THE GTPST AND BROWN-TAIL AND THEIR EUROPEAN PARASITES.

By L. O. HowABD, Ph. D., Chief of the Bureau of JEntomology.

INTRODUCTION AND SPRKaD.OF THE MOTHS IN UNITED STATES. All of the earlier works on the injurious of Europe have contained references to and descriptions of the so-called gypsy mpth {Ocne7'ia dispar Linn.). The brown-tail (Miprootis chrysorrhœa Linn.) is also a native European and for many years has been noted as an enemy to fruit trees. Both of these insects have been introduced into the United States in the vicinity of Boston and have multiplied and spread with alarming i-apidity. The gypsy moth was first introduced in 1868 by Prof. L. Trouvelot, of Harvard University, who was experimenting in the crossbreeding of wild silkworms. An egg cluster of the gypsy moth blew out of his window in Maiden, and he was unable to recover it. Twenty years later, in 1889, the had increased to such an extent that the cater- pillars were a great nuisance in the city of Maiden, and the State under- took an investigation in the hope of exterminating the species. It was found to have spread until it occupied a territory of about 100 square miles, and during the next ten years the State, by constantly increas- ing appropriations and by the active work of a large number of paid employees, had succeeded in practically controlling all further spread and in greatly reducing the numbers of the insect. In 1900, however, appropriations lapsed, and from that year until 1905 the insect was again allowed to multiply and spread, unhindered save by the opera- tions of private persons. It soon became as numerous as it had been early in the State investigation, and the boundaries of the region inhab- ited by it widened out greatly, until now it has reached as far west as Worcester and occurs all along the New Hampshire line on the north, extending over into that State at Seabrook, Hampton, North Hampton, and Portsmouth (see fig. 1). It has also made its appearance in por- tions of Providence, R. I. The brown-tail moth was first noticed in the early nineties in Somer- ville, Mass., where it was probably introduced in a shipment of roses from Holland. It multiplied and spread, although the work of the gypsy moth commission was directed against this insect as well as against the gypsy moth down to the year 1900. It has since become 123 124 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. even more abundant and injurious than the gypsy moth, and, owing to the fact that the female readily, whereas the female of the gypsy moth does not at all, the brown-tail moth has far exceeded the gypsy moth in its spread. It now covers a territory extending from East- port, Me., on the northeast, as far south as Cape Cod, and to the west

FIG. 1.—Sketch map of eastern Massachusetts, showing gypsy moth area. as far as Amherst, Mass. It doubtless also exists in many communi- ties in and out of Massachusetts from which it has not been reported.

LIFE HISTORY AND DESCRIPTION OF THE GYPSY MOTH. The gypsy moth has but a single generation each year. It winters in the egg stage, and the young hatches from the egg about THE GYPSY AJSTD BROWK-TAIL MOTHS. 125 the first of May. It feeds upon the leaves of many different plants. It attacks practically all fruit, shade, and woodland trees, showing some preference for apple, white oak, red oak, willow, and elm. It kills both deciduous and coniferous trees. Woodlands attacked by it in number are stripped bare and many trees are killed. It feeds upon the foliage of shrubs, vines, bushes, and flowers, and will eat grass and garden and field crops. The full-grown caterpillar is 3 inches or a little less in length, and has a dark-gray or sooty color effect. The back is marked with yellow; along the back is a double row of blue spots fol- lowed by a double row of red spots—five pairs of blue and six pairs of red. The young larvae do not show these spots well, but in the full- grown ones they are very evident. About the first of July, or a little later, the changes to pupa (PI. I) in a partial cocoon formed of a few

FIG. 2.—The gypsy moth {Ocneria dispar): a, female moth; 6, male moth; c, halfgrown larva; d, mature larva. Slightly enlarged (original). türeads of silk, sometimes connecting leaves together. From the mid- dle of July to the middle of August the winged moths appear (fig. 2), The male is brownish yellow, and has a slender body and a wing expanse of about li inches. It is an active flier. The female moth is nearly white, somewhat spotted with black. It is very sluggish, and its body is so heavy that it can not fly. Its wing expanse is about 2i inches. The eggs are deposited by the females shortly after issuing, and are laid in masses, each containing about öOO eggs closely packed with yellowish hair from the body of the female, oval in shape and about li inches long by three-fourths of an inch wide. The eggs are laid on the trunks of trees, on the sides of houses, fences, stone walls, and other places. The females seem especially attracted to recesses where the eggs are 126 YEABBOOK OF THE DEPARTMENT OF AÖRIOÜLTURE.

more or less hidden. Large holes in old trees will be found filled with them, and they are often found in the crevices between stones in a stone wall, or in the hollow of an old stump or log. The larvae (fig. 2), especially after they reach some size, feed princi- pally at night and try to hide themselves during the day. In daytime they will descend upon the larger limbs and trunk and try to find some place under the bark or in a large hole where they can secrete them- selves. It is this habit that has led to the use of burlap bands around the trunks of trees, under which they will hide during the day and where they can be found easily and destroyed.

LIFE HISTORY AND DESCRIPTION OF THE BROWN-TAIL MOTH. The caterpillar of the brown-tail moth is primarily an enemy of pear, apple, cherry, peach, and other fruit trees, but it is also found commonly upon various shrubs that grow in door- yards; in Massachusetts it has begun to attack the for- est trees and now affects especially the oaks. Young oaks—oak scrub—are appar- ently particularly attractive to it at present. The insect does not hiber- nate in the egg stage, as does the gypsy moth, but as the young caterpillar. It has, like the gypsy moth, but one generation each year. FIG. Z.—The hrown-t&n moth {EuprocHs chrysmrhœa): Fe- The CggS are laid in maSSCS male moth above, male moth below, right. Slightly enlarged (original). ^^'^^^'^' ^' on the under side of the leaves in the latter part of July. The egg masses are brown and covered with hair, and each con- tains about 300 eggs. The masses.are much smaller than those of the gypsy moth, averaging about two-thirds of an inch in length by about one-fourth of an inch in width. The eggs hatch during August, and the young feed in clusters on the upper surface of the leaves, a little later beginning to spin their winter webs by drawing together a number of leaves with silk, in which web a large number of caterpillars stow themselves away for the winter. These webs or nests, composed of leaves and silk, will average from 5 to 6 inches in length, and each will contain 200 or more caterpillars. They feed until cold weather, when all enter the web and close the exit holes. They are then about one-fourth grown. Early the following spring, as soon as the buds begin to appear on the fruit trees, they issue from the o ver-wintering THE GYPSY AND BBOWN-TAIL MOTHS. 127 nests and.attack first the buds and the blossoms, and later the foliage. The full-grown larva is about 2 inches long, reddish brown in color, with a broken white stripe on each side and two red dots on the back near the hind end. They will migrate from one tree to another, com- pletely stripping the foliage as they go. When full grown they spin their cocoons either on the tree trunks or within the leaves on the branches of the trees.

'r ^

M^ 1 PIG. 4.—Hairs of the caterpillar of the brown-tail moth, highly magni- fied (adapted from Kirkland). The moths are pure white, except that the female has a conspicuous bunch of brown hair at the tip of the abdomen, from which it derives the name '^ brown-tail moth.'^ The female expands about 1^ inches and the male is smaller. Both male and female (fig. 8) fly readily, largely at night, and are greatly attracted by electric lights. It is not alone by its damage to the foliage of fruit and other trees that the brown-tail moth is a . The hairs of the larvae are finely 128 YE AEBOOK OF THE DEPARTMENT OF AGRICTJLTUBE, barbed and brittle (see fig. 4), and where the caterpillar comes in con- tact with the human skin the hairs enter the skin pores, break off, and cause a severe irritation. "Brown-tail rash,"as it is called, has been very common in eastern Massachusetts for the past few years, and, while few people are made seriously ill by it, it is the cause of great annoyance. The free use of vaseline is said to be the best remedy.

REMEDIES FOR THE GYPSY MOTH AKD THE BROWN-TAIL. MOTH, Spraying with Paris green or arsenate of lead is effective during the early summer against the brown-tail moth. It is less effective against the gypsy moth, since this caterpillar seems to be able to absorb larger quantities of arsenic than any other insect known. The ordinary appli- cations of Paris green were found, early in the work of the old State commission, to be entirely ineffective. It was necessary to use so great a strength of the Paris green in order to poison the caterpillars that the foliage of the treated trees was badly burned. It was owing to this fact that arsenate of lead came into use as an insecticide, since this substance may be used in very strong solution without danger of leaf burning. But better remedies than spraying are to be found for both species. With the brown-tail moth, the habit of passing the winter in the young caterpillar nests affords an easy remedy. As soon as the leaves fall in the autumn these nests stand out conspicuously, and in an orchard or garden nothing can be easier than to cut off and burn these nests with the gratifying assurance that with each one burned 250 caterpil- lars are destroyed. In large forest areas, however, or where very tall trees are infested, this becomes an arduous and expensive operation. For the gypsy moth, the most effective remedy is to search for and destroy the eggs during late summer and winter. They are conspicu- ous from their color, and when one learns the character of the incon- spicuous places in which they are sometimes hidden it is not an espe- cially difficult matter to find them and to destroy them with a creosote mixture. When the larvae are young, arsenate of lead at the rate of 10 pounds to 100 gallons of water will destroy them, but when older they are not so readily affected. For the older caterpillars, as has been before suggested, the tying of a burlap band about the trunk of* a tree will result in the capture and destruction of the majority of those present. The burlaps should be examined daily, and the hidden caterpillars destroyed by crushing or by cutting.

INSECT ENEMIES OF THE GYPSY MOTH AND THE BROWN-TAIL MOTH IN AMERICA« When the State Board of Agriculture of Massachusetts published its large report on the gypsy moth in 1896, there were recorded five American hymenopterous and six dipterous parasites of this moth. THE GYPSY AND BEOWN-TAIE MOTHS. 129

In this report wa8 also recorded the fact that certain predaceous wasps and hornets, ants, and several predatory , several spiders, and several species of predatory bugs feed upon the gypsy moth cat- erpillars. The percentage of parasitism, however, was slight, and the predatory insects made no impression upon the armies of the caterpil- lars. In this report also was made the statement that in Europe there are known twenty-seven hymenopterous and twenty-five dipterous parasites, although as a matter of fact a number of the former are hyperparasites—that is, parasites of the true parasites. The question of endeavoring to import the European enemies of the gypsy moth into Massachusetts was considered at that time, and the following par- agraph was publishe

EUROPEAN PARASITES AND PREDATORY INSECT ENEMIES OF THE GYPSY MOTH AND THE BROWN-TAIL MOTH.

As indicated in the preceding section, a large number of parasites are known to affect both of these injurious species in Europe, and the same may be said of predatory insects. Both species are old and well-estab- lished members of the European fauna, and while always injurious and appearing from time to time in especially injurious numbers, at no 2 A1905 9 130 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. time and in no part of Europe is there an outbreak of these insects comparable to the yearly abundance in New England. In fact, in Europe the status of the gypsy moth and the brown-tail moth may well be compared with the status of some of our common species of American origin, as, for example, the tussock moth {Hem er acampa leitcostigma S. and A.) or the fall webworm { cunea Dru.). Of these insects, one can find specimens every year in or about any of our eastern cities or towns. Occasionally one or both species become so numerous as to attract particular attention and to excite some alarm as to the future of our shade trees; but it almost invariably happens that the year following such an appearance in numbers of either of these species very few are noticed, and it is always several years, and may be many years, before they appear in like numbers again. For example, in Washington City in the year 1886 the shade trees of the city were almost entirely defoliated by the fall webworm; since that time—and nineteen years have elapsed—there has been no occurrence of the species in any way comparable to that one. The insect is seen here and there in small numbers almost every year, but the shade trees have not suffered at all seriously. Again, in 1895, Washington suffered from an extraordinary outbreak of the tussock moth, and many trees were defoliated. The following year the insect was scarce, and although it has occurred rather commonly several times during recent years no especial damage has been done in the intervening time. For two years after the outbreak of 1895 the writer made a study of the conditions of parasitism as related to this species. He found that during the autumn of 1895 the primary parasites of the tussock moth caterpillars bred in enormous numbers in Washington—in numbers so great that in many instances where counts were made 95 per cent of the caterpillars were destroyed. With this abundance of their ene- mies the caterpillars hatching from o ver-wintering eggs the following spring were practically annihilated. Then these enemies were them- selves destroyed by an extraordinary multiplication of secondary para- sites, and these in turn were later reduced by their own enemies, which are called tertiary parasites. The few survivors of the tussock moth were, by the destruction of their primary enemies, permitted to repro- duce and to begin to multiply the species. But, although at some future time, through possible weather conditions inimical to the development of the primary parasites, the tussock moth may, and will probably, again become as numerous as it was in 1895, the same round of destruction will again occur. It is in precisely these ways that the multiplication of the gypsy moth and the brown-tail moth is controlled in Europe. There is a definite interrelation of species which controls the situation and renders both gypsy moth and brown-tail moth innocuous as compared with condi- tions existing in Massachusetts. THE GYPSY AND BKOWN-TAIL MOTHS. 131

With the cessation of the exterminative measures instituted by the State of Massachusetts, and the indication of the probability that much can not be expected from native American species, it has become evi- dent that one of the best hopes of lessening the damage done by these insects rests in the importation and establishment of the European parasites and other insect enemies.

ATTEMPTS TO INTRODUCE EUROPEAN ENEMIES OF THESE MOTHS. In the act appropriating for the expenses of the United States Department of Agriculture for the fiscal year ending June 30, 1906, Congress inserted a clause permitting the Secretary of Agriculture to spend an amount not to exceed $2,500 in an effort to import these parasites, and at the same time Massachusetts appropriated $10,000 a year for three years for the same purpose. In the same act the State of Massachusetts provided for the appointment, by the governor, of a superintendent of suppression, with power to appoint agents and assist- ants and to have general charge of the work of suppressing the moths. The bill also required cities and towns to destroy the insects within their limits under certain regulations and restrictions and pecuniary assistance from the State which need not be mentioned here, but which are displayed in Bulletin No. 1, issued from the office of the superin- tendent for suppressing the gypsy and brown-tail moths and published by the State printers in Boston in September, 1905. The superin- tendent appointed by Governor Douglas is Mr. A. H. Earkland, and he, with the consent of the Secretary of Agriculture, placed under the control of the writer a large part of the parasite fund appropriated by the State. Knowing in advance the European conditions surrounding the gypsy moth and the brown-tail moth and their parasites, it was decided to visit different parts of Europe during the months of June and July, and to secure the sending of as many full-grown larvae and pupae of the gypsy moth as possible to Mr. Kirkland in Boston, with the cer- tainty that a certain proportion of them would be parasitized and that the parasites would probably issue in due time on American soil. There would be no danger in sending unparasitized individuals, since issuing moths could readily be killed. The writer therefore sailed from Boston on the 3d of June and landed in Naples on the 15th of that month. He at once consulted Dr. Filippo Silvestri, the entomol- ogist of the Royal Agricultural School at Portici, 6 miles from the city of Naples. Doctor Silvestri stated that neither gypsy moth nor brown-tail moth had been seen in the vicinity of Naples for some time, but that in 1904 he had been informed by the president of the agri- cultural society of the island of Sardinia that the former had been unusually abundant in portions of that island. Here was good fortune from the very start, since, as indicated in an earlier portion of this 132 YEAEBOOK OF THE DEPARTMEKT OF AGRICULTURE. article, in the year following a rather numerous outbreak of the insect the primary parasites are quite certain to be more abundant than usual. At the request of the writer, therefore, Doctor Silvestri consented to send his principal assistant. Dr. G. Leonardi, at once to Sardinia for the purpose of making collections. Accordingly, Doctor Leonardi started on the steamer sailing the next da}^ and his trip was very suc- cessful. He collected and later sent by mail to Boston some 1,250 pupae of the gypsy moth and about 2,500 larvae. He also sent 200 liv- ing specimens of a ground known as sycophanta L. (ftg. 5), a European species with congeneric relatives in the United States, but which has a habit of climbing trees that is not possessed by its American relatives. It is therefore in Europe an effective enemy of tree-inhabiting cat- er pi liars. Unfortunately, these specimens were intrust- ed to the regular mail, and therefore landed in New York and were shipped to Boston in the ordinary course of af- fairs; on arrival in Boston all of the beetles were found to have died on the journey. Had they been shipped by direct steamer from Naples to Boston it is likely that some of them would have survived, and this course will be followed in future sendings from Naples. The larvae and pupae, however, and their con- tained parasites were in bet- FIG. 5. -Calosoma sycophanta, about twice natural size ter condition, and a number (original). of the latter were reared from this material. The most important parasite, and in fact the only one from which may be expected much advantage from the past season's work, is a large táchinid fly known as TacMna larvarum L. (fig. 6), and of this species in the neighborhood of 400 larvae emerged from the gypsy-moth caterpillars and entered the pupal stage in large, oval, dark-colored puparia. In this condition they are resting, and the flies will probably issue in the spring of 1906. This is one of the largest of the European tachinid flies, and is a rather general parasite, laying its eggs upon a number of species of large caterpillars. Not all of the puparia of this Tachina, however, will give out the beneficial parasites, since a number of them prove to have been themselves parasitized by Chaléis ßavipes Fab. (fig. 7). These latter have been destroyed as THE GTPSY AND BKOWN-TAIL MOTHS. 133 fast as they have emerged, since their introduction and establishment would seriously jeopardize the success of the establishment of primary parasites of value. When Doctor Leonardi left for Sardinia the writer started north and stopped at Florence, where he had a long consultation with Prof. Antonio Berlese, the head of the Royal Station if or Agricultural Entomology, who had formerly been in charge of the work at Fortici. Professor Ber- lese and his two assistants, Doctor Del Guercio and Doctor Ribaga, were much interested in the quest and promised every possible assistance. They stated that both gypsy moth and brown-tail moth were rare in the vicinity of Florence, and they knew of no lo- cality where they could be FIG. G.—Tachina larvarum, much enlarged (original). found at that time. Pro- fessor Berlese stated that some years previously ât Portici he had known an army of gypsy-moth caterpillars to be perfectly destroyed by a disease which he identified as the pebrine, so destructive to the domestic silkworm. He promised to make a search during the com- ing season for diseased caterpillars and to rear a number of moths, which will be micro- scopically exami n e d for pébrine corpuscles according to the Pas- teur methods used in the bacological insti- tutions of Italy and France. Should such moths be found, he promised to send the Fio.7.—Chalcisßavipes, greatly enlaTgeá(oTÍgmal). effffS to Mr. Kirkland in Boston. Tt would be a particularly interesting development of the work should relief come in this way, since it was partly with the idea of breeding a race of silkworms which would be resistant to pébrine that Trouvelot first imported his experimental gypsy moths into the State of Massachusetts. 134 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE.

At the advice of Professor Berlese, who stated that the gypsy moth is more abundant in the Province of Lombardy than it is in Tuscany, the writer proceeded to Milan, and for some days searched through the woodland regions in that part of Italy, but without success. He then proceeded to Vienna, and at once visited the famous Natural His- tory Museum in that city, interviewed the curator of , Dr. Hans Kebel, and asked his advice concerning a local collector of energy and the proper attainments. Doctor Rebel recommended Fritz Wagner, a young man who is well versed in the subject of the Euro- pean butterflies and moths and knows all of the best collecting places about Vienna. Mr. Wagner readily undertook the work, and accom- panied the writer on several expeditions. The first trip was taken to

FIG. S.-^Olyptapantelesfulvipes and its cocoon, highly magnified (original). the suburbs of the city, and there the writer found his first European specimen of the gypsy-moth larva. It was resting on the trunk of a locust tree by the side of the street (see PI. H), and further examina- tion showed that there were 100 or more caterpillars on the trunk and limbs of the same tree. There was some evidence of parasitism, and the white cocoons of a Microgaster parasite {Glyptapanteles ful- vipes Hal., fig. 8) were found here and there in crevices of the bark. This patticular tree, and another one to be mentioned later, indicate very well the condition of the gypsy moth in Europe.* Although a hundred nearly full-grown larvae were present, there was hardly any evidence of defoliation. A trained entomologist walking by the tree would not have noticed that insects had been feeding upon it to any ^

VARIOUS STAGES OF THE GYPSY MOTH. [1, FiiU-Krown cntorpillars: -', piiim: :i, femiilo moth liiyins I'gg cliisti'r. Xatnral size (nftor Kirkliiml).] Yeiibook U. S. Dept. of Agriculture, 1905 PLATE II.

THE GYPSY MOTH IN THE UNITED STATES AND IN EUROPE. [Abovv, lalxiniliiry luiiMinif in llie iiiwii of SUUBUS. Mass.. for iisi- in ustalilisliiiiK imported i>ara- sitos of llic i,'.vi)sy inolli and tin- Imiwiitail niolji. (Xotiio the true» defolian-d \i\ (typsy-inotli caterpillars.) Below, at left, tree near WaKrain, .\nstri«. infested by caterpillars of the Kypsy moth. Below, at riulit. liKMi.st tree in subiirlw of Vienna, .\usiri«. infested by pypsy moth larv*. (Notice that the trees in the two lower tiiiiires do not show defoliation.) (OriKliial.)] THE OYPSY AND BROWN-TAIL MOTHS. 135 extent. A similar tree in Maiden or Medford would have carried not 100 larvae but probably some thousands, and at that time of the year would hardly have held a whole leaf. These specimens were collected and sent to Boston. Later, a trip was taken into the country, out by the famous battle- field of Wagram, and here on two roadside trees—poplars—was found another colony of the caterpillars, ranging in size from very small ones to full-grown larvae. Here there was more extensive evidence of parasitism b}^ Microgaster parasites, and here again, although there must have been 250 or more larvae on the trees, the evidences of defo- liation were very slight—^so much so that at a rather short distance the trees appeared in full leaf (see PI. II). Later, during the remain- der of June and July, Mr. Wagner continued the search and sent con- sideiable material to Mr. Kirkland at Boston. After Vienna, the city of Budapest was visited. At the Natural History Museum in that city. Prof. Alexander Mocsary was consulted. Professor Mocsary is one of the first authorities of Europe on the sub- ject of parasitic Hymenoptera, but was unable to give any new points in connection with the parasites of the gypsy moth and the brown-tail moth. The writer then visited the agricultural experiment station in the suburbs of Pesth, and there found Prof. Josef Jablonowski, the entomologist of the station. By this time it was the 4th of July, and the season in Hungary was already far advanced, being about two weeks or more earlier there than at Vienna. Professor Jablonowski said that gypsy moths had been found in certain localities in Transyl- vania, but that the adults were already issuing and that the brown-tail moth had been flying for some time. He showed me, however, a large box full of the last winter's nests of brown-tail larvae, and stated that in the early spring he had bred from these nests many hundreds of parasitic insects. This at once indicated to the writer a very easy way of importing such parasites, since these nests can be collected in numbers and sent to Boston in large packages—a bushel or more in a package—in the late fall or winter season, and Professor Jablonowski consented to make every effort the coming winter to send over a large quantity of them. Taking into consideration the small size of the brown-tail moth caterpillars during hibernation, it seems strange that they should be so extensively parasitized as indicated by Jablonowski. The larger caterpillars in the late spring and early summer would seem more likely to be extensively infested. These winter nests of the young larvae, remaining alone on the trees after the leaves have fallen, would seem to be an attractive place for small Hymenoptera of various kinds, and it is likely that many of the specimens considered at first glance as being true parasites of the brown-tail larvae will prove to have been simply other species which have sought the nests for shelter 136 YE AEBOOK OF THE DEPARTMENT OF AGRICULTURE.

during hibernation. Nevertheless the experiment must be tried, and true parasites will probably be gained in this way. Professor Jablo- nowski also promised his best endeavors to send other material during the summer of 1906. Dresden was the next point visited, and through the kindness of Professor Heller, of the Zoological Ethnological Museum, the writer was placed in relations with Mr. Eduard Schöpffer, a trained collector, who was engaged for the work in hand. Although at the date of the first visit to him the season was already considerably advanced—July 7 was the date of the first call—Mr. Schöpffer had breeding cages in operation in his rooms and in these cages were a number of nearly full-grown of the gypsy moth. He knew the localities about Dresden where these insects were to be found, and at once began send- ing specimens to Boston. The forest school at Tharandt, near Dresden, was visited, and Prof. Arnold Jacobi and his assistant, Mr. Behr, were interested in the work, and promised assistance, especially in the mat- ter of sending specimens of Calosoma sycophanta and C, inquisitor during the coming winter. Other trips were made in the vicinity of Dresden, and then the journey was resumed to Zurich, where, through the kindness of Dr. H. H. Field, director of the Concilium Bibliographicum Zoolog- icum, the writer met Miss Marie Riihl, the editor of Societas Entomo- lógica, who is well posted on matters relating to butterflies and moths. Miss Rühl has a large correspondence with entomologists through North Germany, and was engaged as the official agent of the inves- tigation for that part of Europe. She was able, through her own work and that of her correspondents, to send a large amount of material to Boston before the close of the season, and will continue the work. From Zurich the trip was resumed to Paris, where some time was spent in interviewing Dr. Paul Marchai, the entomologist of the agri- cultural school conducted under the ministry of agriculture, and other entomologists, and in visiting the scientific societies for the purpose of interesting naturalists in the work. Many trips were taken to towns around Paris, in search of pupíB of the gypsy moth, and to visit local collectors in search of information, after which the writer returned to the United States via London. The result of the trip has been to demonstrate that it is an easy niatter and a comparatively inexpensive one to import the parasites of these two destructive insects m a living condition into the United States. The most important part of the European range of the two species has been visited, and the entomologists have been organized into an active body of assistants in this undertaking. They will con- tinue the work for the next two years, and the writer, with the consent THE GYPSY AND BEOWN-TAIL MOTHS. . 137

of the Secretary of Agriculture, expects to visit Europe again in the late spring and early summer of 1906 in order to renew the search, to engage new helpers, and to stimulate operations. The^e can be no doubt that during the months to come there will be a continual send- ing of parasitized specimens of different stages of both gypsy moth and brown-tail moth from Europe to Boston. Just what species will succeed in establishing themselves in Massa- chusetts is a question for the future to decide. That some of fhem will so become established there can be little doubt. And, with the European history of these parasites, it seems reasonably certain that, with care to exclude secondary parasites, the primary species will, with the abundance of food to be found in eastern New England, flour- ish and accomplish, at least in a measure, the result hoped for in their importation.

PREPARATIONS MADE FOR THE RECEIPT AND CARE OF THE PARASITES. One of the first 'steps taken by Mr. Kirkland, after consultation with the writer, was to select an old orchard in the town of Saugus badly infested by both gypsy moth and brown-tail moth, where he had a large and strong framework erected over three old infested trees. This framework was tightly covered with wire netting. In this inclos- ure it is proposed to liberate the parasites of both species after careful examination to remove the secondary parasites. Mr. Kirkland then, after carefully examining the whole range of the infested territory, found a spot in Saugus where there was a good-sized house surrounded by woods in which the trees were all infested by the gypsy moth and fronting a dense growth of scrub oak completely infested by the brown- tail moth (see PI. II). A competent assistant has been engaged who will live in the house, one-half being fitted up for laboratory pur- poses. In front of the house stands a large pine tree which, in July, 1905, was completely defoliated by the gypsy-moth larvae, and which when photographed by the writer, September 21, 1905, had put out sparse new leaves. In the laboratory, in glass battery jars, are the puparia of the parasites received so far from Europe. Some of them will be kept out of doors during the winter and the rest in the labora- tor}^, at a low temperature, however. The brown-tail nests which come in during the winter will be kept at a low temperature, and in the spring, when the buds begin to burst outside and the young larvae begin their work, it is probable that the parasites will begin to emerge. At that time one of the expert entomologists of the Department of Agriculture will be stationed at the Saugus laboratory for a time, to make certain that no secondary parasites are liberated. 138 YEAEBOOK OF THE DEPARTMENT OF AGRICULTUEE.

PROSPECTS FOR EVENTUAL RELIEF.

Such is the condition of the experiment in the introduction of the European parasites of the gypsy moth and the brown-tail moth at the time of writing (October 24), and the prospects are on the whole favor-, able for eventual relief. The relief, however, will not be speedy, and property holders in the infested regions must not relax their efforts to keep the injurious insects down. Observations during the past years have shown that the complete defoliation which results from the attacks of the insects will kill certain varieties of trees in two seasons, and if work against the insects be remitted while waiting for the parasites to develop, the consequent loss will be very great.