings to dry, and then it takes to the air in flight.

The imago is about one-tenth inch in length, slender, dark brown, with smoky-brown wings, legs paler brown, and eyes black. It is easily distinguishable from the wheat-midge, which has stouter body and is of an orange color.

HABITS.

Eggs are laid on the leaves of wheat-plants-those of the first brood in September on winter wheat, and those of the second brood in April or May upon spring wheat. From one to forty may be found upon a single leaf. Sometimes eggs are laid in July and a third brood is brought forth. Normally, however, the insect is double-brooded, the flaxseeds being found in winter and in early summer.

The Hessian fly, then, cannot exist except where winter wheat is cultivated, for it must lie in the straw throughout the cold season. Its greatest damage is in the fall, to winter wheat, and, since wheat is mostly of the spring variety in Nebraska, this insect has hitherto been less abundant than the chinch-bug, which works in the spring wheat rather than in the winter wheat.

Four days after deposition, the egg hatches, and the larva crawls to the angle between leaf and stem, where it attaches itself. It lives upon the sap and does not chew the straw. As it increases in size, it gradually becomes imbedded in the stalk, owing to the swelling caused in surrounding plant-tissue. The wheat turns yellow and dwindles in size, and before winter sets in may be almost destroyed. It sometimes recuperates and sends up a second growth in the spring.

Unlike the chinch-bug, according to Dr. Packard, the Hessian fly prefers a warm, moist climate. Hence rains and dampness, while causing decrease in the numbers of chinch-bugs, may only increase the other pest-which is quite as bad a one, where it appears in large swarms. A cold winter is bad for it, especially a winter without much snow. From its habits, then, it flourishes best where the chinch-bug is least likely to appear.

ITS APPEARANCE IN NEBRASKA.

Although the mere presence of the chinch-bug might seem to be an indication that the Hessian fly is unlikely to do much damage in Nebraska, there are many reasons why it should be watched. As yet no serious injuries have been reported. In 1881, Lawrence Bruner wrote to

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the entomological commission that the insect has been known in Nebraska from 1867, recurring in 1873 as far west as York county, where it did some damage. At that time Prof. Aughey reported the insect from the vicinity of Lincoln. In 1885 I saw several stalks of wheat near Pawnee City, which had galls upon them, and in 1886 I noticed the puparia attached to stalks near the State Asylum for the Insane, in Lancaster county. The fly has been reported to me from Saunders, Gage, Fillmore, Richardson, and Cass counties, during the season of 1887, and I think that it has been observed by farmers in the vicinity of Lincoln. It has certainly been seen in Douglas county during the spring of 1887, but no tracts of wheat land have suffered from it except in Lancaster and Gage counties, where some trifling damage has been done. The present year, 1887, has been dry, and Hessian flies have not abounded. Last year was more favorable, and more have been reported than for this.

In spite of temporary droughts, the annual rain-fall of Nebraska is steadily increasing, and consequently the conditions for the Hessian fly are becoming more and more favorable, so that in ten years, or less, we may reasonably expect it to appear in greater numbers-possibly in numbers great enough to work serious injury.

INSECT PARASITES.

There are several species of Hymenoptera, known in general as "Ichneumon-flies." Semiotel us destructor Say, and Platygaster error Fitch, seem to be the most beneficial. They have so much to do with restraining the Hessian fly that it is not advisable to burn stubble in which the pup may be concealed, because the parasites will also be destroyed.

REMEDIES AND PREVENTIVES.

(1). The larvæ may be killed by an application of lime. One or two bushels to the acre, sown broadcast, is wet by rain or dew and forms a solution very distasteful to the insect.

(). Fultz, Clawson, Underhill, and most red wheats are more vigorous in withstanding attack, and should be sown if there is reason to fear the Hessian fly. Lancaster wheat is also recommended. Prof. Packard remarks: "Whatever kind of wheat is used, much more depends upon a rich soil, a vigorous growth, and careful cultivation, all of which tend to make the stalk stouter, and the growth a few day's earlier, than the choice of particular varieties." (3). Rolling the ground will not be of much use, though often recommended. Though a Sovereign remedy for the chinch-bugs, it does not work as well with the Hessian flies on account of their different habits.

(4). Burning the stubble has been condemned by practical entomologists for the reason given above. It is much better to let it stand.

(5). Pasturing with sheep; this is recommended by some. If the wheat in the fall is strong enough to bear it, sheep turned into the flelds will destroy great numbers of "flax-eeds" and

larvæ.

(b). Late Sowing. After a hard frost most of the insects will be destroyed, and if sown then, the wheat, though in danger of being winter-kilied, enjoys considerable immunity from attack. This is a doubtful remedy."

(7). Early serving. Oddly enough, just the reverse of the last remedy is claimed itself to be a remedy. This is based upon the belief, if the wheat is strong enough by the time the flies beg.n to work upon it, that all will be well. However, the leaves are no sooner out of the ground than they are subject to attack, and, in consequence, it is doubtful again whether such remedy i- real.

(8). Dr. Fitch and Prof. Cook advise the sowing of most of the grain late, but also to put out an early patch which may act as a decoy upon which the flies can lay their eggs. As soon as the late wheat is up, the early wheat may be plowed under and re-sown, thus destroying a large proportion of the eggs and larvæ.

(9). The rotation of crops is to be urged as strongly as in the case of the chinch-bug. It is a device of scientific and practical agriculture which has a definite reason, not to be disregarded. High culture, good soil, rotation, diversified sowing, with most of it late-in short, good farming. will be found to restrain the ravages of the Hessian fly, as well as those of most other insects.

HISTORY.

The Hessian fly is so named because it was supposed to have been introduced into this country during revolutionary times, by the Hessian mercenaries of England. From New York it spread gradually westward and southward. As shown in the carefully prepared map accompanying the monograph of Prof. Packard, its northern boundary is approximately that of a line drawn through St. Paul, Minn., and Portland, Maine. The southern border is wavy, running through Galveston, Cairo, south again to Atlanta, and north to Norfolk, Va. Westward the insect is found in Kansas, Nebraska, a corner of Dakota, and a part of the Indian Territory. 1843 was a bad year for the eastern and central states. In 1871, 1874, and 1877, it was increasingly harmful, and in 1878 it began to dwindle again in significance. This indicates a periodicity in its appearance, and it is noted by Prof. Packard that the years of greatest prevalence were warm and moist, thus indicating that these are favorable conditions.

From the researches of Wagner, it is suggested by Dr. Hagen, one of the most eminent authorities in the country, that the insect was not introduced from Germany by the Hessians, but from Spain and the Mediterranean countries, somewhat earlier in our National history. This view is supported by Prof. Packard, and it seems probable that the name, Hessian fly, is a misnomer. Nevertheless it is firmly established, and no reason can be given why it should uot stand.

THE COLORADO POTATO BEET).E-(Doryphora decemlineata SAY.)

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Riley's Mo. Reports, 1, 5, 7, 8, 9; Le Baron's Ill. Reps., 1st and 2d; Thomas' Ill. Reports, 6th and 9th; Riley, Potato Pests; Inj. Ins. of Mich., A. J. Cook, American and Canadian Entomologists.

HISTORY.

The Colorado potato beetle is a thoroughly western insect, for its native home is in Wyoming, Colorado, and Western Dakota, where it originally fed upon a plant allied to the potato-the Solanum rostratum, or prickly night-shade. With characteristic Western energy, it was not slow to take a new idea, and when the travel between East and West began, it seized the opportunity to ally its fortunes to those of man. In 1861 it had crossed Nebraska into Iowa; in 1865 it was found in Illinois; in 1869 it had made its way into Ohio, and in 1874 it appeared on the Atlantie coast. In Prof. Riley's map of its journeys the line of most direct advance is seen to be almost straight, formed by joining Cheyenne, Omaha, Chicago, Cleveland, and New York.

As it traveled eastward the insect also widened its track, going north into Canada and sou h over Missouri, Tennessee, and Virginia. Wherever it appeared it did great damage, and, at first, on account of its newness and strangeness, it was very difficult to restrain it even in the least degree, but when its approach became certain, farmers abandoned their potato crops in despair.

It has now spread over 1,500,000 square miles, and has even appeared in Germany. Southern heat is distasteful to it, and it is found more abundantly on the line of most rapid advance. From the first, the insect has done great damage, but, owing to the experience gained in our acquaintance with it, and to the careful study of leading American entomologists, it is not so much dreaded to-day as it was ten years ago.

DESCRIPTION AND HABITS.

So common a pest scarcely needs description, for surely it is familiar to every reader of this report. The insect is not a bug, as many continue to call it. It is no more a bug than it is a butterfly or humming-bird. As in all beetles, its two upper wings are hard and armor-like, yellowish in ground color, and striped longitudinally with the ten lines from which it derives its specific name.

The eggs are orange-yellow, and are laid in little clusters on the under side of the leaves. Prof. Cook states that a single beetle will lay eleven hundred eggs, and sometimes upon vegetation near the potato plants, rather than upon the plants themselves. Fortunately this latter custom is not a common one.

The lava are hatched in from five to seven days, and are at first of a dirty-red color. In fifteen days they are mature, being then of a lighter color with a double row of black spots on the back. They now crawl down from the plant where they have been feeding, and bury themselves in the ground, there to change into pupa. After about a week's quiet, the beetle breaks the pupa skin and emerges to the light again. The whole series of transformations occupies from a month to forty days, according to climate.

The last brood of beetles, in the fall, hibernates in its perfect stage in the earth, and emerges the following spring for purposes of pairing and egg-laying.

Considerable discussion was at one time provoked by the question, whether the potato beetle is poisonous or not. Undoubtedly the juices of its body are acrid and disagreeable. A little squirted into the eye is a source of great pain, but well-authenticated cases of serious injury by getting smashed insects upon the hands are rare. In view of the testimony, notably that of Dr. LeBaron, it is not counseled for men whose hands are cut or sore to indulge in very extensive hand-picking.

NATURAL ENEMIES.

The Doryphora is followed up by a small army of foes, and they are looked to for eventual extermination of the pest if given a fair chance at it. Several species of lady birds-those most benevolent insects-two or three spiders and a small mite-Uropoda americana of Riley-wasps, tiger beetles, several H miptera, and two or three Dipterous flies combine their forces with gratifying results. Fowls do not like the potato beetle, and a correspondent of the Rural New-Yorker is led to devoutly pray for a new breed which shall have no qualms of conscience or stomach. Ducks, however, will feed upon the beetles. Quail, crows, and the rose-breasted grosbeak, as observed at Ames by Prof. Bessey, will also devour it. Skunks and toads consider it a delicate morsel, and spend many busy evenings in potato patches catching and eating the larvæ and the mature beetles.

REMEDIES.

Prof. Riley classifies these into four different categories:

1st. Encouragement of natural enemies.

2d. Preventive measures.

3d. Mechanical means of destruction.

4th. Poisonous applications to the plant.

Under the first it may be said that farmers "should learn to discriminate between the smaller eggs of the lady birds and those of the potato beetle." So-called soldier bugs, much like the squash bugs, should not be disturbed, and toads should be penned for a day or tw near potato patches, after which they will stay around and do much good. The potato beet e has been so long established in Nebraska that its natural enemies among insects follow closely upon its track. If not disturbed they will prove exceedingly beneficial.

(2.) Alternation of crops and good cultivation are recommended. It is also a good plan to plow very early in the spring and give a late frost a chance to make way with some of the hibernating beetles. Straw spread over the ground in winter has been recommended. Peach Blow and Early Rose potatoes have been found the best to withstand the attacks of the pest, and they should be given the preference over tenderer varieties.

(3) Here may be mentioned, first and foremost, hand-picking. The "bugs" may be knocked off into a pan of kerosene, or may be crushed upon the leaves with a pair of heavy pincers.

But as Mr. W. H. Woods, of Fort Calhoun, writes me, this method is "too laborious and too disgusting." Mr. Woods adds that, although there are millions of the beetles upon his farm, they do not seem to be so voracious as of old, and are readily kept in check by poisons.

(1.) Poisonous applications may be made either in powder or in solution. The best known is Paris green, and it has become a specific against the beetles. Strictly speaking, the powder cannot be dissolved, but is held in suspension by the water, and answers all the purposes of a solution. For sprinkling, the proportion of one tablespoonful of the Paris green to a bucketful of water is found to be the most satisfactory. This mixture may be applied with a common hand-sprinkler, although devices for applying it on a large scale, by horse-power, are known to most potato growers. There is no danger to the plants from this mixture, nor to the tubers under ground.

l'aris green may also be applied as a powder, but here, as before, it must be well mixed with other ingredients, either lime, plaster of Paris, or flour. One part of the poison in eighteen of the other material, is the proper proportion, and the mixture may be sifted on the vines from a common tomato can, with holes punched in the bottom, or from more aristocratic sifters, as the manipulator sees fit.

Many unpractical men have advised the use of white arsenic, because it is cheaper than Paris green. It kills the beetles but also the plants.

Talking with several market gardeners in the vicinity of Lincoln, I found that air-slacked lime was their favorite remedy, but it is probably inferior to the arsenical poison-Paris green. Various other remedies have been suggested by correspondents, but most of them are of secondary importance. One other remains to be mentioned. It is exceedingly valuable, for many reasons better than Paris green. This is London purple, named by Prof. Bessey, and through his efforts introduced into this country. It is superior to Paris green, as it is not so much adulterated, and it is better held in liquid suspension. It is fully as cheap, and in most places cheaper than the other, and in operation is effective and sure.

The poisons, when applied in the form of powder, should be handled with care, and the Operator should avoid having dust blown from the vines into his face by the wind, otherwise he may follow the beetles.

On the whole, the application of London purple or Paris green in solution, together with hand-picking, seems to be the best method of combating the beetles. Dr. Thomas, in his 9th Ill. Rep., declares against all topical applications, and would use only preventive measures and mechanical appliances. Certainly such methods must be effective or he would not recommend them, and, since poisons are also wonderfully effective, a combination is likely to sweep everything before it.

I judge from correspondence which I have received that the potato beetle is gradually disappearing from Nebraska. Fewer swarms of magnitude are reported each year, and it is possible that the extremely hot and dusty summers which prevail over much of Nebraska are driving it to more congenial eastern climates.

CABBAGE BUTTERFLIES.-(Pieris protodice and P. rapæ.)

(ORDER LEPIDOPTERA.-FAMILY PAPILIONIDE.)

Packard, Half Hours with Insects, Pt. 2; Guide to Study of Insec's; Riley, Mo. Rep., vol. 2; Inj. Insects of Mich., A. J. Cook; 9th Ill. Report, Thomas; Trans. Wis. Hort. Soc., 1877; Io. Hort. Rep., 1871; Canadian Entomologist, 1871; Harris Ius. Inj. to Veg.

GENERAL DESCRIPTION.

As most people know, the white butterflies seen hovering over cabbage fields and about the piles of the vegetable in city markets are responsible for the cabbage worms which eat the leaves and bore into the heads. There are two distinct species of cabbage worms working in Nebraska. These are:

(1.) Pieris protodice Boisduval, commonly called the southern cabbage butterfly. (2.) Pieris rapa Schrank, the rape butterfly or imported cabbage butterfly. These insects are similar in appearance, but may be distinguished in all stages.

The eggs are translucent green, and laid upon the under side of the cabbage leaves. In from six to ten days they hatch and the larvæ come forth to feed upon the plant at hand. The larva of protodice is bluish-green, with four longitudinal yellow stripes and a great number of blick dots scattered over the body. That of rape is paler green, with one yellow stripe down the back, yellow spots along the sides, and fine dots of black distributed as before. When full grown, each is a little over an inch in length.

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The chrysalis of protodice differs from that of rape in being bluish-gray, with more pronounced black dots, while the other is pale green, less heavily dotted and somewhat more slender.

The imagines in both species are marked with black, while the general color is white, and in both, the female is more abundantly marked than the male. In both sexes of both species the fore wings are tipped with black, and a given insect can be placed cor rectly under its appropriate species by this diagnostic feature. Exclusive of the black tips, there are never less than three pronounced black spots upon the fore wing of a protodice and never more than two upon that of a rape. In both species the hind wings of the male are almost immaculate.

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