d

these, and perhaps all for aught I know, issue and seek the various plants above mentioned, and provide for a wintering set of pupæ. Very late in the fall, long after the first frosts here in Nebraska, hundreds of the moths are to be seen about the lights in our cities. Whether or not any of these hiberU nate I can not say.

in

As before stated, the larva is quite a general feeder. In addition to the food habits already mentioned, it gives me pleasure to be able to announce that the larva is also inclined to cannibalism, and sometimes attacks others of its kind, which it not only kills, but entirely devours.

REMEDIES.

FIG. 12. The Corn Worm, (Heliothis Armigera;) a, b, enlarged view of the egg; c, full-grown larva; d, pupa, case; e, and f, moth-natural size. [After Riley.]

The Corn-worm, like other injurious species, can and should be carefully battled against whenever the opportunity presents. A single moth lays on an average about 500 eggs, and from the secluded nature of the larvæ, has but few natural enemies. Hence every moth killed in spring before egg-laying begins means the saving of a considerable later loss.

As remedies that have been tried with success, the following are suggested: hand-picking, attracting by odor and drowning, and attracting by light. The first applies to the larvæ; the others to the moths.

Hand-picking.-Where the larvæ infest gardens, the gathering of them by hand and after

wards destroying is quite

feasible. Even in cornfields

of moderate extent, this method of warfare is of sufficient benefit to pay for the time thus spent. Its presence in the ears is known by the eaten and blackened silk, mingled with excreta. To capture the worms here, the husk can be opened at the top and the depredator killed.

Attracting by odors and drowning. During certain times of the year, when the moths are issuing from pupæ and before they have laid their eggs, these insects can be attracted to baits and destroyed. For this purpose a mixture of molasses and vinegar set out in the fields in shallow dishes, will attract and destroy them. This method will also attract and destroy many other species. The following quotation from the Patent Office Report, (Agriculture,) for the year 1885, page 285, gives some light upon this subject:

FIG. 13.-The Corn Worm (H. Armigera) as a tomato worm. [After Riley.]

"We procured eighteen common-sized dinner plates, into each of which we put half a gill of vinegar and molasses, previously prepared in the proportion of four parts of the former to one of the latter. These plates were set on small stakes or poles driven into the ground in the cotton field, one to about each three acres, and reaching a little above the cotton plant, with a

six-inch-square board to receive the plate. These arrangements were made in the evening soon after the flies (moths) had made their appearance. The next morning we found from eighteen to thirty-five moths in each plate. The experiment was continued for five or six days, distributing the plates over the entire field, each day's success increasing, [? decreasing,] until the numbers were reduced to two or three moths to each plate, when it was abandoned as being no longer worthy of the trouble. The crop that year was very little injured."

Attracting by L'ghts.-The habit among a large number of nocturnal insects of coming to bright lights, has frequently been taken advantage of for the purpose of destroying certain of

FIG. 14.-Lamp arranged for catching moths. [After Lintner.]

the injurious species. This has been done in connection with the one under present consideration. While I do not approve of the general use of this as a remedy against nocturnal-insect pests, it might be resorted to in extreme cases. Just as many of the useful or beneficial species are also attracted by lights, and many of them are certain to be destroyed along with the injurious ones. The best means of applying this remedy is shown in Fig. 14. If this plan is adopted, many of the beneficial species will be enabled to crawl out of the water and escape, while the moths cannot. A very little kerosene oil should be added to the water to prove most beneficial in results. This will also add greatly to the number of the friends destroyed.

Prof. J. A. Lintner, in commenting upon the destruction of the first brood of this moth, has the following remarks to of fer, which will also apply to other injurious species:

"To illustrate the great importance of destroying the insects which would produce the first brood of a many brooded species, and the ease with which subsequent multiplication may at this time be prevented, we present the following calculation, showing the results which would follow the above experiments conducted for a single night, upon the supposition that each female of five successive broods would have deposited its full quota of eggs, and that each egg would have produced a moth. It is scarcely necessary to add that not even a near approach to such an entire exemption from loss in four distinct stages of insect life can ever occur in nature.

"The average number of moths to the plate as given above (referring to the same quotation from the Patent Office Report embodied here) being twentysix, the entire number captured during the night would have been four hundred and sixtyeight. Assuming one-half of these to have been females, and each to contain five hundred eggs, the caterpillars of the first brood would number one hundred and seventeen thousand. By the same method of calculation, we have for the second brood twenty-nine and a quarter millions of caterpillars; and continuing the computation until we reach the fifth and last brood, we have the amazing number of 457,031,250,000,000 caterpillars, or exceeding four hundred fifty-seven trillions.

"To present this computation in a more convenient and comprehensive form: Under the above conditions and by the same progressive increase, a Corn-moth emerging from its pupa in May would be represented by a progeny of nearly two trillions of caterpillars in its last annual brood in November, a number fourteen hundred times greater than that of the entire human population (as estimated) of the globe."

In this computation Mr. Lintner has carried his figures on to the fifth generation or brood, and not made allowance for loss of life by accident, disease, or predaceous foes. Our third brood is the last one we can count on for this state. Of course these figures only show possible results, and are not intended to represent actual facts. At any rate the increase of insect life is sufficiently rapid to warrant the expenditure of prompt and summary measures in dealing with them.

*First Annual Report of the State Entomolgoist of New York, 1882, p. 126.

FIG. 15.-Box-elder plant louse, (Chaitophorus negundinis;) a, winged viviparous female; b, young from viviparous female; c, viviparous apterous female; d, apterous oviparous or true female; e, egg-all enlarged. [Original from drawings by T. A. Williams.]

There are scarcely any of our shade, ornamental, fruit, or forest trees but that suffer more or less from the attacks of various insect enemies. Some of these work upon the foliage, others upon the twigs and branches, others again bore into the wood of the trunk and larger limbs, while still others work upon and in the roots below the surface of the ground. Chief among the above-ground enemies of this class that work upon the Box-elder trees in the state of Nebraska, is a species of plant-louse or aphid. It is a sap-sucker, and is known to entomologists and others by the name of the "Box-elder Plant-louse" (Chaitophorus negundinis Thos.) because of its infesting this particular tree.

This louse, like those infesting various other trees and herbs, occurs in several forms, both winged and apterous. It is green-the color of the tender twigs and leaves upon which it attaches itself by means of its beak, which is used for extracting the juice or sap upon which it is nourished, from the tree.

Early in the spring, even before the tender leaves have made their appearance, the eggs that were deposited the previous fall, hatch, and the little fellows gather about the opening buds, where they wait patiently, and perhaps shiveringly, too, so as to be ready to attack the first green growth that appears. These little lice that come from the eggs are of the form known as agamous females, i. e., females which produce without the intervention directly of the opposite sex. These females are also viviparous; that is to say, their offspring are produced alive, which latter are also of a like nature. Just when the first winged specimens of this louse are to be found, we do not know, nor are we prepared to give an outline history of their especial mission in the cycles of this insect's annual existence, further than, perhaps, the spreading of the species from one locality to another. Some of these winged specimens, at least, like the wingless agamous form, are also viviparous. In the fall of the year, after the first frosts, and when most of the leaves have fallen, the true female, which is a wingless form, lays eggs. These latter are usually thrust into crevices of the bark, and between the bud and twig. By means of these eggs it is carried through winter, and the continuance of the species is insured for the following year.

DESCRIPTIVE.

EGG.-The egg when first laid is light transparent greenish-yellow, but after a time becomes darker, taking on the color of the bark of the twig upon which it is laid. In form it is elongate oval, very smooth and glossy, nearly the same at both ends, and destitute of any perceptible sculpturing under ordinary low powers of the microscope. Like that of other species of the group, it is large for the insect which lays it, being about .8 mm. in length.

VIVIPAROUS APTEROUS FORM.-The "stem mother," or viviparous apterous form, is rather broadly oval, inclining to pyriform in outline, gradually widening from the head posteriorly to about the middle of the abdomen, from which point it tapers more abruptly to the style. The whole body is covered with small tubercles, from which proceed moderately large, stiff hairs or bristles. The legs are also covered with these bristle-like hairs. The general color of this form is green, with the head brownish during the spring and summer. In the fall after the leaves have fallen, and the lice have removed to the twigs, their color becomes darker, resembling that of the bark upon which they are found, that at this time of the year is brownishgreen. The apterous females which lay the eggs differ from the agamous form in being slightly more elongate, more cylindrical, and in having the abdomen somewhat narrower. The antennal joints of the latter show plainer and the eyes are larger than these. The honey tubes are also better developed in the true female than they are in the viviparous form. Her color is also perceptibly darker green or brownish-green than in the form described above.

WINGED FORM.-The winged individuals are very similar in form to that of the apterous female, being of an oblong oval outline. In size it is a little larger than they, being fully 2 mm. in length. The wings are very delicate in their structure, and when folded reach considerably beyond the tip of the abdomen; when spread they have an expanse of about 6 mm. Like the apterous forms, these winged individuals are covered with bristle-like hairs. General color green, with the thorax varying from brown to black.

As above stated, this insect begins its work just as soon as, or before, the leaves appear in spring, with the viviparous agamous female, or "stem mother." She becomes full grown in a few days, and begins the process of reproduction by "budding" internally, and expelling small lice of her kind, which in turn, after maturity, repeat the operation. These successive generations continue without interruption during spring and summer, some of them being furnished with wings, which enable them to migrate from place to place. In this manner new localities become infested. Damp weather favors and very dry weather retards their excessive increase.

Like many others of the family to which it belongs, the Box-elder Louse is provided with a pair of "honey tubes," or nectaries, as they are sometimes called. These are the two short tubular projections which rise from the sixth abdominal segment above, one on either side of the middle. They are connected with internal glands, which secrete a sweet or saccharine fluid, that flows continually while the insect feeds. The "honey dew" has its source here, and is nothing more or less than the secretion of some aphid. Wherever any of the nectar-bearing aphids occur in large numbers, and sometimes even in small numbers, there are many species of different insects congregated about, having been enticed hither by the "honey dew," upon which they are fond of feeding. Among these regular visitors the various species of ants are most numerous. Wasps and hornets are also quite frequent visitors, while butterflies and the two winged flies (Diptera) are common.

Happily for us, these lice as well as others, have their natural enemies that usually keep their numbers within bounds. Were it not so, with favoring atmospheric conditions, their rapid mode of increase would very soon permit of their completely covering the trees-trunks, branches, limbs, twigs, and leaves. Should such be the case the result to trees is evident. Among the enemies of this aphid are the "Lady-birds," with their bright colored dresses, dotted with black, like calico gowns. Several kinds of these beetles occupy themselves, in both mature and larval stages, by feeding upon the lice. The "Lace-wings," which are allies of the dragon fly, also live almost exclusively upon them. In addition to these a large number of "Sun-flies" (Syrphids) in their larval or maggot form live upon the lice. These are all predaceous in their nature, devouring them bodily, as a cat does a mouse. Aside from these predaceous enemies, there are certain others that destroy them in another way. These are very minute four winged insects, belonging to the same order with the bees, wasps, and ants, viz., the Hymenoptera. These little Chalcids, for such is the name given to the group, are parasites in the true sense of the word. They sting their host, drop in an egg, and are away. This egg hatches and discloses a grub that bores into and lives upon the vitals of the victim, which lat

*Winged specimens of this insect were first observed the present season on May 3d.

ter dies when the uninvited guest has attained its growth and is ready to issue forth into the world of conquest on its own behalf. Of course these Chalcids are small-much smaller than the lice within the bodies of which they feed and mature.

Sometimes, notwithstanding all these natural enemies and parasites do toward keeping this insect in check, favoring circumstances arise that permit of its increase in numbers sufficient to materially injure the plants upon which it feeds. When such is the case, other and and artificial means of warfare must be resorted to in order to prevent injury to vegetation. During the past spring and summer one of these favoring epochs in the life history of this louse occurred here in Lincoln and vicinity; and several times before, throughout different parts of the state.

As a remedy at such a time, a couple of sprayings of the trees with strong soap-suds, or an emulsion of kerosene, will effectually rid them of the lice. The "soap-suds" is preferable, if it is sufficiently strong and rightly applied, because the kerosene is sure to leave a more or less disagreeable odor for a time.

THE GREEN-STRIPED MAPLE WORM.

a

Anisto a rubicunda Fabr.

FIG. 16.-The Green-striped Maple Worm, or Rosy Forest Caterpillar, (Anistota rubicunda;) a, larva; b, pupa; c, female moth, all natural size. [After Riley.]

During the summer just passed, the soft maples along the streets and alleys, as well as those in door yards and on the capitol grounds, in the city of Lincoln, were more or less stripped of their foliage, and rendered unsightly. This was done by the larvæ or caterpillars of several species of moths belonging to the family Bombycidæ, aided by one or more of the Geometrids, or measurers. Chief among the former was a rather large, smooth worm, longitudinally striped with pale and darker-green lines, and readily recognizable from the others with which it was occasionally associated upon the same tree, by two anteriorly projecting black horns or spines emanating from the second segment behind the head.

The following descriptions of egg, larva, pupa, and imago are copied from Professor C. V. Riley's fifth annual report as State Entomologist of Missouri:*

"The eggs from which the worms hatch are deposited in batches of thirty and upwards, on the under side of a leaf. Each egg is about 0.05 inch long, sub-oval, slightly flattened, translucent, and pale greenish, becoming more yellow, and showing the black head of the inclosed larva, just before hatching."

The larva, when first hatched, is yellowish, cylindrical in form, and has the head large and black. The spines which are present in the full grown larva are now but little black tubercles. The full grown larva is thus described by the author just quoted:

"Average length, 1.50 inches. General color, pale yellowish-green; longitudinally striped above alternately with eight very light (almost white) yellowish-green lines, and seven of a darker green, inclining to black, the medio-dorsal one usually darkest, and showing palpitations. Characterized by two black, blunt, anteriorly-projecting horns on joint two; two lateral rows of posteriorly-projecting, more pointed, shorter spines, one (the largest) below and one above the stigmata, and most prominent on joints ten and eleven, which are here somewhat dilated and tinged with rose-red. When examined with a lens the body, both above and below, is found to be thickly studded with transparent granulations, and there are four dorsal polished, sub-obsolete spines, the anterior on upper edge, and the posterior on lower edge of second dark stripe, and most prominent on joints eleven and twelve. Head more or less intense

*Fifth Annual Report on the Noxious, Beneficial, and Other Insects of the State of Missouri, by Charles V. Riley. Pages 137-141. [1873.]