COWL'

EXPLANATION OF PLATE I.

[Figures 1 to 8, inclusive, natural size.]

Gypsy Moth, Porthetria dispar (L.).

Fig. i.

2.

3

4

5

6

7

8

9

io.

Female with the wings spread.
Female with the wings folded.
Male with the wings spread.
Male with the wings folded.
Pupa.

Caterpillar, 'j

[■ Full grown.
Caterpillar. J

Cluster of eggs on bark.
Several eggs enlarged.

One egg greatly enlarged.

Plate I

‘Jtf rr

>"' Pr~r ff •

6.

Drawn by Joseph Bridgham

GYPSY MOTH.

GeoH."Wa]ker & Co., Boston

The Gypsy Moth.

PORTHETRIA DISPAR (LlNN.).

A Report of the Work

OF DESTROYING THE INSECT IN THE COMMONWEALTH OF

Massachusetts, together with an Account
of its History and Habits both in
Massachusetts and Europe.

By

Edward H. Eorbush,

Field Director in Charge of the Work of destroying the Gypsy Moth,
Ornithologist to the State Board of Agriculture, former
President of the Worcester Natural
History Society, etc.,

and

Charles H. Eernald, A.M., Ph.D.,

Professor of Zoology in the Massachusetts Agricultural College,
Entomologist to the State Board of Agriculture,
Entomologist to the Hatch Experi¬
ment Station, etc.

Published under the direction of the State Board of Agriculture

BY AUTHORITY OF THE LEGISLATURE.

BOSTON :

WRIGHT & POTTER PRINTING CO., STATE PRINTERS.

18 Post Office Square.

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LETTER OF SUBMITTAL.

Boston, Jan. 1, 1896.

To the Massachusetts State Board of Agriculture.

Gentlemen : — We have the honor to submit herewith
the report on the gypsy moth, which has been prepared
under our direction, as authorized by chapter 71, Resolves
of 1894.

Respectfully,

E. W. WOOD,

AUGUSTUS PRATT,

F. W. SARGENT,

J. G. AVERY,

S. S. STETSON,

WM. R. SESSIONS,

Committee on the Gypsy Moth.

CONTENTS

Page

Preface, . ix

The Gypsy Moth, Porthetria dispar (L.).

Part I., E. H. Forbush.

The gypsy moth : its history in America, . 3

Its introduction, . 3

The unnoticed increase of the moth, . 4

Influences that at first retarded its increase, . 5

The first destructive appearance of the moth, . 7

The outbreak of 1889, . 10

The swarming caterpillars become a serious nuisance, .... 14

The destructiveness of the moth, . 23

How the people fought the moth, . 28

The matter brought to the attention of the public at large, .... 32

The commission of 1890, . 38

The work of 1891, . 45

The work of 1892, . 62

The work of 1893, . 68

The work of 1894, . 72

The work of 1895, . .83

The number of men employed and work done, 1890 to 1894 inclusive, . . 89

The increase and distribution of the gypsy moth, . 94

The rate of increase, . 94

Distribution as affected by food supply and other natural causes, . . 97

The connection of distribution and population, . 99

The distribution of the moth by man’s agency, . 100

A study of the methods and routes of transportation, . 106

The effect of the work of extermination on the distribution of the gypsy

moth, . 113

Methods used for destroying the gypsy moth, . 117

The destruction of the eggs, . 117

The destruction of the caterpillars, . 126

Measures for destroying all forms of the moth, . 164

A summary of the methods most useful to the farmer, .... 194

The annual inspection, . 196

Measures for the information of the public, . 198

Natural enemies of the gypsy moth . 203

Insect-eating birds, . 203

Birds seen to feed upon the gypsy moth, . 207

The progress of extermination, . 244

The Gypsy Moth, Porthetria dispar (L.).

Part II., C. H. Fernald.

Scientific and common names, . 255

Bibliography, . 257

Distribution in other countries, . 267

The gypsy moth in England, . 268

Injuries in the old world, . 273

Methods of destroying the gypsy moth in Europe, . 284

vm

CONTENTS.

Page

The eggs . 288

Scattered eggs . 290

Date of hatching . 294

A second brood . 295

The larva or caterpillar . 299

Feeding habits . 311

Process of pupation, . 332

The pupa, . 333

Pupation in the field, . 335

The imago, . 336

Mating . . . 342

Habits of flight . 344

The assembling of the gypsy moth, . 345

On trapping males, . 357

Oviposition . 363

Parthenogenesis, . ... 365

Internal anatomy, . 36S

Natural enemies of the gypsy moth, . . 375

Hymenoptera . 375

Coleoprera . 3S1

Piptera, . 3S5

TIemtptera, . 392

Spiders, . 404

Insectivorous vertebrates, . 404

Vegetable parasites, . 405

Insecticides . 407

Analyses of poisoned larva? . 474

Effects of insecticides on foliage, . 4S9

Analyses of insecticides . 492

Leaf area of trees. . 494

ArrEXBiCES : —

it of* conference held at the rooms of the Stale Board f

Agriculture. Boston, Mass., March 4. 1891, . iii

Appendix B, revised rules and regulations adopted by the Siaie Board of

Agriculture . xx

Appendix C. an extract front a description of Section 8. Medford, as :: appears
in the section book, showing the condition of that section and the

work done in it in 1891 . xxvii

Appendix D. reports of entomologists who visited the infested region in 189? . xxxii
Appendix E, reports of entomologists who visited the infested region in :

opinion of the United Stares entomologist, . xliii

Appendix F. the dangers of arsenical poisoning resulting from spraying with

insecticides, . Iii

Appendix G. a list of correspondents and observers who have furnished in¬
formation in regard to the gypsy moth in Massachusetts. . . . Iviii

PREFACE.

This report is respectfully submitted for the benefit of
the people of Massachusetts, especially those residing in
the district infested by the gypsy moth, who have suffered
from the injuries inflicted by the insect. The design of the
report is to present, within the prescribed limits, as full a
history as possible of what is known about the gypsy moth
in Massachusetts ; also to give a brief r6sum6 of its history
abroad. We have endeavored to present most fully those
features of the subject which are most important from a
practical and economic standpoint. That clause in chapter
71 of the Resolves of 1894 which authorizes the prepara¬
tion for printing “of the scientific facts ascertained” has
been kept in view, and much matter of a more or less scien¬
tific or technical nature, which has come under our notice in
connection with the field work or while making the inves¬
tigations and experiments with which we have been charged,
has been recorded in this volume. The investigations of
the life history and habits of many of those forms of animal
life which exert controlling influences upon the gypsy moth
have not yet proceeded far enough to allow the results to be
fully chronicled. A summary of the results of some of the
most important experiments is given, and, where observa¬
tions have been made by a sufficient number of individuals
to warrant the drawing of conclusions, such conclusions
have been recorded. A further study of the parasites and
enemies of the gypsy moth is in progress.

Part I. of this volume records such of the most impor-

X

PREFACE.

tant results attained by the State Board of Agriculture in
the work of exterminating the gypsy moth as could be in¬
cluded within the limits of the space allowed to the report.
Part II., besides giving the bibliography of the moth and
instances of its injuries in Europe, deals especially with the
“scientific facts ascertained,” and chronicles many of the
more important experiments made with a view of finding
means to check the ravages of the insect and secure its
extermination.

The authors are well aware of many shortcomings in the
work. They have labored under the disadvantage of resid¬
ing in different parts of the State, and therefore have not
had opportunity to consult together and compare notes as
often as was desirable. All responsibility for error in
either part will be assumed individually by the author to
whom that part is accredited. Other duties which were
imperative in their demands upon our capacity for labor
have at times prevented that painstaking revision which
such work requires. Much valuable information has neces¬
sarily been excluded for lack of space. It was impossible,
for instance, to quote fully from accounts of injuries com¬
mitted by the moth in Europe. For the same reason, one
hundred and forty-six statements in regard to the ravages
of the moth, from residents of the infested district in Mas¬
sachusetts, have been omitted. Extracts from some of them
are given, however, in Part I. Most of that portion of
Part I. which is devoted to spraying was prepared in 1894,
and cannot be considered as up to date, as spraying has not
been one of the chief methods employed in the field work
of the last two years.

The Appendices relate largely to the views expressed by
certain eminent entomologists in regard to the work of ex¬
termination. Appendix F, on the dangers attendant on

PREFACE.

xi

arsenical poisoning by spraying, was written by Mr. For-
bush.

The drawings for the insect plates were made by Mr.
Joseph Bridgham, Miss Ella M. Palmer and Mr. J. H.
Emerton. The drawings of appliances and tools were made
by Mr. C. A. King. Messrs. A. H. Kirkland, R. A. Cooley
and C. P. Lounsbury made the drawings for the anatomical
plates. Most of the other drawings were made by Mr.
Kirkland.

We are under obligations to the Boston Woven Hose and
Rubber Company, W. & B. Douglass, Gould Manufacturing
Company, A. H. Nixon and John J. McGowen for cuts
of spraying apparatus ; also to Estes & Lauriat for three
cuts from “ Coues’ Key to North American Birds,” Little,
Brown & Company for three cuts from Baird, Brewer and
Ridgway’s “ North American Birds,” and J. B. Lippincott
for two cuts from “ Birds About Us,” by Dr. C. C. Abbott.

It only remains to perform the pleasant duty of acknowl¬
edging the many favors which have been bestowed upon us
by those who have assisted in the preparation of this work.
Acknowledgments are due to the scores of foreign corre¬
spondents, both eminent naturalists and government officials,
who have furnished information, and also to residents of
the infested district, who have given useful information,
and whose names appear in Appendix G. In our biblio¬
graphical researches we have been most courteously and ably
assisted by the officials of the Boston Public Library and
those of the libraries of Harvard University, Museum of
Comparative Zoology, Arnold Arboretum, Boston Society
of Natural History, Boston Athenteum, Massachusetts Horti¬
cultural Society and Massachusetts Agricultural College.
To Mr. Samuel Henshaw we are especially indebted for
assistance in obtaining many references concerning the

Xll

PREFACE.

history of the gypsy moth in Europe ; and to Dr. F. B.
Stephenson, U. S. N., for the translation of Russian works.

We are greatly indebted to Messrs. J. A. Farley and A.
H. Kirkland for very valuable services in connection with
the preparation of the report. Mr. Farley, who has made an
exhaustive study of the distribution of the gypsy moth, has
contributed the material for that portion of the paper on
distribution which treats of the ‘ ‘ methods and routes of
transportation.” While certain portions of Part II. are
credited in the text to Mr. Kirkland, he has been of great
assistance to the authors in many other ways. Messrs. F.
H. Jones, F. A. Bates and C. W. Minott have rendered
much aid in the way of criticism and suggestion. Lack of
space forbids the mention by name of the scores and even
hundreds of other intelligent observers, more or less per¬
manently connected with the work, who have furnished use¬
ful notes.

The main credit for the production of this volume is due
to the committee of the State Board of Agriculture, who
have for live years conducted the work with the steadfast
purpose of ridding the Commonwealth of the gypsy moth.
They have recommended that the Legislature authorize the
preparation and printing of the report. They have con¬
ferred upon us the honor of preparing the volume, and our
thanks are due to them for endorsement of our plans and
for their constant and consistent support.

THE AUTHORS.

THE GYPSY MOTH.

PORTHETRIA DISPAR (L.) .

IP ART I.

IE. HI. PORBI7SH.

PLATE II. The Trouvelot house, Wo. 27 Myrtle Street, Glenwood, Medford, where the gypsy moth
was first introduced into America. From a photograph taken in 1895.

The Gypsy Moth.

Its History in America.

Its Introduction.

The gypsy moth (Porthetrio dispcir) a pest of European
countries, was introduced into America in 1868 or 1869
by Leopold Trouvelot, a French artist, naturalist and astron¬
omer of note. Prof. C. V. Riley, then State entomologist
of Missouri, recorded the occurrence in 1870 in these words :
“ Only a year ago the larva of a certain owlet moth {Hy-
pogymna dispar) which is a great pest in Europe both to
fruit trees and forest trees, was accidentally introduced by a
Massachusetts entomologist into New England, where it is.
spreading with great rapidity.” *

Though Professor Riley did not then mention Trouvelot
or Medford, the facts were evidently well known to him, as
twenty years later he wrote in “Insect Life” as follows:
“ This conspicuous insect, although not recorded in any of
our check lists of North American Lepidoptera, has un¬
doubtedly been present in a restricted locality in Massachu¬
setts for about twenty years. It was imported by Mr. L.
Trouvelot in the course of his experiments with silk-worms,
recorded in the early volumes of the ‘ American Naturalist,’
and certain of the moths escaping, he announced the fact
publicly, and we mentioned it in the second volume of the
‘American Entomologist,’ page 111 (1870), and in our
‘ Second Report on the Insects of Missouri,’ page 10.” f

In a Bulletin of the Hatch Experiment Station, published
in November, 1889, Prof. C. H. Fernald wrote: “Mr.
Samuel Henshaw and Dr. Hagen of Cambridge have both
informed me that the entomologist who introduced this

* Riley’s Second Report on Insects of Missouri, page 10.
t Insect Life, Yol. II., No. 7, 8, page 208.

4

THE GYPSY MOTH.

insect was Mr. L. Trouvelot, now living in Paris, but at
that time living near Glen wood, Medford, where he at¬
tempted some experiments in raising silk from our native
silk-worms, and also introduced European species for the
same purpose. Dr. Hagen told me that he distinctly remem¬
bered hearing Mr. Trouvelot tell how they escaped from
him after he had imported them.”

Prof. N. S. Shaler of Harvard University, who knew Mr.
Trouvelot, has also stated to the writer that he remembers
hearing Mr. Trouvelot speak of the importation and escape.
Thus we have evidence from eminent scientific authorities
that settles beyond doubt the approximate time and the place
of introduction of this insect, and who was responsible for it.
During his sojourn in Medford Mr. Trouvelot lived in a
house (now known as No. 27 Myrtle Street) near Glenwood
station on the Medford branch of the Boston & Maine Rail¬
road. It is said by people who lived in the vicinity in 1869
that he imported some insects’ eggs about that time, some
of which were blown out of a window of the room in which
•they were kept, and that he was much disturbed on being
unable to find them. Others state that the insects escaped
in the larval form. Probably the insect was imported in the
egg. Its escape seems to have been accidental, and Trou¬
velot, being aware of the dangerous character of the pest,
and finding his efforts for its eradication futile, gave public
notice of the fact that the moth had escaped from his custody.

The Unnoticed Increase of the Moth.

The historian is considerably embarrassed by lack of evi¬
dence in regard to the increase and spread of the moth dur¬
ing the first ten years. No one except Trouvelot is known
to have observed it during any portion of that time. For
most of the evidence of its spread and ravages during the
decade from 1879 to 1889 we must depend on the testimony
of residents of Medford and Malden. Much information
bearing on the subject has been obtained during the past
three years, letters and carefully revised statements having
been received from a large number of people in these cities.

For several years after the moth escaped, it attracted no
attention in Medford. People who witnessed in 1889 the

ITS INCREASE RETARDED.

5

first extensive outbreak of the moth in Medford, and thus
became acquainted with its voracity and reproductive pow¬
ers, were unable to understand how so destructive a creat¬
ure could have existed unnoticed for twenty years. But
the moth was not unnoticed after the first ten years, al¬
though its identity remained unknown and its spreading
attracted no attention outside the locality where it was first
introduced. Within twelve years from the time of its
introduction it had become a serious nuisance to those
living in and near the Trouvelot house ; but they then sup¬
posed the caterpillar to be a native. Its lack of conspicuous
markings, which to the common eye would distinguish it
from other species, and its habits of concealment and night-
feeding will explain its unheeded distribution. Within
twenty years it had spread into thirty townships and gained
a foothold in each without attracting public attention. Of
these facts we have the most convincing proofs.

Influences that at first retarded its Increase.

A study of the growth of many isolated moth colonies
which have been found existing under conditions similar to
those influencing the Trouvelot colony, gives abundant proof
that the growth of such swarms for the first few years is ex¬
ceedingly slow.

The experiments made have not yet shown conclusively
how much the enforced and continuous inbreeding which re¬
sults from isolation affects the vitality of the species. Field
observations show that in some cases isolated colonies have
come very near extinction in the first years of their exist¬
ence, while others have died out. During the eight or ten
years following its introduction, the moth, while becoming
acclimated, battled against the many influences which served
at first to hold it in check. A consideration of the oper¬
ation of these influences will go far toward explaining its
apparently slow increase during the first few years. It must
be considered that the nev -comer had much to contend
against. It had to encounter : —

1. A new and changeable climate. How potent were cli¬
matic influences in controlling the increase of the species?
Such influences may have been felt for years. If the moth

6

THE GYPSY MOTH.

was introduced from France, our harsher climate may have
destroyed many of the smaller caterpillars before they had
attained strength enough to resist exposure to its sudden
changes. A warm period early in the season, followed by a
cold storm or severe frost, sometimes destroys many of the
young caterpillars. They are first hatched by the unsea¬
sonable warmth, and then killed by the cold immediately
following.

2. Isolation, with all its attendant perils. The isolation
of the species and its small numbers rendered it peculiarly
sensitive to the attacks of new enemies which surrounded it.
Parasitic and predaceous insects were no doubt plentiful
then, as they are to-day. The topography of the locality
and the vegetation of the neighborhood were such as to ren¬
der it specially attractive as a breeding ground for insect¬
eating birds. Myrtle Street was then flanked by gardens
and orchards, and nearly surrounded by woodland and bushy
pasture. Not far to the east is a small swamp and stream,
and the whole locality lies near the marshy banks of the
Mystic River. Many of the birds which frequent such places
feed on the gypsy moth in one or more of its forms wher¬
ever it is found. It is related in Samuels’s “ Birds of New
England,” published in 1870, that Mr. Trouvelot, who was
then engaged in rearing silk-worms, placed two thousand of
them on a small oak in front of his house, and that in a few
days they were all eaten by robins and catbirds. He had a
large area of woodland fenced in and covered with netting
to protect his silk-worms. The birds came from all quarters
to feed on the worms, breaking through the netting, so
that he was obliged to shoot them in defence of his “ infant
industry.” * Mr. Trouvelot, in describing his work on the
American silk-worm ( Telea polyphemus), says that it is
probable that ninety-five out of a hundred worms become
the prey of birds. f

At that time the cuckoos, blue-jays, orioles, vireos, cat¬
birds, bluebirds and warblers which are known to feed upon
the caterpillars were also abundant in that locality during
the season when the caterpillars were feeding. The inroads

* Birds of New England, page 156.

t American Naturalist, Vol. I., page 89.

ITS EARLY HISTORY.

7

made at first by birds alone on the comparatively small num¬
ber of caterpillars would have been sufficient to hold them in
check. Fly-catchers secure many of the moths also ; other
birds destroy the pupae. The restraining influence exerted
by birds and predaceous insects would be greater in propor¬
tion when the moths were comparatively few.

3. Forest or brush fires. The locality in which the moth
was first liberated was favorable for its unnoticed increase
and spread, as there were many forest trees and a dense
undergrowth in the vicinity, which afforded it a liberal food
supply. Undoubtedly it was somewhat checked in this waste
land during the first few years by fires, which frequently oc¬
curred in the woodland near the Trouvelot house. Such
fires destroy some eggs of the moth which are deposited near
the ground, and are also very destructive in the spring to the
young larvae. Mr. John Crowley, formerly one of the select¬
men of Medford, speaks of these fires as follows : —

Glenwood, twenty-one years ago, was a thinly settled district
and consisted largely of brush land. There were brush fires there
every year. The fire department was called out twice in one year
because dwellings were in danger. I think the frequent brush
fires held the moth in check for many years, and will explain why
they were so slow in making their appearance in the orchard and
shade trees of other sections.

The First Destructive Appearance of the Moth.

After the first ten or twelve years following their intro¬
duction the moths increased so rapidly that the larvae did
considerable damage in the immediate vicinity of Mr.
Trouvelot’s house, according to testimony of people in the
neighborhood. During the first few years of their abun¬
dance the insects spread along Myrtle Street and into the
woodland and swamp at the south, across the railroad, but
did not for some years become numerous or destructive north
of the street.

That the moth did not increase faster and spread more
rapidly to other parts of Medford is largely due to the efforts
of certain residents of Myrtle Street, who for ten or twelve
years persistently fought the pest on their own property.

8

THE GYPSY MOTH.

That their efforts were finally without avail is true, hut it
might have been otherwise had the moths not remained
unmolested in the woodland near by, from which, whenever
food became insufficient, they sallied out and overwhelmed
the near gardens and orchards.

Mr. William Taylor, No. 19 Myrtle Street, speaking of
the years from 1879 to 1889, said : —

In the fall of 1879 I moved to 27 Myrtle Street, where Mr.
Trouvelot, who brought the gypsy moth to this country, formerly
lived. In the following spring I found the shed in the rear of his
house swarming with caterpillars. I knew that Mr. Trouvelot
had been experimenting with silk-worms, but I did not know that
the swarms of caterpillars in the shed came from the gypsy moth.
The caterpillars were such a nuisance in and around the shed that
I got permission to sell it, and it was taken to Mr. Harmon’s on
Spring Street. This will explain how the moth was carried into
that section, and why the woods there became so badly infested.
I fought the caterpillars of the gypsy moth for ten years before
the State did anything. In their season I used to gather them
literally by the quart before going to work in the morning.

Mr. and Mrs. William Belclier, well-known residents cf
Glenwood, still residing at No. 29 Myrtle Street, have had
the best of opportunities to observe the increase of the in¬
sect in that vicinity. Mrs. Belcher writes as follows : —

Mr. Trouvelot, who is said to have introduced the gypsy moth
into this country, was a next-door neighbor of ours. The cater¬
pillars troubled us for six or eight years before they attained to
their greatest destructiveness. This was in 1889. They were all
over the outside of the house, as well as the trees. All the foli¬
age was eaten off our trees, the apples being attacked first and the
pears next.

Mrs. J. AY. Flinn of Malden, who lived in Glenwood near
Mr. Trouvelot’s house during a part of this decade, says : —

AYe moved to Myrtle Street, Medford, in 1882, and that year the
gypsy-moth caterpillars were very troublesome in our yard and in
those of our immediate neighbors. At that time they were con¬
fined to our part of Myrtle Street, but they soon spread in all
directions. The caterpillars were over everything in our yard and

PLATE III. View of Myrtle Street, Medford, showing the locality where the first outbreak of the moth

occurred in 1889. From a photograph taken in 1895-

ITS FIRST RAVAGES.

9

stripped all our fruit trees, taking the apple trees first and then
the pears. There was a beautiful maple on the street in front of
the next house, and all its leaves were eaten by the caterpillars.
They got from the ground upon the house and blackened the front
of it. . . . The caterpillars would get into the house in spite of
every precaution, and we would even find them upon the clothing
hanging in the closets. We destroyed a great many caterpillars
by burning, but their numbers did not seem to be lessened in the
least. Other neighbors did not fight the caterpillars as we did,
and so our efforts were in a measure rendered abortive. I think
perhaps that if an organized effort had been made at that time to
destroy the caterpillars they might have been stamped out. We
lived on Myrtle Street for four years, and every year had the same
plague.

It should be noted that the Flinn family moved from
Myrtle Street in 1886, having suffered from the pest from
1882 until that time, which was three years before it became
generally prevalent. Although the moths were so numerous
near the Trouvelot house from 1880 to 1885, they did not
become a serious pest farther down the street until about
1886. We quote Mrs. M. F. Fenton : —

In 1886 wc lived at No. 10 Myrtle Street, and that summer we
could not take auy enjoyment out of doors. The caterpillars were
very thick. We destroyed very many of them, but it seemed
impossible to diminish their numbers. They seemed to be mul¬
tiplying steadily. A mere shake of a tree would bring them down
on one in showers. They strip trees very quickly.

Mr. D. W. Daly, No. 5 Myrtle Street, makes the follow¬
ing statement : —

I moved here in 1884, and the next year got quite a crop of
apples. I have three apple trees and a crab apple. In 1886 the
gypsy-moth caterpillars appeared for the first time in any consider¬
able numbers in my yard. Nobody knew what they were. There
were more of them farther down the street. In 1887 they came in
droves, and before June 17 they had my trees stripped as clean as
in December. After stripping the apple trees, they stripped a
Sheldon pear tree as clean as the others. From 1887 to 1890,
inclusive, I got no fruit. The caterpillars worked some little havoc
on the lilacs. I was more fortunate than some others, whose trees
were killed. I spent much time in killing caterpillars. I used to

10

THE GYPSY MOTH.

sweep them off the side of the house and get dustpanfuls of them.
At night time we could hear the caterpillars eating in the trees and
their excrement dropping to the ground. In the morning the walk
would be covered with the latter. I inked my trees in 1888 and
kept them out of the trees to some extent, but not wholly, for
some of them blew into the trees, and they also got into them from
the house. In 1887 I used to sweep them off in solid masses from
the tree trunks. They used to get on the washing and stain it.
Two of my apple trees since that time have never been the same
as regards fruit-bearing qualities. I do not think I saw six cater¬
pillars all last summer.

The Outbreak of 1889.

During the years from 1869 to 1889, while the original
colony of the moths was increasing and extending its terri¬
tory at Glenwood, stragglers therefrom were constantly
scattering abroad to form new colonies. Later these joined
with the parent swarm in forming the multitude which spread
over the town. No particular attention was paid, during
these years, to the moths which appeared here and there, for
it must be borne in mind that the identity of the insect had
been lost, and it was not generally known that there was a
new insect in the land. The introduction of disjpar by
Trouvelot was forgotten or unknown, and wherever shade
or fruit trees were defoliated, the damage was placed to the
account of such old and well-known pests as the canker-worm
or the tent caterpillar.

Gen. S. C. Lawrence, the first mayor of Medford, who
lives on Rural Avenue, a mile and a half to the west of
Myrtle Street, testifying in 1893 at the hearing before the
legislative committee on Finance, said : —

I helped fight it [the moth] for years before the appoiutment of
the commission, not knowing really what it was.

Mr. John Stetson, living a mile to the west of Myrtle
Street, who in 1889 sent specimens of the insect to the Hatch
Experiment Station at Amherst for identification, said : —

I discovered them in 1888 on a quince bush. I noticed one day
that the leaves were all off from this bush. I examined it, and
found there were worms there clustered on the limbs.

MAP I. Map of that portion of Medford where the outbreak of the gypsy moth occurred in 1889. Names
of citizens indicate their residences in localities referred to in the text.

ITS OUTBREAK IN 1889.

11

At last a season arrived, that of 1889, when the moths
became so abundant in Glenwood and in some other parts of
Medford, and the consequent destruction of foliage so com¬
plete, that the food supply gave out. Armies of “ worms”
suddenly appeared in localities wdiere they had never before
been noticed, and seemed about to destroy every green thing.
The growing caterpillars which had devoured the foliage in the
wooded land around Glenwood, being checked on the south
by the salt marsh, moved east, west and north. They re¬
inforced those in the yards and orchards along Myrtle Street,
wdiere most of the foliage had already been destroyed. The
supply of food there being at once exhausted, the caterpillars
marched from yard to yard and from tree to tree, their num¬
bers constantly augmented by those they met, which in quick
succession were also forced by lack of food to join the hurry¬
ing host. Their enforced movements from tree to tree, from
yard to yard, and from one street to another, in search of
food, in the summer of 1889, are well described by the in¬
habitants. It will be seen that there was no general migra¬
tion in any one direction. The movements were local, and
were directed mostly from those points where the foliage had
been entirely destroyed toward others where some still re¬
mained. Such migrations had before been noticed in Glen¬
wood whenever the foliage had been nearly all devoured.
Said Mrs. Belcher : —

My sister cried out one day, “ They [the caterpillars] are march¬
ing up the street.” I went to the front door, and sure enough, the
street was black with them, coming across from my neighbor’s, Mrs.
Clifford’s, and heading straight for our yard. They had stripped
her trees, but our trees at that time wei’e only partially eaten.

Mrs. R. Tuttle, 22 Myrtle Street, writes : —

As fast as we gathered them, others would take their places.
They seemed to come just like a flock of sheep.

Mrs. I. W. Hamlin, corner Myrtle and Spring streets,
said : —

Our yard was overrun with caterpillars. . . . When they got
their growth these caterpillars were bigger than your little finger,

12

THE GYPSY MOTH.

and would crawl very fast. It seemed as if they could go from
here to Park Street in half au hour.

Park Street, by reason of its nearness to Glenwood, soon
became infested by the moth. Mr. F. M. Goodwin, living
at the corner of Park and Washington streets, testifies inter¬
estingly to this : —

Some years ago I saw the eggs of the gypsy moth plastered
thickly on the bark of a willow tree ou Spring Street. A great
many millers were laying their eggs there. The moths later worked
towards Park Street, and my neighbor’s apple trees across the street
wei’e stripped clean, leaving the young apples hanging on the bare
limbs. They crossed from this yard to mine, and I killed pecks
of them. . . . The caterpillars came into my yard by night. I
killed what I could during the day, and the next morning I would
find them as thick as ever.

While the moths were thus travelling to the west from
Glenwood towards Medford Square, others were moving in
all directions from places where they had become established
in former years. They appeared in great numbers on Cross
Street, at the residence of Mr. F. T. Spinney, Medford’s
postmaster, and crossed to the east side of the street. Their
movements there are recorded in the words of people whose
trees and gardens suffered. Said Mrs. Spinney : —

I lived on Cross Street in 1889. In June of that year I was out
of town for three days. When I went away the trees in our yard
were in splendid condition, and there was not a sign of insect
devastation upon them. When I returned there was scarcely a
leaf upon the trees. The gypsy-moth caterpillars were over
everything.

Three other residents of this neighborhood speak as fol¬
lows : —

In 1889 the caterpillars of the gypsy moth appeared at Spinney’s
place on Cross Street, and after stripping the trees there started
across the street. It was about five o’clock one evening that they
started across in a great flock, and they left a plain path across
the road. They struck into the first apple tree in our yard, and
the next morning I took four quarts of caterpillars off of one limb.
(D. M. Richardson, then living at 8J Cross Street.)

PLATE IV. View of Salem Street, near corner of Fulton Street, Medfoid,
showing elm trees which were defoliated in 1889 by the gypsy
moth. From a photograph taken in October, 1895.

LOCAL OUTBREAKS.

13

The caterpillars would travel on the fences in droves, and we
could not go out of doors without getting them all over us. . . .
When the caterpillars had cleaned out Mrs. Spinney’s trees, they
started across the street in droves for the oi’chards on the other
side, and the next morning you could see the path which they had
made across the street. (Mrs. W. H. Snowdon, 7 Cross Street.)

At this time (summer of 1889) they were crossing from Mr.
Spinney’s by multitudes into yards on the other side of the street.
It seemed but a few hours after they left Mr. Spinney’s before
they were all through my trees. They came literally in droves,
and seemed to have a method in their movements. (J. C. Miller,
3 Lauriat Place.)

Another outbreak occurred on Vine Street, one-half mile
from the Trouvelot house. This colony extended north
across Salem Street to Fulton Street. Miss Helen T. Wild,
63 Salem Street, writes : —

In 1889 the apple-trees in our neighborhood were attacked and
stripped by the gypsy-moth caterpillars. They fed on the apple
trees until there was nothing more to eat, and then started for the
elms on the street. In the morning following the night when they
finished the apple trees they were to be seen crossing the fence in
swarms in the direction of the large street elms. They were crawl¬
ing fast, and were plainly heading for the elms.

Mrs. George Fifield of Fulton Street, Medford, first
noticed the caterpillars at the corner of Fulton and Salem
streets. They were then travelling in lines along the side¬
walk. Several of these lines converged upon a large elm at
the corner of the street, and a constant stream of larvre was
ascending the trunk. A day or two later all the trees in the
neighborhood were stripped, and in going toward Glenwood
she found the same condition everywhere.

Mr. J. O. Goodwin, writing in the Medford “ Mercury ”
in 1890, describes the movements of the caterpillars in his
neighborhood on South Street : —

After devastating my neighbor’s trees, they marched in myriads
for my premises, fairly covering the fences, houses, out-buildings,
grass land, currant bushes and concrete driveways with their troop¬
ing battalions. . . . The number of worms cultivated on the three

14

THE GYPSY MOTH.

or four worthless trees on the premises adjacent to my own is
astonishing ; numbers fail to convey an adequate idea. The earth
seemed to be covered with them.

In June, 1889, there were similar local outbreaks over a
tract extending as far as West Medford, two miles to the
westward, and to Edgeworth in Malden, a mile to the east.

The Swarming Caterpillars become a Serious Nuisance.

The number of caterpillars that swarmed over certain
sections of the town during the latter part of June and most
of July, 1889, is almost beyond belief. Prominent citizens
have testified that the “ worms” were so numerous that one
could slide on the crushed bodies on the sidewalks ; and that
they crowded each other otf the trees and gathered in masses
on the ground, fences and houses, entering windows, destroy¬
ing flowering plants in the houses, and even appearing in the
chambers at night. The huge, hairy, full-grown caterpillars
were constantly dropping upon people on the sidewalks
beneath the trees, while the smaller larvse, hanging by in¬
visible threads, were swept into the eyes and upon the faces
and' necks of passers. The myriads that were crushed under
foot on the sidewalks of the village gave the streets a filthy
and unclean appearance. Ladies passing along certain streets
could hardly avoid having their clothing soiled, and were
obliged to shake the caterpillars from their skirts. Clothes
hanging upon the line were stained by the larvte which
dropped or blew upon them from trees or buildings. In
the warm, still summer nights a sickening odor arose from
the masses of caterpillars and pupae in the woods and orchards,
and a constant shower of excrement fell from the trees. The
presence of this horde of gypsy-moth larvae had become a
serious nuisance, and was fast assuming the aspect of a plague.
The condition of affairs at this time is best shown by the
following extracts from statements of residents : —

The caterpillars were worst in 1887, 1888 and 1889. In the sum¬
mer of those years a good portion of my time was occupied in fight¬
ing the pest. The two large elms in front of our house were full
of caterpillars, and had not a perfect leaf. In the night-time the
noise of the worms eating in the trees sounded like two sticks

THE CATERPILLAR PLAGUE.

15

grating against each other. In the months of July and August I
have gone out in the morning and raked up from under the elms
a pile of leaves three or four feet high. These leaves had been
cut off by the caterpillars, and usually there was a worm on the
under-side of every leaf. I would pour kerosene over the mass
and set it on fire, and the squirming of the caterpillars would
cause it to rise up as if it had life of its own. The caterpillars
used to cover the basement and clapboards of the house as high as
the window-sill. They lay in a solid black mass. I would scrape
them off into an old dish-pan holding about ten quarts. When it
was two-thirds full I poured kerosene over the mass of worms and
set them on fire. I used to do this a number of times a day. It
was sickening work. I have used in burning caterpillars five gal¬
lons of kerosene in three days. I have seen my fence black with
the small caterpillars when they first hatched out in the spring. I
used to kill them on the fence by pouring scalding water on them.
The caterpillars used to be very thick in the grass, and there
would be one under every fallen leaf. On certain occasions
callers have had to wait at the front door until I could sweep the
caterpillars off the steps so that they could come in without get¬
ting the worms on their clothing. (Mrs. Thomas F. Mayo, 25
Myrtle Street.)

On the morning of the fourth of July, 1889, my domestic and
myself went around the whole of our fence and gathered ten or
twelve quarts of caterpillars. A little while afterwards they ap¬
peared to be just as thick as ever on the fence. On another occa¬
sion we gathered two quarts of eggs and caterpillars from the
fence on one side of the yard only. ... It is not easy to give
outsiders an idea of how bad the caterpillars were. If the State
had not done something, I honestly think we should have had to
move away from here. For several summers the women folks on
our street made a regular business of killing caterpillars. We got
fairly worn out catching them. I have seen Mrs. Mayo, across
the way, sweep the caterpillars up in the gutter in great piles and
burn them. . . . Another of our neighbors had the whole front of
her house practically covered with caterpillars. One could hardly
go out-doors without getting caterpillars on the clothing. You
could see them travelling about. When they were thickest we did
not pretend to go out the front door at all. We had the front
doorsteps torn up, and found underneath a good many nests.
There were thousands of eggs and caterpillars under the underpin¬
ning of the houses. In 1889 they got into our cellar, and we had
it whitewashed. When the caterpillars were very small they would
get all over the washing when it was hung out. There were no

16

THE GYPSY MOTH.

trees very near, but they would spin down from somewhere. (Mrs.
It. Tuttle.)

In the summer of 1889, while living on Park Street, Medford,
we were literally overrun with the gypsy moth caterpillars. That
summer we could have got the caterpillars out of the holes in the
trees by pecks. After the caterpillars ate all the leaves off the
trees, they went down into the grass, where they swarmed. When
the plague was the worst that summer, I do not exaggerate when
I say that there was not a place on the outside of the house where
you could put your hand without touching caterpillars. They
crawled all over the roof and upon the fence and the plank
walks. We crushed them under foot on the walks. We went
as little as possible out of the side door which was on the side
of the house next to the apple trees, because the caterpillars
clustered so thickly on that side of the house. The front door
was not quite so bad. We always tapped the screen doors when
we opened them, and the monstrous great creatures would fall
down, but in a minute or two would crawl up the side of the
house agaiu. When the caterpillars were the thickest on the trees,
we could plainly hear the noise of their nibbling at night when all
■was still. It sounded like the pattering of very fine rain-drops.
If we walked under the trees we got nothing less than a shower
bath of caterpillars. We had a hammock hung between the trees
that summer, but we could not use it at all. The caterpillars
spun down from the trees by hundreds, even when they were of
a large size. We had tarred paper around the trees, but they
crawled up the trunks in masses and went right over the paper.
The bodies of those that got stuck in the printers’ ink served as a
bridge for their brethren. The caterpillars were so thick on the
trees that they were stuck together like cold macaroni. A little
later in the season we saw literally thousands of moths fluttering
in the back yard. In the fall the nests were stuck all over the
street trees. (J. P. Dill, then living on Park Street.)

No one who did not see the caterpillars at that time can form
any idea of what a pest they were. They got into the strawberry
bed (although they did not eat the leaves), and I used to go out
with a dustpan and brush and sweep them up by the panful. It
seemed to us absolutely necessary to go out daily and make an
effort to at least lessen their numbers. We killed many with boil¬
ing hot water, and would then dig a hole and bury them, so as to
prevent a stench. Mr. Belcher was poisoned by them. While
killing them upon the trees they would get upon his neck and blis¬
ter and poison it. It was impossible to stay long in the garden,
for they would crawl all over one. We fought them for two or

THE CATERPILLAR PLAGUE.

17

three years before the commission took hold. When they hatched
out in the spring our fence would be one living mass. My sister
and myself blistered the paint all off the fence with the scalding
water that we poured on. When they were small it was almost
impossible to keep them off one’s person. It is a fact that we have
scraped a quart of eggs at a time off the trees. We did the best
we could to keep them down, but we could not get them all, for
many would hide away and lay their eggs. (Mrs. William Belcher.)

In 1889 the walks, trees and fences in my yard and the sides of
the house were covered with caterpillars. I used to sweep them
off with a broom and burn them with kerosene, and in half an hour
they would be just as bad as ever. There were literally pecks of
them. There was not a leaf on my trees. Back of the house and
across the railroad track was a large tract of young-growth oaks
and maples. They were all stripped. The caterpillars did not
leave a leaf. The trunks and branches were covered with their
cocoons. The cocoons hung in bunches as big as a pint dipper.
The stench in this place was very bad. (Mrs. S. J. Follansbee,
35 Myrtle Street.)

When the caterpillars were small they would spin down on their
threads and blow out into the street or even entirely across it.
The caterpillars were a dirty pest. You could hardly go out of
doors or sit down anywhere without getting them over you. Trees
were either completely stripped so that not a green thing was to
be seen on them, or else were eaten so that the skeletons of the
leaves only remained. The caterpillars were very numerous on a
large tree behind my house. I have scraped them off by the quart
ou the fence and shed adjoining the tree. They clustered as
thickly as bees swarm. Before caterpillar time we used to see
bodies of trees plastered all over with their egg clusters. They
were so thick on certain trees that they reminded me of shells at
the sea-shore. (J. H. Rogers, 17 Spring Street.)

I lived on Spring Street when the caterpillars were thickest
there. The place simply teemed with them, and I used to fairly
dread going down the street to the station. It was like running
a gantlet. I used to turn up my coat collar and run down the
middle of the street. One morning, in particular, I remember that
I was completely covered with caterpillars inside my coat as well
as out. The street trees were completely stripped down to the
bark. . . . The worst place on Spring Street was at the houses of
Messrs. Plunket and Harmon. The fronts of these houses were
black with caterpillars, and the sidewalks were a sickening sight,
covered as they were with the crushed bodies of the pest. (Sylvester
Lacy, 9 Daisy Street.)

18

THE GYPSY MOTH.

They [the caterpillars] were so numerous that when they clus¬
tered on the trunks they would lap over each other. A neighbor
gathered in one day in my yard a peck of caterpillars, and poured
kerosene over them and set the mass on fire, but man}? neverthe¬
less walked away from the burning mass. ... I used to scoop
them off the sides of the house and the tree trunks with a dustpan.

. . . Their eating in the trees sounded just like a breeze. Many
got into the house, and we could not open the windows. I found
them in the kitchen and in the bedrooms. I used to find them in
the beds when I turned down the blankets. (Mrs. Spinney.)

In the summer of 1889 the gypsy-moth caterpillars attracted uni¬
versal attention in Medford. They spread very fast over the town.

I believe there were enough that summer to have caused the destruc¬
tion of all the green leaves in town by the following year, had
their spread not been checked. During the summer the caterpillars
were found in great numbers on South Street and in the eastern
section of the town. Myrtle, Park and Pleasant streets and
Magoun Avenue were overrun with the pests. Nobody knew what
these caterpillars were until they had been identified in Amherst.
They clustered on the bark of the South Street elms in multitudes.
From the ground clear to the tops of the trees they lay thickly in
the rough bark. (Ex-Selectman John Crowley.)

The caterpillars were everywhere. They would get under the
doorsteps and on the window-sills and even into the house. We
found them under tables and even under the pillows. The windows
could not be opened unless guarded by a screen. . . . When the
caterpillars were full grown they would herd in great patches on
the trunks. I have seen the end of Mrs. Spinney’s house so black
with caterpillars that you could hardly have told what color the
paint was. In moth time I have seen the moths (it almost seemed
by the bushel) crawling and fluttering around the bases of the
trees. (Mrs. Snowdon.)

In 1889 the trees on South Street were full of caterpillars.
People did not know what they were at first. The four large
street elms in front of my house were covered with them. . . .
The sidewalk under one elm was covered with caterpillars which
had dropped off. They were so thick on the tree that they had
apparently crowded each other off. The front railing of Mr.
Archibald’s house on South Street looked as if it was covered with
mud, the caterpillars were so thick on it. (F. E. Foster, 20 South
Street.)

I remember being at Judge Hayes’s, South Street, one evening
in the summer of 1889. Mrs. Hayes came in and said that she
“ never saw such a sight” in her life as the caterpillars presented.

THE CATERPILLAR PLAGUE.

19

We went out and found the fence rails literally covered with
caterpillars. You could not set your foot down on the walks
without crushing the worms. We took shingles and scraped
quantities off the trunks of the big street elms. People used to
scrape them off into piles and then burn them with kerosene.
(Ex-Selectman W. C. Craig.)

The caterpillars covered one side of my house so thickly that you
could not have told what kind of paint was on it. It was impos¬
sible to keep them entirely out of the house. The women had to
shake their clothing when they went into the house. People used
to come from other parts of Medford to Myrtle Street just to see
the ravages of the insect. (J. C. Clark, 11 Myrtle Street.)

The caterpillars were so thick in the trees that you could hear
them eating. They would get on the fences, until they made them
fairly black. They would crawl upon and into the houses. They
would get inside somehow, and it was a common thing to see them
crawling on the table, and we have even found them on the beds.
They would get under steps, stones, and into old stove-pipes, old
cans, boxes, in short, any place which afforded a shelter. They
crawled into the cellar windows. They were so thick on the street
trees that people would walk out in the middle of the street, where
there were fewer dropping down. It is no exaggeration to say
that I have raked quarts of caterpillars off a tree. ... I have
seen them crawling in great numbers on the rails of the Medford
branch track. After a train had gone along, the rails would be all
green with their crushed bodies. (William Taylor.)

In the old days, when the caterpillars were so bad, the houses
and fences were blackened with them. We used to sweep them off
into a basin of kerosene. As you went up and down the street
you would see no foliage except on pear trees. If you carried a
sunshade down the street, the caterpillars would get all over it.
(Miss R. A. McCarty, 26 Myrtle Street.)

I recollect one elm tree in particular on Park Street which stood
against the fence. There was an inked band around the tree, and
about two quarts of gypsy-moth caterpillars had collected below
the band. Some of the caterpillars had got over the band, and
they had spun threads which served as ladders by which the others
were crossing. (F. M. Goodwin.)

We could not sit under the Porter apple tree, the caterpillars
were so thick on it. They swarmed on the ground at the foot of
the Baldwin. We poured boiling water on them. The fence was
one mass of caterpillars, and they lay thickly under the clapboards
and gutters. Our apple trees were stripped two years in succession.
(Mrs. John Benson, 3 Cross Street.)

20

THE GYPSY MOTH.

About four to five p.m. they [the moths] flew about in thousands.
Later in the season (1889) their eggs could be seen in clusters on
the stone walls, fences, buildings and trees in great numbers, often
nearly covering such objects. (James Bean, High Street.)

Nothing too bad can be said of the caterpillars. If you sat down
anywhere you would crush caterpillars. If the washing was hung
out under trees infested with them, they would get on and stain
the clean clothes. They were all over the sidewalks, and would
drop down upon one from the trees. (Miss R. M. Angelbeek,
24 Myrtle Street.)

In 1888 and 1889 the gypsy-moth caterpillars were a terrible
pest on Cotting Street and in that neighborhood. In a neighbor’s
yard [Mr. Rugg’s] they brushed off of one apple tree at one time
fourteen quarts of caterpillars. (Almon Black, 10 Cotting Street.)

The elm trees in our yard were badly eaten by the gypsy-moth
caterpillars. The ribs of the leaves alone were left. In the after¬
noon, when the sun got low, the caterpillars in the trees would get
into the sun, and you could see the long line of them stretching
away up the tree trunk. (Miss A. B. Bookman, 21 Franklin Street.)

The willows at the corner of Magoun Avenue were completely
stripped for two years in succession. The moths were so thick at
one time under the willows that I have collected them by the hand¬
ful and fed them to my hens. (Walter Sherman, 23 Spring Street.)

In the evening we could hear the caterpillars eating in the trees.
It sounded like the clipping of scissors. We kept the caterpillars
down in our yard as much as possible, but it was discouraging to
see them coming straight across the street in droves to our yard.
They almost seemed to have a concerted plan of action. (Mrs.
M. M. Ransom, 18 Lawrence Street.)

The trees of our next-door neighbor, Mr. Randall, suffered very
much. The caterpillars got into his evergreens, and were so thick
that they made them look black. (Mrs. Hamlin.)

In 1889 the brush lot at the corner of Lawrence and Spring
streets swarmed with gypsy-moth caterpillars, and the young oaks
were all stripped bare. Our house stood next to the brush lot.
The caterpillars got upon the outside in great numbers, and we
also found many inside. (J. G. Wheeler, Daisy Street.)

The outside of my stable was literally black witli caterpillars at
the time when the gypsy moth was the thickest in this section. It
was a disgusting sight. (R. Gibson, 5 Lawrence Street.)

The year before the State began fighting the gypsy moth, I visited
an acre of brush land in Glenwood, where the nests of the moth
wrere laid by the hundred on stumps, bush stalks and other objects.
This was in the fall of 1889. (J. Sherman, 76 Riverside Avenue.)

THE CATERPILLAR PLAGUE.

21

The caterpillars were thickest iu Glenwood, where in places they
were like a carpet on the ground. Since the State took hold of
the matter the trees have been in good condition, and excellent
work has been done. (G. C. Russell, 11 Washington Street.)

The caterpillars were a sickening sight when they were at their
thickest. They used to make a living path, as it were, from the
ground up into a tree. (Richard Pierce, foreman of the Sparrell
estate, No. 90 Main Street.)

We did what we could in our neighborhood to fight the cater¬
pillars, but they were so thick that one hated to go out of doors
or on the street. We could plainly hear them at night eating in
the trees. (Miss Helen T. Wild.)

Many a time I have swept the caterpillars off by the dustpanful
from the underpinnings of the house. (Mrs. E. M. Russell, then
living on Cross Street.)

In 1889 our apple, pear and crab-apple trees were all stripped
by the gypsy-moth caterpillars. They either bore no fruit or else
bore so late that the frost destroyed it. When the caterpillars
were small we could see them in the daytime spinning down from
the trees. At night you could not dodge them, and they would
get into your neck and eyes. (F. H. Haushalter, 42 Myrtle
Street.)

A few years ago the caterpillars were terrible in Glenwood.
You could not go down Myrtle Street without getting your shoul¬
ders covered. . . .We spent hours killing caterpillars, but there
seemed to be two to every one Ave killed. (A. P. Perry, Myrtle
Street.)

I believe that, had the State taken no action in this matter, they
would have increased to such an extent that they would have bred
a pestilence in our country. They soon greAV to the size of your
finger, and the stench that arises from them when they are in large
quantities is nauseating. (W. W. Fifield of Medford, before the
legislative committee on Agriculture, Feb. 27, 1894.)

Before public measures were taken in the matter, the foliage
Avas completely stripped from all the trees in the eastern part of
our toAA’n, presenting an aAvful picture of devastation, and promis¬
ing in a short time to kill eATery tree and shrub and all Aregetation
in any region visited by the creatures ; which shows how inade¬
quate individual effort was to cope with the subject. (J. O. Good-
Avin, Medford.)

People who wished to avoid the plague by removing to
other towns or localities are said to have had some difficulty
in disposing of their homes on account of the desolate appear-

22

THE GYPSY MOTH.

ance of the surroundings and the disgusting presence of the
caterpillars.

The bad condition of this section as regards the gypsy-moth
plague was detrimental to real-estate valuations. (Mrs. Mayo.)

The gypsy-moth plague hurt property in this section. Our
house was advertised for sale, and when people came to look at
the property they were apt to inquire why the leaves of the trees
in the neighborhood were so badly eaten. When we told them it
was the work of caterpillars, they would say that they would not
live in such a locality. (Mrs. Flinn.)

The condition of the Edgeworth district of Malden in
1889 was similar to that of Glenwood. Space permits but
a few statements of residents : —

The first year that the caterpillars were very bad was in 1889.
They took the leaves off the trees so that they were as bare as in
midwinter. We could not sit out on the lawn a minute, for the
caterpillars would be all over one. My son used to climb a shade
tree in front of the house and shake the caterpillars off. We
would put a sheet underneath, and they would come down in
showers. The top of the fence was covered so thickly with cater¬
pillars that you could not put a pin between them. The apple
trees in the yard next to ours were stripped. The ribs of the
leaves were left, and they looked ghastly. They leafed out again
in June, but they bore no fruit. We used to gather the cater¬
pillars in a dustpan and put them in a pail. When the pail was
full we would dump them out and burn them with kerosene. Our
next-door neighbor, Mrs. Cahill, used to devote much time to
killing the caterpillars. She would sweep them off the fence with
a broom and burn them. We would see them in droves on the
ground coming and going. (Mrs. John Dowd, 194 West Street.)

In 1889 we were overrun with caterpillars. We did not know
what to make of them. During that summer I could not use my
front door, they were so thick around it. They were as thick as
leaves. We had four apple trees, and they were stripped entirely
bare. A second growth of leaves came out, but we got no fruit.
For three years there was not an apple nor even a blossom on the
trees. We could not have endured the plague, had the State not
done something. (Mrs. Daniel Kelly, 209 West Street.)

In 1889 the caterpillars were very bad. Every leaf was taken
off my sycamore tree. I used to go out with a hoe and scrape the
caterpillars off the trunk. If I sat out on my steps after dark

ITS DESTRUCTIVENESS.

23

I could bear them eating iu the tree. My other trees were also
badly eaten. (Mrs. Margaret Cronin, corner of Oakland and
Sheridan streets.)

The trees in the lower part of Edgeworth were badly eaten by
the gypsy-moth caterpillars in 1889. They were thick on Oakland
and Malden streets and the Common. (T. J. Neville, Pearl
Street.)

In 1889 we had as many caterpillars as anybody. You could
take a knife and scrape them off the trees. (Mrs. Margaret Con¬
nell, 97 Malden Street.)

The Destructiveness of tiie Moth.

The caterpillars devoured the foliage of nearly all species
of trees and plants in the worst infested region. During the
years when the moth was most abundant, the destruction of
or injury to fruit, shade and forest trees and fruit and garden
crops was of course greatest. The destruction of trees was
greatest in those localities w here the moth had been longest
abundant, for, though the smaller plants were often killed in
one season as were also the less hardy trees, those trees
which were lusty and vigorous would frequently withstand
defoliation for two or three successive years before they finally
gave up their hold on life. Thus the trees and gardens of
residents of Glenwood suffered more in these respects than
those of people in other parts of Medford.

Trees Killed.

In some cases where shade trees near dwellings were at¬
tacked they became such a nuisance as a harboring place for
the caterpillars that they w^ere cut down while still alive, as
the only practical means of abating the nuisance. Fruit trees,
however, were generally allowed to stand, and a fight was
made to save them, which was in some cases successful, but
in others all efforts to check the ravages of the moth and
save the trees were futile. They finally died, were cut down
and the stumps rooted up.

The statements following are given in the words of people
whose trees suffered : —

We had three apple trees, four pear trees, one plum tree and one
mountain ash killed by the gypsy-moth caterpillars. These trees

24

THE GYPSY MOTH.

were stripped of their foliage in the summer of 1887. They began
to leaf out again late in the season, but were immediately stripped.
The apple trees also put forth a few blossoms at this time. The
following year they did not leaf out at all. They all died, and we
cut them down. The apple trees were good-sized trees. One was
a spice greening, another a Porter and a third an August sweeting.
We also cut down a little locust tree which was badly eaten by
the caterpillars, and the limbs of which died. The caterpillars
swarmed in a tall Norway spruce in our back yard. They ate
every bit of foliage on this tree, so that we had to cut all the limbs
off. Nothing but the pole of this tree remains in our yard to-day.
This tree was so full of caterpillars that when I shook a limb with
a rake they would fall off in a shower and blacken the ground.
There were so many of them that it sounded like pebbles falling.
In addition to the trees, our currant bushes were stripped by the
pest. (Mrs. Mayo, next-door neighbor of Trouvelot’s.)

The moths ruined me as regards fruit. They were worst in
1889. Their ravages caused me to lose five nice apple trees, two
cheiTy trees, one pear tree and five plum trees. ... I had a crab-
apple tree that blossomed very full that spring, but the caterpillars
covered it, and it died. One of the apple trees which the cater¬
pillars killed was a beautiful Hubbardston. Some years I would
get four barrels off of it to put away. All you will see of it to¬
day in my yard is the stump, over which we train nasturtiums.
The spring following the ravages of the moth these trees leafed out
a little, but not much, and finally died. (J. C. Clark.)

In 1889 we lost three apple trees because of the caterpillars.
They were stripped clean, and then leafed out and bloomed again
in September. The next spring they leafed out a little, but did
not bear, and finally died. (L. M. Clifford.)

In another yard two large apple trees were stripped by the
caterpillars, and died. The way this was brought about was as
follows : the caterpillars stripped the trees early in the season,
and, as they continued their ravages for nearly the whole summer,
the trees had no chance to recover. The next year the trees
would leaf out and be stripped again, and so on, until, unable
longer to withstand such treatment, they died. (Almon Black.)

Our next-door neighbor, Mrs. Kelly, had a fine Baldwin apple
tree which the caterpillars stripped clean. They kept it stripped.
One year it blossomed twice. It leafed out and blossomed and
was stripped, and then leafed out and blossomed and was stripped
again. Finally it would leaf out and blossom once, perhaps, and
then it would leaf out but not blossom, and last year only one
branch leafed out. The tree is nearly dead. This tree stood very

PLATE V. Residence of J. C. Clark, No. 11 Myrtle Street, Medford. The
picture shows a portion of the yard formerly occupied by
fruit trees killed in 1889 by the gypsy moth.

TREES KILLED AND CUT DOWN.

25

near our window, and as we ate supper in the early evening we
could distinctly hear the caterpillars chewing among the leaves.
In the night-time I have frequently heard their “ chip-chip¬
chipping ” out in the shade trees on the street. In a yard adjoin¬
ing ours there is another apple tree which is more than half dead
because of the ravages of the caterpillars. It used to bear
splendid Baldwins, but last year there were not more than a dozen
apples on the tree. The caterpillars used to strip it twice a year
up to two years ago, when their numbers were greatly reduced.
For two years in succession the caterpillars stripped two maple
trees in front of our house. They ate all of the leaf except the
ribs. We had two shade trees cut down which were in a dying
condition because of the ravages of the caterpillars. This was
some five or six years ago. On Otis Street also we had two trees
which we cut down because the caterpillars ate them so badly.
In Mrs. Kelly’s yard there was a large balm of Gilead tree which
was cut down because it was nothing more or less than a breeding
place for the gypsy moth. The tree was a sight. The trunk and
limbs were black with caterpillars. The tree stood close by Mrs.
Kelly’s house, and you can still see the discoloration under the
eaves where the caterpillars clustered so thickly. Mrs. Meach,
across the way, had a weeping willow cut down. (Mrs. Tuttle.)

One of our sweet-apple trees died from the effects of the strip¬
ping by the caterpillars. The branches died one by one, but we
let it stand one year, hoping that it would revive, but it did not.
Our four Baldwin apple trees bore good crops until the caterpillars
attacked them. By June you would not see a leaf on them, and
they would remain in that leafless condition all summer. In the
fall of 1892 we got our first crop of apples in seven years. (Miss
R. A. McCai’ty.)

A young maple wThich had been set out on the street in front of
our house was stripped by the caterpillars and died. ... A young
peach tree died, apparently because it was stripped by the cater¬
pillars. (Mrs. Flinn.)

Two oaks on the street in front of our house were entirely
stripped. The next year they did not leaf out, and were cut
down. (J. W. Harlow, 58 Spring Street.)

We cut down two cherry trees in our own yard because there
were so many eggs, cocoons, etc., in the seams and holes. (Mrs.
Snowdon.)

I cut down three tall poplars in front of No. 19, where I now
live, because they were so badly infested. I also cut down an
apple tree because it attracted so many caterpillars and was so
badly eaten. (William Taylor.)

26

THE GYPSY MOTH.

I had several balm of Gilead trees cut down because they were
so badly eaten by the caterpillars. (Walter Sherman.)

Our four apple trees which we cut down because of the pest
yielded the year before eleven or twelve barrels of fine Baldwin
apples. (J. P. Dill.)

An apple tree was stripped twice, and we had no fruit. The
caterpillars so nearly killed the tree that it has since that time
borne very little. (Miss C. E. Camp, 28 Myrtle Street.)

Fruit , Garden Crops and Flowering Plants Destroyed '.

The caterpillars destroyed not only the foliage of trees,
but also fruit and vegetables. The long period of feeding
made it possible for the larvae to secure a great variety of
food. When the supply of leaves in the trees fell short (and
oftentimes before) they attacked the gardens. Little was
spared but the horse-chestnut trees and the grass in the fields,
though even these were eaten to some extent. There was
evidently some choice exhibited ; for instance, pear trees
were not so badly injured as the apple, but eventually most
forms of vegetable life in the caterpillars’ path were either
injured or entirely destroyed.

When fruit trees were stripped of their leaves, the imma¬
ture fruit either failed to develop or dropped from the tree.
In some cases the fruit itself was partially eaten by the vora¬
cious caterpillars. The destruction of berries was often as
complete. Many vegetables were ruined. Flower gardens
were destroyed, and even greenhouses were invaded and rose
bushes and other flowering plants eaten. Our space per¬
mits but a portion of the evidence of such devastations in
Medford : —

They [the caterpillars] ate nearly everything green in the yard,
killing my rose bushes and doing much damage to the vegetables.
(Mrs. Belcher.)

I had quite a little vegetable garden, which was nearly ruined by
the caterpillars. They destroyed the cucumbers and ate the tops
of the tomatoes. They also destroyed some flowering plants.
(Wm. B. Harmon, 5 Spring Street.)

They [the caterpillars] even nibbled the young green pears, and
I lost a good man}? in that way. My large cherry tree, which usu¬
ally bears two bushels, was stripped clean for two years running,
and I got no fruit. The caterpillars ate all the young tomato vines

Apple trees that worn sprayed. twico wit.li Purls green and afterward stripped by the gypsy
moth caterpillars. Prom a photograph taken In Swampscott, Aug. 5, 1801.

GARDEN CROPS DESTROYED.

27

and injured my rose bushes. . . . For three years previous to 1891
my Baldwin apple tree bore no fruit on account of the ravages of
the moth. It was stripped every year. (Mrs. Follansbee.)

At my place on Woburn Street I had a small bed of spinach
and dandelions which the caterpillars completely destroyed. My
tomatoes suffered a like fate. (Ex-Selectman Craig.)

In 1889 I had twenty-seven hundred young carnation pinks set
out of doors, and the biggest part of them were destroyed by the
caterpillars. This was in June. They were eaten off close to the
ground. In 1890 the gypsy moth appeared in my greenhouses,
and the foliage of the bushes in one rose house was completely
eaten up. (A. W. Crockford, 81 Spring Street.)

It was almost impossible to have plants or green things of any
sort. The caterpillars would eat anything that they could get hold
of. The rose bushes were stripped. My mother plants yearly
beans, peas, etc., but that year we did not get much from them.
The parsley also was almost all eaten. (Miss R. M. Angelbeek.)

The rose bushes were completely stripped, all the leaves and
blossoms being lost. Despite the utmost efforts of two of us, it
was impossible to keep the rose bushes free of caterpillars. They
were very fond of the deutzias in the garden, and completely
ruined them. (Mrs. Ransom.)

They seemed particularly destructive to the Porter apple tree.
The apples very largely fell off, and the inside of those that re¬
mained on the tree was not fit to eat. . . . The caterpillars ate
the leaves of a white rose bush and a syringa in our yard, and the
latter died from the effects of the stripping. (Mrs. Benson.)

Our vegetable garden was practically ruined by them, peas,
beans, corn, etc., being eaten. The garden of our next-door
neighbor, Mr. Camp, suffered a like fate. . . . Our raspberry
bushes were also stripped of their leaves. We lived later on
Lawrence Street, and here also the caterpillars were trouble¬
some. An umbrella bush in the yard was killed by them. (Mrs.
Flinn.)

My usual apple crop was from fifty to one hundred barrels
yearly ; but the second year of the caterpillar plague I did not
get more than forty barrels. The third year I do not think I got
more than thirty barrels. (D. M. Richardson.)

After they had eaten the foliage of trees, the caterpillars would
devour almost any green thing. (J. N. French, 7 Lawrence
Street.)

They were the most ravenous worms I ever saw. They wrould
eat almost everything, taking the apples and the elms first.
(John Cotton, 16 Cotting Street.)

28

THE GYPSY MOTH.

The caterpillars ate almost everything, feeding on small fruits
and shrubbery as well as the trees. (Almon Black.)

Our blackberry and raspberry bushes were badly eaten, and we
got but little fruit from them that summer [1890]. (J. W.

Harlow. )

After eating the foliage of the trees, the caterpillars would at¬
tack the vegetables. (J. G. Wheeler.)

The caterpillars even ate the grape-vine to some extent.
(William Taylor.)

How the People fought the Moth.

No doubt the citizens of Medford did all that the people
of any community would have done individually in fighting
the pest. Many of them owned their homes, and gave much
attention to the care of their grounds. Each householder
had a small lot of land, and most of them had gardens or
small orchards to protect from insect ravages. There were
many people in a given area each of whom had an interest
in protecting his own small portion of that area. Many of
these people spent most of their leisure time during the sum¬
mer months in fighting the caterpillars, killing great numbers
of them. The number thus killed on Myrtle, Spring, Wash¬
ington, Park and Cross streets during a summer must have
checked considerably the increase of the moth. Many peo¬
ple banded the trunks of their trees with tarred paper, to
which they applied tree ink as a protection against the mi¬
grating worms. This was a partial success, if the bands
were carefully watched and the caterpillars which gathered
below them killed in time to prevent their crossing the bands
by mere force of numbers. A considerable part of the fruit
crop was saved in some orchards in this way, the tree ink
having the effect of turning many caterpillars away from
banded trees to those left unhanded. Yet, in spite of all
checks, the moths on Myrtle Street increased and spread so
as in time to overwhelm the town. It is known that people
there fought them with fire, water and coal oil from five to
eight years before they became prevalent in other parts of
Medford.

Extracts from statements graphically describing the meth¬
ods used are given herewith : —

FOUGHT BY THE PEOPLE.

29

Many citizens scraped off all the caterpillars that they could,
and killed them. The caterpillars were scraped off in masses as
high up as a man could reach. Some people burned them off by
means of a rag soaked in kerosene and tied to a pole. (Ex-
Selectman Crowley.)

At the time when the gypsy-moth caterpillars were thickest in
this neighborhood I used to spend all my leisure time fighting
them, and then failed to keep them down. . . . We used to take
a can with a little kerosene in the bottom and pick the caterpillars
off into it and later bury them in the ground. In a half-hour I
have picked a canful off one apple tree. (Mrs. Ransom.)

The caterpillars were of an enormous size, and would lie in clus¬
ters on the tree trunks. We used to scrape them off into a pail.
(Mrs. Charles A. Lawrence, then living at 10 Cotting Street.)

We used to destroy the caterpillars on the fences by pouring
scalding water on them. We burned with kerosene those in the
trees. We would go out several times a day and kill them. We
also used to scrape them off into cans. (Mrs. A. H. Plummer,
14 Lawrence Street.)

We spent hours killing caterpillars on them [street elms]. We
would get two quarts off at a time. They were very large. They
got into every crevice and under every piece of bark. Our neigh¬
bor across the way, Mrs. Turner, used to go out with a pail of hot
water and poke the caterpillars into it with a stick. My son used
to tie a rag soaked in kerosene around a pole and set it on fire and
singe them off the trunks of the trees. (F. E. Foster.)

I put a piece of stout paper about a foot wide around the tree at
my place for the gypsy-moth larvae to go under. I visited it a
number of days later and found the trunk of the tree under the
paper to be entirely covered with the insects. There were hun¬
dreds of them. A neighbor, Mr. Dutton, tried a similar experi¬
ment with a strip of carpet, with like results. (James Bean.)

We used to take lighted candles and run them along under the
fence rails and scorch the eggs there. (Miss R. M. Angelbeek.)

I had charge of this estate [Sparred estate, Main Street], and I
killed a great many caterpillars by brushing them off the trees with
a broom and crushing them. After brushing them off the trees, I
would wait half an hour and then there would be just as many
again on the trees. I could have gathered a half-bushel of cater¬
pillars every evening through their season. (Richard Pierce.)

I used to burn them in the trees with torches. . . . We killed
them on fences with boiling water. (Mrs. Spinney.)

We used to sweep them off into a dustpan and burn them, but in
a short time they would be as thick as ever on the tree again. . . .

30

THE GYPSY MOTH.

The next spring (1890) I found the apple trees in my own yand
were pretty well infested with nests. I had my hired man scrape
them all off with a putty knife. We collected them in a dish and
burned them up in the furnace, where they snapped and crackled.
(J. E. Wellington, Wellington.)

I fought the caterpillars in my own yard by placing cloths in
the crotches and around the trunks of the trees. The caterpillars
collected in great numbers under the cloths, and were then easily
destroyed. (S. F. Weston, 11 Fountain Street.)

We had both the steps and the fence split up and burned, so
as to deprive the pest of its harboring places. I have frequently
gathered half a coal-hodful of caterpillars from the fence within a
short space of time. In twenty minutes they seemed to be just as
thick as ever. We burned many pecks of them in all. (William
B. Harmon.)

In the evening, after the men had come home from work, you
could see fires in all the yards, where they were burning cater¬
pillars. (Mrs. Fenton.)

For four or five years I fought the gypsy-moth caterpillars, as
did my neighbors, but could not keep them down. . . . By put¬
ting tarred paper around the trees and keeping the printers’ ink
fresh, I succeeded in a measure in keeping the caterpillars out of
the trees. One tree which was very full of caterpillars I sprinkled
with the garden hose and knocked the pests out of it. The tarred
paper kept them from crawling up again, and they would collect
in a mass below the band. (J. N. French.)

When the caterpillars were very small the fences wei’e black
with them. We used to kill them on the fences by taking tea¬
kettles and walking along beside the rail and pouring boiling water
on the vermin. . . . We would scrape them from the tree trunks
with hoes and burn them with kerosene. We used to build little
fires at the base of a tree and collect the eggs and burn them.
(Mrs. Snowdon.)

The greenhouse was full of them [caterpillars]. The warmth
caused them to hatch out early. I destroyed most of them by
picking off the leaves and burning them, and also by spraying
with an emulsion of whale-oil soap, kerosene and ammonia. (A.
W. Crockford.)

For six weeks a great deal of our time was devoted to killing
these caterpillars. ... We would go out in our yard time after
time during the day and gather the caterpillars in dishes. Time
and again I have stayed out in the yard for two hours at a time,
catching caterpillars ; but in half an hour afterwards they seemed
to be just as thick again. (Mrs. Hamlin.)

PLATE VII. Cherry, red cedar and yellow pine trees attacked
by the gypsy moth. From a photograph
taken in Medford.

INCREASING ON NEGLECTED ESTATES. 31

During the summer of which I speak (1889) my currant bushes
were also attacked. They were covered with caterpillars, but I
saved them by sprinkling them twice a day with a solution of soap¬
suds and kerosene. (J. C. Clark.)

The Moth multiplies on Neglected Lands.

Though there were many people who did their utmost to
destroy the moths, there were others who made little effort
in that direction. There was waste land which no one cared
for, and in such places the moth increased apace, until the
advances of the ravenous larvae could no longer he stayed by
individual effort : —

I think, if every one had taken hold and fought the moths in the
beginning, they might have been stamped out right in the place
where they originated. The trouble was that some people would
not do anything. Some people on the street were tenants only,
and therefore took little or no interest in the condition of their
yards. I remember the case of one house which was vacant dur¬
ing one summer. The caterpillars in that yard were a sight.
Another neighbor, not owning his house, and not intending to
stay there, was overrun in a like manner. (William Taylor.)

Other residents make similar statements : —

A house near by being unoccupied, the caterpillars in the gar¬
den there had full swing, there being no one to fight them. This
yard was a recruiting place for the whole neighborhood. No
sooner would we get our own yard comparatively free than a lot
more would crawl around on the fence from the other yard.
(Mrs. Plummer.)

One difficulty in fighting the caterpillars used to be that now
and then a neighbor would not do anything to keep them down on
his own land. As a consequence, the caterpillars, after stripping
this man’s trees and getting about three-quarters grown, would
migrate into the other yards and be even more destructive, their
voracity increasing with their size. (J. N. French.)

The only way I suffered was because my neighbors were negli¬
gent. The caterpillars blew over on to my trees. ... I saw them
coming from my neighbor’s premises on a concrete walk extending
along where my fruit trees grow. The walk was literally covered
with these worms when they were about the size of your little
finger, so that it appeared like a carpet. (,T. O. Goodwin, before
the legislative committee on Agriculture, Feb. 27, 1894.)

32

THE GYPSY MOTH.

There were some people on Cross Street who used to do nothing
in the way of fighting the caterpillars, and for that reason the work
of individuals failed to cope with the pest. (Mrs. Spinney.)

The Plague brought to the Attention of the Public

at Large.

Messrs. John Stetson, W. C. Craig, J. O. Goodwin and
Dr. Pearl Martin, all of Medford, were among the first to
call public attention to the ravages of the moth. Mr. Stetson
first noticed the larvte of the moth in 1888 at his place on
South Street, nearly a mile from the Trouvelot house. In
June, 1889, when they began to defoliate the trees in his
neighborhood, he took a specimen for identification to Hon.
Wm. R. Sessions, secretary of the State Board of Agricult¬
ure. Mr. Sessions, being unable to identify it, advised
sending specimens to the Hatch Experiment Station at
Amherst. This was done, and the caterpillars were received
at the station June 27. Professor Fernald, the entomologist
of the station, was absent at that time in Europe, and no one
at the station immediately recognized the species. After a
thorough search through American entomological literature,
the conclusion was reached that the ipsect was foreign.
Recourse was then had to European works in the library of
the entomologist, and after a slight search through the
authorities, Mrs. Fernald and her son, Dr. H. T. Fernald,
identified the caterpillars as those of Ocneria dispar , known
in England as the “gypsy moth,” in Germany as the
“ sponge spinner” or stem caterpillar, and in France as “ le
zigzag.” Mr. Stetson was notified of the identification, and
information regarding the outbreak was immediately sent to
Professor Fernald. Later he observed in Germany the
ravages of this insect, and consulted with European ento¬
mologists in regard to the matter. All these authorities
regarded the gypsy moth as a serious pest, and the opinion
was expressed that it would become far more destructive
than the potato beetle, by reason of the number of its food
plants.*

In the mean time the people of Medford were becoming
alarmed.

* See Bulletin of the Hatch Experiment Station, November, 1889.

IT IS FOUGHT BY THE TOWN.

33

The Medford “Mercury” of June 23, 1889, contains this
item : —

The army-worm has struck Glenwood and Park Street gardens,
stripping trees of their foliage.

About this time Mr. Craig, then one of the selectmen of
Medford, became interested in the outbreak. The condition
of the trees and gardens so alarmed him that he immediately
brought the matter to the attention of the town officials. He
writes : —

In 1889 I was connected with the town government of Medford.
Coming out one day on the train from Boston, I noticed that the
trees in Glenwood had the appearance of having been burned. I
made a remark to the effect that the trees had been burned, when
a lady said, “ That is the work of the army-worm.” In company
with Mr. J. O. Goodwin I investigated the matter, and found that
the insects which were preying on the trees were not army-worms.
Being a selectman, I conferred with the other members of the
Board, but we had nothing to do with the trees on the streets or
in the orchards of the town. Mr. Goodwin and myself waited on
the road commissioners and asked them to expend some money in
stopping the ravages of the pests, which were the gypsy-moth
caterpillars. The commissioners at that time had no money which
they could expend for such a purpose, but were in full sympathy
with the movement and did all they could to further it. I saw
ex-Senator Boynton, General Lawrence, J. Henry Norcross and
other leading citizens in regard to the matter, and it was agreed
that some action must be taken. ... It was the sentiment that
the road commissioners should do what they could to stop the rav¬
ages of the caterpillars.

The alarming condition of the shade trees was considered
sufficient cause for immediate action. At a meeting of the
road commissioners on July 1, it was decided (pending action
by the town authorities) to put fresh ink on the bands of the
trees on the streets where the caterpillars were most numer¬
ous. These trees, in common with other street trees in the
town, had been banded earlier in the year as a guard against
the ravages of the canker-worm. The inking of the tree
bands was done the next day, and at night “ it was found

34

THE GYPSY MOTH.

that thousands of the pests were bunched beneath the printers’
ink” (Medford “ Mercury,” July 5).

Though this protection of the trees had the effect of allevi¬
ating the injury to those protected, it hastened the diffusion
of the caterpillars and drove them to other plants and to
other localities where trees were not banded, thus extending
the area of the injury until it included most of the trees in
the eastern part of the town. There were some localities,
however, that escaped the general devastation. At a town
meeting held on July 15 it was voted, on petition of the
road commissioners, to appropriate the sum of three hundred
dollars for the care of shade trees. This appropriation of
three hundred dollars was in addition to the usual appropri¬
ation of five hundred dollars for the care of shade trees made
earlier in the year. It was expended under the direction of
Dr. Pearl Martin, one of the road commissioners. A num¬
ber of men were employed in scraping off the egg clusters of
the gypsy moth from shade trees, chiefly on Park and Salem
streets, where the trees were badly infested. The eggs were
burned with kerosene. In addition to the work done by the
town, much effort and money were expended by citizens in
the endeavor to free their premises of the moth.

Professor Fernald, having meantime returned from Europe,
visited Medford and viewed the infested district. Later, in
company with Hon. Wm. R. Sessions, secretary of the State
Board of Agriculture, he visited and inspected Medford
again. These two gentlemen waited on Chairman Wadleigh
of the Board of Selectmen, and urged that the selectmen take
action to petition the General Court for legislation authoriz¬
ing the State Board of Agriculture to exterminate the cater¬
pillars. This course was approved by the selectmen at their
next meeting, October 25 ; but, as the Legislature was not then
in session, no immediate action was taken. In November an
illustrated bulletin on the gypsy moth was issued by Professor
Fernald at the Hatch Experiment Station. By authority of
the State Board of Agriculture and with the co-operation of
the Massachusetts Society for Promoting Agriculture, an edi¬
tion of forty-five thousand copies was printed, and mailed
to tax-payers in Medford and vicinity. The bulletin was
printed in full in the Medford “ Mercury” on December 6.

PUBLIC INTEREST AROUSED.

35

The task of destroying the eggs, which had been delegated
to the Medford road commissioners, was far greater than had
been anticipated, and the money appropriated was soon ex¬
pended, while only a small part of the eggs had been
destroyed. While the work was in progress Dr. Martin saw
that the moths were so numerous and so widely distributed
that the town authorities could not cope with them. At a
meeting of the selectmen, December 10, he appeared in
behalf of the road commissioners and advised applying to
the Legislature for State aid. The Board voted that the
clerk should communicate with Secretary Sessions of the
State Board of Agriculture “ in relation to measures to be
taken to place this matter properly before the next Legis¬
lature.”

At the next meeting of the selectmen, December 17, a
communication was received from the Hatch Experiment
Station, advising that the Legislature be petitioned for an
appropriation to exterminate the moth. The clerk, reporting
in regard to his interview with Secretary Sessions, recom¬
mended that petitions in favor of such an appropriation be
circulated in Medford and vicinity for presentation to the
Legislature. Messrs. Wadleigh and Lawrence were appointed
a committee to draw up such petitions. Mr. Lawrence was
also appointed a committee to confer with Secretary Ses¬
sions in regard to preparing a bill to be presented to the
Legislature.

In December, Prof. H. H. Goodell, president of the
Massachusetts Agricultural College, wrote to Governor-elect
Brackett, urging that measures should be taken by the in¬
coming Legislature to provide for the extermination of the
gypsy moth.

In his message to the Legislature of 1890 Governor
Brackett said : —

A new enemy is at present threatening the agriculture, not only
of our own State, but of the whole country. It is the gypsy moth,
said to attack almost every variety of tree, as well as the farm and
garden crops. The pest is spreading with great rapidity, and, if
its eradication is to be attempted, immediate measures are of the
utmost importance.

36

THE GYPSY MOTH.

A petition for legislation for the extermination of the
gypsy moth was presented to the Legislature by the select¬
men of Medford, Jan. 15, 1890. Other towns joined in the
movement. On January 21, the selectmen of Arlington pre¬
sented a petition. Soon after, petitions were presented by
the boards of selectmen of Everett, Winchester, Stoneham
and Wakefield, and by city officials of Malden and Somer¬
ville. A petition was presented from the State Board of
Agriculture, headed by President Goodell of the Agricultural
College ; also one from the Essex County Agricultural So¬
ciety. The Massachusetts Horticultural Society took an
active part in the movement, petitioning the Legislature as
follows : —

The Massachusetts Horticultural Society, recognizing the dan¬
gers threatening the agricultural interests of the State by the sud¬
den appearance in the town of Medford of a dangerous insect pest,
petitions the Legislature, in support of the petition of the citizens
of Medford and adjacent towns, for State aid in stamping it out.

The joint standing committee on Agriculture of the Massa¬
chusetts Legislature visited Medford early in 1890, and saw
the masses of egg clusters on the trees.* Public interest
having in the mean time been aroused, an act appropriating
twenty-five thousand dollars “for the extermination of the
Ocneria dispar or gypsy moth” was passed. f This was ac¬
complished mainly through the influence and untiring efforts
of Mr. J. Henry Norcross of Medford, then a member of the
House of Representatives, aided by hearty co-operation of
Representatives from the neighboring towns. The act was
approved March 14, 1890, and is here given in full : —

[Chapter 95.]

An Act to provide, against depredations by the insect known

AS THE OCNERIA DISPAR OR GYPSY MOTH.

Be it enacted , etc., as follows :

Section 1. The governor by and with the consent of the coun¬
cil is hereby authorized to appoint a commission of not exceeding
three suitable and discreet persons, whose duty it shall be to pro-

* “ The walls and almost every tree were almost wholly covered with nests.”
(Ex-Senator Low, before the legislative committee on Agriculture, Feb. 27, 1894.)
t Dispar has now been referred to the genus Porthetria.

PROVIDING AGAINST ITS DEPREDATIONS. 37

vide and carry into execution all possible and reasonable measures
to prevent the spreading and to secure the extermination of the
ocneria clispar or gypsy moth in this Commonwealth ; and to this
end said commission shall have full authority to provide itself with
all necessary material and appliances and to employ such compe¬
tent persons as it shall deem needful ; and shall also have the right
in the execution of the purposes of this act to enter upon the lands
of any person.

Sect. 2. The owner of any land so entered upon, who shall
suffer damage by such entry and acts done thereon by said com¬
mission or under its direction, may recover the same of the city or
town in which the lands so claimed to have been damaged are sit¬
uate, by action of contract ; but any benefits received by such
entry and the acts done on such lands in the execution of the pur¬
poses of this act shall be determined by the court or jury before
whom such action is heard, and the amount thereof shall be applied in
reduction of said damages ; and the Commonwealth shall refund to
said city or town one-half of the amount of the damages recovered.

Sect. 3. Said commission shall have full authority to make
from time to time such rules and regulations in furtherance of the
purposes of this act as it shall deem needful ; which rules and
regulations shall be published in one or more newspapers published
in the county of Suffolk, and copies of such rules and regulations
shall be posted in at least three public places in each city or town
in which said ocneria dispar or gypsy moth shall be found by such
commission to exist, and a copy thereof shall be filed with the city
or town clerk of each city or town. Any person who shall know¬
ingly violate any of the provisions thereof shall be punished for
each violation by a fine not exceeding twenty-five dollars.

Sect. 4. Said commission shall keep a record of its transac¬
tions and a full account of all its expenditures, in such form and
manner as shall be prescribed by the governor and council, and
shall also make return thereof to the governor and council at such
time or times and in such form as shall be directed by the governor
and council. The expenses incurred under this act shall be paid
by the Commonwealth, except claims for damages by the entry
upon the lands of any person and acts done thereon by said com¬
mission or by its direction, which shall be paid as provided in sec¬
tion two of this act.

Sect. 5. The governor and council shall establish the rate of
compensation of the commissioners appointed under this act, and
the governor may terminate their commissions at his pleasure.

Sect. 6. Any person who shall purposely resist or obstruct
said commissioners or any person or persons under their employ,

38

THE GYPSY MOTH.

while engaged in the execution of the purposes of this act, shall
be punished by a fine not exceeding twenty-five dollars for each
offence.

Sect. 7. It shall be unlawful for any person to knowingly
bring the insect known as the ocneria dispar or gypsy moth, or
its nests or eggs, within this Commonwealth ; or for any person
knowingly to transport said insect, or its nests or eggs, from any
town or city to another town or city within this Commonwealth,
except while engaged in and for the purposes of destroying them.
Any person who shall offend against the provisions of this section
of this act shall be punished by a fine not exceeding two hundred
dollars or by imprisonment in the house of correction not exceed¬
ing sixty days, or by both said fine and imprisonment.

Sect. 8. To carry out the provisions of this act a sum not ex¬
ceeding twenty-five thousand dollars may be expended.

Sect. 9. This act shall take effect upon its passage. [Ap¬
proved March 14 , 1890.

The Commission of 1890.

In accordance with, the provisions of the act of March 14,
Governor Brackett appointed a salaried commission, consist¬
ing of Warren W. Paws on of Arlington, then a prominent
member of the State Board of Agriculture, Dr. Pearl
Martin of Medford and J. Howard Bradley of Malden.

The commission organized in Medford, March 22, with the
choice of Mr. Rawson as chairman and Mr. Bradley as
secretary and general superintendent. The records show
that in April, Mr. Samuel Ilenshaw of the Boston Society of
Natural History was appointed entomologist to the com¬
mission. Headquarters were established in Medford, and
meetings of the commission were held almost daily until the
last of July and several times per month during the rest of
the year.

The commission began its labors by a partial inspection
of the known infested district, for the purpose of discovering
and marking the infested trees, shrubs and other objects.
The infested trees were marked with a red tag. The moth
was soon found in many localities outside the restricted dis¬
trict to which it was at first supposed to be confined. This
district did not exceed one-half mile in width and one and
one-half miles in length. The inspection of 1890 justified

PLATE VIII. Tract of land, formerly wooded, south of the railroad in Glenwood. The woods were
infested and were cut by the commission of 1890. From a photograph taken
in 1895. (See page 39 and Map I.)

THE FIRST COMMISSION.

39

the commissioners in the assumption that fifty square miles
of territory were then more or less infested.

It soon became apparent that the appropriation of twenty-
five thousand dollars would be entirely insufficient for the
needs of the season’s work, chief of which was the expensive
item of spraying. On May 9, in a communication addressed
to Governor Brackett, the commission reported having found
the infested territory “ some sixteen times as large as first
represented,” and asked for an additional appropriation of
twenty-five thousand dollars. This appropriation was made
by the Legislature and approved June o, 1890. The force
of employees was increased as the season advanced, and
reached its maximum strength in June, eighty-nine men
being employed from June 16 to 28.

During the month of April many eggs of the moth were
scraped from the trees and destroyed by the employees of the
commission. Early in May the spraying of infested trees
and foliage with Paris green was begun and continued until
about the middle of July. This was the principal work of
the summer. Fifteen teams were in use, and spraying was
done in Medford, Malden, Arlington, Chelsea and Everett.
The greatest amount of spraying was done in the Glenwood
and Wellington sections of Medford and the Edgeworth dis¬
trict of Malden.

Another feature of the season’s work was the guarding of
highways leading out of Medford and Malden, with the view
to preventing the further dissemination of the moth by means
of vehicles. About a dozen special policemen were em¬
ployed in this duty from early in June until the last of July.
They were on duty twelve hours in the day. Caterpillars of
the moth were found on many vehicles going out of the in¬
fested district.

Large kerosene torches were used during the summer to
burn the clustering caterpillars. Considerable cutting and
burning of infested trees and bushes was also done, the chief
work of this sort being in the badly infested woodland north
and south of the railroad at Glenwood. About twenty acres
of ground were thus cleared.

In September and October a few men were engaged in
scraping eggs from the trees in Medford, Malden, Somerville,

40

THE GYPSY MOTH.

Arlington, Everett, Cambridge and Chelsea. In November
the force was slightly increased, and an inspection was made
of certain parts of the infested territory. The cavities of
some trees along the highways were closed with cement.
On December 6 all men in the employ of the commission
were discharged, and the field work of 1890 closed.

The Abundance and Destructiveness of the Moth in 1890.

Deferring to the work of 1890 and the numbers of the
moth, Mr. E. J. Cadey, an ex-employee of the commission,
said : —

At the time when the commission first started I saw the eggs of
the moth on trees in such numbers that the trees had a spongy
appearance, and the men who gathered them used large-sized pails,
holding about a peck. Some days we filled these pails twice and
occasionally three times. Especially was this the case at the Wel¬
lington willows, in Glenwood, where the moths originated. The
walls of an old shed were one yellow mass of eggs. Early in the
summer, previous to the spraying season, on sixteen acres of
woodland and brush on land of Mr. Pinkert near the Boston &
Maine Railroad, there was not a green leaf to be seen. We after¬
wards cut these sixteen acres. There were five or six willows on
the corner of Spring and Magoun streets that were so thickly
covered with pupse that the bark could not be seen. In 1890 I do
not think there was a whole leaf in Medford, and the people com¬
plained of a very disagreeable stench.

Mr. William Enwright, who was also employed by the
commission in 1890, writes : —

I was sent to Glenwood to the brick yards. Here I found the
bricks completely covered with the caterpillars. Nearly opposite
here, on Lawrence Street, there was an old barn literally covered
inside and out with nests and caterpillars. Trees were com¬
pletely stripped. The streets and sidewalks were so covered that
it was almost impossible to step without crushing some of the
caterpillars. In the fall of the first year, when we were cleaning
the nests from the rubbish, we used shovels to shovel them into
cans. You could not walk in the woodland without being covered
with caterpillars. In 1890 Mr. Bradley drove his horse through
the woods, and the horse’s mane and tail were covered with
caterpillars.

ITS RAVAGES IV 1890.

41

Mr. G. T. Pierce, who was employed in 1890, writes : —

When I was working at Dr. Newton’s place on Highland Ave¬
nue, Somerville, on seventeen or eighteen apple trees you could
not find a leaf that had enough left of it to call it a leaf. Most
of them were only a stub of the midrib. In a large bunch of
willows at Wellington, which the old commission cut down almost
the first thing they did, the trunks were literally covered with egg
clusters from the ground up, so that I doubt if you could find
many places where you could put your hand on the surface of the
tree without covering one or more nests.

Mr. C. S. Mixter, an ex-employee, testified as fol¬
lows : —

In one place in Chelsea the nests were so thick in 1890 that you
could not put your finger down without striking a nest. We
scraped the nests off. We had several panfuls.

Despite the great destruction of the moth by the commis¬
sion during the work of 1890, the ravages of the creature
in Medford were still serious. Although the injury wrought
was not as widespread as in 1889, the stripping of trees
and the consequent loss of fruit crops still continued. On
Spring Street, in 1890, the moths appear to have been at
their worst. Mr. W. B. Harmon, of No. 55 Spring Street,
says : —

In the summer of 1890 the caterpillars destroyed all our fruit.
They attacked and stripped the apple trees first, and then turned
their attention to the pear trees, which they also stripped. The
young fruit was entirely ruined, and we had nothing that fall.
The trees in places were actually black with the caterpillars.
They would collect in great bunches, and we would sweep them
off with a broom. . . . We could not step out of doors, either
upon the grass or the walk, without crushing the caterpillars
under foot. Over our front door the house was black with them.
We would clean them off every morning, but in an hour it would be
black again. People could not come in that way. It is no exag¬
geration to say that there were pecks of the caterpillars under the
doorsteps and on the fence. . . . The next lot to ours was a
vacant brush lot. It actually swarmed with caterpillars, and they
came from there into our yard by thousands.

42

THE GYPSY MOTH.

Other residents of the neighborhood give similar testi¬
mony : —

In 1890 we lived on Spring Street, and that year the caterpillars
seemed to be at their worst. You could not go along the street
after dark without getting them all over you. (Mrs. Fenton.)

Four years ago (1890) I saw the gypsy-moth caterpillars by the
thousand on the Sherman lot on Spring Street. I never saw such
a sight. Their eggs were as thick on the big willows as spawn in
a fish. (A. W. Crockford.)

In 1889 the washing on our clothes reel seemed to have a dingy
appearance, and I found tiny black worms on the clothes. These
would blow over from the Myrtle Street yard adjoining. They
were young gypsy-moth caterpillars, although at that time I did
not know what they were. The next year they appeared in our
yard by swarms. The board walks were completely covered with
them. It was impossible to walk without crushing them under
foot. On going out of doors they would get on one’s clothing.
Our trees and other green things were stripped twice and leafed
out twice. The foliage of everything that was set out in our yard
was riddled; the woodbine alone escaped. We became dis¬
couraged, and let things go. The grape-vine suffered. One
morning Mr. Merrill picked caterpillars for an hour and a half off
one rose bush. The trunk of the umbrella tree in the yard was
completely hidden by the mass of caterpillars stuck together. I
scraped the caterpillars off into a tin can, but in a short time they
were just as thick again on the trunk. Some of our small fruit
trees which were stripped at that time have not done much since.
In that year (1890) if you went down the street with a sun um¬
brella, the caterpillars would drop down on it just like rain.
(Mrs. E. E. Merrill, Lawrence Street.)

In 1890 the street trees were badly injured by the gypsy-moth
caterpillars. At night in the lindens in front of the house there
was a noise like the gentle falling of rain. This was the noise of
the caterpillars eating the leaves. (Mrs. Plummer.)

In 1890 the whole place was full of gypsy-moth caterpillars. I
think I scraped off half a peck of caterpillars from the sills of the
house and from under the porch and from off the trees. (E.
Loeffler, Lawrence Street.)

The caterpillars did much damage in the Cross Street
neighborhood. Says Mr. J. C. Miller : —

The next year (1890) all the orchards in this section were com¬
pletely ravaged, and there was no fruit. The caterpillars simply

ITS RAVAGES IN 1890.

43

swarmed. I destroyed thousands of them by burning them with
rags soaked in kerosene. I spent many hours in destroying them,
but without making any perceptible difference in their numbers.
They were over everything, and even got into the cellars. Some
of my apple trees overhang my shop. In the evening when the
caterpillars were liveliest the noise of their droppings falling on
the shingles sounded like a steady shower. The gutter was brim¬
ful and running over with the droppings.

Other sections of the town were afflicted in like manner : —

In 1890 the apple trees on Fulton Street, Allen Court and
Fountain Street were more or less stripped by the gypsy-moth
caterpillars. Some of the apple trees were wholly denuded of
their foliage, and the crops in some cases were lost. In some
cases the limbs of the apple trees were killed by the ravages of
the caterpillars. Even pear trees were sometimes badly eaten,
and cherries also suffered. The leaves were completely destroyed
on a little German willow in my yard. Rose bushes were very
badly eaten. (S. F. Weston.)

The large elm in front of my house was full of caterpillars in
1890. The leaves were riddled and many were cut off. We would
sweep up daily these bits and fragments of leaves which fell from
the tree, but the next day the ground beneath would be littered
with them again. This elm stands in front of the piazza, and
many caterpillars came from the tree upon the house. They were
so thick that we could not sit out on the piazza at all that summer.
When we opened the front door the}7 would string down all over
one. The caterpillars at one time were so thick on a fence on
Salem Street that I could have run my hand along the top rail and
scooped them up. In this same year a maple tree standing in
front of my house on Allen Court was badly eaten by the cater¬
pillars. You could hear them eating up in the tree. (Mrs. P. N.
Ryder, Salem Street.)

The gypsy-moth caterpillars were very numerous in 1890 on the
Sparrell estate, No. 90 Main Street. . . . As evening came on
you would see them everywhere on the ground heading for the
trees. I have heard the noise of their feeding after dark. They
kept coming into my yard from the yards of other people who paid
less attention to destroying them. The leaves of the trees were
just as if they had been scorched. One tree did not bear for
several years. (Richard Pierce.)

In 1890 I saw the caterpillars clustering in a mass on the body
of an elm tree on South Street. I destroyed a great many of these
by burning. (John Hutchins, 16 South Street.)

44

THE GYPSY MOTH.

Four years ago (1890) in the yards on the north side of Cotting
Street the g3Tpsy-moth caterpillars stripped the trees bare of their
leaves. (John Cotton.)

In 1890 I fought the pest. They came on to my place in mill¬
ions in April. The top of my fence rail would be covered with
gypsy-moth caterpillars about as small as ants. ... I would
take a brush broom and fight them perhaps an hour and a half. I
would destroy them in the morning, and at noon would find as
many more and cleau them every one from my premises. At
night I went through the same operation. I destroyed undoubt¬
edly millions. (W. W. Fifield, before the legislative joint stand¬
ing committee on Agriculture.)

Residents of Edgeworth make similar statements : —

The caterpillars were very thick ou the house in 1890. When
I went out of my side door I had to take a broom aud brush them
off the platform. I killed quarts that summer. At the next house
they were just as bad. I swept them off above the door again
and again, and they seemed to be back again as thick as ever in
five minutes. An apple tree back of the house looked as if the
leaves had all been burned. A few blossoms would come out and
then wither away. I saw the gypsy-moth men burn the cater¬
pillars by the pailful. (Mrs. B. Wallace, West Street, Edge-
worth.)

In 1890 they were also plentiful, although not as thick as in
1889. I got few if any apples in either year. The caterpillars
were larger than your little finger. They would lie thickly to¬
gether on the trunks of the trees. In the evening they were so
thick that they would drop down on the steps from above the
door. (William McLaughlin, 107 Oakland Street.)

>> a,

& o3

THE WORK OF 1891.

45

The Work of 1891.

Appointment of the Second Commission.

Governor Russell, having removed on Feb. 15, 1891, the
salaried commission for the extermination of the gypsy moth,
appointed another commission which organized as follows :
Prof. N. S. Shaler of Harvard University, chairman, Francis
H. Appleton of Peabody, secretary, both members of the
State Board of Agriculture, and Hon. Wm. R. Sessions,
secretary of that Board. These gentlemen served without
remuneration, accepting office with the understanding that
legislation would be asked for with reference to placing the
work under the control of the State Board of Agriculture,
where they believed it properly belonged. The new com¬
missioners, having received information of their appoint¬
ment by the governor, lost no time in obtaining information
from the best authorities in regard to the possibility of ex¬
terminating the moth and the best methods of procedure.
They received their commission on March 4, and the same
day held a conference at the office of the State Board of Ag¬
riculture, with several eminent entomologists. Many promi¬
nent men from the towns in the region infested by the gypsy
moth were also invited to attend. Among those present were
Professor Riley, entomologist of the United States Depart¬
ment of Agriculture, Professor Fernald, entomologist of the
Hatch Experiment Station and of the Board of Agriculture,
Mr. Samuel Scudder of Cambridge, Mayor Wiggin of Malden,
Chairman L. S. Gould of the selectmen of Melrose, Select¬
man W. C. Craig of Medford and W. A. Pierce of Arling¬
ton. The prevailing opinion of the entomologists was that
recourse must be had to spraying with some of the arsenites
in order to bring about the extermination of the moth. (See
Appendix A for a report of the conference.)

Preliminary Arrangements.

On March 12 the commissioners invited the members of
the first commission to a consultation at the office of the
State Board of Agriculture. Ex-Commissioners Rawson and

46

THE GYPSY MOTH.

Bradley met with the commissioners. They gave the com¬
mission such information as they possessed in regard to the
habits of the moth, the methods used in controlling it and
preventing its spread, its distribution and the extent of terri¬
tory infested by it. They also outlined on a map the territory
known by them to be infested by the moth. (See map.)
The “ director of field work” who was appointed on that day
was present and consulted with the commissioners in regard
to taking immediate steps for the eradication of the moth.

In view of the conflicting opinions expressed in regard to
the effectiveness of spraying as a means of extermination,
it was decided to organize at once a force of men, and to
destroy as many of the eggs of the gypsy moth as possible
before the time for hatching arrived. The director took the
train at once for Amherst, and visited the Hatch Experiment
Station, where two days were spent in consultation with the
entomologist, Prof. C. H. Fernald, and in examining insecti¬
cide appliances and the literature germane to the subject.

It had been proposed by the commissioners that the di¬
rector secure the services of some of the students or gradu¬
ates of the Massachusetts Agricultural College as assistants.
Through the good offices of Professor Fernald and Dr. H.
H. Goodell, president of the college, in advising the students,
several young men were induced to engage in the work
of extermination. Some of these students had studied eco¬
nomic entomology under the guidance of the entomologist,
and were especially fitted for the work in hand. From that
time Professor Fernald’s advice and assistance were always
freely sought by the committee and director, and as freely
given. All plans made were submitted to him for approval,
and were only perfected after a careful consideration of his
recommendations. The students who had been engaged were
released in a few days from their college engagements, and
on March 19 nine of them reported at the office of the State
Board of Agriculture and received instructions. In the
mean time the office and storehouse, which had been used by
the first commission, had been opened, an inventory of prop¬
erty taken, and a hasty inspection made of the infested region
by the director, in company with Ex-Commissioner Bradley.
A few experienced men had also been employed.

THE WORK OF 1891.

47

Oil March 20 actual work in the field was begun. The
director and sixteen men visited the farm of Mr. Gilman
Osgood in Belmont, which was the only locality in that town
known by the first commission to be infested. It was then sup¬
posed that this was an isolated moth colony, and an attempt
was made to stamp it out by gathering the eggs.* During
the day, however, other colonies were found in Belmont.

The Work delegated to the Board of Agriculture.

The commission of 1891 was superseded after a few weeks
by the State Board of Agriculture, the act (chapter 210,
Acts of 1891) placing the work in the hands of the Board
being approved April 17. The act follows : —

[Acts of 1891, Chapter 210.]

An Act to provide against depredations by the insect known

AS THE OCNERIA DISPAR OR GYPSY MOTH. ,

Be it enacted , etc., as follows:

Section 1. The state board of agriculture is hereby authorized,
empowered and directed to provide and carry into execution all
reasonable measures to prevent the spreading and to secure the
extermination of the ocneria dispar or gypsy moth in this Common¬
wealth ; and to this end said board shall have full authority to
provide all necessary material and appliances, and to employ such
competent persons, servants and agents as it shall from time to
time deem necessary in the carrying out the purposes of this act ;
and said board shall also have the right itself or by any persons,
servants or agents employed by it under the provisions of this act
to enter upon the lands of any person.

Sect. 2. The owner of any laud so entered upon, who shall
suffer damage by such entry and acts done thereon by said state
board of agriculture or under its direction, may recover the same
of the city or town in which the lands so claimed to have been
damaged are situate, by action of contract ; but any benefits
received by such entry and the acts done on such lands in the
execution of the purposes of this act shall be determined by the
court or jury before whom such action is heard, and the amount
thereof shall be applied in reduction of said damages ; and the
Commonwealth shall refund to said city or town one-half of the
amount of the damages recovered.

* The attempt to eradicate the colony was not at that time successful, hut was ac¬
complished later. The moths were found that season in many localities in Belmont.

48

THE GYPSY MOTH.

Sect. 3. Said state board of agriculture shall have full
authority to make from time to time such rules and regulations in
furtherance of the purposes of this act as it shall deem needful,
which rules and regulations shall be published in one or more
newspapers published in the county of Suffolk ; and copies of such
rules and regulations shall be posted in at least three public places
in each city or town in which said ocneria dispar or gypsy moth
shall be found by said board to exist and a copy thereof shall be
filed with the city clerk of each such city and with the town clerk
of each such town ; and any person who shall knowingly violate
any of the provisions thereof shall be punished for each violation
by a fine not exceeding twenty-five dollars.

Sect. 4. Said state board of agriculture shall keep a record of
its transactions and a full account of all its expenditures under this
act, and shall by its chairman or secretary make report thereof,
with such recommendations and suggestions as said board shall
deem necessary, on or before the fourth Wednesday in January, to
the general court.

Sect. 5. Said state board of agriculture shall establish the rate
of compensation of any persons, servants or agents employed by
it under this act.

Sect. 6. Any person who shall purposely resist or obstruct said
state board of agriculture, or any persons, servants or agents em¬
ployed by it under the provisions of this act, while engaged in the
execution of the purposes of this act, shall be punished by a fine
not exceeding twenty-five dollars for each offence.

Sect. 7. It shall be unlawful for any person knowingly to bring
the insect known as the ocneria dispar or gypsy moth, or its nests
or eggs, within this Commonwealth ; or for any person knowingly
to transport said insect, or its nests or eggs, from any town or city
to another town or city within this Commonwealth. Any person
who shall offend against the provisions of this section shall be pun¬
ished by a fine not exceeding two hundred dollars or by imprison¬
ment in the house of correction not exceeding sixty days, or by
both such fine and imprisonment.

Sect. 8. The said state board of agriculture may exercise all
the duties and powers herein conferred upon said board, by and
through its secretary and such members of said board as it may
designate and appoint to have in charge, in conjunction with its
secretary, the execution of the purposes of this act.

Sect. 9. All moneys heretofore appropriated or authorized to
be expended under the provisions of chapters ninety-five and one
hundred and fifty-seven of the acts of the year eighteen hundred
and ninety or by any other act, and not heretofore expended, are

A NEW STATUTE.

49

hereby appropriated and authorized to be expended by the said
board in carrying out the purposes of this act.

Sect. 10. All the property acquired and records kept under the
provisions of said chapter ninety-five of the acts of the year eigh¬
teen hundred and ninety shall be delivered into the custody of said
board, and said board is authorized to take, receive and use the
same for the purposes of this act.

Sect. 11. Chapter ninety-five of the acts of the year eighteen
hundred and ninety is hereby repealed, but all claims for damages
under said chapter ninety-five for entry upon and acts done on
the lands of any person may be prosecuted, as therein provided,
against the city or town wherein the lands entered upon are situate,
and the damages shall be ascertained and one-half of the amount
thereof recovered against any city or town shall be refunded to
such city or town as provided in said chapter ninety-five. [ Ap¬
proved April 17 , 1891.

A special meeting of the Board of Agriculture was held
on April 28, and Messrs. Sessions, Shaler and Appleton
were appointed a committee in accordance with the provi¬
sions of section 8 of the act.

This committee organized on May 19, with the choice of
Mr. Sessions as chairman and secretary. The committee
continued the work which it had begun as a commission,
confirming the appointment of the field director, and directed
that the work being done in the field should be continued.
A code of rules and regulations for the public was adopted.
(See Appendix B.) At the time of appointment of the
second commission there remained unexpended of the ap¬
propriation of 1890 the sum of $24,460.68. On May 19
$11,003.22 only remained. On June 30 an additional ap¬
propriation of $50,000 was made by the Legislature.

Mapping the Infested Region.

In apportioning the territory to different inspectors, it was
found necessary to make a hasty survey of the field and to
plat it on maps of the towns known to be infested and those
contiguous to them. These maps were divided into sections
of such size as could be conveniently carried by the men
engaged in field work. For convenience these sections
were so drawn as to be bounded by town lines, streets and

50

THE GYPSY MOTH.

railways, or by natural bounds, such as streams and lakes.
Each map was accompanied by a written description of the
boundaries of the section which it represented. The work
was done, under the supervision of the director, by Mr.
J. O. Goodwin of Medford, an experienced engineer, well
acquainted with the topography of the region. It was in¬
tended so to divide the region that each inspector or foreman
could be held responsible for a certain tract or section with
definite and well-marked boundaries. Each section in each
town was numbered. Each inspector, on entering the field,
was required to run the boundaries of the section allotted to
him, and mark the section number prominently with white
paint on fixed objects at each angle of the boundary. To
avoid any possible confusion of lines, each inspector was
also required to “ blaze ” or mark the line with white paint
wherever it was not otherwise easily distinguishable. When
this system was extended into the towns farthest from the
infested centre, it was not found necessary to divide such
towns into sections on account of the comparatively small
number of moth colonies found in them. They were treated,
therefore, as sections, and an inspector with a gang of men
was placed in charge of each. If, however, it was found, on
close inspection, that a town that had not been “ sectioned”
was badly infested, and would require several gangs of men,
it was then “ sectioned.” Each inspector was required occa¬
sionally to sketch maps ; also to locate and mark infested
localities on section maps, and to make such additions to the
maps as were from time to time necessitated by the con¬
struction of new streets or railways in the infested towns.

Organization and Instruction of the Field Force.

Whenever suitable men could be found they were added
to the force. Some of the most capable men of the force
of 1890 were re-employed. Others, whose previous expe¬
rience in field study in entomology or kindred sciences had
fitted them for careful observation, were engaged and trained
to act as inspectors.

When field operations were commenced the eggs of the
moth were the only living form of the pest. The men
were taught how to recognize and destroy them, and to

THE INSTRUCTION OF EMPLOYEES.

51

distinguish them from those of native moths. They were
taught to observe all evidences of the presence of the gypsy
moth, and were requested to secure by personal observation
as the season advanced all possible information in regard to
its habits. When the inspectors had gained sufficient knowl¬
edge to enable them properly to instruct others, laborers
were employed, and each inspector was put in charge of a
few men, over whom he was given full authority with in¬
structions to recommend the discharge of any man who
proved inefficient or untrustworthy. Each inspector was
given a short time in which to instruct his men by engaging
them in practical work in the worst-infested portions of
Malden and Medford. Then a section (indicated by a map)
was allotted him, with instructions to inspect it and destroy
the eggs therein. When eggs were found on a tree or other
object, certain characters were marked upon it with white
paint, and the locality was designated on the map.

As the season advanced and the extent of the region occu¬
pied by the moth became known, it was found necessary to
employ two hundred and fifty men, and distribute them over
this region. It became evident that it was impossible for
one man to keep the entire field under supervision. Six
superintendents were then selected from among the most
efficient of the inspectors. Each of these was required to
supervise the work in several towns. When spraying began,
one man was placed in charge of tools and supplies, including
spraying apparatus and teams. A code of rules and regula¬
tions was prepared and printed early in the season, and copies
were distributed among the employees. (See Appendix B.)

Daily Reports and Records.

Each inspector was instructed to make out daily a written
report of the work done by himself and men, and to incor¬
porate in these reports his observations on the habits of the
moth and its parasites, notes on its distribution and all
useful information acquired by him in regard to the moth or
methods of eradicating it. In these reports the number of
trees, buildings, fences, walls, hedges and other objects
inspected daily was recorded ; the number of each on which
the moth was found ; the number of each form of the moth

52

THE GYPSY MOTH.

found and destroyed by hand on each estate ; the number of
trees cut or treated by banding, burlapping, cementing or
scraping ; and the number of acres of brush or woodland
burned over. Mention was also made of any work left
unfinished for the time being, or thought to be necessary
later. Whenever the moths were found in a locality not
before known to be infested, the inspector was required to
sketch on the day’s report a map of the locality, marking the
colony in a manner prescribed and in such a way that it could
be found at once by one not familiar with the place.

The name of the inspector appears on each of his daily
reports, together with the names of his men. The number
of hours per day that each man works is also recorded on
the report. The reports are filed, and by them it is pos¬
sible to determine which inspector and men are responsible
for any work done at any point on a given day in any year,
and to fix the responsibility should any omission of duty or
any misdemeanor occur on the part of the employees. An
account with each infested estate is kept in the office in
books known as “ section books.”

The section books in which the records of field work are
kept now number seventy-eight, of one hundred pages each.
On the first page of each book the bounds and a general de¬
scription of the section are given, and the work done in it
and the results attained for the year are recorded on the
succeeding pages. There is also a “ blue print” map marked
in such a way as to designate each infested locality. (See
Appendix C.) It is possible by consulting these books to
learn how much work has been done on each infested estate,
how many units of each form of the moth have been killed
by hand, and whether the moth has been eradicated from
that locality or not. There is thus kept a complete record
of the progress made.

The Spring Inspection.

An inspection of the infested region was begun in March,
with a view of determining its extent. This inspection com¬
menced in Medford and Malden near the centre of the region,
and extended to the surrounding towns as the organization
of the force was perfected and its size increased. Each

THE SPRING INSPECTION.

53

inspector was first sent with his squad to inspect a section in
one of the towns then known to be infested. He was in¬
structed to inspect the entire territory within the boundaries
of the section, and destroy all the eggs found therein.

It was at once seen that the moth was most numerous
along the thoroughfares. A few of the most expert men
were sent into the towns nearest Malden and Medford to
examine the roadsides and mark any colonies found. These
men speedily found the moth in Lexington, Winchester,
Wakefield, Melrose, Revere and Saugus, thus greatly adding
to the knowledge of the extent of the infested region. Work
was hurried forward in all these towns. The eggs were cut
or scraped from the trees with knives, gathered into cans
and burned with oil in small stoves made for the purpose.
Rubbish and undergrowth containing eggs were also de¬
stroyed by fire. As much more territory was found infested
than was at first estimated, it was found impossible to secure
and train men enough to make a thorough search of the entire
region and destroy all the eggs before hatching time. As it
was necessary to determine as soon as possible how for the
moth had become disseminated, a portion of the work in
Malden and Medford was given up, and the men who had
been engaged in destroying eggs there were sent into the
outlying towns. For this reason, when the eggs began
hatching a considerable area yet remained in a few of the
inner towns where the eggs had not been destroyed. Many
eggs which had been scattered about, both by the work of
the first commission in the fall of 1890 and by the work in
the spring of 1891, hatched, and caterpillars began to appear
in large numbers over a wide area. Alien work was begun
the time remaining for this inspection and egg killing did
not exceed six weeks, as the eggs begin hatching before
May 1. Yet in that short time the moths had been found
for beyond the utmost limits of the region previously known
as infested.

The Condition in which the Infested Region was found in

1891.

When work was begun by the second commission the eggs
of the moth were found in great numbers upon the trees in

54

THE GYPSY MOTH.

certain localities in which little work had been done in the
fall of 1890 by the first commission. In some of these
places the bark of the trees was so covered with egg clusters
that it presented a yellowish appearance. This was the case
only in parts of Medford and at a few points in Malden.
Wherever the first commission had worked the previous
autumn, few egg clusters were found on the trees. It was
decided, however, to make a thorough search of all localities
wherever it was practicable. With this in view, the base
boards of fences were taken off, plank walks raised, the
steps of houses torn up and cellars and buildings entered.
In such places the eggs of the moth were found concealed
in great numbers. In some cases quarts of eggs were taken
out from beneath piazzas or flights of steps. Many eggs
were also found in some cellars. As the inspection pro¬
gressed, a few badly infested localities were found in other
towns and many eggs were destroyed. In most of these
towns the moths had not been colonized long enough to
become numerous, but were found in isolated colonies along
the roads. Such inspections as were made of woodlands
revealed in most cases comparatively few colonies, most of
them small and isolated.

A careful estimate has been made from the daily reports of
inspectors, which shows the number of egg clusters destroyed
during the first six weeks of 1891 to be 757,760. The num¬
ber of eggs contained in these clusters would probably be
from three to five hundred millions.

The Enforcement of Police Regulations.

When in May the caterpillars were seen to be dropping
by their threads from the trees upon passing teams and
vehicles, it was deemed necessary to do something to check
their distribution in this manner. The method (used by the
commission of 1890) of guarding the roads leading out of the
worst-infested district was tried. The police were required
to inspect all horses and vehicles going out of the infested
district, record all facts regarding their destination, and
destroy any caterpillars found upon them. They were also
required to enforce the regulations of the department in
regard to the hauling of hay or manure without covers, and

SPRAYING.

55

other matters relating to team traffic. The police outposts
were inspected by Professor Shaler of the committee in
charge of the work, by the director and by the superintend¬
ents, and it was soon seen that the method was impracti¬
cable. A perfect cordon could not be maintained, and the
results obtained were not proportionate to the expense
incurred. At the end of two weeks the plan was abandoned.
In the mean time some good had been done by destroying
caterpillars found on vehicles, and by gaining a knowledge
of the destination of the teaming between badly infested
localities and towns outside of the known infested district.
This knowledge was utilized in the fall inspection.

Spraying.

In April the director’s office was removed to Malden, at a
point near the centre of the infested region and having better
railway communications with the surrounding towns. More
commodious rooms were here secured, and experimenting
with insecticides was begun. Most economic entomologists
concurred in recommending spraying with arsenical poisons
for killing all leaf-eating larvae. Following such advice, ex¬
periments with arsenites were begun. An early supply of
gypsy-moth larvae was obtained by artificial hatching, and
the experimental work was continued during the spring and
summer, the experiments with Paris green giving the best
results. In the laboratory it was found that young cater¬
pillars, fed upon plants to which this poison had been
properly applied, died within a few days. In later experi¬
ments it was noticed that a considerable proportion of the
larger caterpillars survived. In the experimental work in
the laboratory, no injury to the foliage was observed when a
mixture of one pound of this poison to one hundred and fifty
gallons of water was used. Glucose was also added to
retain the poison upon the leaves.

Alien it became evident that Paris green was the most
effective of the arsenites, preparations were made for its use
on an extensive scale. In the first part of May teamsters
were employed, and twenty spraying outfits were put upon
the road in Medford. The number of men and teams was
soon found to be insufficient. Ten additional spraying out-

56

THE GYPSY MOTH.

fits were purchased, and the capacity of each was doubled
by improved appliances. Each outfit with the accompanying
squad of men was under the immediate charge of an inspect¬
or. When the apparatus had been tested and the men had
gained the skill necessary for its intelligent use, the entire
force was sent to the periphery of the region then known to
be occupied by the moth and ordered to work toward the
centre. The infested area was thus sprayed until the middle
of July. At that date numbers of caterpillars were fully
grown and had stopped feeding ; some had pupated and
others were wandering from tree to tree. Other means
were then used for the destruction of both caterpillars and
pupa?.

Considerable opposition to the use of Paris green for
spraying was manifested by many people living in the in¬
fested towns. A mass meeting of opponents of the spraying
was held in Medford. One citizen, who attempted to cut
the hose attached to one of the spraying tanks, and threat¬
ened with violence the employees of the Board who had
entered upon his land, was arrested and fined. ' Others neu¬
tralized the effects of the spraying by turning the garden
hose upon trees and shrubs that had been sprayed, and
washing off the solution. The opposition to the spraying
affected the results of the work unfavorably to a consider¬
able extent. In June a bulletin of information was issued
by the State Board of Agriculture, containing quotations
from Professor Riley and other economic entomologists as to
the lack of danger to man or beast attending the use of Paris
green. This bulletin was distributed freely among the people
of the district, but it failed to allay the popular prejudice
against the spraying.

During the spraying season Professor Riley and Mr. Sam¬
uel Henshaw (at that time an entomological agent of the
United States Department of Agriculture) visited the dis¬
trict and inspected and criticised the operations in the field.

It became evident before the close of the season that the
spraying, while reducing the numbers of the moth, could
not be relied upon as a means of extermination, for many
caterpillars survived its effects. In June, when the cater¬
pillars had reached the fourth molt and begun to cluster in

PLATE X. Trees stripped by caterpillars of the gypsy moth, Arlington,
Mass. From a photograph taken July 9, 1891.

THE SUMMER WORK.

57

cavities of the tree tranks and in other hiding places, they
were destroyed by spraying with insecticides which killed
them by contact. The arsenites have no effect when used
in this way. Burlap bands were also placed about the trees
to serve as artificial hiding places for the caterpillars, and
many were destroyed beneath the bands. This method was
so successful that it was generally adopted, and more than
sixty-eight thousand trees were banded during the season.

Entomological Work.

On June 18 Prof. Charles H. Fernald was appointed en¬
tomological adviser to the committee. Arrangements were
made by which he could give a portion of his time to the
work, and one of his assistants, Mr. E. P. Felt, was em¬
ployed in making observations and experiments. Professor
Fernald critically examined the field work, reported thereon,
and made frequent subsequent visits of inspection to the in¬
fested territory, directing the experiments and giving advice
concerning the work in the field. At his suggestion the in¬
spectors were directed to watch for parasites of the moth in
its various stages. Several parasites were discovered. All
dead pupre found during the season in the central towns were
collected and preserved, in order that the parasites preying
upon them might be obtained. The dead pupae found in the
outer towns of the infested territory were left on the trees,
that the parasites might escape from them and continue their
work. The inspectors were encouraged in their observations
on the habits and life history of the moth. The feeding
habits were made the subject of especially careful observa¬
tion, and all the information thus gained was recorded and
tabulated for future use.

Numbers and Destructiveness of the Noth in the Summer of

1891.

Though a great number of eggs had been burned in the
spring, and thousands of caterpillars had been killed by
spraying, burning, burlapping and other means, they were
still so numerous in the summer of 1891 that some dam¬
age was done in certain localities. A few trees in some
orchards in Malden and Medford were almost defoliated.

58

THE GYPSY MOTH.

In one ease in Medford three apple trees which had been
sprayed were only saved from defoliation by the use of con¬
tact insecticides. Two bushels of dead larvae and pupae
were gathered from the ground beneath these trees. The
injury was most severe wherever a locality had been over¬
looked in the spring inspection, and numerous eggs thereby
allowed to hatch. Early in June a colony of moths was found
in a small grove of trees in Arlington. Although the trees
were sprayed twice with a mixture of Paris green and water
(two pounds to one hundred and fifty gallons), the foliage
was entirely destroyed, and the caterpillars then spread in all
directions through the fields, eating the grass as they went.
In spite of all that was done to stay them, many reached the
woodland one-eighth of a mile away. Others, having de¬
foliated the trees, clustered in masses on the trunks and
branches and about and upon the rocks beneath. These
were finally destroyed by fire. After the larvae upon the
trees and undergrowth had been destroyed, the stones
beneath the trees were overhauled and pupre were gathered
at the rate of about eleven hundred per hour per man.
There were similar but less destructive outbreaks in other
parts of Arlington, and in Winchester, Chelsea and Melrose,
but the one of greatest magnitude occurred in Swampscott.
This was beyond the range of the spring inspection, and the
colony was found in July by an inspector who had been sent
out to search that region for caterpillars. It was situated on
a hillside near Humphrey Street. There were several trees
infested in a yard and others in a small orchard on a hillside
in the rear. Back of the orchard was a pasture somewhat
overgrown with trees and shrubs. On the east and extend-
ing over the highest point of the hill there was woodland
composed of a great variety of trees, both deciduous and
coniferous. Beginning at the edge of the orchard a dense
undergrowth or jungle of creeping vines and bushes extended
into the woodland.

When this colony was first found the caterpillars had be¬
gun eating the foliage of nearly all species of trees and
plants in the immediate vicinity of the house and outbuild¬
ings, and were fast spreading into the woodland and pasture.
A gang of men was sent to the spot with a spraying tank

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RAVAGES OF 1891.

59

which was set on a hill near by. Water was drawn by a
hose from a near hydrant, and the trees, shrubbery and vege¬
tation in the whole neighborhood were sprayed heavily with
Paris green. As this did not appear to check the ravages
of the larvae, the locality was resprayed at once. Within a
few days of the time of the last spraying nearly every green
leaf on several acres was eaten by the caterpillars. This
destruction continued incessantly, and the injury spread in
all directions. Six gangs of men were despatched at once
with orders to surround the infested locality and work
from the outside to the centre, and burn with an oil spray
all undergrowth and everything on which the larvae could
feed, destroying at the same time with the fire all the cater¬
pillars possible. This treatment effectually checked their
diffusion, thereby preventing further injury. The pupae
were raked off the worst-infested trunks and burned or other¬
wise destroyed.

Air. C. R. Drew of Medford, writing of the numbers of
the moth in 1891 at his place, says : —

There seemed to be almost millions of gypsy-moth caterpillars
in 1891 at the corner of Fountain and Salem streets, where I then
lived. They very nearly destroyed a blue pearmain apple tree.
It bore no fruit that year. This tree blossomed out in the spring,
but when it began to leaf out the caterpillars attacked it and every
vestige of green disappeared. It looked as if fire had run through
the tree. Several sweet-apple trees were also badly eaten. You
could hear the noise of the caterpillars eating in the trees at dusk.
They were so thick that you could scrape them off anywhere. They
crawled all over the concrete, and we crushed them as we walked.
We had seats on the grass under the trees, but we could not sit
there because the caterpillars dropped down so thickly. It was
possible daily to gather a half water- bucketful of them, but the
next day they would be just as bad.

Mr. L. B. Sanderson, an employee of the Board, re¬
ports : —

At Mr. Drew’s yard we got one day twenty-two quarts of cater¬
pillars.

Such cases, however, were exceptional, for the greater
portion of moths in the worst-infested places were destroyed

60

THE GYPSY MOTH.

by the agents of the Board of Agriculture before serious
injury had been done.

Fall Inspection and Egg Gathering .

In September, when the moths had laid their eggs, the
force of men was reduced. The most expert employees
were retained, and these were engaged in destroying eggs
in the worst-infested districts of Malden and Medford, until,
by practice, they had become efficient in this sort of work.
As soon as the leaves had fallen from deciduous trees, the
men were sent into the towns and cities beyond the region
which the moth was known to occupy, and the inspection,
which had been interrupted in the spring by the growing-
leaves, was continued. An inspector was assigned to each
town, and instructed to inspect that town hastily, and if
moths were found there to proceed immediately to the next,
and so on until a wide belt of territory around the infested
region had been inspected in which no moths could be found.
Eighteen towns and three cities outside of the known infested
region were thus inspected in November and December.
The moths were found in each of the cities and in four of the
towns, and it was reported to the Legislature that whereas
in the spring the moths had been supposed to be confined to
a few towns, they were now known to be in thirty townships,
as follows : Arlington, Belmont, Beverly, Brighton (Ward
25, Boston), Cambridge, Charlestown (Wards 3, 4 and 5,
Boston), Chelsea, East Boston (Wards 1 and 2, Boston),
Everett, Lexington, Lynn, Lynnfield, Malden, Marblehead,
Medford, Melrose, Peabody, Reading, Revere, Salem,
Swampscott, Saugus, Somerville, Stoneham, Waltham,
Wakefield, Watertown, Winchester, Winthrop and Woburn.

Results of the Work.

During the season of 1891 the work carried on was effective,
inasmuch as it destroyed all the large colonies of the moth,
and protected the fruit and shade trees of the State from
further injury. The spraying and other treatment of the
trees redoubled the fruit crop of the district. The measures
used disposed of the annual increase of the moth, and reduced
the numbers originally found by about ninety per cent.

RESULTS OF THE WORK OF 1891.

61

The inspection of 1891 gave a closely approximate idea of
the size of the region infested by the moth, as it has not
since been found in any numbers or to any distance outside
of the boundaries then laid down. As the work was neces¬
sarily hurried in order to complete it by Jan. 1, 1892, so
that the size of the infested region might be reported to the
Legislature, many small colonies were overlooked. Thus,
though the approximate area of the infested region was
determined, its condition was not thoroughly known at the
close of 1891. It was seen early in the season that the
appropriation made would not be sufficient to exterminate
the moth in one year, but it was thought that $75,000 was
all that could be used to advantage until such time as the
exact area and condition of the infested region could be
ascertained.

62

THE GYPSY MOTH.

The Work of 1892.

On the first of January, 1892, there remained of the
appropriation of 1891 the sum of $5,213.13. This could
have been used to good advantage before January 1, but it
was thought to be of more importance to retain it, so that
the most expert men might be kept at work until such time
as another appropriation would become available. The
nucleus of an organization was thus maintained during the
winter. Early in January, 1892, when the Legislature con¬
vened, the State Board of Agriculture by its secretary made
a report recommending an appropriation of $75,000 for the
vear. Though the money available in 1891 had proved in¬
sufficient to maintain as large a force as was needed to obtain
the best results, the committee deemed it unwise to recom¬
mend more than $75,000 for the work of 1892. The
experience of 1891 had determined that spraying with
arsenical insecticides (the method which had been most
strongly recommended by the best authorities) was a failure
as a means of extermination. The experimental work of the
first year had not resulted in providing a better insecticide,
and further experiments were necessary. Again, much
difficulty had been experienced in securing efficient and
trustworthy men. It was evident that a large portion of
another season must be occupied in selecting and training a
body of men which could be used in organizing a larger force.

Although the moths had been found scattered over a region
of two hundred square miles, there was considerable doubt as
to whether the extent of the infested area had yet been
determined. Though the outlook was not altogether en¬
couraging, nine-tenths of the moths in the region found
infested had been destroyed, and there was no immediate
danger from them so long as they were kept under control.
The committee were confident that the moths could be con¬
trolled and their numbers at the same time still further
reduced with the amount of money recommended, while in
the mean time experimental work could be carried on to
determine the policy for the future.

THE WORK OF 1892.

63

Only forty of the most efficient men had been retained
from the field force of 1891, and by reason of delav in
granting the appropriation, the committee were obliged to
discharge them all. Some of the most capable of these men
soon obtained employment elsewhere, and this loss reduced
the efficiency of the working force. Very little work was
accomplished during the month of February. Finally, on
March 1, an act authorizing an appropriation of $75,000 was
passed by the Legislature. This made it possible to make
arrangements to resume field work, although unseasonable
snow-storms still further delayed the spring inspection. The
old method of scraping the eggs froth the trees and burning
them was discarded, and the eggs were left on the trees and
treated with acids or creosote. The scattering of eggs was
thus avoided.

The experimental work of 1891 resulted in the trial in the
field in 1892 of several new insecticides. Xone of them,
however, proved generally effective, although bromine and
chlorine were useful in destroying eggs in hollow trees.

Professor Fernald had recommended in December, 1891,
‘ ‘ that the nests of the gypsy moth hereafter gathered be pre¬
served in such a way that the eggs of parasites that may have
been laid in such eggs of the gypsy moth be allowed an
opportunity to develop into the perfect insect/’ This plan
was put into operation early in 1892 in the towns of Malden
and Medford. All the eggs gathered were taken to a central
point in each town, and were there kept in a closed case until
all were hatched. As only a single specimen of an egg
parasite was obtained in this way, the plan was aban¬
doned.

Owing to the lateness of the appropriation, which caused
delay in examining and employing men, and the unseason¬
able weather, it was impossible before hatching time to make
a thorough inspection of the infested region, but an attempt
was made to destroy all egg clusters found along the roads.
This was done to prevent the spreading of the caterpillars.
This method was intended to take the place of police out¬
posts on the roads. It was a preventive measure, for, if the
eggs were removed from the trees, there would be no cater¬
pillars to spin or drop down upon the passing vehicles and

64

THE GYPSY MOTH.

teams. It was in this manner that the moths had been dis¬
tributed in former years. Wherever large trees near high¬
ways had been cleared of eggs, they were banded with tree ink
or with “Raupenleim” (“insect lime”) to prevent the cater¬
pillars ascending them from the ground. This was intended
to keep the moth out of such trees for the season. Very
little spraying was done during 1892. Two spraying outfits
were kept busy for a short time, and were sent from place to
place wheie\ er the caterpillars appeared in considerable num¬
bers. The trees in such localities were sprayed when the
caterpillars were small, and many of the latter were killed.
This served to lessen the dissemination. The method of
burlapping trees was used in place of spraying, and was ex¬
tensively employed over most of the infested region. The
force of employees, numbering two hundred and thirty-four
during the spring inspection, was afterwards reduced, but was
again increased during the inspection of burlaps. The ap¬
propriation was not sufficient, however, to provide enough
men to thoroughly examine the burlaps. Notwithstanding
this disadvantage, burlapping and hand-killing during the
summer disposed of nine-tenths of the gypsy moths in the
places known to be infested, and in many localities they
were exterminated by this work alone.

During the fall inspection an attempt was made to search
the country thoroughly, but again the lack of money was
felt, and it was found necessary soon after the first of Sep¬
tember to discharge a large proportion of the force. Only
about forty ot the most expert men could be retained. It
was impossible with this number of men to make a thorough
examination of the entire infested region. A great deal of
effort was devoted to determining whether the moth had
spread farther than had been reported in 1891. A consider¬
able proportion of the later expenditure of the year was thus
used in the towns immediately surrounding the infested
region. But the moth was not discovered in any other
towns in 1892.

The infested region was so well covered by the distribu¬
tion of the force that no serious outbreak of the moth
occurred in 1892. Enough had now been learned of the
condition of the infested territory to convince the committee

PLATE XII. View of woodland at Cedar Hill, Swampscott, showing the progress of extermination.
From a photograph taken in August, 1892, one year after the dead trees had been
cut and the ground burned over. (See plates IX and XI.)

LARGER APPROPRIATIONS NEEDED.

65

that larger appropriations were needed. They believed that
they had now learned by experience how to eradicate the
moth. A large number of colonies had already been exter¬
minated, and it had been proved that the moths could be ex¬
terminated wherever they were found. The committee in its
annual report to the Board recommended that an appropri¬
ation of $165,000 be granted for the work of 1893. The
report was accepted by the Board, and presented to the
Legislature of 1893. The report begins as follows : —

In presenting the report of the gypsy moth department of the
State Board of Agriculture, in accordance with the provisions of
chapter 210, Acts of 1891, the committee desires to call attention
to the fact that this effort to exterminate the Ocneria disjjar is the
first attempt on a large scale ever made in this Commonwealth to
destroy a species of insect, consequently there was no trustworthy
experience to guide the work. As it was an imported insect, its
habits and peculiarities in this country had to be ascertained
before the most effective methods of destruction could be deter¬
mined.

Much of the work that has been done may be considered as in
a measure experimental. As we have become more familiar with
the extent of the territory invaded by the moth, the magnitude of
the task has become more apparent. "When the Legislature made
the first appropriation, it was supposed that the moth occupied
but a small part of one town. Careful inquiry has shown that it
infests thirty cities and towns. From our observations we have
n > doubt that it was in nearly every one of these localities in 1890,
when the campaign of extermination was commenced.*

During the year much had been done toward inspecting
the towns on the borders of the infested district. Of this,
the committee reports : —

Much effort, involving a large expenditure, has been devoted to
the inspection of territory outside the infested limit. Numerous
letters have been received from different parts of the State and
from adjoining States, to the effect that supposed gypsy moths
had been found. These notices have in all cases led to an inspec¬
tion of the suspected locality. The toAvns just outside those

* Report of the State Board of Agriculture on the Extermination of the Gypsy
Moth, January, 1893, page 5.

66

THE GYPSY MOTH.

infested have also received some attention, bnt in no case has the
gypsy moth been found outside of the limits reported last year.*

Such expert men as could be spared from other work had
been detailed to examine as much as possible of the large
wooded region in the infested territory, so that its condition
might be reported on as fully as possible to the Legislature.
The woodland was found to be more or less infested, but its
exact condition could not be determined, owing to a lack of
money and trained men. On what was known of its condi¬
tion, the committee based their recommendation for a larger
appropriation, setting forth their plans in regard to it in the
following words : —

We desire to present to the Legislature the state of the problem
and various plans for solving it, with an estimate of the cost of
each class of work for the next year. There are large areas of
woodland in the infested towns. There are points in these forested
districts known to be infested. There are probably other points
where colonies have been established, and possibly many such.
The dense growth of the underbrush in this woodland, and the
thick carpet of dead leaves on the ground, make perfect inspection
almost impossible. There are about four hundred acres of this
woodland, which will, if it is allowed to remain, continue to be an
uncertain element in our problem.

If the timber could be felled and burned on the ground during
the winter and early spring, and the ground carefully burned over
twice during the summer, that element would be eliminated. We
estimate the cost of this work at Si 25 per acre, or a total of
$50,000 ; but we are confronted with the fact that most of the
forest is situated in Medford, Malden, Arlington, Melrose, Win¬
chester and Stoneham, and that much of it is valued for prospective
parks. Its destruction would be considered a calamity by the in¬
habitants of these places.

We believe that with sufficient means, and in several years’
time, these forest lands can be cleared of moths without destroy¬
ing the timber. To accomplish it all the underbrush and all the
decayed and worthless trees must be cut and destroyed by fire,
the ground burned over, and the -whole carefully inspected at least
twice each year. Burlaps must be placed wherever the moth
appears or has been found previous to the clearing up. The latter

* Report of the State Board of Agriculture on the Extermination of the Gypsy
Moth, January, 1893, page 6.

A LARGER APPROPRIATION URGED.

67

plan will in the aggregate cost more than the former, bnt, as the
work need not necessarily be all done at once, and as it could be
done in connection with the other work of the department, utilizing
the time of the men in the winter and early spring, it may be the
best plan to pursue.*

The committee had undertaken to secure as full informa¬
tion as possible in regard to European experience with the
gypsy moth and the methods used in Europe to combat it,
as well as the probabilities regarding its future in this coun¬
try and the destruction which would be caused by it if it
were allowed to spread unchecked except by individual
effort. The information thus gained was tersely embodied
in the report to the Legislature, as a warning to show what
might be expected in the future. Tables of damage done to
crops in the United States by insects were presented in the
field director’s report. The entomologist, who had at first
grave doubts of the possibility of complete extermination,
stated in his report that he had been led to believe that such
a thing was really possible, provided the work were continued
for several years with sufficient appropriations to keep the
entire territory under careful supervision. The State Board
of Agriculture, approving the action of its committee, urged
that the appropriation recommended be granted, and that
every effort be made at once to rid the State of the pest.

* Report of the State Board of Agiiculture on the Extermination of the Gypsy
Moth, January, 1893, page 7.

68

THE GYPSY MOTH.

The Work of 1893.

Pursuant to the recommendation of the State Board of
Agriculture, the joint standing committee on agriculture of
the Legislature of 1893 reported a resolve appropriating
$165,000 for the extermination of the gypsy moth. While
this resolve was before the committee on finance, the com¬
mittee on the extermination of the gypsy moth voted “to
suggest to the committee on finance that they advise the
appointment of a committee of three or five of the Legislat¬
ure to investigate the work of the committee of the Board
of Agriculture during the year 1893, and make such a report
to the next Legislature as in their judgment seems wise.”
Xo such committee was appointed. Members of the Board
of Agriculture appeared before the committee on finance to
advocate the appropriation of $165,000. Expert entomol¬
ogists and many citizens of the infested district also appeared
or sent communications, advising that every possible effort
be made to exterminate the moth, and that the Board of
Agriculture be given the full appropriation. But the finance
committee reported in favor of reducing the amount to
$100,000.

There was considerable delay in granting this appropria¬
tion, and, as the money remaining from 1892 was nearly
exhausted, it became necessary to suspend all field work.
While the work was thus suspended and the committee was
awaiting an appropriation, as in 1892, several of the most
experienced men obtained other situations. This loss reduced
the efficiency of the force. By reason of the delay several
weeks of the best working time of the year passed unutilized.
On April 12 an appropriation of $100,000 was made by the
Legislature. A resolve was also sent to Congress by the
Legislature, asking for $100,000 additional to continue the
work. This resolve got no further than the committee room,
and was never entertained by Congress.

As soon as the appropriation became available, field work
was again commenced. The force of men was increased as fast
as was compatible with their proper examination and training.

VISITS FROM ENTOMOLOGISTS.

69

The short time remaining before egg-hatching time was util¬
ized in destroying eggs in the worst- infested towns, and
searching for them in the outer and less-infested towns.
The trees in infested localities were banded with burlaps.
During the summer the burlaps in the outer towns were
visited daily, and the trees were occasionally examined,
both by the regular men and by special inspectors. By
this means the moth was almost completely eradicated
from such towns, and in some of these towns no eggs were
found during the autumn. Owing to the insufficiency of the
appropriation and the consequent lack of men, the burlaps
in the central towns were not as often visited. As the effec¬
tiveness of this method depends on daily visits to the bands,
the results here were not as satisfactory as in the outer towns,
but the moths were held in check and somewhat reduced in
numbers.

During the summer an experiment in trapping the male
moths was tried, with a view of determining whether the
number of fertile eggs would be decreased thereby. Experi¬
ments with insecticides during the season proved the useful¬
ness of a new insecticide, — arsenate of lead. Raupenleim
was used to a considerable extent in 1893, as it was during
1892, but was not found so effective, perhaps by reason of
its inferior quality.

In May the committee voted to request Professor Fcrnald
to invite six of the most prominent entomologists in the ad¬
joining States to visit the infested region and critically
examine the field and office work, and report the results of
their observations. Prof. Clarence M. Weed, D.Sc., of the
New Hampshire State College, Dr. A. S. Packard of Brown
University, Dr. J. A. Lintuer, State entomologist of New
York, Professor John B. Smith of Rutgers College, State
entomologist of New Jersey, and Dr. H. T. Fernald, profes¬
sor of zoology at the Pennsylvania State College, visited the
territory in the summer, examined and criticised the work,
and reported upon it. Their reports will be found in Ap¬
pendix D. The recommendations of these entomologists
were carefully considered by Professor Fernald and the
director, who reported to the committee that the suggestions
made should be carried out as far as practicable.

70

THE GYPSY MOTH.

With the increased force provided by the larger appropria¬
tion, it was possible to accomplish in 1893 much more than
had been done in former years. Every effort was made to
determine how far the moth had spread, and whether it had
passed beyond the limits of the region known to be infested
in 1891. Careful inspection was made of a large number of
towns on the borderline of the infested region, which resulted
in small colonies being found in three places just outside the
line drawn in 1891. It was evident that these colonies had
been in existence for several years, even before the work of
extermination was begun. One other colony was found at
Franklin Park in Boston. This had evidently been growing
for at least four or live years. Efforts were made to exter¬
minate the moth from the outer belt of towns of the infested
region. These efforts were so successful that at the end of
the year no form of the moth was found in any of the follow¬
ing towns : Beverly, Brighton, Burlington, Charlestown,
Danvers, Lynnfield, Marblehead, Reading, Waltham and
Watertown.

During the season more than eight hundred colonies of
the moth had been exterminated. But a detailed search of
certain portions of the woodland in the infested region, which
had been suspected but had not been known before to be
infested, revealed small colonies scattered here and there,
indicating that while a large proportion of the force had
been concentrated upon the outer towns with a view to
exterminating the moth there, the problem had been increas¬
ing from within by the spreading of the moths into the
woodlands in the interior towns.

The Board of Agriculture in its annual report on the
gypsy-moth work to the Legislature again advised that
everything possible be done to exterminate the moth, and
recommended that $165,000 be appropriated for the work
of the ensuing year. The magnitude of the work and the
possibility of destruction to the forests were stated, and
the plans for dealing with the moth in the woodland were
described. Statements from citizens were given showing the
destruction of trees and garden plants which had been accom¬
plished by the moth in Massachusetts during the years before
the State began the work of extermination.

THE INFESTED REGION REDUCED.

71

It was shown in the report that the region occupied by
the moth had been considerably reduced by the work already
done, and the belief of the committee was stated that with the
appropriation asked for still more could be accomplished
toward reducing the infested area. The report described the
probable condition of the parks, woodlands and farms of
the State should the moth be allowed to go on unchecked.
Every effort was made to place fully before the Legislat¬
ure the necessity of continuing the work with a view to
extermination.

72

THE GYPSY MOTH.

The Work of 1894.

Remembering the experience of former years, and con¬
sidering the likelihood of similar delay on the part of the
Legislature and a consequent embarrassment of the work,
the committee had laid their plans for 1893 so as to retain
a considerable portion of that year’s appropriation with which
to begin the season of 1894. On Jan. 1, 1894, $29,744.69
of that appropriation remained unexpended. This was re¬
tained in order that the most expert men of the force of 1893
could be employed until such a time as the Legislature should
make another appropriation. There were eighty-three men
at work on January 1.

Early in the year, Prof. N. S. Shaler, who had been a mem¬
ber of the committee from its organization in 1891 and who had
been most active and prominent in the work, was obliged to
resign from the Board of Agriculture on account of the press¬
ure of other duties. Since his resignation, however, he has
kindly given his advice and assistance whenever called upon.

On January 16, an order was presented to the Legislature
by Representative Bullock of Fall River, which was after¬
wards adopted. This appears below, together with the
answer made to it by the Board of Agriculture : —

Ordered , That the State Board of Agriculture be instructed to
report in writing to the General Court, on or before the first day
of February next, the following facts and estimates relative to the
work of exterminating the gypsy moth : —

1. The amount appropriated and amount expended annually
for such purpose since the work began.

2. The amount per year which, in the estimation of said Board,
it will be necessary to expend upon such work during the next ten
years.

3. Whether, in the estimation of said Board, it will be neces¬
sary to continue the work of extermination for an indefinite period.

4. If it will not be necessary to continue said work for an in¬
definite period, what is the probable limit of time during which it
will be necessary to continue said work, and what will be the
probable necessary expenditure therefor, in the aggregate, after
the expiration of ten years from date.

THE EXPENSE OF THE WORK.

73

Reply by the Board.

To the Senate and House of Representatives of the Commonwealth of

Massachusetts.

In response to an order of the Legislature under date of Jan.
15, 1894, the State Board of Agriculture, by its gypsy moth com¬
mittee, presents the following “ facts and estimates relative to the
work of exterminating the gypsy moth.” The amounts of appro¬
priations and expenditures have been reported in the several
annual reports of the committee, and a summary of the same ap¬
pears in the report of the work of 1893, now in the hands of the
Legislature. The original bills and pay-rolls, showing the details
of all expenditures, may be found in the office of the State Auditor
in the State House.

The following is a condensed account of the appropriations made
and the amounts expended annually : —

March 14, 1890,
June 3, 1890,
June 3, 1891,

1892,

1893,

Appropriations.

. $25,000 00

25,000 00
. 50,000 00

75,000 00

. 100,000 00

Total appropriated, . . $275,000 00

Expended in 1890 by First Commission.

Salary of commissioners, . $3,1 18 27

W ages of employees, ...... 15,278 32

Other expenses, . 7,142 73

Total expended in 1890, ..... . . $25,539 32

Expended in 1891 by Second Commission.

Balance of salaries due members of

first commission, .... $630 95
Salary of director, one and one-half

months, . 300 00

Wages of employees, .... 10,147 97
Other expenses, including travelling
expenses, teaming, rent, supplies and

tools, . 2,378 54

- $13,457 46

Amounts carried forward.

.$13,457 46 $25,539 32

74

THE GYPSY MOTH.

Amoimts brought forward , .... $13,4.57 46 $25,539 32

Expended in 1891 by the State Boakd of
Agriculture.

Expenses of committee in charge of

the work, . $121 53

Director’s salary, seven and one-half

months, . 1,500 00

Advising entomologist’s salary and ex¬
penses, . 280 84

Wages of employees, .... 41,096 86
Other expenses, including travelling
expenses, teaming, rent, supplies and

tools, . 12,790 86

- 55,790 09

Total expended in 1891, .... - 69,247 55

Expended in 1892 by the State Board of Agriculture.

Expenses of the committee in charge of the work, $130 49

Director’s salary, . 2,400 00

Advising entomologist’s salary and expenses, . 525 60

Wages of employees, . 59,505 03

Other expenses, including travelling expenses,
teaming, rent, supplies and tools, . . . 11,979 84

- 74,540 96

Expended in 1893 by the State Board of Agriculture.

Expenses of committee in charge of the work, . $110 28

Director’s salary, ....... 2,400 00

Advising entomologist’s salary and expenses, . 730 16

Wages of employees, . . . . " , . 59,039 65

Other expenses, including travelling expenses,

teaming, rent, supplies and tools, . . . 13,647 39

- 75,927 48

Total expended to Jan. 1, 1894, . $245,255 31

The estimates called for must, from the nature of the attending
circumstances, be only opinions. The plans for the work of 1893,
for which an appropriation of $165,000 was asked, contemplated
a careful tree to tree search of all the forest land within the in¬
fested territory. This search would have cost a very large sum ;
but as only sixty per cent, of the sum asked was appropriated,
this, with much other work planned for the central district, was
necessarily postponed. It was decided that the work of extermi¬
nation in the outer infested towns and the inspection of the terri¬
tory surrounding them still further out was most necessary and
would contribute most toward extermination. Were the uncer-

FUTURE EXPENSE ESTIMATED.

75

tainties which confront us in the condition of these forest lands
eliminated, our opinions would more nearly approximate to the
character of estimates made by experts when all the conditions of
a problem are known.

In 1893 considerable progress toward extermination was made.
Ten towns were apparently cleared, comprising more than one-third
of the territory originally infested. In 1894, with the appropriation
asked for (8105,000), the committee ought to be able to bring
into the same category Swampscott, Salem, Peabody, Wakefield,
Woburn, Lexington, Winthrop and Franklin Park. This would
leave Belmont, Arlington, Cambridge, Chelsea, East Boston, Ever¬
ett, Lynn, Malden, Medford, Melrose, Revere, Saugus, Somerville,
Stoneham and Winchester still infested. Several of these towns
should be very nearly or quite cleared in 1894. But we have, in
our estimates, left them with the list of probably uncleared. If,
in 1895, 8150,000 is appropriated, the work of that year should
clear all towns but Arlington, Chelsea, Everett, Malden, Medford,
Melrose, Revere, Saugus and Somerville. The moth in these
towns should then be brought to the verge of extermination so
that, with an appropriation of 8100,000, the work of 189G would
be quite likely to bring them very near to the condition of the
cleared towns. During all this time a large amount of this money
must be expended in closely inspecting the towns supposed to be
cleared. In 1897 an appropriation of 850,000 would be necessary
to provide for the completion of the work in the last-mentioned
towns and for the necessary careful reinspection of the whole
territory. We think this appropriation would also provide means
to stamp out any possible remains of colonies supposed to be
exterminated that might be found by the careful reinspection.
For the live succeeding years wm believe that an average annual
appropriation of 825,000 would be necessary to continue the care¬
ful inspection of the whole territory and provide the means to deal
with any colonies that may possibly have been overlooked. While
it is our opinion that it is quite possible to exterminate the moth
if large appropriations, such as have been mentioned, are granted
for the next few years, we believe it also probable that should an
appropriation of only 850,000 per year be granted the work would
have to be continued indefinitely, as a very large proportion of
such an appropriation would necessarily be expended in watching
the outside territory and taking measures to prevent the spreading
of the insect.

Another method of estimating the probable future cost of exter¬
mination would be to multiply the average cost of extermination
per estate in the towns already cleared by the number of estates

7G

THE GYPSY MOTH.

still infested. We estimate the number of estates still infested at
eight thousand. Our records show that the average cost of exter¬
mination, per estate, in the towns cleared has been $41.10. At
the same rate, the cost of exterminating the moth from eight
thousand estates would be $328,800. This statement is made on
the assumption that the estates yet infested are now in no worse
coudition than were those wrhich had been cleared. This computa¬
tion does not include the large sum which must necessarily be
expended in inspecting territory already cleared, that outside which
must be watched, and the cost of reinspection for several years of
these eight thousand estates after extermination is believed to
have been accomplished.

In the opinion of the committee the above-mentioned estimates
afford the closest approximation to a forecast that can wrell be
made. It is proper, however, to state that the questions asked
by the Legislature cannot be answered with certainty.

Respectfully submitted,

Per order of the Gypsy Moth Committee

of the State Board of Agriculture,

Wm. R. Sessions, Chairman.

Jan. 29, 1894.

At the annual meeting of the Board of Agriculture on
February 8, new by-laws were adopted, affecting a reorgan¬
ization of the Board. The committee in charge of the gypsy-
moth work was thereafter known as the “ committee on the
gypsy moth, insects and birds,” and its number was increased
to six.

The following is the article under which this committee
acts : —

It shall be charged with the duties of the .gypsy moth committee,
as provided for in chapter 210 of the Acts of 1891. All matters
relating to birds and insects shall be referred to this committee,
who shall report to the Board from time to time.

The following members of the Board were elected to serve
upon this committee : E. W. Wood of Newton, Chairman,
Wm. 11. Sessions of Hampden, Francis H. Appleton of Pea¬
body, Wm. H. Bowker of Boston, F. W. Sargent of Ames-
bury, and Augustus Pratt of North Middleborough.

MR. APPLETON’S RESIGNATION.

77

In the mean time the recommendation of the Board for an
appropriation of $165,000 for the work of the year had been
considered by the legislative committees. The joint stand¬
ing committee on agriculture had unanimously endorsed the
recommendation and had reported a bill to the House provid¬
ing for an appropriation of $165,000. The committee on the
gypsy moth, insects and birds, together with many citizens
from the infested district, appeared before the committee on
expenditures and urged that the full amount of the appro¬
priation be granted. But the latter committee, disregarding
the recommendation of the committee on agriculture, reported
a bill recommending an appropriation of $100,000. The
committee on the gypsy moth, insects and birds also urged
that a committee of the Legislature, consisting of three or
five, be appointed to fully investigate the gypsy-moth work
during the season and report to the next Legislature. This
was not done.

When it became known later that the Legislature had not
approved the recommendation of the committee, and that only
$100,000 had been appropriated, Mr. Francis H. Appleton,
one of the original members of the committee, tendered to
the Board of Agriculture his resignation as a member of the
committee. The reasons given by Mr. Appleton were that
inasmuch as the committee had plainly stated that a certain
sum must be available in order to do all possible toward
extermination in one year, and as the committee was required
by law to use “all possible and reasonable measures” to
secure the extermination of the moth, and as with the $100,-
000 the committee could do no more, in his opinion, than to
continue the suppression of the moth, he felt it incumbent
upon him to resign rather than to attempt a task which he
believed impossible to accomplish with a less sum than had
been recommended.

As the committee had been elected by the Board and del¬
egated to this work, and as the Board would have no meeting
during the spring or summer, the other members of the com¬
mittee considered it their duty to do all that was possible
with the appropriation made, and report the result to the
Board at its next annual meeting with such recommendations
as should at that time seem best.

78

THE GYPSY MOTH.

On June 19 the executive committee of the State Board of
Agriculture petitioned for an additional appropriation of
$65,000, but the petition was referred by the Legislature
to the next General Court.

The work of destroying the eggs of the moth had been
carried on, whenever the weather permitted, in January,
February, March and April. During these months the Leg¬
islature had been considering the advisability of making the
appropriation recommended by the committee in charge of
the work. On March 6 the committee held a joint meeting
with the Metropolitan Park Commission. Arrangements
were made so that the work of the Board of Agriculture in
the Middlesex Fells might not conflict with the plans of the
Park Commission. The public forest reservation controlled
by the Park Commission and situated in Malden, Medford,
Melrose, Stoneham and Winchester, includes most of the
Middlesex Fells.

On May 1, the appropriation of 1893 having been ex¬
pended, all field work was discontinued. Nothing was done
in the field from that time until May 23, when the Legis¬
lature appropriated $100,000. More than three weeks of
the best working time of the season were thus lost. Those
portions of the infested region in which it had been planned
to destroy the eggs or young caterpillars were left entirely
unguarded and the caterpillars hatched and scattered over
the surrounding country. Thus the delay of the appropria¬
tion made the work far more costly. Trained and experi¬
enced employees were obliged to seek positions elsewhere,
and the indirect loss and delay occasioned were as detrimen¬
tal to the work as the loss of time when the men were laid
off. ‘ ‘ This enforced suspension of the work was most unfort¬
unate, occurring as it did when the men were destroying
the egg-clusters at the rate of thousands per day. Before
work was resumed the remaining eggs had hatched and the
larvae had scattered. Had the work not been thus inter¬
rupted, it would have been possible in many places to
destroy these young larvae en masse by means of burning.”*

* Fourth Report of the Board of Agriculture on the work of Extermination of the
Gypsy Moth, January, 1S95.

VISITS OF ENTOMOLOGISTS.

79

As soon as possible after the appropriation was available
all those experienced and trustworthy men who could be
reached were re-employed. The trees were burlapped and
all haste made to prepare the infested trees for the summer
work. In many places the caterpillars appeared in large
numbers and it required the work of the entire season to
hold them in check.

The hatching and scattering of the caterpillars, which the
delay of the appropriation allowed, necessitated the burlap¬
ping of a greater number of trees and the employment of a
larger force for the summer. There were 624,673 trees bur-
lapped during the summer and 265 men were of necessity em¬
ployed to attend the burlaps. The result was the destruction
at a great expense of a great number of caterpillars, many of
which would not have existed had the appropriation been made
at an earlier date. A large part of the appropriation having
been used in burlapping trees and killing caterpillars during
the summer, it became necessary to discharge a large part
of the force at the end of the burlapping season on August
25. Thirty-three men were then discharged and others
were discharged in September, so that by October 1 only
133 men remained. This force was entirely insufficient to
inspect thoroughly the 220 square miles in the known infested
region, to say nothing of the belt of territory outside of it
which the committee believed ought to be inspected. The
men were kept at work during every day when it was possi¬
ble to work to advantage, and everything was done that
could be done with the small force remaining to inspect the
outer towns of the infested region. It was found necessary
again to neglect the central towns to a certain extent that
the outer towns might be inspected as thoroughly as possible
and that the moth’s spreading might be prevented.

In June Dr. George II. Perkins of the University of Ver¬
mont, entomologist of the Vermont State Agricultural Ex¬
periment Station, visited the infested region upon invitation
of the committee and inspected the work. In July Prof. F.
L. Harvey, botanist and entomologist of the Experiment
Station at the Maine State College, Prof. J. Henry Comstock
of Cornell University, formerly United States entomologist,
and Mr. L. O. Howard, entomologist of the United States

80

THE GYPSY MOTH.

Department of Agriculture, examined the infested region
and inspected the work. These gentlemen gave the com¬
mittee the benefit of their criticism and advice in the field,
and Professors Perkins, Harvey and Comstock made written
reports to the committee. (See Appendix E.)

Mr. Howard, later, in his annual address before the sixth
annual meeting; of the Association of Economic Entomolo-
gists, of which he was president, gave his impressions and
opinions of the work. (See Appendix E.)

During the summer the experiment in trapping male
moths was tried on a larger scale than in 1893. While many
moths were destroyed, the results as a whole were not suc¬
cessful enough to warrant the adoption of the method in
field work. Arsenate of lead (first experimented with in
1893) was used in spraying to a limited extent during the
spring. While more effective than Paris green, it was
determined that it could not be depended upon to exter¬
minate.

The fall inspection in Boston revealed the presence of
moths in three sections of the city not before known to be
infested — Roxbury, Dorchester and the city proper. One
colony was found in each section. Two of them had been
established evidently for several years, but the demands of
the work elsewhere had hitherto prevented an inspection of
this large territory.

The inspection of towns which had been apparently cleared
in 1893 revealed a few egg-clusters or other forms of the
moth in all of them. A careful search of a portion of the
unexplored wooded region revealed a number of small col¬
onies in the Lynnfield woods. With this exception very
few moths were found in any of these towns. The discovery
of the moths in these towns emphasized the necessity of
keeping them under surveillance for a few years after they
had been apparently cleared and as long as there were moths
in any of the adjacent towns.

The discovery of the moths in the Lynnfield woods verified
the prediction which the committee made in 1893, of the
probability of the moth’s existence in the wooded region, and
showed the necessity of a sufficient appropriation to thor¬
oughly search the woodland. The committee in its report

CONDITION OF THE REGION.

81

to the Legislature stated the condition of the infested region
as follows : —

In ten of the outer towns the moth has been apparently extermi¬
nated ; in five more it has been very nearly exterminated. More
than a thousand well-marked moth colonies have been stamped
out of existence. In all of the infested towns such sections as
have been worked over year after year by the employees of the
State Board of Agriculture are now nearly cleared of the moth,
and the general condition of the inhabited and cultivated lands
is better than ever before. Against this favorable condition of
such portions of these towns we must place the fact which has
been revealed by the inspection of the past season, — that the
woodlands in many of the towns are much more generally infested
than has been hitherto supposed. Scattered colonies of the moth
are known in the woods of Lexington, Winchester, Arlington,
Belmont, Stoneham, Medford, Wakefield, Melrose, Malden, Lynn-
field, Saugus, Revere, Swampscott, Lynn and Salem.

This condition of the forested lands is due to the fact that there
has not been money enough to provide for destruction of these
colonies whenever found. It has been impossible, with the means
at our command, to make a thorough search of all this woodland ;
but during the past season special efforts have been made to in¬
spect it so far as was possible under the circumstances, and enough
is now known to justify the presumption that colonies of the moth
are scattered through the woods from Lexington to the sea. Though
many of the colonies found have apparently had their origin within
two or three years, many others originated at least ten years since.
The woodland which is thus more or less infested probably covers
fifty square miles of the central and north-central portions of the
infested district.

In the attempt to exterminate the gypsy moth it was early
ascertained that the species was spread over a region many times
greater than that which was at first known to be infested, and that
it was not confined to lands under cultivation, but had penetrated
to some extent into the woodlands. These discoveries made it
certain that extermination would be extremely difficult, requiring
years for accomplishment even under the most favorable condi¬
tions. The best methods known and used at first wrere not effect¬
ual in securing extermination, and the methods which later proved
effective were so expensive that they could not be carried out over
so large an area without larger appropriations than those which
have been granted.

Although the extent of the infested region, the existence of the

82

THE GYPSY MOTH.

moths in the woods and the great expense of exterminative
methods have been all repeatedly presented to the Legislature in
the annual reports of this Board, the amount appropriated for
each of the past two years has been only about two-thirds of that
recommended by the Board as absolutely necessary to do all that
could be done to advantage under the circumstances.

The law requires the Board “ to use all reasonable measures to
prevent the spreading and to secure the extermination ” of the
moth. The Board has apparently been successful in preventing
the spread of the moth and has considerably lessened the area
known to be infested. It has never had an appropriation sulli-
ciently large to do all that might have been done in one year toward
the extermination of the moth. If the work is to be carried on
under the present statute, and the policy of extermination is to be
continued, we believe that two hundred thousand dollars should be
appropriated for the work of the coming year.

The committee believes that the work of extermination should
be continued, but is also firmly of the opinion that, if the Legis¬
lature is unwilling to appropriate the sum necessary for an aggres¬
sive campaign for extermination, the law should be changed so
that the Board of Agriculture shall be required to conduct the
work only along the line of preventing the spread of the gypsy
moth. The committee further believes that, if the Legislature is
unwilling to provide sufficient funds for restricting the spread of
the gypsy moth and holding it in check, the work should be dis¬
continued entirely. The committee is not in favor of appropri¬
ating inadequate funds for the work in hand. It seems unjust
to require the extermination of the pest while providing inadequate
means for the purpose. The Board of Agriculture has recom¬
mended for each of the past two years an appropriation of one
hundred and sixty-five thousand dollars, believing that sum was
absolutely required for the successful prosecution of the work.
The Legislature has appropriated only one hundred thousand
dollars, or about sixty per cent, of the sum asked for each of
these years.*

* Fourth Report of the State Board of Agriculture on the work of Extermination
of the Gypsy Moth, January, 1895.

PLATE XIII. Oak and pine woods attacked by the gypsy moth. From a
photograph taken in Lexington, July 11, 1895.

THE WORK OF 1895.

83

The Work of 189 5.

The Legislature of 1894 had adopted a resolve request¬
ing the senators and representatives from Massachusetts in
the Congress of the United States to urge upon Congress the
necessity of prompt and vigorous action to exterminate the
gypsy moth, and to use their influence to secure from Con¬
gress an appropriation of one hundred thousand dollars to
assist this Commonwealth in defraying the necessary ex¬
penses of the work.

The Board of Agriculture was notified by the agricultural
committee of the United States Senate that a hearing would
be given on Friday, Jan. 4, 1895, upon the resolve presented
by the Massachusetts Legislature. A committee consisting
of Francis H. Appleton, vice-president, and Wm. R. Ses¬
sions, secretary, of the Board of Agriculture, accompanied
by the director of field work, appeared on January 5 before
the Senate committee on agriculture, and also before the
committee on agriculture of the United States House of
Representatives, at a special hearing upon a resolution in¬
troduced into Congress by Hon. William Cogswell, which
provided for the appropriation asked for by the resolution
of the Massachusetts Legislature. The committee also pre¬
sented the matter to Hon. J. Sterling Morton, secretary of
the United States Department of Agriculture. Later, a re¬
solve appropriating forty thousand dollars for the extermina¬
tion of the gypsy moth passed the United States Senate but
was defeated in a conference committee chosen from both
houses.

At the annual meeting of the Board of Agriculture, Feb.
6, 1895, Mr. Wm. H. Bowker, a member of the committee
on the gypsy moth, insects and birds, retired from the Board,
his term having expired on that day. Mr. Bowker had been
a prominent member of the Board, and its reorganization
was the outcome of his suggestions. The two vacancies in
the membership of the committee, left by the resignation in
1894 of Mr. Appleton and the retirement of Mr. Bowker,

84

THE GYPSY MOTH.

were filled by the election of Messrs. John G. Avery of
Spencer and S. S. Stetson of Lakeville.

The report of the Board of Agriculture, containing a recom¬
mendation for an appropriation of two hundred thousand dol¬
lars, was presented to the legislative committee on agriculture
immediately after its organization in January. Some oppo¬
sition to the appropriation developed in the committee, and
the time and attention of the members were occupied for
some weeks with other important measures. This committee
held public hearings during the week beginning February 11,
at which hundreds of citizens from the infested towns were
present. The preponderance of sentiment was in favor of
granting the appropriation asked for. On March 21 the
committee finally acted upon the matter, and reported a
resolve calling for an appropriation of one hundred and fifty
thousand dollars. Although this amount was looked upon
by the Board of Agriculture as entirely inadequate, there
appeared to be fully as much danger to the work by delay in
making the appropriation as by reduction of its size. The
committee on the gypsy moth, insects and birds therefore
endeavored to urge upon the General Court the immediate
passage of the bill as reported by the committee on agri¬
culture. But it was not until May 17 that the appropriation
of one hundred and fifty thousand dollars finally became avail¬
able. Early in the year the appropriation of 1894 was nearly
exhausted and on February 6 the field force was discharged.
The work of destroying the eggs of the moth, which should
have been carried on during the spring in those portions of
the infested towns not wholly cleared of them in the fall, was
thereby brought to an end. Thus the experience of 1894 was
repeated, but the amount of working time (three months) lost
in 1895, owing to the lateness of the appropriation, was much
greater than in the previous year. The discontinuance of the
field work in 1895 was especially disastrous because occurring
in an early spring which later developments showed was par¬
ticularly favorable for the moths’ increase. The great mul¬
tiplication of the numbers of the moth which occurred during
this favorable season, their scattering abroad and the con¬
sequent injury to trees by their feeding, might have been
prevented by destroying the eggs in the spring.

PLATE XIV. Oak trees stripped by caterpillars of the gypsy moth, Sar¬
gent Street, Dorchester. (Ward 16, Boston.) From a
photograph taken July 24, 1895.

DELAY IN LEGISLATION.

85

When it became evident that there would be considerable
delay in legislation, the committee authorized the director to
employ as a nucleus of an organization such experienced men
as were willing to wait for their pay until such time as the
Legislature should make an appropriation. The office force
was employed ; the records were closed up ; examinations of
applicants for positions on the force were begun ; arrange¬
ments were made for the purchase of supplies ; and other
preliminaries, providing for the early employment of a full
force of men, were arranged. When the appropriation
became available, it was too late in the season to accom¬
plish much by the destruction of eggs, for most of them had
hatched. As the men were put at work, those who were
inexperienced were given a week or more of training in
clearing up infested woodlands and cutting and burning
brush. They were then organized into burlapping gangs
and employed in placing burlap bands around the trees in
infested localities.

It was found necessary to increase the force as rapidly as
the careful selection and examination of men allowed, for the
caterpillars of the moth were appearing numerously wherever
the egg-clusters had not been destroyed. As the season
advanced the great increase in the numbers of the moth was
noticeable. More men than were ever before employed in
the work were engaged to meet the emergency. On July
20 three hundred and fifty men were at work, and even with
this force it was not possible to prevent occasional injury to
foliage in certain places. A swarm of caterpillars appeared
in one locality in Dorchester, within a few rods of the point
where the inspection of the winter previous had ceased on
account of snow. Many of the trees in an oak grove were
defoliated before the presence of the caterpillars was dis¬
covered. Immediate steps were taken to destroy them and
in a short time some eighteen bushels of caterpillars were
killed in this locality.

Various points in the woods of Lexington and Woburn
were found to be swarming with the caterpillars of the gypsy
moth. Here they defoliated several acres of woodland.
Later in the season similar colonies were discovered in the
woods of Medford, one being situated in the southern por-

86

THE GYPSY MOTH.

tion ol the metropolitan park reservation known as the
Middlesex Fells. Others were found in the Saugus woods.
In some of the localities where the moth appeared in num¬
bers in the woods the injury extended over from one to
three acres, leaving the trees as bare as in winter.

\\ herever the forest was defoliated in this manner the
infested trees presented from a distance the appearance of
having been killed by lire. These reddish patches on the
hillsides stood out strongly in contrast with the green of the
summer foliage by which they were surrounded. On enter¬
ing one of these infested spots during the time when the
caterpillars were feeding, one was immediately struck by the
rustling sound caused by their movements and the falling of
their droppings and the bits of foliage which they were con¬
tinually cutting from the leaves. A little later in the season,
during the warmer part of the day, the male moths fluttered
in swarms about the trees while the white females were scat¬
tered over the trunks and branches of trees and upon the dry
leaves on the ground.

Nearly all species of trees and most herbaceous plants in
this badly infested woodland were stripped by the caterpil¬
lars. In some places they ate the foliage of the pines, both
young and old. Some of these trees appear now to be dy¬
ing. But on account of the unusually rapid development of
the moths this season, their consequent maturing and ces¬
sation of feeding, the trees were not continually stripped
throughout the summer ; therefore the deciduous trees began
to throw out new foliage late in July and early in August,
when the female moths were laying their eggs. This rapid
development of the moths during the past season appears to
be unprecedented in this country so far as can be ascertained.
As the probable result, a second brood of the moths appeared
in one locality in Woburn. Young caterpillars were found
leaving the egg-clusters in the first weeks of September.
As the summer waned, many localities in the woods were
found where the egg-clusters of the moth were quite numer¬
ous, bidding fair, if not destroyed, to produce a brood of
caterpillars during 1896 which may prove even more de¬
structive than those of the present season.

This condition of affairs fulfilled the predictions which the

PLATE XV. Woodland colony of the gypsy moth as seen at a distance of
one-third of a mile. The light area in the woods in the background
shows the appearance of a defoliated tract as compared with
the surrounding uninfested trees. From a photo¬
graph taken in Woburn, July 19, 1895.

THE WOODS INFESTED.

87

committee made to the Legislature in former years, namely,
that the moths were distributed generally through the wood¬
land in the inner towns of the infested region, and demon¬
strated that they might prove a serious danger to wooded
parks and forests. Experts were sent into the woods to
examine them as thoroughly as was possible during the
summer. They discovered that a large portion of the Mid¬
dlesex Fells was more or less infested by the moth. At
least one thousand acres of this reservation now appear to
be in this condition. In Saugus a tract of about the same
size appears to be similarly affected, and another even larger,
situated in Woburn, Lexington and Arlington, is also more
or less infested. There are at least three thousand acres of
woodland in the foregoing towns that are now known to be
infested by the gypsy moth. This condition had been sus¬
pected, but the appropriation had never been sufficient to
watch the cultivated lands and highways and also to care
for the forested region.

Throughout the season of 1895, as in previous seasons,
experiments on insecticides were conducted in the field and
observations were made on the habits of the moth and its
enemies. A small building was erected in the Malden
woods for use as an experiment station, and to facilitate the
breeding of parasites and predaceous insects to be used for
experimental purposes. In all probability the results ob¬
tained from observations and experiments in 1895 are more
valuable than those of former years. The experiments and
their results are treated of in the report of the entomologist.

In some localities, where the moths were numerous upon
valuable ornamental shrubs or trees, the foliage was sprayed
with arsenate of lead. Where it was used at a strength of
thirty pounds to one hundred and fifty gallons of water all
the caterpillars appeared to be destroyed.

During the season fire was used with good effect in many
cases to check the ravages of the caterpillars in waste land.

At the time of going to press little can be said of the
results of the work of 1895. It may be predicted, however,
that considering the phenomeual increase of the moths in
those sections where egg killing was not done in the spring
because of the delay of the appropriation, and considering

88

THE GYPSY MOTH.

also the large number of men employed later, the results
of the season’s work will show a greater number of the dif¬
ferent forms of the moth destroyed than at any time since
1891.

We have long feared that unless appropriations suffi¬
cient for complete eradication were granted, some favorable
season might give the moths a sudden impetus which would
cause them to increase beyond immediate control. Such an
emergency has arisen, and in the centres of population, in
cultivated lands and along the highways, it has been fully met.
It is true that in the woodland where the greatest infestation
occurred some injury was done for a time by the moths, but,
in such places, they are now under control, and with vigor¬
ous measures they may be entirely exterminated from these
localities within two or three years. Yet there is a large
wooded region in the north-central towns which never has
been thoroughly cared for and never can be unless larger
appropriations are made. In many portions of this wood¬
land the moths are doubtless steadily increasing in numbers,
and all that has been done or can be done there, with the
means thus far furnished by the Commonwealth, is to check
them whenever they appear in such numbers as to threaten
serious injury to the trees.

The results of the work of 1895 will be presented in the
next annual report to the Legislature.

PLATE XVI. View of woodland infested by the gypsy moth, Swampscott, Aug. 5, 1891

NUMBER OF EMPLOYEES.

89

The Number of Men employed and Work
done, 1890 to 1894 Inclusive.

In order to give an opportunity for comparing the number
of employees and the amount of work done each year we
give tables taken from the pay-rolls of 1890 and the reports
of the years 1891 to 1894 inclusive : —

1890.

Date.

Number of
Men.

Date.

Number of
Men.

Mar.

24-29, .

27

Aug. 4- 9, .

7

“

31-April 5,

57

“ 11-16, .

-

April

7-12, .

74

“ 18-23, .

-

“

14-19, .

62

“ 25-30, .

-

Cl

21-26, .

59

Sept. 1-6, .

-

U

28-May 3,

51

“ 8-13, .

2

Mav

5-10, .

53

“ 15-20, .

2

“

12-17, .

36

“ 22-27, .

4

Cl

19-24, .

65

“ 29-0ct. 4,

5

“

26-31, .

72

Oct. 6-11, .

7

June

2- 7, .

76

“ 13-18, .

5

“

9-14, .

88

“ 20-25, .

18

(l

16-21, .

89

“ 27-Nov. 1,

40

Cl

23-28, .

89

Nov. 3- 8, .

25

cc

30-July 5,

84

“ 10-15, .

28

July

7-12, .

79

“ 17-22, .

28

“

14-19, .

80

“ 24-29, .

30

Cl

21-26, .

42

Dec. 1- 6, .

29

Cl

28-Aug. 2,

9

1891.

Mar.

20, 21, .

16

June

22-27, .

217

“

23-28, .

40

Cl

29-July 4, .

209

CC

30-April 4,

103

July

6-11, .

192

April

5-11, .

129

CC

13-18, .

170

“

13-18, .

140

“

20-25, .

104

CC

20-25, .

146

“

27-Aug. 1, .

106

cc

26-May 2,

167

Aug.

3- 8, .

99

May

4- 9, .

173

10-15, .

98

“

11-16, .

199

“

17-22, .

96

Cl

18-23, .

195

“

24-29, .

88

Cl

25-30, .

211

“

31-Sept. 5, .

83

June

1- 6, .

238

Sept.

7-12, .

75

Cl

8-13, .

242

“

14-19, .

73

1C

14-20, .

211

21-26, .

67

90

THE GYPSY MOTH

18 91 — Concluded.

Date.

Number of
Men.

Date.

Number of
Men.

Sept. 28-Oct. 3,

62

Nov. 16-21, .

45

Oct. 5-10, .

58

“ 23-28, .

43

“ 12-17, .

58

“ 30-Dec. 5,

41

“ 19-24, .

61

Dec. 7-12, .

41

“ 26-31, .

59

“ 14-19, .

42

Nov. 2- 7,

44

“ 21-26, .

42

“ 9-14, .

44

“ 28-Jan. 2,

42

18 92.

Jan.

4- 9, .

46

July

4- 9, .

95

“

11-16, .

46

CC

11-16, .

102

Ct

18-23, .

47

“

18-23, .

120

“

25-30, .

48

“

25-30, .

120

Feb.

1- 6, .

48

Aug.

1- 6, .

126

CC

8-13, .

48

8-13, .

129

C(

15-20, .

31

cc

15-20, .

122

“

22-27, .

68

cc

22-27, .

107

CC

29-Mar. 5,

88

cc

29-Sept. 3, .

107

Mar.

7-12, .

111

Sept.

5-10, .

97

ct

14-19, .

127

cc

12-17, .

95

“

21-26, .

141

cc

19-24, .

37

ct

28-April 2,

191

“

26-30, .

33

April

4- 9, .

219

Oct.

3- 8, .

38

“

11-16, .

234

cc

10-15, .

36

“

18-23, .

233

“

17-22, .

37

“

25-30, .

230

cc

24-29, .

37

]\lay

2- 7, .

232

“

31-Nov. 5, .

38

Ct

9-14, .

183

Nov.

7-12, .

38

“

16-21, .

140

CC

14-19, .

37

cc

23-28, .

140

cc

21-26, .

34

“

30- June 4,

91

cc

28-Dec. 3,

36

June

6-11, .

90

Dec.

5-10, .

36

cc

13-18, .

87

cc

12-17, .

35

“

20-25, .

89

“

19-24, .

34

cc

27-July 2,

93

cc

26-31, .

•

33

1893.

Jan.

2- 7, .

30

Mar.

20-25, .

8

“

9-14, .

28

CC

27-April 1, .

27

“

16-21, .

28

April

3- 8, .

44

“

23-28, .

27

CC

10-15, .

93

CC

29 -Feb. 4,

25

“

17-22, .

115

Feb.

6-11, .

24

“

24-29, .

125

“

13-18, .

24

May

CC

1- 6, .

128

cc

20-25, .

22

8-13, .

132

“

27-Mar. 4, .

25

cc

15-20, .

132

Mar.

6-11, .

25

cc

22-27, .

132

4

13-18, .

—

cc

29- June 3, .

131

NUMBER OF EMPLOYEES

91

18 9 3 — Concluded.

Date.

Number of
Men.

Date.

Number of
Men.

June

5-10, .

128

Sept.

18-23, .

93

“

12-17, .

131

25-30, .

89

U

19-24, .

132

Oct.

2- 7, .

86

“

26-July 1,

149

“

9-14, .

85

July

3- 8, .

153

“

16-21, .

89

10-15, .

154

“

23-28, .

88

U

17-22, .

147

it

30-Nov. 4, .

88

“

24-29, .

151

Nov.

6-11, .

88

“

3l-Aug. 5,

146

“

13-18, .

88

Aug.

7-12, .

144

“

20-25, .

85

14-19, .

126

U

27-I)ec. 2, .

85

“

21-26, .

125

Dec.

4- 9, .

85

“

28-Sept. 2, .

121

U

11-16, .

86

Sept.

4- 9, .

101

u

18-23, .

85

11-16, .

95

25-30, .

83

1894.

Jan. 1- 6,

82

June 25-30, .

261

“ 8-13, .

86

July 2- 7, .

265

“ 15-20, .

85

“ 9-14, .

270

“ 22-27, .

86

“ 16-21, .

265

“ 29-Feb. 3,

83

“ 23-28, .

270

Feb. 5-10, .

82

“ 30-Aug. 4, .

261

“ 12-13, .

82

Aug. 6-11, .

266

“ 14-17, .

23

“ 13-18, .

260

“ 19-24, .

81

“ 20-25, .

216

“ 26-Mar. 3,

81

“ 27-Sept. 1, .

15

Mar 5-10,

82

Sept. 3- 8, .

16

“ 12-17, .

84

“ 10-15, .

147

“ 19-24, .

85

“ 17-22, .

148

“ 26-31, .

91

“ 24-29, .

133

April 2- 7, .

95

Oct. 1- 6, .

133

“ 9-14, .

121

“ 8-13, .

131

“ 16-21, .

157

15-20, .

123

“ 23-28, .

159

“ 22-27, .

125

“ 30-May 1,

156

“ 29-Nov. 3, .

128

May 2- 9,

15

Nov. 5-10, .

128

“ 10-12, .

164

“ 12-17, .

133

“ 14-19, .

173

“ 19-24, .

133

“ 21-26, .

213

“ 26-Dee. 1,

132

“ 28- June 2,

228

Dec. 3- 8, .

132

June 4- 9,

230

“ 10-15, .

134

“ 11-16, .

229

“ 17-22, .

135

“ 18-23, .

225

“ 24-29, .

132

Summary of Work done during Four Years.

During the year 1890 no account of the number of dif¬
ferent forms of the moth destroyed was kept by the first

92

THE GYPSY MOTH.

commission, and the reports of the work are not in a form
that can be used in making tables of the kind given below.
It would have been almost impossible to keep any accurate
account of the immense numbers of the moth destroyed
during 1890. This was also true of the first few months of
1891. Therefore no figures or estimates of the numbers
killed during those years are given in the tables. The
egg-clusters destroyed during the first weeks of 1891 were
estimated at eight cart-loads. During the latter part of
that year a systematic account was kept of the number of the
different forms of the moth found on each infested estate, and
from that and the other accounts of the season, a somewhat
incomplete table of the work of 1891 has been made. A
fuller account is given of the work of the succeeding years.
Yet even this summary cannot be considered as complete,
for the tables pertain mainly to the hand work done annually,
and only such figures are given as from their nature can be
accurately recorded. Obviously no account could be kept
of the number of moths destroyed by spraying, fire and other
wholesale measures.

It will be seen that though a larger number of men was
employed in 1893 and 1894 than in 1892, fewer trees were
found infested in the later years, although the number of
the different forms of the moth killed by hand was larger.
This may be chiefly accounted for by the extension of the
work into woodlands in the inner towns, where the moths
had increased unmolested. In badly infested places in the
woods the number of moths per tree was very great. Many
caterpillars, pupae and egg-clusters were destroyed in bushes
and young growth. This greatly swelled the sum total of
forms of the moth destroyed. The larger appropriation of
1894 made this woodland work possible.

1891.

1893.

1893.

1891.

Trees (fruit, shade and forest) : —

Inspected, .

3,591,982

2,109,852

4,108,494

6,828,229

Found to be infested with caterpillars,
pupa;, moths or eggs, ....

213,828

108,428

44,716

48,752

Cleared of eggs, .

212,432

99,989

12,172

2,068

2,176

Cemented .

19,296

4,583

7,844

Banded (insect lime or tree ink), .

12,000

21,251

19,453

SUMMARY OF WORK

93

1801.

1803.

isoa.

1804.

Trees (fruit, shade and forest) — Con.
Burlapped, .

68,720

110,108

419,434

624,673

Sprayed, .

177,415

7,372

5,145

14,857

Trimmed .

-

-

1,906

8,618

Scraped, .

-

-

2,406

6,068

Cut, .

-

395

4,055

10,296

Acres of brush land and woodland cut
and burned over, .

120

115

184

336^

Buildings : —

Inspected, .

87,536

22,102

8,828

27,430

Found to be infested, ....

3,647

1,557

348

508

Cleared of eggs, .

3,574

1,427

232

55

Wooden fences : —

Inspected, .

53,219

24,936

15,092

35,276

Found to be infested, ....

6,808

2,365

713

798

Cleared of eggs, .

6,570

2,159

541

99

Stone walls : —

Inspected, .

-

2,213

814

1,620

Found to be infested, ....

-

672

225

423

Cleared of eggs, .

-

354

93

44

Number of each form of the moth destroyed
by hand . —

Caterpillars, .

935,656

1,173,351

1,153,560

Pupm, .

-

80,021

77,029

92,225

Moths, .

-

9,338

5,655

18,084

Hatched or infertile egg-clusters,

-

40,954

6,868

18,036

Unhatched and probably fertile egg-
clusters, .

-

99,790

46,101

94,706

94

THE GYPSY MOTH.

The Increase and Distribution of
the Gypsy Moth.

The Rate of Increase.

The study of the increase and dissemination of the gypsy
moth in Massachusetts is most interesting. Perhaps there
never has been a ease where the origin and advance of an
insect invasion could be more readily traced. As the moth
appears to be confined as yet to a comparatively small area,
and as the region has been examined more or less thoroughly
for five successive years, the opportunities offered for the
study of the multiplication and distribution of the insect
have been unequalled.

When it is considered that the number of eggs deposited
by the female averages from 450 to 600, that 1,000 cater¬
pillars have been seen to hatch from a single egg-cluster,
and that at least one egg-cluster has been found containing
over 1,400 eggs, there can be no doubt that the reproductive
powers of the moth are enormous. Mr. A. H. Kirkland has
made calculations which show that in eight years the unre¬
stricted increase of a single pair of gypsy moths would be
sufficient to devour all vegetation in the United States. This,
of course, could never occur in nature, and is mentioned
here merety to give an idea of the reproductive capacity of
the insect.

It seems remarkable at first sight that an insect of such
reproductive powers, which had been in existence in the State
for twenty years, unrestrained by any organized effort on the
part of man, did not spread over a greater territory than
thirty townships, or about two hundred and twenty square
miles. Some of the causes which at first checked its increase
and limited its diffusion in Medford have already been set
forth (pages 5-7 ) . Most of the checks which at first served
to prevent the excessive multiplication of the gypsy moth in
Medford operate effectively to-day wherever the species is iso¬
lated. True, it has now become acclimated. But any small
isolated moth colony still suffers greatly from the attacks

ITS RATE OF INCREASE.

95

of its natural enemies and from the struggle with other
adverse influences which encompass it. The normal rate of
increase in such isolated colonies as are found to-day in
the outer towns of the infested district is seen to be small.
The annual increase can be readily ascertained by noting
the relative number of egg-clusters laid in successive years,
the uuhatched or latest clusters being easily distinguished
from the hatched or “old” clusters, and the age of these
latter, whether one, two, three or more years, being indi¬
cated by their state of preservation. The ratio of the aver¬
age annual increase of ten such colonies was found to be
6.42, — that is, six or seven egg-clusters on an average may
be found in the second season to one of the first season.

Though even at this rate of increase the progeny of a
single pair of moths would be numerically enormous within
twenty years,* yet for the first few years, under normal con¬
ditions, the increase of a small and isolated moth colony is
not great enough to work any serious or extended injury.
The great army of moths does not advance rapidly by the
skirmish line, as it were, but only by the main body, for a
great increase and rapid spread to a distance can only occur
where the moths have become so numerous over a consider¬
able area as to have nearly reached the limit of their food
supply.

Conditions favoring Rapid Increase.

When any colony under average normal conditions has
grown to a considerable size and then receives an added
impetus from exceptionally favorable conditions, its power
of multiplication and its expansive energy are greatly aug¬
mented and its annual increase rises above all calculations.!
Under such influences hundreds of egg-clusters will appear
in the fall where few were to be seen in the spring, and
thousands are found where scores only were known before.
It is probable that the season of 1£89 was particularly favor-

* At this ratio the number of egg-clusters produced in the twentieth year would be
14,148,179,507,899,404.

f The increase of these large colonies seems to be limited only by the supply of food.
Whenever food becomes scarce many of the moths are less prolific. The larvse which
do not find sufficient food either die or develop early, and the female moths lay fewer
eggs than those which transform from well-nourished caterpillars.

96

THE GYPSY MOTH.

able for the moths’ increase. The season of 1894 and that
of 1895 appear also to have furnished conditions especially
favorable for an abnormal multiplication of the insect.

The operation of the causes of these sudden outbreaks
is not fully understood. It is evident, however, that the
warm, pleasant spring weather of the past two years (1894
and 1895) hastened the development of the caterpillars,
thereby shortening their term of life. The length of life of
the caterpillar varies from six to twelve weeks. During cold,
rainy weather the caterpillars eat little and grow slowly.
During warm, dry weather they consume much more food
and grow with great rapidity. In the unusually warm
spring and early summer of 1895 many of the caterpillars
moulted a less number of times than usual, and their length
of life did not exceed six or seven weeks. Under these
conditions they proved more quickly injurious to foliage
than in a more normal season, and were more completely
destructive within any given area in which their numbers
were great. And they were not so long exposed to the
attacks of their enemies. While it may be true that the
parasitic enemies of the moth will also develop rapidly
under conditions that hasten the growth of their host, birds
and other vertebrate enemies will secure fewer of the moths
in six or seven weeks than in ten or twelve. This would
probably be true of many predaceous insects. It is believed
that dry weather is unfavorable for vegetable parasites of
insects, but to what extent the caterpillars are affected by
them in a humid season it is impossible to say.

The past two years have been “ canker worm years” in
the infested region. Many of the birds which habitually
feed on the caterpillars of the gypsy moth have been largely
occupied during May and the early paid of June in catch¬
ing canker worms, which they seem to prefer, turning their
attention to the gypsy-moth caterpillars in the latter part
of June and July, when the canker worms have disappeared.
The birds, therefore, have not been as useful in checking the
increase of the gypsy moth as in years when the canker worms
were less numerous.

A few of the restraining influences which have been less
active than usual during the past two years have been men-

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CONDITIONS FAVORING INCREASE.

97

tioned, and possibly many others have escaped observation,
but those given may serve in a measure to explain the un¬
usual increase of the moth. It is during such seasons that
its destructiveness is most apparent. It is then that the
groves and forests are stripped of their leaves, and whole
rows of trees in orchards and along highways appear to have
been stripped in a single night.

Distribution as affected by Food Supply and other
Natural Causes.

If the number of gypsy-moth larvae in a given territory
is small and their food supply is large, they do not usually
spread of their own volition to any appreciable extent. So
long as the supply of food is abundant and accessible the
caterpillars usually remain on or near it, and will move only
when disturbed or dislodged from the trees or other plants
on which they feed. In such cases they will reascend the
same tree or crawl to near-by vegetation. When a tree is
overcrowded with caterpillars, and by reason of their vo¬
racity food becomes scarce, they will crawl rapidly in all
directions in search of it, and thus they spread out from a
common centre over a limited area. Wherever the moth is
introduced it has the advantage of such species as the canker
worms ( Paleacrita vernata and Anisopteryx pometaria) and
the tent caterpillar ( Clisiocampa cimericana ) , which are con-
tined to a few kinds of food plants. Because of the great
number of its food plants it is capable of subsisting in almost
any locality whereto it may migrate or be transported. Its
spreading is, therefore, more general and its distribution less
localized than that of the canker worms. But as the female
moth does not fly, the species is limited in its powers of
migration, and though the larger caterpillars are very rest¬
less, their movements show little method except when food
becomes scarce. It has been seen that isolated colonies of
the moth in woodlands not frequented by men do not often
spread to a considerable extent until the caterpillars have
increased in numbers so as to destroy all the foliage in the
originally infested localities. They then migrate in search
of food, and when this movement is once begun they some-

98

THE GYPSY MOTH.

times scatter to a considerable distance. Though this is the
rule there are some exceptions. In some localities, presum¬
ably where the larvae are persecuted by many enemies, they
are found scattered abroad over a considerable area even
when food is abundant.

The moths are sometimes distributed by birds. Many
birds feed upon the caterpillars, and in some cases they have
been known to drop them alive while carrying them to their
young. As the larvae are very hardy and are likely to
survive rough treatment, they may be scattered somewhat
in this way. Some of the distribution in woodlands may
be thus accounted for. The smaller larvae may even be
occasionally carried a short distance on the feathers of a
bird. The caterpillars are also occasionally transported
by the wind. As they hang by threads from the trees
they are sometimes swept off by sudden gusts of wind and
carried to a distance of perhaps a hundred yards. As the
moths are found distributed along running streams, it is
probable that caterpillars and imagoes are occasionally swept
down stream, and that now and then an egg-cluster is car-
ried away on a floating piece of bark or dead twig or branch.
Pieces of driftwood with eggs upon them have been found
on the banks of streams and on the shores of islands in
ponds. Egg-clusters thus exposed to the action of water
have been known to hatch. The moth has been distributed
in the same way along tide-water streams and even to trees
and bushes growing on spots above the level of tide-water
in salt marsh. Wherever the insect is numerous the eggs
are sometimes laid on the leaves of the trees. They are fre¬
quently laid on dead leaves on the ground. In either case
the leaves may be afterwards blown to some distance by the
autumnal winds. Egg-clusters may be broken during gales
by the branches of a tree beating against each other or the
trunk, and the scattered eggs will then be blown away by
the wind. Other ways in which distribution might happen
will occur to those familiar with the subject. But the pe¬
culiar distribution of the moth over a region more than two
hundred square miles in extent cannot be accounted for
either by the movements of the caterpillars or by any of the
foregoing causes, for there are well-marked isolated colonies

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the gypsy moth to population.

CAUSES AFFECTING DISTRIBUTION.

99

at a distance of a mile or more from other infested localities.
When the action of the regulative influences which at first
checked the increase of the moth and the limitation of its
powers of locomotion are considered, it seems improbable
that the moths could have spread over thirty townships in
less than twenty years unless transported by some human
agency.

The Connection of Distribution and Population.

The study of the infested territory made in 1891 showed
that the most densely infested areas were very nearly coin¬
cident with the centres of population. In other words, the
moth colonies were larger and more numerous in or near
thickly populated districts. (See map IV.) It was noted
that as the inspection receded from Medford, where the moth
was first introduced, the towns w7ere less and less infested.
When, in this inspection, the centre of a town next adjoin¬
ing Medford was reached many moths were found. As the
centre was passed they grew less numerous until few, if any,
appeared along the highways. Such trees as were found
infested were generally near farm-houses and other resi¬
dences. On approaching the next town the moths were
again found in considerable numbers, although not as nu¬
merously as in the first town. After the second town was
passed none were found upon the country roads leading
farther out. This led to the hope that there were no
moths in the region beyond. But an inspection of the next
town revealed a few, while in the towns beyond none were
found.

Outside of Medford the moths were most numerous in
portions of the cities lying nearest to that town, such as
Malden, Chelsea, Somerville and Cambridge. Next, the
larger towns, as Melrose, Arlington, Belmont and Win¬
chester, and the more distant cities, Lynn and Salem, were
most infested. Comparatively few moths were found in the
more sparsely settled towns, like Lynnfield, Reading and
Lexington. This distribution of the moth along the roads
and over populated districts led to the assumption that
man wTas accountable for its diffusion as well as its intro¬
duction.

100

THE GYPSY MOTH.

The Distribution of the Moth by Man’s Agency.

The distribution of the moth by man, and the means by
which it was accomplished, will be better understood if a
description of the territory comprised by the infested towns
and cities is tirst given.

This region extends along the coast of Massachusetts Bay
from Boston harbor to the Beverly shore. North of Boston
a considerable portion of the land surface next to the shore
consists of salt marsh, penetrated here and there by tidal
streams like the Mystic and Saugus rivers. Nahant and
Marblehead Neck are bold, rocky peninsulas extending out
into the sea. The Salem “Great pastures,” lying not far
from the sea, consist of rolling pasture land covered to some
extent with a scrubby growth of red cedars and the charac¬
teristic barberry and other wild shrubs of the locality.

A long beach extends along the outer border of the salt
marsh from the Saugus River to the shores of Beachmont,
and is known locally as Crescent or Revere Beach. It is a
popular summer resort. High bluffs front the sea on the
Winthrop peninsula, and beyond them to the south is a
strip of gravelly shore called Winthrop Beach. A tide of
summer travel ebbs and flows along all these shores.

Back from the shore in the valley of the Mystic River an
open and quite level country extends from the salt marsh
through Medford and Arlington to the Mystic lakes, where
the river has its source. The Charles River valley through
Cambridge, Watertown and Waltham consists of a beautiful
open country. A range of rocky hills traverses the north-
central portion of the infested district and extending northerly
and easterly from Lexington reaches the sea at Marblehead.
At the Marblehead shore these hills are almost treeless, but
in Swampscot-t and through Lynn, Saugus, Melrose, Malden,
Medford, Stoneham, Winchester, Arlington and Lexington
they are more or less clothed with trees. This rocky, wooded
region is of no great agricultural value. Portions of it have
been reserved for public parks by the towns and municipal!,
ties. A large tract situated in Malden, Medford, Winchester
and Stoneham has been taken by the State as a public forest
reservation. This region, which is known as the Middle-

DISTRIBUTION BY MAN.

101

sex Fells, contains some of the finest natural scenery in the
eastern part of the State. These rocky hills, crowned
with a growth of pines, cedars, oaks and other characteristic
trees, intersected by running streams with here and there
miniature cascades and occasional reedy fens, together form
a succession of delightfully picturesque scenes of rugged
beauty. 'Woodlands interspersed with open spaces, fresh¬
water meadows, towns, villages and farming lands extend-to
the northern and western boundaries of the infested region.
Nearly all of the southern portion of this region is occupied
by Boston and its adjacent cities.

The situation of the towns and cities of the infested
region, and their relative positions, may be seen by reference
to the map. A large proportion of the population of Mas¬
sachusetts is contained within this district.* Boston and
the cities in its immediate vicinity lie in or near the Charles
and Mystic valleys. It will be seen that Somerville, Cam¬
bridge, Chelsea, Malden, Medford, Everett and Waltham
are all cities lying in the immediate neighborhood of Boston.
Along the shore to the north-east are Lynn, Salem and Bev¬
erly. Woburn is the only city in the north-western part of
the district.

The following cities and towns are comprised within the
territory which is or has been infested : Arlington, Belmont,
Beverly, Boston, Burlington, Cambridge, Chelsea, Danvers,
Everett, Lexington, Lynn, Lynnfield, Malden, Marblehead,
Medford, Melrose, Nahant, Peabody, Beading, Revere, Sa¬
lem, Saugus, Somerville, Stoneham, Swampscott, Wakefield,
Waltham, Watertown, Winchester, Winthrop and Woburn.

The larger portion of the region infested by the gypsy
moth lies north of Boston. Boston’s avenues of communica¬
tion to the north and east and in part to the west run through
it. The main lines of the eastern and western divisions of
the Boston & Maine Railroad pass through the infested
district but east of its centre. Several branch lines lead to
or through different parts of the district. Two lines run
from Boston to Medford, — the Medford branch, ending in

* By the State census taken in 1895 (first count) the population of the cities and
towns of the district infested by the gypsy moth is 963,159.

102

THE GYPSY MOTH.

the centre of the town, and the main line of the southern
division of the Boston & Maine Railroad, passing through
Somerville and West Medford. The old turnpike roads from
Boston to Salem, Newburyport, Lawrence and Lowell all
pass through the infested region. The roads which pass
through this region from Boston lead outward toward the

O O

north, north-east and west.

The continual and immense traffic between Boston and
towns to the northward, coming and going through the badly
infested region, together with that in and out of the region
itself, has resulted in spreading the moth to many of these
outer towns. This has been brought about chiefly by means
of the transportation of caterpillars on vehicles. In the
spring of 1889, and in other years when the moths were in
greatest abundance in Malden and Medford, the young
caterpillars, when disturbed by wind or by any object strik¬
ing the branches, hung in great numbers by their silken
threads from the trees in a manner similar to that habitual
with the common canker worms. While suspended in this
way above the street they were often struck by passing
vehicles upon which they dropped, remaining either until a
stopping place was reached or until shaken off along the
roadside.* Regular teaming, daily or at stated intervals to
or from a badly infested spot during the time when the
caterpillars were very numerous on wayside trees, would
finally result in transporting numbers of them to certain
localities where the wagons stopped. A market gardener’s
wagon going regularly through the infested region to Boston
and return, and passing under infested trees along the way,
would be very likely to carry caterpillars into the yard at the
end of the route. If a single pair of the caterpillars thus
transported survived and passed through their transforma¬
tions, and the resulting pair of moths mated, the seed for a
colony might be planted. Even if one female caterpillar
survived and transformed into a moth, and there were a simi¬
larly surviving male moth in the neighborhood, under favor¬
able conditions the latter might be attracted to the former

* All forms of the moth have been found on wagons standing under trees. The
caterpillars frequently crawl for shelter under the bodies of standing vehicles.

DISTRIBUTION BY MAN.

103

and fertile eggs result. There were many ways in which
the regular traffic with towns round about was kept up to or
through the infested region. Florists and nurserymen were
constantly sending plants to all parts of the region and to
Boston. Truck farmers’ teams hauled loads of produce to
Boston and returned with loads of manure. Expressmen
made their regular trips ; butchers, bakers, peddlers and
milkmen daily went their rounds, and the premises of many
of these people who were constantly driving about the
infested region or through it became infested. During the
summer there was much carriage driving through the in¬
fested district, especially along the North Shore, and this
also served to distribute the moth to some extent. In addi¬
tion to the transportation of the moth in its various forms by
means of vehicles there were other means of distribution
more strictly local. The caterpillars were carried about to
some extent on the clothing of pedestrians and on the backs
of cattle, goats, dogs and other animals.

While the spread of the moth has been mainly due to the
transportation of the caterpillars, the eggs of the creature
were also carried about in various ways. Wood was cut
from infested trees and carried with eggs upon it from one
town to another. Packing cases and barrels left under in¬
fested trees are sometimes selected by the female moth as
receptacles in which to deposit her eggs. Barrels and cases
which had been exposed to such infestation were not only
shipped about through the infested region but were some¬
times sent to a considerable distance outside. If an e<zir-
cluster laid on an article thus shipped escaped destruction en
route, there would be danger of the seed of a new colony
being planted at the article’s place of destination.

Instances of Distribution by Man.

It was learned in 1891 that the area occupied by the moth
was practically included within the boundaries of thirty town¬
ships. Since that time it has been found outside of this
boundary in a few isolated cases only, each of which was
accounted for by the existence of driving or teaming from
the infested district. The moth had reached these places
during the few years previous to 1891, when it was most

104

THE GYPSY MOTH.

abundant in Medford. These years of its greatest abundance
were also the years of its greatest diffusion, for during the
period when it was most numerous on trees, about buildings
and along highways, many more caterpillars were carried out
on vehicles from the worst infested localities than at any time
before or since. From the small size and general appear¬
ance of most of the colonies found in 1891 at a distance from
Medford, it was apparent that they had originated but two
or three seasons previous to that time. On further inspec¬
tion it became evident that the moth had become widely
distributed in 1888, 1889 and 1890 over the region occu¬
pied by it in 1891.

Most of this diffusion to a distance from Malden and
Medford was accounted for by teaming and driving to and
from the district originally infested. Therefore, it may be
termed the primary distribution, as it was caused by trans¬
portation direct from the towns first infested. Here and
there, however, large colonies were found that must have
been growing for eight or ten years. These colonies, if on
or near highways, had already become centres of infestation
from which the moths had been distributed widely, not only
along the roads leading out of the infested locality but also
back toward the originally infested centre by means of
vehicles bound toward Boston. This spreading from these
colonies may be called a secondary diffusion. Of this there
are some interesting examples. From the large colony
in Swampscott (see page 58) the moths were not only dis¬
tributed on to Marblehead but they were also taken back
into Lynn. The Lynn residence of the owner of the place
where the Swampscott colony was situated was found in 1892
to have been recently infested, and it was learned that the
owner had been accustomed to drive frequently to the
Swampscott place and leave his horse and buggy in the yard
under the infested trees.

Early in 1891 a colony was found in North Cambridge in
the yard of Muller Brothers’ tannery. As thirty-five thousand
egg-clusters were taken there the colony must have originated
several years previous to 1891. Dead horses were frequently
carted from Malden and Medford to the Muller place, where
there were at that time facilities for making such use of these

DISTRIBUTION BY MAN.

105

remains as was compatible with their character, age and
general utility. It is probable that the moths were originally
carried there on the wagons which were used for this dolo¬
rous traffic. The Cambridge almshouse Avas situated a few
rods in the rear of the tannery. The city swill Avas hauled
from all parts of Cambridge to this almshouse and Avas then
distributed for miles around to farmers and others who kept
hogs. These swill-takers’ wagons in going and coming were
obliged, to pass under the branches of some badly infested
trees that overhang the street. A tide-water stream ran
through the tannery yard. An inspection revealed that the
ti •ees along the stream for many rods were infested. Here
Avas a secondary centre of distribution of the tirst magnitude.
Persistent efforts were made to stamp out this colony. When
this had been done the locality was carefully watched. As
the country roundabout was inspected the moths were found
scattered all over neighboring portions of Cambridge, Somer¬
ville and Arlington. In 1893 a list of the persons to Avliose
places swill had been teamed was secured from Capt. M. L.
Eldridge, superintendent of the almshouse. This comprised
the names of nearly three hundred people residing in the
following towns : Arlington, Bedford, Belmont, Brighton,
Burlington, Cambridge, Carlisle, Concord, Lexington, Lin¬
coln, Medford, Somerville, Waltham, Watertown, Weston,
Winchester and Woburn. The places of more than fifty
people in the list have since been found to be infested. The
results of the investigation did not indicate that in all cases
they had become infested by the carriage of swill, for it was
seen that some places to which swill had been hauled during
the months when the caterpillars were numerous upon trees
were not infested, while others to which swill had been hauled
in the winter only were infested. Yet it seems probable from
all the data obtained from inquiry in these localities that
more than half the infested places had received infestation
from the hauling of swill from the almshouse.

Localities in the infested district that are much visited on
account of their historical associations are usually found in¬
fested, and if cleared of the moth are likely to become re¬
infested. Many eminent men have been buried in Mount
Auburn Cemetery, which lies partly in Cambridge and partly

106

THE GYPSY MOTH.

in Watertown. This cemetery is often thronged with visitors
from far and near. It was well cleared of the moths in 1892
and 1893, but in 1895 the caterpillars appeared again in
such quantities near the graves of the poets Lowell and
Longfellow that much effort was required on the part of the
workmen employed by the Board to prevent serious injury
to the trees in the cemetery. Though Charlestown was
cleared of the moths in the first three years of the work,
they were found in 1895 at Monument Square. These
grounds about Bunker Hill monument are much frequented.
Many people coming from other parts of the infested region
have visited the monument within a year. The carnival in
Charlestown on the 17th of June, a time when the cater¬
pillars are most numerous, draws thousands of people from
the region round about to the vicinity of the monument.

A Study of the Methods and Routes of Trans¬
portation.

In 1891 hasty inspection of the infested region finally
revealed its apparent extent. This inspection was carried
on until, in 1893, a wide belt around the region had
been examined. The question whether the moths had been
transported to any distance beyond this belt in sufficient
numbers to continue the existence of the species and thus
form other centres of distribution remained unsolved. It
was not possible under the appropriations made to extend
the search over the entire Commonwealth. As it was evi¬
dent that the moth was distributed principally by man, a
study was made first of the nature and direction of the
traffic and travel which had caused the dissemination of the
moth through the region known to be infested ; next a study
was made of such similar traffic as extended to a distance
from the infested region and which, therefore, might expose
other localities to infestation.

In studying methods of transportation special attention was
paid to the steady and constant traffic back and forth between
points within and without the heart of the infested district.
Information was also secured as to the character, routes and
destination of outward freight shipments by road and rail,
and of the vast miscellaneous traffic and pleasure driving

DISTRIBUTION BY MAN.

107

over the road. Inquiries were first made in the inner and
worst infested towns. Supplementary and additional infor¬
mation was gathered later outside the infested district in those
localities known to have had more or less communication with
the “ danger tract” of the infested region during the greatest
prevalence of the moth. This ‘ ‘ danger tract” was the heart of
the infested region (Medford and Malden) because the swarm¬
ing numbers of the caterpillars there had made possible their
frequent transportation by vehicles to other points. At first
there was not so much danger of such transportation from
anywhere else in the infested district because of the com¬
parative scarcity of the moths in other localities and the
usual small size of their colonies. This study shed a flood
of light upon the manner of the distribution of the moths in
the territory originally infested from Medford, and explained
the existence of many colonies in woods and other retired
places. It also indicated the places which had been most
exposed to infestation in the territory lying beyond the
known limits of the moth’s spread.

The investigation of the transportation of the moth was
confined mainly to the traffic and communication to the north,
east and west of Medford. The great bulk of all driving over
the road and the still greater proportion of “ dangerous” or
constant traffic was to the north and west and along the
North Shore to the north-east, and consequently the moth
had been diffused farther in those directions. There is little
constant and direct teaming traffic to any other southern
point than Boston, and the latter place, by reason of the
small number of trees in its business sections, was a com¬
paratively safe point for the reception of such traffic.

In the inquiry in regard to the traffic over the road, all
information possible was obtained concerning the routes of
expressmen and movers, market-gardeners, farmers, milk,
hay and wood dealers, swill-takers, butchers, peddlers and
junk men. Local boards of health and milk inspectors in
and around Boston furnished information by means of which
those engaged in the milk business and in swill taking were
located and their routes ascertained. Much information was
secured in regard to the great market-gardeners’ traffic over
the road between Boston and towns within the infested district

108

THE GYPSY MOTH.

or to the north and west of it. Information was sought in
regard to excursions and picnics to the groves situated on all
sides of the worst infested district. Much knowledge was
obtained in regard to the grounds used by church and Sunday
school picnic parties from Malden, Medford, Revere, Somer¬
ville, Cambridge, Arlington, Melrose, Lynn and Everett.
Places of great public resort, like militia and camp-meeting
grounds, were also noted and were later examined. Facts
bearing upon the hauling of wood to or through the infested
district were carefully gathered. Inquiries were made of
expressmen and movers in regard to the destination of families
which had moved from badly infested localities, and as to
the large amount of summer moving and teaming along the
North Shore, and the amount of teaming over the road weekly,
monthly or yearly between the infested district and centres
of traffic like Lawrence and Lowell. The matters of ship¬
ments of nursery stock and greenhouse plants over the road
and of towns visited and routes taken by peddlers and junk
dealers wTere also investigated. A vast amount of facts
bearing on the subject of miscellaneous driving was also
obtained. The inquiry was not entirely confined to the
heart of the infested district but was extended to less infested
places like Lynn and Salem. The scope of the whole in¬
vestigation quickly broadened. Clues obtained within the
infested district were followed out, and this led to much
additional inquiry in many towns to the north-east, north
and west of the infested region. Every possible fact and
item bearing upon the subject of communication with the
moth-region were obtained. It was not difficult in country
towns to learn who were the regular and who the occasional
visitors to or from the infested district and what was the
nature of their business. The lines of travel were also easily
learned. In cities like Lawrence and Lowell which, although
farther away, were in a sense exposed because of their being
centres of population, lists were obtained of teamsters and
movers who went more or less frequently to the district to
the south and the character of their business was learned.
These local teamsters as a rule made their return trips empty
banded, and thus the danger of moth transportation, except
by the vehicle itself, was avoided.

DISTRIBUTION BY MAN.

109

The investigation and the subsequent inspection based
thereon revealed the important fact that the most dangerous
traffic was that going only a short distance from the centre
of the infested district. A large proportion of this did
not even go out of the district, and nearly all the re¬
mainder went but little farther. The proof of this is ample.
The most dangerous traffic is the steady and constant traffic
back and forth between the same points which, by its regu¬
larity, makes possible the occasional transportation of cater¬
pillars to the same locality. This regular traffic includes the
trips of market-gardeners, farmers, milkmen, swill-takers
and others living in the outer towns of the infested district
or in the towns next beyond, who go daily or weekly in and
out of the heart of the infested district or through it to
Boston and return. Nearly all of the foregoing classes of
people live comparatively near the heart of the infested dis¬
trict. None of them live very far away. In a word, in
proportion as the distance from the heart of the infested dis¬
trict increased, the regularity and frequency of traffic to and
fro decreased, and in the same ratio the danger of moth
transportations and consequent possible establishment of new
colonies diminished. The work of four years has proved
that new colonies at a distance from the infested centre
have owed their origin and rise, not to a single transportation
of the moth but to various cases of the sort which have
been made possible by steady communication over the road
between two points. Even pleasure driving, when con¬
stant and frequent between an infested locality and one out¬
side, has been responsible for the establishment of a new
colony.

In the study of traffic and driving of all sorts over the
road, the question of routes became of the utmost impor¬
tance. The vast aggregate amount of wheeling by its very
existence caused the roadsides of all main highways and the
neighborhoods of hotels, village stores, blacksmith shops
and watering troughs to become more or less exposed, the
danger, of course, decreasing as the distance increased from
the infested district. There were two reasons for this :
first, the great bulk of all wheeling, miscellaneous as well
as regular, did not go to a great distance ; second, the ma-

no

THE GYPSY MOTH.

jority of larvse transported on vehicles are undoubtedly shaken
or brushed off before many miles are traversed.

The possible danger attaching to freight shipments by rail
from Malden and Medford was investigated by an examina¬
tion of “freight forwarded” books at the various stations.
The examination of these books revealed the origin, character
and destination of shipments since 1880. The origin and
character of shipments immediately revealed the danger, if
any, attaching to them. To illustrate : Manufactures and
household goods, constituting the bulk of shipments, com¬
ing as they do from in-doors, are practically safe shipments ;
while articles which have been exposed out of doors, such as
empty boxes, nursery stock, bricks, stones, scrap iron or
builders’ materials, may, if coming from an infested locality,
be dangerous shipments. In this connection the matter of
date of shipment was important. Some articles, by reason
of their place of origin, might be dangerous shipments only
during the larval season ; others, only during the months
when the eggs are the only living form of the moth. Fi¬
nally, the examination of the freight books revealed the
receivers of goods (whether in or out of the infested district) .

The danger of moth transportation on freight sent by rail
was shown by the investigation to be very slight. The
proportion of shipments which on account of their character
or frequency might be considered as dangerous was extremely
small.* The -destination of these being known, it was possible
to do supplementary work in the nature of inquiry and
inspection at these points of destination. In most cases such
work was done.

The matter of shipments of bricks from Medford deserves
special mention in this connection both because of its intrinsic
importance and as an illustration of the methods of inquiry
pursued. The premises of the Anderson Pressed Brick
Company were in the past badly infested. Shipments ot
brick had been made to many points outside the infested
territory. Most cases were investigated and an inspection
made at the places to which the brick had been shipped. In
this work the agents of the Board visited a number of towns

* This is equally true of freight shipments over the highway.

DISTRIBUTION BY MAN.

Ill

widely scattered over the State. Although the danger of
the transportation of the moth in the egg form had appeared
serious, no trace of the insect was anywhere found.*

In addition to the freight shipments, another danger of
moth transportation lay in the possibility of the cars them¬
selves carrying some form of the moth. This might happen
in case a car had stood for some time on a siding near infested
trees or other objects. Two instances are recorded where
egg-clusters have been found on freight cars standing on
sidings. This led to an inquiry into the condition of rail¬
road sidings, whether treeless or not, and if the latter,
whether infested or not. It was obvious that if moths were
transported by cars and new colonies started, these would
be found along the lines of railroad, probably at sidings and
stations. This later led to the inspection, as a measure of
precaution, of the lines of railroad running north and west
out of the infested district, the eastern and western divisions
of the Boston & Maine road being followed out as far as
Portland, Me., the southern division as far as Concord, N. II.,
and the Fitchburg road as far as Fitchburg. In the matter of
possible danger of moth transportation by cars, the shipment
of wood to the Bay State Brick Company in Medford de¬
serves mention. The premises of this brick company are
infested. Thousands of cords of wood are shipped there
yearly from New Hampshire points, and the same platform
cars were in the past often sent back and forth again and
again. A certain amount of danger had unquestionably
attached to this species of traffic. The places of shipment
in New Hampshire were consequently visited and the sidings
in their neighborhood carefully examined, but no trace of the
moth was found. In this work additional information was
secured whenever possible as to any communication between
outside points and the infested region. This inspection of
suspected localities outside the State was rendered necessary
in connection with the policy of extermination, which pro¬
ceeded on the theory that the moth was confined to a limited
area in the State of Massachusetts.

* The danger of transportation of eggs was lessened by the fact that the finest
bricks, the only ones sent to a distance, were cleaned before being shipped.

112

THE GYPSY MOTH.

At the height of the caterpillar plague in Medford, it is
said that it was almost impossible for people going through
the streets leading to the Glenwood station of the Medford
branch railroad to avoid carrying caterpillars which dropped
down upon their clothing from the wayside trees. (See the
statement of Mr. Sylvester Lacy on page 17.) As the rail¬
road ran only from Medford to Boston, there was not as
much danger of the caterpillars being transported to a dis¬
tance by means of the luggage and clothing of passengers
as there would have been had the railroad passed through
Medford to other parts of the State or to other States.
Nevertheless, during 1888, 1889 and 1890 very many cater¬
pillars undoubtedly were carried in this way not only to
Boston but to other parts of the State. Even in 1891 cater¬
pillars were thus frequently carried. An agent of the Board
of Agriculture stated to the writer that in 1891 he took a
gypsy-moth caterpillar from the cloak of a lady standing in
front of the ticket office in the western division station of
the Boston & Maine Railroad in Boston. The lady had
come from Medford and had just bought a ticket for North¬
ampton, a city in the Connecticut valley. Had the cater¬
pillar not been removed from her cloak, it might have been
carried a long distance, or if left upon the cars it might have
escaped observation, dropping off eventually at some point
along the road. If such cases have frequently occurred the
question at once arises, why have not moth colonies been
formed far and wide? While at first sight it would seem
probable that they have been thus formed, yet upon con¬
sideration it is seen that the carriage of caterpillars in this
way to a distance is not necessarily dangerous. The farther
a caterpillar is carried from others of its kind the less be¬
comes the probability of its reproduction. The female moth
does not fly. With favoring winds in open country the male
can find the female, by means of his sensory organs, at a
distance of about half a mile. The change of cars wffiich was
necessary in Boston, and the radiation of the railroads to the
north, east, south and west, served to decrease the chances
of propagation, for the farther a caterpillar was carried from
Boston the greater became the distance which separated it,
not only from the infested region, but from other lines of

DISTRIBUTION BY MAN.

113

railroad leading out of Boston on which other caterpillars
might be carried out. Thus, though many caterpillars might
be accidentally carried to a long distance outside the infested
region, there was very little probability that any number of
such individuals would be dropped within half a mile of each
other. Furthermore, the chances that isolated caterpillars
would complete their transformations and emerge as perfect
insects are very small. Therefore, there would he hardly a
possibility of a colony being started by the accidental trans¬
portation of caterpillars to a distance unless it should be
proved that parthenogenesis (the reproduction of the species
by the virgin female) occurs.* If, however, the moths should
at any time become abnormally numerous on the line of an
extended railway, their chances of accidental distribution by
regular and constant travel would greatly increase and a
wide dissemination would almost certainly follow. So far,
notwithstanding the unhindered carriage of caterpillars in
this way on the Medford branch railroad for several years
previous to 1892, no evidence of the moths’ existence at a
distance from the infested towns has ever been found along
the lines of other railroads.

The Effect of the Work of Extermination on the
Distribution of the Moth.

While the work of destroying the gypsy moth has much
reduced the numbers of the moths and the extent of territory
occupied by them, it has been necessary to exercise great care
to avoid accidental distribution of the caterpillars by the
workmen.

The work of spraying is responsible for some slight local
scattering of the caterpillars. When the branches of a tree are
disturbed by the sprayers, many of the caterpillars spin down
and either fall to the ground or are carried about upon the
clothing of the workmen or others passing beneath the tree.
Unless great care is taken they may be carried from place to
place on the spraying team. Those falling to the ground

* Observations 60 far made in this country have not revealed a case of partheno¬
genesis in this species, but, on the contx-ary, many instances have shown isolation
to result in extermination. A few European instances of parthenogenesis have been
recorded.

114

THE GYPSY MOTH.

frequently crawl to other trees, and if later these trees are
sprayed many of the caterpillars crawl still farther. It is
almost impossible to avoid scattering the moths when spray¬
ing is resorted to, which makes it necessary to spray all
vegetation near an infested spot, that the scattering cater¬
pillars may find poisoned food.

As the work of burlapping has progressed since 1891 the
proportion of caterpillars seeking the shelter of the burlap
appears to have diminished. Many either remain in the
tops of trees or seek out places near the ground in which
to secrete themselves. There also seems to be a tendency
to scatter farther and farther from the infested localities.
These habits may have been induced by the frequent dis¬
turbing of the caterpillars in the work of burlapping, or here
may be another illustration of the survival of the fittest.
When the caterpillars are very young and while the workmen
are placing the burlap bands about the trees they are likely
to dislodge some of the caterpillars which, falling upon their
clothing, may be carried about from place to place. To lessen
the risk of such carriage the workmen in summer are dressed
in a uniform suit of a light color so that any dark object
falling upon them may contrast strongly with their clothing.
The men are also cautioned to examine carefully each other’s
clothing when leaving an infested place. Notwithstanding
this precaution it is possible that a few localities from which
the moths have been entirely exterminated have become re¬
infested in this way, for occasionally a place in which no
form of the moth has been found for a year or two becomes
again infested. In such cases from one to three or four
caterpillars have been found during the season, not a suffi¬
cient number to indicate that eggs had been laid there in the
previous season.

The Distribution Restricted and Changed.

As far as the work of extermination has proceeded it has
radically changed the distribution of the moth. It is often
the case that the most persistent and thorough work will not
exterminate the moths from a locality in one year. It is
necessary to search a locality for several years in order to
be assured that the moths are all destroyed and no seed is

IV. Map showing the region found infested in 1891; the colonies of the moth found since 1891 outside
that region ; and the three principal centres of infestation and distribution in the woods. The moths
are scattered through the southern portion of the woodlands from Lexington nearly to the
sea at Salem. Most of the woodlands, however, are only slightly infested.

ITS DISTRIBUTION CHANGED.

115

left. But we have now sufficient data for the belief that the
moths found in most colonies in the outer towns in 1891,
1892 and 1893 have been exterminated. In this way the
outward spread of the moth to new territory has been
restricted. It has been necessary, as a part of the policy pur¬
sued in preventing the spreading of the moth towards towns
outside the boundary of the infested region, to search carefully
the borders of highways and streets in towns and cities, as it
was from cultivated grounds in populous towns and by high¬
ways leading from the towns that the moths were mostly dis¬
tributed. As the moths in the woods spread slowly, and were
less liable to transportation outside the infested region than
those in the residential and business sections, work was con¬
centrated upon these districts to the neglect of the woodland.
As has already been stated, the centres of distribution in 1891
coincided with the centres of population, and in the attempt to
clear these centres and prevent injury to valuable trees and
plants the larger part of each appropriation was used. From
what was learned yearly by the woodland searchers it was be¬
lieved that the moths were increasing and spreading in the
woods. The committee in charge of the work stated this be¬
lief year after year to the legislative committees and strongly
urged in their reports to the Legislature that more money be
appropriated for the inspection of the woodlands and the
destruction of the moths within their borders. Sufficient
appropriations not being forthcoming the result of the neg¬
lect of the woodland is now shown in the present distribution
of the moth. The normal diffusion from centres coinciding
with the centres of population has given place to a much
slower dissemination from centres situated in the woodlands
of the north-central infested towns. Though much work
has been done in these woodlands it has been from necessity
superficial and has merely resulted in partially holding the
moths in check. In some localities where the woods were
not searched the increase and spread have been unimpeded
because the colonies were not known.

In the report of the work of the year 1894, made by the
Board of Agriculture to the Legislature, it was stated as
probable that the moths were scattered through the woods
from Lexington to the sea. That this probability has be-

116

THE GYPSY MOTH.

come a certainty is shown by the developments of the season
of 1895. As has before been stated, there are in this region
three centres of infestation of at least a thousand acres each.
(See page 87.) These centres are included in a belt of wood¬
land a mile in width, which is all more or less infested,
reaching with some interruptions from East Lexington to
Salem, a distance of about eighteen miles.

As compared with 1889 the moths in open and cultivated
lands are now much reduced in numbers in the worst in¬
fested sections and are elsewhere extinct or comparatively
rare. On the other hand, in the belt of woodland north of
the centre of the infested region they occupy more ground
than in 1889, and the number of badly infested places is

greater.

©

PLATE XVIII. Destroying the eggs of the gypsy moth in a stone wall by means of the cyclone burner.

From a photograph taken in Medford. (See page 121.)

THE DESTRUCTION OF THE EGGS.

117

Methods Used for Destroying the
Gypsy Moth.

The Destruction of the Eggs.

As the egg-clusters of the gypsy moth are of a conspicuous
color and may he found upon trees and other objects during
at least eight months of the year, the possibility of stopping
the moth’s increase by destroying great numbers of cater¬
pillars in embryo becomes apparent. In each buff egg-cluster
temptingly displayed upon the tree trunks during the fall,
winter and spring there are from three hundred to fourteen
hundred potential caterpillars. Destroy the egg-cluster and
apparently you have disposed of the coming brood. You
have prevented the hatching of the eggs and the consequent
spreading of the caterpillars which otherwise would have
scattered abroad, feeding upon nearly all kinds of trees,
shrubs and garden plants. Obviously it is safer, easier and
less expensive to destroy the egg-cluster in which the brood
is united and stationary than to find and destroy the cater¬
pillars after they have hatched and scattered. The destruc¬
tion of eggs may not always secure extermination, as the
female imago sometimes scatters fertile eggs upon the ground,
and concealed egg-clusters may sometimes be overlooked.
Yet persistent and thorough egg-destruction in the autumn,
winter and spring may be relied upon to so reduce the num¬
ber of the moths that they will do comparatively little injury
in the ensuing summer. Egg-killing is recommended by
many European authors as the first and chief method of pre¬
venting the ravages of the moth.

Bechstein wrote in 1804: “The clusters of eggs can be
looked for from the last of September or October to March,
upon the trunks of trees, walls, hedges and fences, and may
be crushed or knocked oft' into a pot and burned by kindling
a fire upon them.” *

Canon Schmidberger, who wrote the papers on “Insects

* “ Vollstandige Naturgeschichte der schiidliehen Forstinsekten,” Leipzic, 1804,
page 372.

118

THE GYPSY MOTH.

Injurious to Fruit Trees” for Vincent Kollar’s work, pub¬
lished at Vienna, Austria, says : “ With respect to destroy¬
ing these insects, the first thing that is necessary is to find
out the egg-masses and destroy them.”*

This method is quite generally employed in European
countries where the gypsy moth is plentiful. We have con¬
ducted a considerable foreign correspondence to determine
what methods are now in use in European countries to check
the ravages of the moth. Under date of Aug. 29, 1895,
Dr. Antonio Augusto Carvalho Monteiro writes from Lis¬
bon, Portugal: “We generally endeavor to kill the larvae
at about the end of June, or to destroy the cottony discs
which enclose the eggs during autumn, by scraping the
trunks of the trees, the walls, etc., and then crushing or
burning them, or sometimes even covering them with a
thick layer of coal tar by means of brushes.”

Professor Henry of the School of Forestry at Nancy,
France, writes under date of July 27, 1895: “The best
thing to do is to kill the heavy female wherever it is met
with, and especially to coat the egg-clusters, generally very
easily seen, with a thick coat of tar by means of a brush at
the end of a pole.”

Prof. N. Nasonov writes from Warsaw University Mu¬
seum of Zoology in Russia, Aug. 7, 1895, stating that the
first method used is scraping the bark from the trees after
the deposit of the eggs.

Prof. Max. Finger ling writes from Leipzic, Germany, on
Aug. 9, 1895 : “ The best method of holding the insects in
check is by destroying their eggs. In this particular case
nature has provided a means in the easily recognizable egg-
clusters.”

When in 1891 the people of the infested region were con¬
sulted by the agents of the second commission for the exter¬
mination of the gypsy moth, it was found that there existed
among them a strong prejudice against spraying, and also a
belief that it was not effective with the gypsy moth. Gather¬
ing the eggs was believed by those who had fought the moth
in Medford to be the most effective method of destruction

* “ A Treatise on Injurious Insects,” by Vincent Kollar, English translation by
J. and M. Loudon, London, 1840, page 202.

BURNING THE EGGS.

119

then in use. Egg-killing was begun by the commissioners,
who, fearing that spraying might not prove effective, deter¬
mined to leave no stone unturned, but to give all promising
methods a thorough trial.

Burning the Eggs.

Professor Fernald had recommended in 1889 that the eggs
of the moth be scraped from the trees and burned. This
was the most effectual method of egg-killing pursued by the
first commission. During the spring of 1891 it was used
by the second commission and later by the employees of the
State Board of Agriculture. The eggs were scraped off or
cut away from the objects upon which they rested, placed in
tin cans and burned in stoves or brush tires. A tierce heat
is required to ensure their destruction. When exposed to
such heat they finally burst with a snapping like a bunch of
miniature fire-crackers or the cracking of corn in a popper.
Whenever the eggs were very numerous in undergrowth or
waste land, fire was run through the dead leaves and debris
as an experiment ; but this method seemed to have little
effect, as the heat was not sufficiently intense. The hairy
covering of the egg-clusters seems to possess remarkable
non-conductive properties, rendering the eggs almost imper¬
vious for a time to sudden intense heat. Even with the
hottest fire that can be applied to the egg-clusters, some
minutes are required to destroy them utterly. A running
brush fire merely scorched the outside of the cluster, killing
perhaps a few of the eggs in the external layer, but leaving
the majority uninjured. Experiments were next made with
crude petroleum, by spraying it over the ground and vegeta¬
tion by means of watering pots and then igniting it. The
fire thus made was fierce enough to destroy the small under¬
growth and the upper layer of leaves, together with most
of the eggs, but such egg-clusters as remained under roots
or rocks were not injured. Considerable oil was wasted by
soaking into the ground, and the remainder did not give
the degree of heat which is obtained by atomizing. Experi¬
ments were then made with a view of perfecting a burning
machine which would incinerate all undergrowth in a given
tract. The first experiments were not entirely successful,

120

THE GYPSY MOTH.

as the machines were either too cumbersome or could not
be used on rough or uneven ground. It was found necessary
to provide an apparatus which would distribute the oil in
a spray, as when thus thrown in fine particles in the air and
ignited, it formed an extremely hot gas flame and was con¬
sumed to the best advantage. For economy’s sake such an
apparatus must be light enough to be carried and operated
by two men, as wagons could not be driven over much of
the ground upon which this work was done. Experiments
were made with the cyclone nozzle. ( Plate XXVII. , Fig. 2. )
An oil spray from this nozzle when ignited was found to

Crude oil was first

used as a burning
©

fluid, but as it is
very objectionable
on account of its
rank odor, “ paraf¬
fine gas ” oil was
substi tuted later.
This oil has less
odor and burns to
b e 1 1 e r advantage ,
but is somewhat
more expensive. A
fifteen-gallon tank
which could be readily carried about by two men was pro¬
vided. On such a tank a Johnson pump with a fine strainer
placed over the suction pipe was mounted, and a short
hose of the kind made for the delivery of oil was attached.
Ordinary rubber hose is worthless for such a purpose, as it
is soon destroyed by the corrosive action of the oil, and in
the mean time the disintegrated particles frequently clog the
nozzle.* A pole, consisting of an iron pipe twelve feet
long, braced by being surrounded by wood for three-fourths
of its length, was coupled to the hose. (See Fig. 1.) No
solder could be used in the fittings of the pipe or nozzle,

give a very hot and effective flame.

Fig. 1. The cyclone burner.

* The best “ oil hose ” that can be obtained will soon become corroded, clogging
the nozzle. If an “automatic clearing nozzle ” could be devised which would with¬
stand the heat, much time might be saved which is now necessarily used in clearing
the nozzle.

BURNING THE EGGS.

121

as the fierce heat of the flame would fuse it. The wooden
cylinder into which the pipe was thrust was one and one-
fourth inches in diameter. The wood, being a non-conductor
of heat, was of great convenience in handling the pole. The
end of the pipe was fitted with a cyclone nozzle. The aper¬
ture of this nozzle is very small, hence the value of the
strainer before mentioned, which prevents the entrance of
foreign substances with the oil and a consequent clogging
of the nozzle. The two men handling this apparatus filled
the tank with oil and then carried it to the spot where the
burning was to be done. One man then operated the pump
while the other handled the pole and nozzle. As soon as the
pump was started a fine spray of oil was thrown into the air
and ignited by a match. By means of the pole the resulting
fierce flame was carried among the undergrowth and over
the ground, destroying every living thing in its path. A lien
this work was carefully done, no eggs escaped except such
as were hidden in ledges or holes in the ground. An at¬
tempt was made also with this apparatus to destroy eggs
which had been deposited in stone walls. (See Plate
XVIII.) Though this was partially successful in so far as
the fire reached and destroyed most of the eggs, those which
were deposited under the lower stones of the wall were un¬
harmed, even though in many cases the stones were cracked
and broken by the heat. As it sometimes became necessary
to use this apparatus in burning out walls near growing
crops, a sheet-iron screen was set up between the flame and
the growing vegetables to protect them from the heat, being
moved along the wall as the work progressed. Burning
was thus done without any resultant injury to the gardens.
This machine, which has been christened the “ cyclone
burner,” would be most useful in checking invasions of
crawling pests like the army worm.

Fire was also used in hollow trees, the eggs hidden within
them being destroyed by burning out the decayed wood. If
this is judiciously done, there will be no injury to the tree.
Unless great care is used, however, to extinguish the flame in
time, there is much danger of destroying apple trees in this
way. Cherry, oak and willow trees have rarely been injured
by burning out cavities ; indeed, some old trees appear to

122

THE GYPSY MOTH,

have been benefited by such burning, as they have shown a
better growth during the season following. Oil is poured
in at the top of the hollow, and a sufficient aperture made
at the bottom to ensure a good draft. The oil is then
lighted, and the draft in the funnel thus made fans the
flame until the decayed wood has been consumed. This
should be done only in the winter, when the sap is dor¬
mant, and the fire should be extinguished before it has done
serious injury to the live wood. This treatment is unnec¬
essary in cavities so accessible that the eggs and dead wood
may be removed by other means.

The naphtha burner, an instrument commonly used by
painters and plumbers, was used in 1891 as a substitute for
the scraping of eggs from trees and rocks, which sometimes
resulted in their being scattered. This burner is supplied
with an air pump, and furnishes an air-blast flame of an ex¬
tremely fierce heat. If this flame is applied directly to the
egg-cluster, it will reduce it to ashes on the tree, although
occasionally eggs exposed to such great heat will burst,
possibly scattering others. The burner should be used only
on the trunks of large trees having thick bark, or in such
cavities in trees or rocks as cannot be reached by other
methods.

Killing the Eggs with Chemicals.

Early in the work of 1891 it was seen to be impossible to
detach the egg-masses from their various places of deposit
without occasionally scattering and losing some of the eggs.
Experiments made during the following winter proved that
eggs scattered and exposed to the vicissitudes of the season
were not all destroyed by frost or snow, but that about two-
thirds of them hatched in the spring. It was seen that it
would be wiser and safer to destroy the eggs without re¬
moval, and experiments were made with that end in view.
The most successful method at first used was the application
of acids which in combination destroyed the eggs. The
apparatus was designed and the method invented by Mr.
F. C. Moulton, a chemist employed in the gypsy-moth work.
The apparatus (Fig. 2) was composed of a small tin case hold¬
ing two bottles, each of them having a rubber stopper with
two glass tubes, each of which projected into the bottle as

USE OF ACIDS AXD CREOSOTE.

123

well as out at the top of the cork, where it was bent at a
right angle. One of the tubes in each bottle was drawn
down to a point with a small aperture,
and served as a discharge pipe. The
other was connected with a rubber tube
having a mouth-piece of glass. One
of the bottles held a mixture of phenol
or carbolic acid and turpentine (fifty
per cent, of each) ; the other, chemi¬
cally pure nitric acid. By blowing into
the month-piece of the bottle containing
the carbolic acid mixture, a jet of this
acid was thrown upon the egg-mass.

This carbolic acid at once penetrated
the cluster and in all probability de¬
stroyed the life of the eggs. To render

the destruction of all the eggs an abso¬

Fig. 2. Acid apparatus.

lute certainty, a jet of nitric acid from the other bottle was
then thrown in the same manner upon the mass. While
nitric acid of itself will not penetrate the egg-clusters, it is
alone sufficient to kill the eggs if they are divested of their
hairy covering and immersed in it. The two acids in combi¬
nation reacted and produced an extreme heat and corrosion,
and a few applications entirely destroyed the egg-cluster.

While this apparatus was being used in the field, experi¬
ments were made to find some simpler method of destroying
the eggs. Although the acids were effective, they were
expensive and there was some danger of injuring the men
using them. Clothes, ropes, tools and apparatus were also
injured by the fumes of acids which were kept with them in
the tool boxes. The experiments finally resulted in the choice
for use in the field of a cheap creosote oil manufactured by
the Carolina Oil and Creosote Company, Wilmington, N. C.
This oil was recommended for trial by Prof. N. S. Shaler.
It requires neither preparation nor complex apparatus, but
can be drawn from the barrel into cans and applied with a
brush. If a cluster is thoroughly soaked with this liquid, it
penetrates and kills all the eggs, and is very effective except
in the coldest weather, when it may sometimes thicken. It
may then be made more penetrative by being mixed with

124

THE GYPSY MOTH.

carbolic acid and turpentine, as follows : creosote oil, fifty
per cent. ; carbolic acid, twenty per cent. ; spirits of turpen¬
tine, twenty per cent. ; coal tar, ten per cent. The coal tar
is always added to color the egg-clusters, so that those which
have been treated may be distinguished. The creosote itself
is not strongly colored, and often fades after application,
leaving; the egg-clusters of their original color. Tar is used
in preference to ordinary pigments because it mixes well
with the creosote, and does not settle to the bottom of the can
but is held in suspension. Almost any mixture of sufficient
penetrative qualities and containing considerable carbolic
acid will kill the eggs.

A pocket receptacle has been devised for convenience in
carrying paint and creosote and applyiug them to infested
objects. This consists of a tin can or box (Figs. 3 and 4), in
which two tubes are fastened. One of these tubes contains
creosote and the other white paint. Each of these tubes is
stopped at the mouth by a cork through which the handle of a
small paint brush is thrust. The space inside the can and about
the tubes is packed with cotton waste (Fig. 4), which receives
all drippings from the tubes. Paint and creosote can be
carried thus in the pocket with little danger to the clothing.

Fig. 4. A sectional view, show¬
ing manner of packing.

Fig. 3. Paint and creosote
can.*

When a tree or other object is found infested, it is marked
with paint to indicate the fact. The egg-clusters are then
treated with the creosote. In woodland in outer towns each

* Every tool issued to workmen in the field has its number stamped upon it.

PLATE XIX. Treating egg-clusters with creosote

IMPLEMENTS USED.

125

egg-cluster when treated is surrounded with a ring of white
paint to prominently mark its location, (see Plate XIX.).

The most recent preventive method used in Europe is the
covering of the eggs with a coat of tar or with raupenleim,
a substance much used to prevent caterpillars from ascending
trees. Though these substances, as well as varnish, have
been used here experimentally with some success, the use
of creosote oil is much to be preferred, as it penetrates the
eggs at once and destroys their life, while the other sub¬
stances merely prevent the larvae from emerging, provided
the covering remains intact.

Destroying the Eggs by Gases.

Experiments were made to find some agent other than fire
that would destroy the eggs in hollow trees. A little bro¬
mine or chlorine poured into the hollow of a tree, branch or
stump will destroy all animal life within the hollow if the
cavity can be thoroughly sealed or closed.

Implements used in the Search for the Eggs.

Each inspector is provided with a small binocular glass of
opera size, which he carries in a leather case suspended by a
strap from his shoulder. By means of this he is able while on
the ground to distinguish the eggs of the gypsy
moth from those of other insects when attached
to the higher limbs of large trees. This glass
is useful in dark or cloudy weather, as well as
in the morning or evening twilight of the short
winter days. Its use often renders tree climb¬
ing unnecessary, and thus much time is saved.

Each man is provided with a pocket mirror so
constructed that the glass, if broken, can be
quickly and cheaply replaced (Fig. 5). This
is extremely useful in many ways during the
search for eggs. Whenever the lower rail of a
board or picket fence is so near the ground that
its under side cannot be seen, a mirror placed at
a slight angle underneath will reflect the whole
lower surface for several feet, and show anv

. . J Fig. 5.

egg-clusters which may be deposited there. Pocket mirror.

126

THE GYPSY MOTH.

Mirrors are also useful in reflecting sunlight into the holes and
cavities of trees and rocks, so as to determine whether or not
the eggs are hidden within these recesses. Occasionally hol¬
lows in the under surfaces of high limbs are inspected from the
ground by the combined use of the opera and hand glasses,
the hand glass throwing the light into the hollow, and the
opera glass enabling the inspector to determine its contents.

During the spring of 1891 the egg-clusters, being then
very numerous, were found in almost every conceivable
situation. They were deposited on the under surface of
steps, under piazzas, floors, beneath the baseboards of fences,
in hollow fence posts, in sheds, out-buildings, cisterns, con¬
ductors, ventilators, basements, cellars, chimneys and many
other places both within and without dwellings. Their num¬
bers in many such places were so great that it was deemed
unsafe to allow them to hatch, lest the caterpillars should
prove very destructive before their ravages could be stayed.

^ _ Boards were therefore removed

Hi ~~ from fences, steps and buildings,

and this work required the use of
such implements as crow-bars,
pinch-bars and hammers. Dark
lanterns w7ere frequently required
fig. 6. cleaning knives. jn cellars, under piazzas and in
barns. Special knives with blades bent at different angles
were made for removing the eggs from the recesses of fences
and trees. With the aid of such implements most of the
hidden eggs were found and destroyed.

The Destruction of Caterpillars.

When the larvae first emerge from the eggs, they usually
remain for several hours on the outside of the egg-cluster,
or if the weather becomes cold or stormy, for two or three
days. While in this position they may be quickly destroyed
by the flame of a naphtha burner or by an application of
creosote or kerosene.

Banding Trees.

After the eggs on trees have been destroyed, the young
caterpillars which hatch elsewhere may be kept from ascend-

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BANDING TREES.

127

ing the trees by encircling the trunks with some appliance
or substance which the larvae cannot cross.* The protection
of large trees by banding is most important as their size
favors the distribution of the moth, rendering it both diffi¬
cult and expensive to care for them.

Such trees are often situated near buildings, lumber piles,
ledges, accumulations of loose rock or other objects which
offer many hiding places to the caterpillars and other forms
of the gypsy moth. Occasionally sheds or hencoops are
built about the trunks of trees. When such places of shelter
as are not readily accessible to the workmen are thus offered
to the moth, the caterpillars must be prevented from ascend¬
ing the trees, and either destroyed by starvation or driven
to other quarters. Where there is no other vegetation near,
this may be accomplished by banding the trees in the early
spring. If there is no other food in the vicinity, the young
caterpillars prevented from ascending the trees will starve.
If there are other trees within crawling distance which are
so located and environed as to have no shelter about them
inaccessible to man, the migration of the caterpillars thither
will facilitate their destruction by the workmen. In wood¬
lands, if the eggs upon the trees are destroyed and the trees
well banded previous to the hatching of eggs, which may have
been overlooked on the ground, and all vegetation on the
ground is killed by means of the cyclone burner soon after
the caterpillars appear, extermination will result. The
method of burning caterpillars in infested brush is shown
in Plate XX.

Bands are most useful for these purposes when put on just
before the young caterpillars appear. They will then be
fresh and sticky when the young larva are weak and unable
to crawl far if deprived of the sustaining and strengthening
nourishment Avhich they eagerly seek. Before the hatching
of the eggs in 1891 and 1892 many of the large street trees
in Malden and Medford and some in Somerville were banded
with strips of tarred paper. This work was first undertaken
in Medford. It was proposed by the selectmen of that town
as a means of protecting the trees from the gypsy moth and

* In 1891 bands of loose cotton batting were experimented with for this purpose,
but they did not prevent the larger caterpillars from ascending the trees.

1 28

THE GYPSY MOTH.

the canker-worm, and a part of the expense was borne by
the town. The bark of the tree was first scraped or planed
at a height of about six feet from the ground, so that a
reasonably smooth surface about six inches wide was formed
extending around the trunk. A band of cotton waste was
then placed on the smooth surface about the trunk, and a
band of tarred paper about the cotton. A cord about the
paper drew it closely to the cotton waste, which was thus
pressed firmly against the tree. This waste was placed
beneath the paper to prevent the newly hatched caterpillars
(which can pass through very minute crevices) from crawling
under it and so on up the tree. The tarred
paper was then covered with a mixture con¬
sisting of three parts tree ink, one part pine
tar and one part petroleum (residuum oil).
The cotton waste prevented this mixture
from penetrating to the bark of the tree.
Fig. 7 shows the band about the tree with
the string removed and a piece torn away
to show the cotton packing. The black
band represents that part of the paper

j«'iu. I . i arreu paper A 1 L A

band. which was covered with the mixture.

Tacks and staples were used where necessary to draw the
paper and string closely to the tree.

It was necessary at first to apply several coats of the mixt¬
ure, so that the tarred paper might become so well saturated
that it would not absorb subsequent applications. When
this was effected, an application was made at least twice a
week for the rest of the season where trees on dusty streets
were banded, but it was not required so often (except in very
hot, dry weather) in orchards or woodland. As a result of
the banding, most of the caterpillars were kept out of trees
along the streets, and therefore there was little danger of
their being distributed along the highways in such numbers
as in former years. In badly infested localities this method
can only be effective when the eggs on the trees have been
destroyed and a large part of the egg-clusters in the vicinity
gathered. Otherwise, the massing caterpillars will bridge
the tarred paper with their bodies and on this bridge others
will cross, or else the young caterpillars will be borne on the

THE USE OE INSECT LIME.

129

wind from the branches of one tree to those of another, ren¬
dering all precautions useless.

In banding, all poles, dead trees and other objects which
in any way communicate with banded trees must be removed
or banded. Where the limbs of trees touch houses, fences,
rocks or the earth, they must be so trimmed as to prevent
such contact. Unless all such means of communication are
cut off, banding will not produce the desired effect. Much
discrimination must be used in banding trees in cultivated
lands, lest the caterpillars be driven from trees and scattered
abroad among shrubbery, weeds or garden crops, where they
cannot be so readily dealt with.

Rcmpenleim Bands.

In 1891 Mr. B. F. Fernow, chief of the Division of For-
restry of the United States Department of Agriculture,
recommended that “raupenleim” or “insect lime,” a Ger¬
man preparation for the protection of trees, be used in this
work.* A sample was ordered, but it arrived too late in
the season to be experimented with that year. In 1892
experiments were made, and later thirteen and one-half tons
of the “leim” were ordered and used in banding 40,704
trees during that season and the next. The raupenleim used
in 1892 was very effectual, but much of the importation of
1893 was apparently inferior in quality to that used the
previous year, and the results obtained were anything but
gratifying. If results similar to those of 1892 can be secured,
this material will be of great value for use in this country
against such insects as the canker-worms, which pupate in
the ground and whose female imagoes are wingless.

Raupenleim was used in the gypsy-moth work to take the
place of the tarred paper bands. The advantages obtained
from its use are that when of a good quality and properly
placed upon the tree, it will remain soft and viscid for several
months, and during that time will prevent the ascent of
nearly all larvae and also wingless female imagoes. The sub-

* Raupenleim, translated literally, would read “ caterpillar glue.” According to
Webster, lime (a viscous substance) is akin to the German word “leim.” It is
used here in connection with the word insect in much the same sense as it is used
in connection with bird as “bird-lime.”

130

THE GYPSY MOTH.

stance has been used abroad, especially in Germany, for
several years past. The government forestry authorities of
Bavaria employ it to prevent the ascent of the nun moth.
This insect in 1890 devastated the German forests to such
an extent that 1 1 three thousand men were employed to check
its ravages, and in one instance it was necessary to cut and
burn a strip of timber four miles broad by five miles long to
prevent further devastation.” *

It was ascertained by experiment that the application of
this insect lime did not injure the trees, nor has any injury
been observed to trees where it has been used in this country.
Though the death of three or four young frees has been
reported and credited to the injury caused by liming, it is
possible that the primary injury was caused by too deep scrap¬
ing of the bark. In such a case the oil contained in the lime
might penetrate the liber and cambium of the inner bark and
eventually destroy the life of the tree. There is no necessity
for scraping a smooth-barked tree. Though over 40,000
trees have been banded in the work in Massachusetts, these
are the only cases where injury is believed to have resulted.
This agrees with the experience of the foresters in Ger¬
many. f

* Dr. R. Hartig in “Forstlich — naturwissenchaftliche Zeitschrift,” January,
1892.

f “ The excellent results of the lime-rings for the prevention of larvae ascending
the stem and feeding on the foliage of our forest trees has been proven during the
past ten years. Not content with this, however, — for it became our duty to see if
the lime itself did not injure the tree, — we examined the different layers of the bark,
and can confidently assert that no harm to the most tender trees has been done by
liming them.

“ We firmly believe that the man who scrapes the bark off the trees can do more
harm in one hour than he could by ringing trees with lime the rest of the year ; and
we would therefore recommend for the work, men who know the difference between
the inner and outer bark of trees infested, and especially warn them to be careful of
smooth-barked trees, from which they have to remove only such mosses and lichens
as are found on them. On the trees — Dr. R. Hartig says — that were limed twenty-
five years ago no bad results have been observed. In fact, on the part of the tree
where the ring was laid on, the growth of wood was larger than either above or below,
which he ascribes to the action of the lime on the outer bark, softening it somewhat
and giving freer circulation of the sap in the inner bark.

“ Only in instances where the bark was scraped to the quick has the lime pene¬
trated, and therefore all harm must be ascribed to the scraping knife and not to the
lime.

“There is, therefore, no occasion for alarm as regards the ringing of trees with
insect lime to preserve them from the ravages of insects of all kinds.” — (Translated
from “Forstlich — naturwissenchaftliche Zeitschrift,” July 7, 1892.)

LIME MACHINES.

131

A variety of machines have been devised in Europe for
applying raupenleim to the trees. One of these, the “ Eich-
horn machine” (Eig. 8*), was imported by the Board and
was used to some extent. It
consists of a triangular wooden
box with two handles, one of
which is hinged and acts as a
lever. At the apex of the box
is an aperture of the size de¬
sired for applying the lime to
the trunk of the tree. This
receptacle being first filled
with lime, a handle is grasped
in each hand of the workman,
who, by pressure brought to bear on both handles, forces the
contents through the opening. In the mean time the machine
is passed around the trunk, and a band of lime adheres to
the bark. This machine can be used to advantage where the
rings are put on at a height of three or four feet from the
ground ; but where it is necessary to place them at a height
of six feet or more, as on street trees, great strength is
required to force the lime out, and the use of the machine is
not practicable. In the machine as imported the aperture
through which the lime passed was about one-fourth of an
inch in width and one and one-half inches in length. It was
found by experiment that the lime remained viscid for a
longer time and was more effective in stopping the ascent of
the gypsy-moth caterpillars if the band was made wider than
the length of this opening, and of greatest thickness on the
lower edge ; consequently the opening of each machine was
enlarged to such dimensions as to deposit a band on the tree
about one-half inch in thickness on the lower edge and two
and one-half inches in width. The lime could be so put on
by trowels or spades made for the purpose that the lower
edge of the band projected more than half an inch from the
bark. If this lower edge was made even thicker than this,
and shaped at an acute angle, the oil, which gradually tried
out from the surface of the band when exposed to the sun-

See also the single-handed Eichhorn machine, Plate XXII., Fig. 4.

132

THE GYPSY MOTH.

light, would trickle down to the edge and hang there, form¬
ing an impassable obstacle to the caterpillars. The intent
of the lime bands used in the work on the gypsy moth was
to prevent any caterpillars from ascending the trees. If a
few reached the branches and remained in the trees, passed
through their transformations and laid their eggs, it is obvious
that the bands would be worthless for the purpose for which
they were intended, though even then they might be useful
in controlling certain other caterpillars which frequently
spin or drop to the ground, as they would prevent most of
them from reascending the tree. But in a case where exter¬
mination is sought, and destruction of all gypsy caterpillars
is a consequent necessity, it is imperative to prevent their
ascending large trees. Quite frequently the bands were
injured or displaced in some way by people or animals
brushing against them, and often leaves or twigs from the
trees dropped and stuck upon the bands, forming bridges over
which the caterpillars could climb. To lessen the chances of
their reaching the branches, two or even three bands were
sometimes put upon the same trunk, one above the other.*
The same thing has been done in Germany during great
invasions of the nun moth ( Lijoaris monacha), and for this
purpose a machine has been devised for applying insect lime
at a greater height on trees than could be otherwise reached
by hand from the ground.

The Hochleim machine (Plate XXI., Fig. l)f is a tin
cylinder attached to a long pole. A top that acts as a plunger
is fitted to the cylinder and may be depressed by pulling on
a cord that is fastened to a strong spiral spring. This spring
is connected with iron wires which are attached to the upper
part of the machine. When this is depressed, the lime is
forced out at the bottom of the machine through a round hole
bored in a brush which is fastened to one side, as seen in the
figure. The lime, which must necessarily be of a more or
less liquid consistency, is applied around the trunk of the

* This would not be ordinarily necessary in protecting trees against attacks of
native caterpillars.

t Figures of the implements and machines appearing on plates XXI. and XXII.
have been previously published, together with others, in “ Die Nonne,” by Dr. H.
Nitsche, Ed. Holzel’s Verlag, Vienna, 1892.

PLATE XXI.

PLATE XXII.

LIME MACHINES.

133

tree with the brush. The tools (Plate XXI., Fig. 2, a, 5, c)
are also attached to poles, and are used for scraping and
smoothing the bark at a height. Tool c has a scraper upon
one side and a stiff brush upon the other. The lime hose
(Plate XXI., Fig. 4) is an elongated cone-shaped bag made
from some thick fabric. It has a mouth-piece at the small end
for the outlet of the lime, while on the large end is attached
a tin ring or cover, by means of which the bag may be tilled
and closed. This apparatus is carried by a strap or band
passing over the right shoulder, and the lime is squeezed out
by forward pressure of the right hand. It is inexpensive,
easily carried and durable ; still, it cannot be entirely satis¬
factory, as the oil with which the lime is mixed will gradually
work through the fabric and soil the clothing of the workman.

The Eck lime hose is illustrated also (Plate XXI., Fig. 5),
but, as the tilling is done at the smaller end, requiring an
expensive apparatus for forcing the lime in, it would hardly
seem a desirable machine, although its cost in Germany is
small (1 mark, about 25 cents). A very simple machine is
a large tin cylinder (Plate XXI., Fig. 6) with a piston, the
handle of which is pushed in by the man using it, who in
this way drives the lime through the tin mouth-piece. This
mouth-piece can be removed and others of different sizes can
be substituted, according to the thickness and shape of the
lime ring desired.

The Seitz lime machine (Plate XXII., Fig. 2) is a large tin
apparatus holding about two and one-half quarts. The cover
is fastened with a “bayonet” lock. The piston, which is
geared, is wTorked back and forth by a geared wheel or cog
fastened to the cover, and turned by a handle. This larger ap¬
paratus, rather heavy when filled, is carried crosswise in front
of the wTorkman, who turns the handle with his rig-lit hand.

The Hauenstein lime machine (Plate XXH., Fig. 3) is
operated on the same principle as the last, except that the
piston is driven forward by spring-power. The tin mouth¬
piece is connected with the main body of the machine by a
piece of hemp hose, which is movable. The spring is drawn
by the aid of a wire rope with a loop at its end. The work¬
man sets his foot in the loop, draws the machine upward and
so draws the spring, which is arrested by a snap latch. The

134

THE GYPSY MOTH.

machine is then filled. When in use the spring is released
from the latch. Like the other machines, this machine is
carried by a harness or carrying band.

A simple utensil (Plate XXII., Fig. 1) is like the “Eicli-
horn” machine, a lime “ squeezer,” and consists of a wedge-
shaped box, one side of which is movable and may be pressed
into the opening formed by the four stationary walls of its
other sides. Spades or trowels (Plate XXI., Fig. 3, a, b, c)
are often used to apply the lime and shape the bands where
the work is done by hand. Where a number of men are at
work, a lime hod (Plate XXII., Fig. 5) is also used. This
hod is carried by one man, who keeps several others supplied
with the lime.

There are some disadvantages in the use of insect lime.
It is not cleanly, as under a hot sun more or less running oil
exudes, especially on smooth-barked trees. Unless placed
at a considerable height from the ground, cattle and horses
frequently rub against it, plastering their coats in a very
disagreeable manner. Complaints have been occasionally
received that pet cats returning from excursions up the tree
trunks have “tracked” the insect lime over their owners’
carpets. Xot withstanding all care that has been used in the
application of the material, certain spring overcoats and fine
shawls have been ruined when the owners of these garments
carelessly leaned against trees which had been banded. The
insect lime does not adhere well to trees when they are wet,
and occasionally heavy showers will cause it to drop oflf in
lumps. These lumps when trod upon adhere to the shoes
and are sometimes a source of considerable annoyance to
housekeepers. Such accidents may be avoided by applying
the lime when the trees are dry, and by forming the band
with its upper edge bevelled toward the tree so as to shed
water. It is then not likely to be displaced by rains.

If the lime is used on trees standing on lawns, it is likely
to prove a source of unpleasantness. Some complaints in
regard to this have been received from owners of lawns and
croquet grounds. Such objections to its use will apply, how¬
ever, to any material of the kind, and are not to be avoided
as the lime is ordinarily used. It is sometimes recommended
to place a band of stiff paper about the tree, turn up the

LIME AND DENDROLENE.

135

lower edge in such a way as to form a trough and then apply
the lime upon this. If this band of paper is placed at a
considerable height, it may prevent many of the disagreeable
accidents which otherwise frequently happen. Thus far we
have had no experience in applying the lime in this manner.

Other Uses for Insect Lime.

Dr. John B. Smith, entomologist of the New Jersey Ex¬
periment Station, in a paper read by him as president of the
Association of Official Economic Entomologists at a meet¬
ing of that society held Aug. 27, 1895, in connection with
the meeting at Springfield of the American Association
for the Advancement of Science, gave the results of his
experiments with raupenleim and a similar material, “den-
drolene.”* Dendrolene was invented by Prof. F. L. Nason
of New Brunswick, who, at the request of Dr. Smith, experi¬
mented with a view of obtaining a material of home manu¬
facture possessing the insecticide and protective properties
of the raupenleim. According to Dr. Smith, raupenleim and
dendrolene are both crude petroleum products, though the
raupenleim has some admixture of a substance resembling tar
in color and odor; but in both cases the base is, or seems to
be, a very crude or impure vaseline, which has the appearance
of the base of such lubricating mixtures as wheel-grease.
Dr. Smith has used both substances on trees to prevent
both the entrance and the emergence, of certain tree borers.
So far he has seen no injury to the tree resulting from the
use of either material, even when large areas of bark were
covered. While the raupenleim seemed more effective
against borers, the dendrolene remained soft longer, making,
as Dr. Smith says, “a perfect barrier against insects
attempting to cross it.” He also says that “ such materials
may be employed against scale insects on comparatively
small trees where they cover only the trunks and larger
branches, and where even a thin coating applied with a brush
early in the season before the eggs have hatched or before
reproduction has begun in the case of the viviparous species,
will absolutely prevent thu emergence of young. The appli-

* See Bulletin of Experiment Station, New Jersey Agricultural College, No. Ill,
Sept. 16, 1895.

136

THE GYPSY MOTH.

cation of a coating on the trunks of peach trees made early
in the season will prevent oviposition by the adult of the
peach tree borer.” But it may be questioned how far this
covering the bark with such a material can be carried with¬
out eventually injuring the tree. Our experiments go to
prove that raupenleim will usually prevent the ascent of
the female canker-worm moth. It is quite probable, however,
that after wet or cold weather, some of the moths may cross
the band before the warmth of the sun has rendered it viscid,
as the lime hardens somewhat in such weather and does not
again become soft until affected by the sun’s warmth.
Climbing cutworms and many other caterpillars have been
caught on the bands. Most insects, however, seem to prefer
to turn back rather than attempt to cross. The larger gypsy-
moth caterpillars will cross when the bands have become
somewhat hardened by rain or cool weather, but the smaller
caterpillars seldom crawl over the bands. The raupenleim
was therefore very useful for banding trees which had been
cleared of the moth, providing the young caterpillars could
be destroyed by lire or other means before they attained
sufficient size and strength to cross the lime. The bands are
useful also in preventing the ascent of such common pests
as the tent caterpillar and tussock moth after trees have been
cleared of the caterpillars or eggs of these species. * Dr. Smith
says that as a protection against mice and hares, “dendro-
lene will serve an entire season when put on one-fourth of an
inch thick or more.” As much cannot be said of the raupen-

* The application of bands of insect lime appears to prevent the common tent
caterpillars from crawling either up or down trees. A wild cherry tree which con¬
tained a great number of these caterpillars was banded with insect lime. When the
caterpillars had devoured all the foliage upon the tree they crawled down the trunk
to the band and there remained clustering upon the trunk within two feet of the
upper edge of the band, where they died, apparently of starvation. This would
indicate that by banding worthless trees infested by this insect it might be prevented
from migrating to other trees, and compelled to perish from lack of suitable food. Yet
no instance of this kind has been observed with any other insect, and no record was
kept of the number of caterpillars originally on the tree, so it is impossible to tell
how many may have escaped. It is not safe to base any conclusions on a single
observation of this sort. It is given here merely to show the necessity of further
observation and experiment with insect lime, which can probably be used in many
ways as a preventive to insect attacks or an insecticide application.

The application of the insect lime to esg-clusters has already been mentioned
(page 125), but it has been superseded in Massachusetts by more economical and
effective measures (page 123).

PLATE XXIII. Spraying apparatus used in 1891.

SPKAYING.

137

leim used for the gypsy-moth work, although the best of it
remained in good condition from one to three months ; yet
in some cases it became necessary to make two or three ap¬
plications during a season. During windy weather bands
upon dusty streets require frequent attention and occasional
renewal. Dr. Smith says that in no case has he ever ob¬
served any injurious effect of dendrolene upon the trees.

Dendrolene is supplied by Prof. F. L. Nason, New Bruns¬
wick, N. J. Insect lime can be obtained of the Bowker
Fertilizer Company, Boston, Mass., and of Wm, Menzel &
Son, New York.

Spraying with Paris Green .

When the second commission began work in the spring
of 1891, it was learned that the efficacy of Paris green as an
insecticide for the gypsy moth was doubted by many people
in Medford. Experiments were therefore immediately begun
to determine whether spraying with Paris green would kill
the caterpillars. In April young caterpillars were hatched
by artificial means in the office of the commission and fed
upon leaves which had been carefully sprayed with a solution
consisting of one pound of Paris green to one hundred and
fifty gallons of water. Not only was the ordinary Paris
green experimented with, but samples of finely bolted poison
were secured. The experiments showed that the use of
either quality of Paris green caused death. It was noticed,
however, that the caterpillars which ate the leaves sprayed
with the pulverized poison died soon after beginning to feed,
or within twenty-four hours ; wffiile those which ate of the
leaves sprayed with the ordinary Paris green lived for several
days, very few dying within twenty-four hours. The ma¬
jority lived three or four days and some even a longer
time. Samples of both the pulverized and ordinary Paris
green were analyzed and the analyses gave substantially the
same amount of arsenic in each. From this it would appear
that both wTere equally poisonous. Why they were not
equally effective has not been fully determined. But as the
ordinary Paris green was made up of fine crystals which were
more or less insoluble, while a larger proportion of the finely
powdered Paris green was apparently soluble in "water, the

138

THE GYPSY MOTH.

latter would be more quickly dissolved in the digestive
fluids of the caterpillars. This subject, however, needs
more scientific investigation, as the experiments made were
too limited in scope to allow any conclusions to be based
on the results. As it was found later that neither brand
of Paris green gave as satisfactory results in the field as
had been obtained in-doors, and as the use of this arsenite
was finally given up, the subject of the comparative efficiency
of the pulverized and the ordinary Paris green was not
further investigated.

The results obtained by in-door experiments with the pul¬
verized Paris green led to experiments on a larger scale in
the field and accordingly a ton of this poison was purchased.
Early in May spraying in the field was begun (see page 55).
Most of the sprayers were supplied with the fine Paris green,
which, though not proving as efficacious as in the laboratory,
nevertheless killed many of the smaller caterpillars. As the
spraying continued it was observed that a considerable pro¬
portion of the caterpillars of middle age were also destroyed.
Sometimes, though rarely, persistent spraying appeared to
destroy most of the larger caterpillars. By this time it had
been determined by experiments in the laboratory that Paris
green would not kill all the larger larvae ; yet as it had
given better results than any other insecticide, it was thought
best to continue its use at varying proportions in the field,
and the poison was used at a strength of from one to four
pounds to one hundred and fifty gallons of water. As a
rule the spraying did not seriously burn the foliage when a
solution was used consisting of one pound of Paris green to
one hundred and fifty gallons of water ; but with larger
proportions of poison the foliage was considerably burned.
The injury developed so rapidly that within a short time the
leaves were all killed and the surviving larvae were obliged to
go elsewhere to feed. Therefore, a strong Paris green mixt¬
ure had little better effect than a weak one. Lime was
then used with the Paris green with a view of neutralizing
the burning but considerable injury to the foliage still con¬
tinued.

Though even when three or four pounds of the Paris green
were used to a tank of water, many of the larger feeding

EFFECTS OF SPRAYING.

139

caterpillars survived. Yet a difference in the effect of the
spraying on the caterpillars was noticed. Occasionally in
badly, infested places so many of the caterpillars died within
two or three days after the spraying that the people living
on the infested estates were obliged for the sake of cleanliness
to sweep up the dead from the walks and burn them. The
unevenness in the effect of the spraying at once aroused
suspicion that it might be caused by improper mixing or
application of the insecticide. Although some inefficiency
on the part of inexperienced sprayers was expected, a great
difference in the effect of the insecticide was observed even
when the poison was most thoroughly and carefully mixed
and uniformly applied.

Every effort was made during the spraying season to de¬
termine why the results of spraying were not uniform and
satisfactory. The feeding caterpillars were watched day and
night by many observers. The spraying was most carefully
superintended and the conclusion finally arrived at was that
under ordinary conditions spraying with Paris green for the
gypsy moth was ineffective and unsatisfactory.*

* In a few cases, where spraying was done just after a storm, an unusual mortality
among the caterpillars was noticed during the next few days. At first it was thought
that this result was due to the poison being more effective at such times, on account
of its better retention on the foliage. It was known, also, that the caterpillars sought
shelter and ate but little during rains, but that they fed ravenously during the warm,
clear weather that frequently follows a storm. It was believed that the unusual
amount of poisoned food taken at such a time, when the system was weakened by
fasting, might have been sufficient to cause a greater mortality than usual. It was
soon noted that the poison appeared to produce the same effect occasionally in dry
weather or after light rains. This seemed to disprove the first hypothesis advanced,
and raised the question whether the larvae, which sometimes succumbed in such
numbers, were not first weakened by disease or other causes.

In some cases the accuracy of the observations was doubted. It is difficult to make
accurate observations on the results of such work done in the field. For instance,
it is almost impossible to determine the proportion of larvae killed by spraying.
When they disappear immediately after spraying, there is no certainty as to whether
the spraying alone is responsible for their disappearance, or whether they have not
been carried off by birds or predaceous insects, or have not crawled to other localities
or to more congenial food. In some places, where the dead larvae fell to the ground
in considerable numbers, most of them were immediately carried away by ants or
other scavengers, which left few behind to tell of the results of the spraying. Cor¬
rect conclusions cannot be drawn where there is such liability of error, unless obser¬
vations recorded by many careful individuals and extending over a considerable
period of time agree in the main. As no extended spraying with Paris green was
done after 1891, the opportunity passed for an exhaustive study of the effect of
meteorological or other conditions on the results of spraying. The cause of the
apparent differences in the results of carefully conducted spraying with Paris green
for the gypsy moth is a question which deserves further investigation.

140

THE GYPSY MOTH.

It is interesting to note that while many of the gypsy
caterpillars were apparently uninjured by the spraying, the
canker-worms and tent caterpillars were almost exterminated,
and the tussock moths ( Orgyia leucostigma ) disappeared.
The trees of the infested region were never in better con¬
dition than at the end of the spraying season of 1891, and
the fruit crop was larger than it had been for many years.
Though this cannot all be credited to the spraying, the con¬
trast between sprayed and unsprayed trees was often very
marked, the sprayed trees bearing more and finer fruit.

During the spraying season thirty heavy spraying outfits
were worked back and forth between the outer part of the
infested region and its centre. Fifteen towns were thus
covered. There were also a dozen light fifteen-gallon hand
tanks which were sent into the outer towns. They were
carried in wagons, two men being assigned to each wagon.
The tanks and pumps used were the same as are used with
the cyclone burner (Fig. 1, page 120). The men with the
light outfits went to the outlying orchards and residences,
where a few trees were infested. They filled their tanks at
brooks or wells and carried them by hand to such infested
spots as were not accessible by a team, sprayed the trees in the
vicinity, reloaded the tanks upon the wagons and drove to the
next infested place. In this way the isolated colonies in the
outer towns were covered by the sprayers. The large tanks
mounted upon wagons and handled by from four to six men
were used mainly in towns where water service was available
and were filled from hydrants or stand-pipes. The order was
given to spray everything green within two hundred feet of an
infested plant or tree. An adherence to this regulation caused
the spraying of all vegetation in the worst infested towns.

No extended spraying with Paris green has been done since
1891. While spraying with Paris green cannot be considered
a successful method of extermination, it destroyed a consid¬
erable proportion of the number of very young caterpillars
wherever it was done efficiently and in season. It thus
checked the multiplication and assisted in preventing the
spreading of the species. Though it failed to accomplish
the end sought, it was certainly the most effectual method
known at that time of disposing of the young caterpillars.

LONDON PURPLE.

141

In looking back over an experience of five years we are
unable to see how any better method of destroying the young
larvae could have been devised from the knowledge of in¬
secticides then possessed.

Spraying with London Purple.

London purple was used both in-doors and m the field in
the season of 1891 but the results of the experiments with it
were not as satisfactory as those reached with Paris green.
While it was quite as effective as Paris green in destroying
larvae, it injured the foliage more. London purple is more
finely powdered and lighter than Paris green and requires
less stirring. It also has the advantage of cheapness. The
great objections to its use are its partial solubility in water,
which causes burning of the leaves, and the unevenness of
the effects produced by it. While one sample may give fairly
satisfactory results, the next may not only burn the foliage
badly but even the young fruit on fruit trees. According to
Professor Bailey the arsenic in London purple is in the form
of arsenite of calcium, which in some samples is about seventy-
two per cent, of the whole compound. Over fifty per cent, of
this arsenite or nearly forty per cent, of the London purple is
quickly soluble in water.* The analysis of leaves injured by
Paris green shows no arsenic in the texture of the leaf ; but
when leaves injured by London purple are analyzed, arsenic
is found in their texture. This shows the penetrative powers
of the latter poison. The London purple was used in the
field to some extent, but the conclusion arrived at was that
while, as it is ordinarily used, one might be justified in ex¬
perimenting with it upon his own premises, its use in public
work on the premises of others was unwarrantable.

Spraying with Arsenate of Lead.

Although nearly all poisons known to us which can be
used as insecticides have been experimented with during the
past five years in the hope that something would be found
which woidd prove fatal to the gypsy moth, only one which
is more effective than Paris green has been discovered. This

* See “Experiences in Spraying Plants” by Prof. L. H. Bailey, Report Agricultural
Experiment Station, Itbaca, N. Y., Bulletin 18, 1890, page 98.

142

THE GYPSY MOTH.

is arsenate of lead, a poison slower in its action than the
other, hut which has three distinct advantages: (1) It can
be used at any desired strength without serious injury to
the foliage; (2) It is visible wherever used, as it forms
a whitish coating on the leaves ; (3) It has adhesive quali¬
ties, given it, probably, by the acetate of lead, and therefore
remains on the leaves for a much longer period than Paris
green. When sufficient glucose was added to a strong mixt¬
ure of arsenate of lead, it withstood rainstorms and remained
on the foliage during an entire season.

When in 1891 it became evident that the arsenites would
not accomplish the desired result, other means of destroying
clispar were sought. Yet it could be hardly credited that
the larva was indifferent to the action of arsenical poisons as
ordinarily used, and the experiments of 1891 were duplicated
during the season of 1892. They were performed by Pro¬
fessor Fernald and his assistants, but the results of these
experiments confirmed those of 1891.

When it was seen that the known arsenites could not be
used at the requisite strength for killing gypsy-moth cater¬
pillars without serious injury to the foliage, Mr. F. C.
Moulton, one of the inspectors employed in the field, who
was also a chemist graduated from the State College of Agri¬
culture and Mechanic Arts, Orono, Me., was detailed to make
experiments to determine what portion of the compound
produced the caustic effect upon the foliage. The results
of the experiments confirmed the conclusions of previous
experimenters that the soluble arsenic burned the foliage. It
was obvious that if a form of arsenic entirely and quickly
soluble in water could be precipitated, it would become
insoluble and obviate the burning.

In the winter of 1892-93, at a hearing before the legis¬
lative joint standing committee on agriculture, a bill for the
destruction of caterpillars within the State was considered.
At this hearing Mr. Andrew H. Ward proposed the use of
arsenate of soda as an insecticide. At the hearing we ob¬
tained from Mr. Ward the particulars in regard to the price
of arsenate of soda and where it could be procured.

Upon consultation with Professor Fernald (who had also
been previously asked by Mr. Ward to try the insecticide

AKSENATE OF LEAD.

143

properties of arsenate of soda), he advised experimenting
with it. A sample was procured and was found to be entirely
soluble in water. When used it burned the foliage to a
greater extent than the other arsenical poisons. Mr. Moul¬
ton was detailed to find some material which would precipi¬
tate the arsenate of soda in water and thus obviate the
burning. He proposed acetate of lead and after several
experiments the desired result was obtained and the pro¬
portions were fixed. The effect of the mixture of acetate
of lead with arsenate of soda in water is to throw down the
arsenate of lead in a fine precipitate which is held well in
suspension by the water and is therefore more evenly dis¬
tributed than Paris green.

While the complete insolubility of arsenate of lead is an
advantage as far as its effects on the plants are concerned,
it is less effective on the insect than Paris green when used
in equal quantities. Though the action of arsenate of lead
is slower than that of Paris green and London purple, this
may be partially accounted for by the smaller proportion
of arsenic in the composition. Caterpillars poisoned with
arsenate of lead have quite a different appearance from those
poisoned with Paris green. Inflammation and the shedding *
of hair appear to be symptoms of poisoning by arsenate of
lead. As it is slow in its action, it is well to apply it early
in the life of the caterpillar or in great strength.

The experience with arsenate of lead is in some respects
analogous to that with Paris green. While in-doors there is
no difficulty in destroying caterpillars with small quantities
of the poison, the effects obtained out-doors are not so satis¬
factory. Indeed, it is only wThen applied at a strength of from
twenty-five to thirty pounds to one hundred and fifty gallons
of water that it appears to do exterminative work. This, to
some extent, may be due to the difference in the material.
The arsenate of lead used in the laboratory was furnished in
the form of a fine dry precipitate. In the field the two
poisons were furnished in a cruder state. They were added
to the water and precipitation took place in the tank. The
preparation was much less expensive when made in this
way but was not as finely powdered. Indeed, it required
considerable stirring in warm or hot water to dissolve the

144

THE GYPSY MOTH.

lead sufficiently for it to pass through the strainers of the
pump. When arsenate of lead has been applied in pro¬
portions of from twenty-five to thirty pounds to one hun¬
dred and fifty gallons of water, occasional burning has been
noticed. This was due to the fact that the lead was not
thoroughly dissolved, for in such cases there was a lack
instead of an excess of acetate of lead in the mixture as it
came from the nozzle. When applied in this strength it
is a question whether it is safe to use it in pastures where
cattle are feeding or near where poultry are quartered.

It is evident that spraying with arsenate of lead should be
used as an exterminative method only in exceptional cases
where there is no danger to animals and where more drastic
measures, such as fire, cannot be used. While it will un¬
doubtedly be useful with many other insects, we would not
recommend that implicit reliance be placed upon it unless
used early in the season and at a strength of at least three
pounds to one hundred and fifty gallons of water. However,
it will probably not be necessary to use it at this strength
for all leaf-eating insects though some may require a greater
strength. Many experimenters have made trials of this ma-
' terial since the formula was first published in the annual
report of the State Board of Agriculture in 1894, but we
are not aware that it has yet come into general use in practi¬
cal out-door work. Professor Fernald’s experiments with
arsenate of lead on the tent caterpillar indicate that it would
be effective with this species in the field when used at a
strength of one pound to one hundred and fifty gallons of
water. It has given good results when used by him at the
same strength for the Colorado potato beetle ( Doryphora
deceinlinecita. Say) . Larger quantities have been required for
some other insects.

At first sight it would seem that if it were necessary to use
three pounds of arsenate of lead to one hundred and fifty
gallons of water, the expense would be prohibitory. Yet it
should be borne in mind that when mixed with glucose and
properl}'' applied to dry foliage, much of the solution will
remain throughout most, or all, of the feeding season. Its
application is not, therefore, as expensive as that of poisons
which have to be applied three or more times during the season.

SPRAYING APPARATUS.

145

By making a strong application early, the expense of the
labor of making the later applications is done away with.
Experiments being made by entomologists in different parts
of the country will soon indicate the degree of usefulness
of this arsenate in destroying different species of native and
introduced leaf-eating insects. Practical use in the held
later will determine its value as a general insecticide.

In the field work of the Board of Agriculture the formula
of arsenate of lead most used was sodic arsenate, 29.93 per
cent., plumbic acetate, 70.07 per cent. Two quarts of glu¬
cose were generally added to 150 gallons of water to give
better adhesive qualities.

Professor Fernald directs that arsenate of lead can be
prepared in the proportion of eleven ounces of acetate of lead
and four ounces of arsenate of soda in water.

Apparatus used for Spraying Large Shade and Forest Trees .

Fig. 9. Spraying tank.

The heavy spraying outfits used by the first commission
in 1890 were again put in service by the State Board of

146

THE GYPSY MOTH.

Agriculture iu 1891, but were so improved and modified by
labor-saving attachments as to render them doubly effective.
For each of these outfits a tank or hogshead holding one
hundred and sixty gallons (Fig. 9) is provided, bearing on
its upper end a plank foot-board six feet long and one foot
wide. A double-acting Douglass or Gould force-pump (see
Plate XXV., Fig. 1, and Plate XXVI., Fig. 2) is mounted
near the middle of the foot-board. Either of these pumps
when well manned furnishes sufficient force for all kinds of
spraying with several nozzles at once. The suction pipe of
the pump descends into the tank at the side and reaches to
within two inches of the bottom, where it is terminated by a
fine wire gauze strainer made from No. 32 wire, woven forty
or fifty meshes to the inch, which serves to exclude all foreign
substances which may clog the pump or nozzle. The diame¬
ter of the strainer should not be less than twice that of the
suction pipe. In the head of the tank is inserted a stirrer
made from two pieces of two-incli spruce scantling, one six
feet and the other two feet in length, the two being joined at
right angles at the lower end of the longer piece. When
placed in the tank the long arm is hinged on a bolt or rod
at the opening in the head of the hogshead while the short
arm swings just clear of the bottom. This lever projects
above the top of the tank. By moving it back and forth
the liquid is thoroughly agitated. The pump is operated
by means of a powerful lever or brake worked by one or
two men, according to the amount of pressure needed. It
is connected by means of a Y coupling with two lines of hose
upon which from two to six nozzles can be used. The men
when pumping stand on the foot-board already mentioned.
The whole apparatus is lashed on a wagon or cart and trans¬
ported from place to place as required. When in use one
man operates each line of hose, the driver of the team usu¬
ally does the stirring, while the whole work of spraying
is directed by an inspector. With this apparatus there is
no difficulty in spraying at any required height. Two
men on the brakes furnish force sufficient to throw a good
spray from a Gem nozzle when held ninety feet from the
ground.

SPRAYING APPARATUS.

147

Thorough and constant stirring is the prime requisite for
obtaining satisfactory and uniform results in spraying, as
the arsenical compounds used do not enter into true solution
with water, but having greater specific gravity remain in sus¬
pension only. For this reason the particles of the poison
have a constant tendency to settle to the bottom of the tank.
Therefore the strength of the solution varies according to
the amount of agitation given it. Hence the necessity of
a continuous stirring of the contents of the spraying tank
even when the pump is not being used, as while it is
being taken from one tree to another. Even with con-
tinuous stirring the liquid issuing from the nozzle when
the tank was nearly emptied usually contained more poison
than that taken from a full tank or one half full. In most
spraying machines the liquid is agitated only when the pump
is in motion and the insecticide settles when the pump is
not in use. It then becomes necessary to scrape the bottom
of the tank and stir vigorously.

Several kinds of hose were used in spraying. The half¬
inch, rubber-lined, cotton-covered Eureka ho»e was found to
be most convenient for the heavy apparatus on account of
its light weight. For light machines, where only one small
nozzle is used to each line of hose, quarter-inch rubber tub¬
ing is large enough. Each spraying gang was supplied with
eight pieces of hose, each fifty feet in length, which were
used in two lines of two hundred feet each. These were
sometimes united to form a single line so as to spray places
which, from their locality, could not be reached otherwise.
In general use, however, the two lines of hose were used
simultaneously. A “shut off” was coupled on each line of
hose near the pump and also at the nozzle.

Not the least important part of the spraying apparatus is
the nozzle. The desirable qualities of a nozzle for spraying
large trees are that it shall throw voluminous jets of spray
to a distance of eight or ten feet, clear itself readily, and
be easily adjusted to varying distances, thus enabling the
workmen to work rapidly. A series of tests was made with
thirty-three different kinds of nozzles. The Lowell and Gem
nozzles were found to be most effective. Both of these noz-

148

THE GYPSY MOTH.

zles are operated on the same principle and both have been
much used in the gypsy-moth work. A good climber us¬
ing the Gem nozzle can spray large trees both thoroughly and
rapidly.

When it is impossible to reach the ends of branches with
a fine spray, a turn of the nozzle will cause a heavier spray
to be thrown to a distance of ten or twelve feet. If neces¬
sity requires, this can be reduced to a stream which can be
forced upward for thirty feet, where it will break into drops ;
but when the foliage can be reached with a spray, the use
of the stream should not be permitted, as such work does
not give the best results.

There are some objections to the use of these nozzles. They
waste more or less of the liquid and do not distribute it so
finely as some other nozzles. They also may tempt the
workman to avoid climbing by substituting the stream for the
spray where the branches are not easily accessible, thus im¬
pairing the efficiency of the spraying. Yet if the operations
are superintended by competent men, this may be guarded
against and the work done far more rapidly than with non-
adjustable nozzles throwing a finer spray.

The Lowell nozzle (Plate XXIV., Fig. 2) consists essen¬
tially of two brass tubes placed one within the other. The
inner tube at its posterior end bears a coupling by means of
which it is connected with the hose, while the anterior end
terminates in a tapering point at the base of which on op¬
posite sides are two openings which allow the fluid to escape
into the chamber between the tubes. The cone-shaped point
of the inner tube tapers for about two-thirds of its length, at
which point its diameter is abruptly enlarged and then tapers
again at an increased angle to its apex. On the outside of the
inner tube is a coarse screw thread which moves on a blunt
screw inserted through the side of the outer tube and by
this arrano-emeut the latter is moved forward and backward.

O

This outer tube, which is slightly shorter than the inner one,
closes on the latter at the posterior end by means of a band
of packing held in place by a movable nut. At its anterior
end it is widened to form a bell-shaped opening which at
the centre closes tightly around the tapering point of the
inner tube. When in use the outer tube is slid forward by

Plate XXIV.

Fig. 2.

Fig, 3.

Plate XXV

Fig. 2

Plate XXVI

Fig. 2

Plate XXVII.

SPRAYING APPARATUS.

149

a rotary motion on the screw bearing of the inner tube, and
the spraying solution is forced out through the circular space
thus opened between the point of the inner tube and the
inner surface of the outer tube, which surround it. By
turning the outer tube the density of the spray and the dis¬
tance to which it can be thrown are regulated.

The Gem nozzle (Plate XXIV., Fig. 4) is made on the
same principle as the Lowell. In using these nozzles a strong
pressure is required to insure a fine spray.

For spraying orchard trees and shade trees of ordinary
size, light hand ladders were found to be very serviceable.
But when the tops of tall street elms were sprayed, extension
ladders, thirty, forty or even sixty feet in length, were nec¬
essary. A heavy extension ladder sixty-five feet in length,
such as is used by firemen, was purchased for the latter
purpose. This ladder could be readily and skilfully handled
by six men with the aid of blocks and tackle. The small
hand ladders were carried on the spraying wagons and the
larger ones by hand or upon wagons, hand-carts or wheels,
as was most convenient. Ladders mounted permanently
upon wheels could not be used to advantage on account of
the uneven nature of the ground where much of the spraying
was done. Ladders twenty to twenty-five feet in height with
braces so made that they could be set up like step-ladders
were used at first, but they were unwieldy and it was soon
seen that more effective work could be done by using light
ladders and climbing into the trees themselves. In climbing
fruit and shade trees care must be taken not to injure the
branches.

Machinery for Spraying Orchard Trees and Garden Plants.

Although in spraying small gardens and orchards any good
tank or pump may be used, the heavy and more cumber¬
some outfits are not necessary. A small portable tank and
pump which can be taken about by the operator, either
attached to his person or upon a wheelbarrow, will suffice
for all the spraying required in small estates.

For spraying garden plants and small fruit trees the

“ knapsack pump,” which is fastened on the shoulders,

has been otten recommended for use in small gardens and

©

150

THE GYPSY MOTH.

orchards. The Gould handy knapsack spraying pump
(Plate XXIV., Fig. 1) has been used experimentally in
the gypsy-moth work and gives fairly good results. These
knapsack sprayers, however, are inconvenient when spraying
is required on a large scale as they do not carry sufficient
liquid.

The hand tank and pump used with the cyclone burner
(page 120, Fig. 1) has been found very useful in spraying
small orchards. With the pole attachment most of the trees
can be sprayed from the ground. This tank may be carried
and operated by two men.

Gould’s barrel sprayer is shown in Plate XXV., Fig. 2.
It has been very useful in our experimental work, and could
no doubt be used to advantage in spraying small orchards,
gardens and held crops. It has the advantage of being
movable without the aid of a horse. Its wide tires can be
run over ground where it would not be possible for a horse
to go without doing injury.

In spraying in gardens where tender and valuable plants
are grown or in orchards containing choice varieties of fruit
trees, it is most essential that the liquid be thoroughly
stirred, and especially that the spray be distributed evenly
and in a hne mist, otherwise injury to the plant may result.
Spraying may be done with the crudest implements. Corn-
brooms and whitewash brashes have been used with good
effect in some cases, but for uniformly good results we have
seen nothing better than some of the modifications of the
cyclone nozzle (Plate XXVII., Fig. 2). This nozzle was
originally brought to public notice by Professor Riley, then
chief of the United States Entomological Commission. When
used in its original form, it throws a finer and more even
spray than any nozzle which has come to our notice, yet it
has faults which preclude its use except in very limited
fields. It sprays very slowly and is frequently clogged by
the coarser particles of the insecticide or by foreign sub¬
stances, the perforation through which the liquid passes out
in spray being very small. It is then necessary to remove
the cap and clear the nozzle. Therefore much time is con¬
sumed in its use. When first tried experimentally at
Medford it was found that an hour was required to spray

SPRAYING APPARATUS.

151

thoroughly a large apple tree. Still the cyclone nozzle has
been used to some advantage against the gypsy moth by
uniting four nozzles in one (Fig.

10) and slightly enlarging their aper¬
tures. The nozzles radiate some¬
what so that the spray from the
four covers a much larger held than
that from only one. The amount
of the spray thrown in a given
time, as well as the area of the
foliage covered, is more than quad¬
rupled. Yet clogging occurs more
frequently on account of the greater number of nozzles.

The Vermorel modification of the cyclone nozzle (Plate
XXIII., Fig. 1) is an improvement on the original inven¬
tion. It throws more liquid than the cyclone but gives a
fine, even spray which, because of its tineness, cannot be
projected to a distance. This spray will drift on the wind,
however, so that spraying can be done for some distance to
the leeward of the operator. Though this nozzle uses less
of the spraying fluid than the Gem or Lowell nozzles, it
uses more than the cyclone and therefore will spray more
rapidly than the latter. It distributes the spray more finely
and evenly than the Gem or Lowell nozzles and gives better
satisfaction in spraying small trees or shrubbery. Experi¬
ments indicate that in the number of caterpillars killed, there
is a slight difference in favor of the
Vermorel nozzle over the nozzles
previously mentioned. Spraying
may be done more rapidly by at¬
taching two or more nozzles to the
same hose by means of the Y coup¬
ling (Fig. 11).

The Vermorel nozzle consists of
a short brass tube bent at right
angles, having a coupling at one
end by means of which it is at¬
tached to the hose and at the other
end entering at right angles a small cylinder, which is divided
by a transverse partition into two chambers.

152

THE GYPSY MOTH.

The stream from the hose is carried through the bent tube
and enters at a tangent the anterior chamber of the cylinder.
The posterior chamber serves as a packing box for a small
brass rod which passes through the centre of the partition
dividing the chambers, and lying in the axis of the cylinder,
projects half its length in the rear, where it is terminated by
a screw cap. Around the rod between this cap and the nut
closing the packing box is a spiral spring which keeps the
rod drawn back when not in use. The anterior part of the
rod has a flange in front of the partition which prevents it
from being drawn back out of the chamber and its anterior
end has a tine needle point. The outer chamber of the noz¬
zle is closed by a screw cap, hollowed at its centre where it
is perforated by a tine hole which serves as the exit for the
spray. When this hole becomes clogged, it may be cleared
by pressing on the cap or thumbpiece at the base of the rod,
thus forcing the needle point out through the opening.

The climax or Nixon nozzle is better adapted for spraying
large orchard trees than the cyclone, as it throws a good
spray to a considerable distance, but it is not adjustable like
the Gem and Lowell nozzles. It is shown in Plate XXIV.,
Fig. 3. No. 1 shows the entire nozzle, No. 2 the nipple
end of the same, and No. 3 the end of the nozzle, which
screws over the nipple and is covered with a line screen
which breaks up the stream into spray. All these parts are
fitted with standard pipe thread, and will fit corresponding
sizes of gas pipe and hose coupling. They are made of
various sizes which will produce spray from the density of
a heavy fog to any coarseness that may be required, the
smaller sizes giving the finest spray.

The McGowen nozzle (Plate XXVII., Figs. 3, 4 and 5)
has been used only experimentally in the gypsy-moth work.
This is the only nozzle we have yet used which appears to
give equal satisfaction in all kinds of spraying. It pos¬
sesses to some extent the qualities of all the nozzles previ¬
ously mentioned. It can lie regulated at will to throw a fine
spray, project a coarse spray to some distance, or send a
stream to a considerable height, where it will break into
fine drops. Its effective use, however, requires some skill
and mechanical knowledge on the part of the workman.

SPRAYING APPARATUS.

153

Fig. 3 represents a side view of the nozzle and a cross
section of the piston about three-fourths natural size. The
cylinder u projects at right angles from the top of the tube
w. This cylinder is closed at the end by a bevelled block.
The orifice v is closed by a sliding piston which is composed
of one or two pieces. The cross section of the piston shown
in Fig. 7 represents the form having two parts, an inner
piston which can be screwed out, as represented by the dot¬
ted line e, and an outer part or sleeve c. By turning the
screw s the spray can be changed instantly from a long-
range spray suitable for orchards to a spray fine and mist-
like. However the opening may be adjusted, it so remains,
except when obstructions become lodged in the nozzle. The
spring x is designed to hold the sliding valve in position
except when obstructions are forced into the nozzle. As
such obstructions prevent the passage of the fluid, the pres¬
sure upon the walls of the opening in the nozzle instantly
increases. This forces the piston back from the outlet orifice
so that the opening will admit the passage of any object not
larger than one-fifth by three-sixteenths inch. When the
obstruction passes out, the force of the spring sets the valve
back into position and the nozzle works again as desired.
The tension of the spring x can be varied by moving the ring
2 up or down. Figs. 4 and 5 represent two pistons, each
composed of one piece. No. 4 is adapted for long-distance
work; No. 5 is adapted for short-distance work, as it
throws a very fine spray which cannot be forced to a dis¬
tance. These parts are made to be used where a change of
spray is not desirable. All the pistons are interchangeable.
Fig. 6, Plate XXVII., represents a lighter nozzle, designed
for knapsack pumps. The spray is fan shaped. The advan¬
tages of such a nozzle are evident. When the spraying is
done by means of a pole extension, such small particles as
clog some other nozzles are quickly released without any
delay or stopping of the pump or lowering the pole to clear
the nozzle.

The extension nozzle consists of a metal pipe, sometimes
inclosed in a bamboo pole. It is made to enable the opera¬
tor to raise the nozzle to a height of twelve feet or more
from the ground, so that orchard trees may be sprayed with-

154

THE GYPSY MOTH.

out climbing. The extension nozzles ordinarily made, being
but five or six feet in length, are not particularly useful for
this purpose, but may be used to advantage when the work¬
man stands on a firm step-ladder. In the work on the gypsy
moth a light wooden pole twelve feet in length was used
in orchard spraying. The nozzle and hose were attached
to this pole by means of snap hooks, or the nozzle was
secured to the end of the pole by means of a cap provided
for the purpose. In using this pole the workman carried
the lower end in a socket attached to a belt around the
waist.

Power Spraying Machines for Orchards and Field Crops.

Several horse-power spraying machines have been pro¬
duced with the intent of saving time, labor and money to
the user. In using such of these machines as we have seen,
it is necessary to keep the horse moving in order to work
the pump by horse power, and it is difficult to get sufficient
power without driving too fast to give time for thoroughly
spraying the trees in passing. Therefore in spraying trees
the pump must be operated by hand. These machines are
valuable in spraying potatoes and other crops grown on the
ground.

The “giant, automatic power sprayer” (Plate XXVI., Fig.
1) has been adopted for use in the gypsy-moth work, but as
yet has not been thoroughly tested in the field. It consists
of a sixty-gallon oak tank suspended between two wheels
with wide tires. The diameter of the wheel is three and
one-half feet. The frame is strongly made to enable the
operator to use the machine upon rough ground. Endless
sprocket gears attached to the wheels communicate the power
to the handle of the pump by means of a shaft. The gear¬
ing may be thrown out of action in an instant to prevent
waste when it is not desired to operate the sprayer. The
pump can be disconnected from the horse-power machinery
and operated by hand in spraying large trees. This sprayer
in operation is shown in Plate XXVIII. Several steam
spraying machines have been invented, but we have had
no experience in their use.

PLATE XXVIII. Automatic sprayer in operation.

SPRAYING APPARATUS.

155

The Care of Spraying Machinery.

The operations of spraying are frequently more or less
delayed by minor accidents or imperfect working of parts
of the machinery. The action of the insecticide mixtures
corrodes certain parts and the pumps require constant at¬
tention to keep them in good working order. Unless their
construction is understood by either the workmen or the man
in charge, considerable delay and loss of time are occasioned
by sending the pumps away for repairs or awaiting the
services of experts called in to remedy the difficulty. lret
most of the trouble may be easily and quickly remedied if
the men using the apparatus have a sufficient knowledge of
the different parts of the pump to take out those that work
imperfectly, repair and replace them. .Most of the delays in
the field are caused by either a clogging of the strainer in
the tank, some obstruction in the valves or the wearing
of the packing of the piston in the cylinder.

Before the spraying apparatus is sent into the field in
the spring, it should be thoroughly overhauled and tested.
While the spraying is in progress, each of the spraying
gangs should be furnished with a tool box containing
wrenches, tools, packing and other materials which are use¬
ful in taking apart the pumps and making repairs. Mr. E.
C. Ware, who superintended the spraying teams in 1891,
gives the following information and directions in regard to
the care of pumps in the field : —

If a pump fails to throw a stream, it is well to put some
clean water in at the top, as it is quite often the case that
the valves are made or lined with leather, which, in drying,
has become hard or warped out of shape. If the pump is
an old one and the valves are of leather, it may require new
valves before it can be made to work. If the pump still
fails to operate satisfactorily, examine the strainer to see
whether it has become clogged, as the trouble with the pump
can be quite often found at the bottom of the strainer. If the
pump has not been used for a day or two, the strainer may
have become corroded. Sediment from the material used for
spraying will sometimes dry on the meshes of the strainer so
as to prevent the passing of the liquid through the pump.

156

THE GYPSY MOTH.

When Paris green, lime, arsenate of lead or similar com¬
positions are used with glucose or other adhesive constituents,
and the pump is not thoroughly cleaned after using, trouble
with the valves may be expected. When the trouble cannot be
found at the strainer, it is well to clean the valves thoroughly,
being careful to put them back in their original positions,
seeing that the packing is clean and in place before putting
the screws back or screwing any nuts down. In tightening
the nuts or screws, put them down until they come to an
easy bearing all around ; after which go over them again and
settle them down tightly. In case the pump should be a
heavy one having a piston working through packing, and the
liquid escapes around the piston, loosen the large nut and
take out the ring which will be found pressed in by the nut.
If the packing which will probably be found there is hard
and dry, it will be well to replace it with some hemp packing
such as is used by steam titters (or if this is not at hand,
with cotton wicking), saturating it with heavy oil or tallow
mixed with a liberal supply of black lead (graphite). Soak
the packing thoroughly and wind it loosely about the piston,
pushing it in the mean time toward the pump until you have
about as much wound on as the ring will push in without
preventing the nut from catching. Then screw the nut up
as far as it will go without preventing the pump from work¬
ing easily. It is not well to screw it up too tightly at first,
but to turn it a little at a time, just enough to keep the
pump from leaking.

In connecting hose to pumps, it will be found necessary
to use rubber washers at all connections to prevent leakage
when couplings are screwed together. Wherever the cast¬
ings or other parts of the pump are broken by accident, much
time may be saved if duplicate parts are kept ready for such
an emergency. Before the pumps are stored at the end of
the spraying season, they should be taken apart and care¬
fully cleaned and oiled.

When to Spray for the Gypsy Moth.

Spraying should be done early in the season, as soon as
the leaves are well grown, for at that time there is least
risk of injury to the foliage. The insecticide also will be

WHEN TO SPRAY.

157

more effective if applied soon after the caterpillars hatch.
As the young gypsy-moth caterpillars hatch at intervals
from the latter part of April until the middle of June, and
as the leaves are constantly growing during the early part
of the season, thereby offering daily more fresh unpoisoned
surface upon which the caterpillars may feed, it may be neces¬
sary to spray once or twice more in May or June. Spraying
with the best insecticides known (arsenate of lead excepted),
if done late in the season, has little effect on the gypsy-moth
caterpillars where they are numerous, as they will strip all
foliage from the trees before being seriously affected by the
poison. The uselessness of such spraying is shown by the
illustrations in plates IX., XI. and XVI. The caterpillars
thus destroyed the foliage in the Swampscott woods early in
August, after the trees had been sprayed twice with Paris
green . *

It is well not to spray fruit trees when in blossom. If
sprayed at all at that time, the work should be done with a
nozzle throwing a fine, mist-like spray. A coarser spray is
likely to injure the blossoms, as well as to wash off the
pollen. There is danger also of' poisoning bees. Prof. F.
M. Webster, entomologist of the Ohio experiment station,
has experimented by spraying apple trees in full bloom and
giving bees access under natural conditions to the sprayed
blossoms. Many of the bees which visited the trees died
suddenly, as well as the young larvae of a brood from
uncapped cells. Arsenic was found in the contents of the
abdomen as well as on the external parts. The bees all gave
evidence of having died from the effects of arsenic which
could only have been introduced from without the hive. If
the pollen is washed off the blossoms by the spraying and
the bees which distribute pollen are killed by the poison, the
spraying of fruit trees when in blossom will affect their
fruitfulness.

Spraying should not be done during showers or after
showers before the leaves dry, or when a heavy dew is
on the foliage. When spraying is done during showers,

* Many of the failures that have been recorded in spraying for other insects may
be traced to the fact that the work was done too late, and not until after the injury
was so serious that the spraying could not stop it in time to save the foliage.

158

THE GYPSY MOTH.

much of the poison will be washed off or gather in spots.
If the trees are sprayed in dry weather or at a time in the
day when the leaves are dry, the poison adheres to the leaves
as it falls and is thus most effective.

How to Spray for the Gypsy Moth .

In many cases spraying for insect pests is a failure. Where
tender plants and choice fruit trees are sprayed, more harm
than good is often done. This is not to be attributed, how¬
ever, to the method, but to either poor machinery or to
ignorance or carelessness in the use of insecticides. When
spraying is thoroughly and carefully done according to the
rules given by the best authorities, it will almost always give
good results with most leaf-eating insects. Yet, as has been
shown, the most careful spraying with the best insecticides
may fail to check the gypsy moth. If spraying is done
when the caterpillars are young and feeding mostly on the
lower surface of the leaves, it will be most effective. Use
not less than fifteen pounds of arsenate of lead and two
quarts of glucose to one hundred and fifty gallons of water.
Be sure that the acetate of lead is dissolved in water (warm
if need be) before it enters the tank. Stir the mixture con¬
stantly and spray evenly and thoroughly with a fine spray.
If this does not kill, double the dose.

Spray fruit trees to as high a point as possible from
the ground by the use of a long pole or extension with any
nozzle which will throw a very fine spray, spraying always
in such a way as to reach the under side of the leaves.

On tall shade or forest trees spraying may be best accom¬
plished by the use of a ladder. A nozzle which will throw
a coarse spray to a distance, like the Gem, Lowell, Nixon
or McGowen, may be used. Often the lower limbs may be
sprayed from the ground by means of a pole. The pole can¬
not be so well handled in the tree, and the workman can
spray best by climbing up the main trunks and branches
and spraying from below as he climbs. If the spraying is
done later in the season, particular attention must be paid
to the ends of the branches and to the tops of the trees, for
many of the larger caterpillars crawl to the very tips of the
branches and to the tops of the trees to feed.

PLANTS INJURED.

159

Injury to Plants caused by Spraying.

The strong prejudice against the use of Paris green for
spraying which was met with in Medford in 1891 was partly
caused by the belief that both trees and garden plants would
be injured or killed thereby. This belief was shared by many
people and was largely based upon the results of the work
of the first commission, as observed in 1890. Many indi¬
viduals who had experimented with London purple and Paris
green in an attempt to protect their trees had succeeded
only in destroying the foliage. It is true that the foliage
of many trees was injured in 1890, and that to a less extent
this occurred in the work of 1891. Yet much of the appar¬
ent injury was effected by other causes than spraying. In
the investigation of complaints that the foliage of trees had
been burned, it was found that in some cases the injured
trees had not been sprayed. In at least one case the sup¬
posed burning was caused by the effect of a late frost. A
blight upon fruit trees early in the season closely resembled,
upon superficial examination, the appearance produced by
arsenical burning. Later in the season, during the drier
portion of the summer, many leaves on trees, which had
not been sprayed, turned yellow and fell, presenting much
the same appearance as was observed on fo’iage which had
been burned by spraying. Many reports were received that
trees had been killed by spraying, but in most of these cases
it was not clearly proved that death was not due to some
other cause. Still there is evidence that some young trees
were either killed by spraying or were so weakened by
burning or defoliation resulting from spraying that they
succumbed to the heat of the summer. Such a result is un¬
usual, however. An apple tree which was sprayed in 1890
with the contents of fifteen tanks of the Paris green mixture,
each tank containing a pound of Paris green, was not per¬
manently injured. It is said that many young and tender
plants in gardens were not only seriously injured but actually
killed by spraying ; yet where this happened it was prob¬
ably due to some ignorance or carelessness in the use of the
insecticide. Some species of trees a*re more susceptible than
others to the effects of the poison. The foliage of plum

160

THE GYPSY MOTH.

trees and especially that of peach trees is often destroyed
by an application which will not injure the apple or many
other species. There appears to be a difference among
varieties of trees of the same species in their susceptibility
to poison, and some individuals of the same variety seem
more susceptible to injury than others. This is also true
of shrubs and garden plants.

Causes of the Burning Effect.

We have already stated that the burning of foliage by
arsenites appears to be caused by the soluble arsenic in the
insecticide ; yet it is known that poisons like Paris green,
which are comparatively insoluble in water, will burn the
foliage under natural conditions if applied in great strength.
This seems to indicate that the arsenic on the leaf is dis¬
solved more or less by dews and rains, the dehydrating
effects of the sun’s rays, a moist atmosphere or the
exhalations from the leaf, or by all combined. We have
noted that although experiments with arsenites performed
in a dry atmosphere in the laboratory produced no burn¬
ing effect, the same strength of material burned badly out
of doors. Professor Fernald’s experiments in the insectary
indicate that Paris green burns more in warm damp weather
than in cool dry weather.* The larger the amount of
arsenic deposited on the leaf the greater will be the amount
eventually dissolved, and the greater the burning effect. If
the liquid is distributed evenly in minute drops over the leaf,
there is less danger of burning than if it is distributed in
large drops, or if the tree is so copiously showered as to
cause the arsenic to settle and accumulate in spots upon the
leaf. Wherever such accumulations occur, the burning is
the more serious and the injury spreads from the burned
spots. Therefore, there will be the least burning from a
fine spray, lightly and evenly distributed.

How to prevent Burning the Foliage.

What should be done and what avoided to prevent or lessen
the burning of the foliage may be summarized as follows : —

* Bulletin No. 19, Hatch Experiment Station, page 118, May, 1892.

PREVENTION OF BURNING.

1G1

1. Avoid the use of London purple.

2. If Paris green is used, keep the spraying liquid con¬
stantly and thoroughly agitated.

3. Use only a very tine spray and distribute it lightly.
This applies especially to tender plants and valuable fruit
trees where burning may mean serious loss.

4. Do not let the spraying liquid stand in the tank but
use it as soon as mixed.

5. Spray early in the season when the injury to leaves
will be least.

6. If Paris green does not give good results, use arsenate
of lead, which will not burn if properly mixed and applied.

Reports of Injury to Man and Animals by Spraying.

The prejudice against spraying in Medford and other
towns was intensified by the belief that there was danger of
fatal poisoning to man and animals. When the spraying
was in progress, sensational reports were circulated. State¬
ments were made in the daily press that a man had died
from the effects of chewing leaves taken from trees sprayed
in Medford, and that a child had been fatally poisoned by
eating bread and butter on which some of the spray had
fallen from the trees. On this at least one newspaper editor
advised his readers to shoot at sight the workmen employed
in spraying. It was reported that there was great danger
from eating sprayed fruit. Several quarts of cherries which
had been taken from sprayed trees and preserved in jars were
analyzed, and no trace of arsenic was found. Yet even before
they were analyzed, it was reported that they had been sent
to Amherst and that arsenic enough had been found on them
to kill a dozen people. A large portion of the cherries on
these trees were stolen by boys or given away, yet no im¬
mediate mortality occurred among the juveniles of the neigh¬
borhood. It was frequently reported that people had been
badly poisoned by having a spray thrown in their faces. It
is possible that this statement had some slight foundation in
fact. While in eating fruit there is little danger of the con¬
sumption of sufficient poison to have any appreciable effect
on the system, there is a certain amount of danger from the
absorption or inhalation of arsenic, and great care should

162

THE GYPSY MOTH.

be always exercised in its use. About ten per cent, of the
men employed in spraying suffered more or less from arseni¬
cal poisoning. Some appeared to be much more susceptible
to its effects than others. This subject is more fully treated
in Appendix F, where instances of the ill effects produced by
the careless use of arsenic are given. Numerous sensational
tales were promulgated in regard to the effect produced on
animals by eating grass or foliage poisoned with Paris green.
That there is no danger of serious results to the larger
domestic animals from ordinary spraying has been proved
by Prof. A. J. Cook’s experiments.* He fed to his horse
and to sheep grass on which the poison had been allowed
to drop copiously from sprayed trees. We have frequently
fed a horse in the same way without any apparent harm to
the animal. A Medford milkman was accustomed- to take
as a gift the grass which people feared to use, it having been
cut on lawns where the trees had been sprayed. This grass
formed the principal food of his cows during the summer and
they showed no ill effects. At one farm in Somerville, where
the trees were liberally sprayed, three cows suddenly died.
A suit was threatened, but on account of lack of evidence it
never came into court, f Several flocks of fowls were stricken
with sudden mortality immediately after the trees which hung
over hen yards had been sprayed. Fowls show a great sus¬
ceptibility to arsenical poisons. It is a question, however,
whether the fowls were killed by eating poisoned caterpillars
or grass on which the spraying liquid fell, or whether they
did not die from some epidemic disease. The matter was
not fully investigated. One instance wTas noted where a hen
died just as the workmen walked into the yard to begin
spraying. The owner was immediately notified so that the
impression might be avoided that it was killed by Paris

green 4

* Bulletin No. 53, Agricultural College of Michigan Experiment Station, August,
1889.

t Cows have fed without apparent injury on grass under trees which have been
twice sprayed with arsenate of lead at a strength of fifteen pounds to one hundred
and fifty gallons of water.

X If wild birds are likely to be destroyed by eating poisoned vegetation or poisoned
insects, the benefits derived from spraying must be largely discounted, as birds are
most useful as insect destroyers.

CONTACT INSECTICIDES.

163

Spraying with Contact Insecticides.

When it was seen that spraying the foliage with Paris
green had little effect on the larger gypsy-moth caterpillars,
experiments were made with insecticides which were intended
to kill by contact. This was done to find a means of dispos¬
ing of the masses of caterpillars which did not seem to be
much affected by the use of Paris green and which clustered
on many trees where fire could not be used. Contact in¬
secticides, when of a strength sufficient to kill the gypsy-
moth caterpillars, are likely to cause injury when used on the
foliage. Therefore they can only be used to advantage as a
last resort where the caterpillars have stripped trees or
where they are clustered in such numbers on the trunks
as to make it less expensive to spray with an insecticide
than to kill them by hand.

Kerosene emulsion was first tried. A strong emulsion
gave fairly good results but its preparation in the field was
not economical. The only way in which it could be made to
give satisfactory results was to mix it at a central point and
distribute it to the different towns. When it was made in
the field the men did not iret uniform results.

Fish oil and whale oil soap gave better satisfaction when
used as follows : —

Take one pound of whale oil soap and slice into thin,
small pieces. Place the pieces of soap in a pail and add
about a gallon of boiling or nearly boiling water ; then stir
until the soap is dissolved ; dilute at the rate of one pound
of soap to twenty gallons of water. This formula was pre¬
pared by Mr. E. P. Felt.

Solutions made from soap powders also proved effective.
The following formula was prepared by Supt. F. H. Jones : —

Place one pound of “Gold Dust” in a pail; add one
gallon of lukewarm (not hot) water; stir briskly until the
powder is dissolved ; then add three gallons of cold water ;
stir well.

Where the larva; and pup® are clustered together on the
trunks of trees and in stone walls or other sheltered places,
they should be well drenched with the solution. The hand
tank (Fig. 1, page 120) and Gem nozzle were found useful

164

THE GYPSY MOTH.

in spraying with contact insecticides. A tree in Swarnp-
scott, the trunk of which was covered with caterpillars,
was sprayed, killing nearly all at one spraying. Excellent
results were obtained wherever the liquid was carefully
mixed and applied. It is poor economy, however, to use
contact insecticides except where the larvae are very numer¬
ous, for elsewhere they may be more rapidly and cheaply
killed by hand, either by burlapping the trees or by other
methods.

While the use of soap powders upon the gypsy moth has
some advantages, it is not to be recommended except in the
most extreme cases and with the exercise of great care and
judgment.

Measures for Destroying all Forms of the Moth.

The methods thus far described have each been intended
for the destruction of a particular form of the moth. The
methods hereinafter described are intended to facilitate or
secure the destruction of all forms of the moth, and have
been used with a view to preventing the creature’s spread
and securing its extermination. It has sometimes become
necessary to destroy all vegetation in an infested spot in
order to prevent the moth’s rapid spread and wide dissemina¬
tion. For this purpose tire and the axe have been resorted to.

Cutting and Burning.

As an exterminative method for use in wooded tracts, the
felling of trees and their destruction, together with that of
all other vegetation, by means of tire has no equal in point
of expedition and economy. This can only be done advan¬
tageously, however, on lands where the timber is of little
value, as the damage caused and expense incurred by treating
valuable woodland in this way would be great. This method
is expedient only where a badly infested spot is found in
woods not otherwise infested and where by vigorous and
immediate exterminative methods the pest may be stamped
out. When a colony of this kind is discovered, the trees may
be felled to best advantage in the fall or early winter. At the
same time the undergrowth can be cut close to the ground and
burned together with the tree-brush, or it may be left to dry

PLATE XXIX. Cutting and burning infested woods. Starting the fires. From a photograph taken in

Woburn, December, 1895.

CUTTING AND BURNING.

165

where it falls and burned later with the wood by means of a
running tire. Fire will dispose of the eggs upon the trees and
undergrowth, yet many will remain among the dried leaves
on *the ground. In order to secure the destruction of the
caterpillars which hatch from these, the territory cleared
should be thoroughly burned over in the spring with the
cyclone burner. This should be done shortly after the young
caterpillars hatch. The cutting and burning should extend
for several hundred feet beyond the utmost confines of the
infested spot. The immediate effect of this treatment will
be to destroy all vegetation above ground, and as a conse¬
quence any young caterpillars not reached by the dames will
starve. From the stumps of deciduous trees cut down,
sprouts will in time spring up. The burning will not kill
the roots and a new growth of trees will finally develop.
There will be no sprouts from the older coniferous trees,
as they do not renew their growth in this way, but are
replaced by deciduous trees. The burning is not entirely
without beneficial effect on the land. The ashes resulting
from the combustion of wood and dry leaves stimulate the
growth of such roots as are buried in the ground or beneath
the leaves and which send forth shoots under the influence
of sun and rain. Within a few months the entire burned
area will be covered with a growth of young plants and trees.

A locality in Woburn where timber land is being cleared
in this way is shown in our illustration (Plate NXIX.).
The appearance of this woodland when attacked by the
gypsy moth may be seen by referring to Plate XVII. The
owner was willing that the ground should be cleared in
order to secure relief from the pest. The trees were first
cut down and the wood cut in eight-foot lengths and the
brush piled and burned, leaving the land ready for the final
burning with the cyclone burner in the spring.

Valuable woodlands generally infested have been treated
by clearing away the undergrowth so as to leave nothing on
the ground for the insects to feed upon. In this work great
care must be taken to avoid injuring the trees by making too
hot a fire about their trunks. It is better to rake away the
dead leaves and undergrowth from the bases of the trees and
burn them than to risk girdling the trees by running a hot

166

THE GYPSY MOTH.

fire close to their trunks. They may then be banded with
insect lime so that the caterpillars may find nothing on which
to feed, or they may be burlapped and the caterpillars caught
under the burlaps. This method will not injure the growing
timber, and if a cleared grove is desired the timber may be
thinned by cutting away the least valuable trees. This will
render the later treatment less expensive.

In 1891 nearly all the trees were felled on a tract of more
than one hundred acres near Myrtle Street, Medford, where
the moths were first introduced. (See Plate XXX.) The
undergrowth was then burned by a running fire. The ex¬
termination of the moths at that place was not then attempted,
but the work was done as an experiment in preventing their
increase and spread from a badly infested locality. As such
it was a success. A fire run through dry leaves and under¬
growth before the middle of May will destroy the greater
portion of the young larvae if done when they are small, and
when the dry vegetation burns with a quick heat.

When worthless and badly infested trees are found in
orchards or elsewhere, the most effectual and economical
method is to cut and burn them. Such trees are usually
full of holes, cracks and cavities, and in such hiding places
all forms of the moth are found in numbers. They can be
immediately disposed of by burning the trees, thereby obvi¬
ating the necessitv of further search and treatment.

There is much waste land covered with undergrowth and
scrubby trees in the infested region. It receives no care
from its owners, being held, not for its productive value, but
for speculative purposes. Fire often runs over such land,
killing the bushes and young pines and injuring the larger
growth so that it is comparatively worthless. Such land
can be cut over with little or no loss to the owner ; indeed,
clearing may often enhance its value. It is not well to cut
the growth during the spring months, when the caterpillars
are upon it, as they will be disturbed by such work and
scattered in all directions. It is much better to cut over
such land in the fall, and burn the brush as it is cut or let
it lie on the ground until it is well dried and then run fire
through it, destroying as many of the eggs of the gypsy
moth as possible. Then when the larvae hatch in the spring,

PLATE XXX. View of an infested one hundred acre tract which was cleared of trees and brush and
burned over in the gypsy moth work. From a photograph taken in Medford in 1895.

BURLAPPING.

167

there will be nothing for them to climb upon, and they may
be all destroyed by burning the ground over with a cyclone
burner. (See Plate XX. ) If it is desired to prevent a new
growth of brush, the ground should be burned over in August
while the sap is in the plants, and again in the following
spring. After such treatment the plants will not so readily
sprout and a frequent repetition of the burning will result
in killing their roots.

Burlapping .

Early in the summer of 1891 burlap or bagging was lirst
used by the employees of the State Board of Agriculture as
a means of assembling the gypsy-moth caterpillars so that
they might be readily found and destroyed. It was noticed
that before the caterpillars had attained half their growth,
they daily left the leaves on which they had fed during the
night and clustered in sheltered places, such as cavities in
the trunks of trees or the under sides of branches or other
natural objects. They began thus swarming in the second
week in June. As they grew larger the tendency to seek
shelter during the day became more and more noticeable.
They often wandered in search of shelter, leaving trees
which did not offer secure hiding-places and retiring to
rubbish heaps, stone walls and other places of refuge to
pass the day. It was seen that whenever old garments,
cloth or paper were thrown in the forks or wound around
the trunks or branches of infested trees, the shelter of such
materials was sought by the larvae during the heat of the
day. The bulky nests of the English sparrow also served
them as hiding-places.

The conclusion having been reached at this time that
spraying with Paris green was only partially successful in
destroying the caterpillars, other means of destruction were
sought. Experiments were made to find an inexpensive yet
durable shelter which would prove attractive to the cater¬
pillars, and which could be readily examined by the men,
thus serving in a measure the purpose of a trap. A cheap
eight-ounce burlap was found to be the best material for
this purpose. A large quantity of baled burlap was pur¬
chased and cut into strips about twelve inches wide. These

168

THE GYPSY MOTH.

strips were made into rolls which the workmen carried sus¬
pended from the shoulder. Each man was provided with
a sheath knife. When a tree was to be “ burlapped,” the
end of a roll was passed around the trunk at a height of
four or live feet from the ground, and enough cut off to
encircle the tree and lap sufficiently at the ends to allow
for shrinkage. (See Plate XXXI.) The burlap was held
in place by twine tied around both tree and cloth. (See
Fig. 12, a .) The upper half of the burlap was turned down
over the twine, so that it hung like a tablecloth suspended
from a clothes line, and made a band of double thickness
around the tree. (See Fig. 12, b.) Although the edges
hung loosely, the centre was bound quite securely to the

trunk of the tree. If the
trunk and branches offered
no better hiding-places to
the caterpillars, most of those
on a tree would crawl down,
morning after morning, and
seek the shelter of the bur¬
lap, remaining there during
the greater part of the day.
When thus assembled, they
were killed by the employees

Fig. 12. Manner of applying the burlap. Qf ^ Board} who dajly went

their rounds from tree to tree, raising each half of the bur¬
lap separately and cutting or crushing the caterpillars be¬
neath. Most of the larvae are found on the bark behind
the burlap, but some are taken between the folds. When,
in the search for larvae, the burlap is examined for the first
time, it is left turned up against the tree. At the second
examination it is turned down. It is turned up at the next
visit, down at the next and so on. By following this plan
any band that has been missed will attract attention. Ex¬
perience indicates that the number of caterpillars taken is
not materially affected, whether the band is left up or down ;
yet for general use it should lie turned down, as it sheds rain
better and presents a neater appearance.

Where the caterpillars are massed, they may be quickly
crushed by a wisp of straw or a wad of old cloth. Where

PLATE XXXI. Putting on the burlap,

BUKLAPPING.

169

few are found, they may be cut in two by the knife and
brushed off the tree. Care must be taken not to crush them
with the bare hand, as their hairs when brought forcibly in
contact with the skin sometimes cause an irritation much
like that produced by nettles.

The burlap band in no way prevents the caterpillars from
ascending or descending the tree, neither does it entrap those
which it shelters. But it was soon seen that most of the
caterpillars which descended the tree remained under the
burlap during the day, and that others which were restlessly
roaming about on the ground often ascended the tree to the
same shelter. Still others, fully grown and ready to pupate,
retired to the cover of the burlap to undergo their last trans¬
formations, and the female moths emerging would often
deposit their eggs upon or beneath it.

The larvae seek the burlap in greatest numbers during very
hot weather, when they usually come down the trees in the
early morning hours, go under the burlap and remain there
during the heat of the day. The greater number keep on
the shady side of the tree, moving with the sun so as to
avoid its direct rays. A few leave the burlap during the day,
but most of them remain until evening. Observations made
on a small apple tree showed that an average of sixty-six
per cent, of the larvae on the tree gathered daily under the
burlap. This habit is illustrated by Plate XXXII.

The following quotation from the notes of Mr. W. L.
Tower, one of the inspectors engaged in the gypsy-moth
work, indicates that the antipathy the larger larvae have for
sunlight is not uniformly shared by the younger or smaller
individuals : —

The small larvae on the tree were less restless and were disposed
to remain longer in the sun than were the older ones. Some of
the smaller ones would remain all day in the sun on the upper side
of a branch, and in one or two cases when placed in a shady place
on the tree returned to their first position in the sunshine.

The burlap band to be effective must entirely encircle
the trunk, and its edges must hang loosely. If under the
influence of sun and rain it shrinks too closely to the tree,
the larvae may not be able to crawl beneath it. This may be

170

THE GYPSY MOTH.

obviated by cutting the burlap once or twice from its edges
nearly to the twine on the side of the tree opposite the lapped
ends. This wTill facilitate the entrance of the larvre, as they
can easily push their way under the loose corners. If a
large cord is used to bind the burlap to the tree, there will
be more room left under the upper half of the burlap when
it is turned down. When the larvae are very numerous, the
burlap may be tacked on and pleats taken in it, to afford
more room for the larvae to pass beneath. On large trees,
where the trunk is of irregular conformation, tacks will
be sometimes required to hold the burlap to the tree.

To those familiar with the habits of the moth, other devices
which might serve a similar purpose will occur. Old tin
cans or wisps of hay or straw may be placed in the forks of
branches or near the roots of trees or beneath hedges to
attract the caterpillars, which may be then disposed of by
lire. Old blankets hung on fences or walls near infested
trees will collect great numbers of caterpillars.

When caterpillars were found to be plentiful in shrub¬
bery, stakes with pieces of burlap attached were frequently
driven into the ground in the midst of the bushes. This
made an attractive shelter for the caterpillars, and many were
assembled and destroyed. Burlap was often left in the forks
of branches or thrown over rubbish or stone heaps in badly
infested localities. If it was repeatedly examined, many
caterpillars were found and destroyed. It was early noted
that not all the caterpillars would come down from the larger
trees, suck as street elms, but that some of them would
remain in the upper part of the tree. In such cases bur¬
laps were banded about the trunk or branches at a height of
twenty or twenty-five feet from the ground. An examina¬
tion of these burlaps necessitated the use of a ladder, but
the results often justified the time and labor expended.

The only considerable expense required by the burlapping
method is that of labor. To secure the best results the
bands must be examined each day so long as any form of the
moth can be found beneath them. Old cloth will answer
the purpose equally as well as burlap.

There are no valid objections which can be urged to the
use of burlap. There seems to be no injury to the tree.

PLATE XXXII. Section of burlap band raised, showing gypsy moth
caterpillars that had gathered beneath it on the
trunk of an elm tree.

B URL APP IX G .

171

from its use, although if it is not visited often and watched
carefully, other insects injurious to trees will use it as a
hidinof-place. In the fall the larva of the codling moth
( Carjjocajpsci jpomoneUa, Linn.) will crawl under the burlap
and gnaw away the bark while preparing a place to pupate ;
but if the burlap is watched and all injurious insects found
beneath it destroyed, its use will prove of great benefit to
the tree. Should it be applied to very young fruit trees
(which is seldom necessary, as a cloth thrown in a fork
of the tree may be used in such cases), there may be some
little danger that the cord, if large, will shrink too tightly
and crease the bark of the growing tree.

Though the use of the burlap for the destruction of the
gypsy moth grew out of observation and experiment by the
employees of the State Board of Agriculture, later research
in the literature of economic entomology showed that similar
devices had been used in the past for other insects.

Dr. Harris, in his report on the injurious insects of Massa¬
chusetts (first published in 1841), writes as follows of the
use of bands for attracting the larvse of the codling moth : —

Mr. Burrelle says that if any old cloth is wound around or hung
in the crotches of the trees the apple worms will conceal themselves
therein ; and by these means thousands of them may be obtained
and destroyed.*

Ivollar wrote of the use of the same method in Europe : —

The following mode of destroying the insects injurious to fruit
trees, communicated to me by M. Scheffer of Modling. is so simple
and yet so efficacious that I cannot do better than to lay it before
my readers. M. Scheffer lays loosely rolled-up pieces of old cloth
or blotting-paper in the forks of his trees. The caterpillars eat
during the night and while the dew is on the leaves in the morn¬
ing ; but they seek protection from the heat of the day. and creep
into these rolls for that purpose. Thus it is only in the middle of
the day that these rolls should be examined, and the caterpillars
concealed in them destroyed. i

* *• A treatise on some of the insects injurious to vegetation,” by T. W. Harris,
M.D., page 487. See also “ New England Farmer,” first series, Yol. IS, page 398.
f “ Practical Entomologist,” Yol. 1, page S3.

172

THE GYPSY MOTH.

As Ivollar resided in Austria, where the gypsy moth was
sometimes injuriously abundant, it is probable that this crude
means of assembling the caterpillars was used in destroying
this species with others.

A few people in Medford who had observed the habits of
the gypsy moth had also used similar bandages with good
effect prior to 1891. (See statements of James Bean, page
29, and S. F. Weston, page 30, of this report.)

The burlap bands are used most successfully on trees that
are well kept and in good condition, with sound and smooth
trunks and branches. If the trees were originally in such
condition or were first properly prepared for the work, the
moths were eradicated from many localities by the burlap-
ping method alone. When trees with decaying branches,
hollow trunks and rough or loose bark became infested, the
caterpillars often preferred the shelter offered by such cavities
and inequalities to that provided by the burlap. Many of
them would not come down the tree to the burlap until the
cavities wrere filled or covered, the dead branches cut away
and the loose outer bark removed by scraping. It was
necessary also to remove rubbish, weeds and brush from the
ground about the trees.

There are, therefore, four auxiliary processes (all beneficial
to trees or grounds) which must be resorted to to ensure
the greatest measure of success in the use of burlap. They
are : judicious pruning or trimming of trees ; treating and
filling cavities ; removing loose bark ; removing and de¬
stroying rubbish, undergrowth and weeds.

Pruning Infested Trees.

To any one who has critically examined any considerable
number of orchard or wayside trees in this Commonwealth,
the insertion here of an exhaustive treatise on the pruning
and care of trees would seem of great utility. This, how¬
ever, is not the function of this volume. It is our purpose
to consider here only: (1) the proper removal of dead, de»
caying or broken branches, which, if allowed to remain, offer
hiding-places for the gypsy moth and other injurious insects ;
(2) the removal of clusters of small shoots or suckers, wdiicTi,
growing thickly on the trunks or larger branches, offer shel-

PRUNING INFESTED TREES.

173

ter to the gypsy-moth caterpillars, which, by remaining in
such hiding-places instead of going to the burlap, may escape
destruction. At least seventy-five- per cent, of the older
orchards in the region infested by the gypsy moth have been
either ruined or greatly injured by their owners’ neglect or
improper pruning or by both. Thousands of trees have been
killed by having large limbs chopped or sawn off or other¬
wise mutilated in such a manner that the exposed and unpro¬
tected stubs have died and communicated decay to the hearts
of the trees. This condition of so many trees, by furnishing
numberless places of shelter for the moth, adds greatly to
the labor of extermination.

Dangers of Bad Pruning. — One of the most fruitful
causes of hollows in trees in which the caterpillars may hide
is the neglect of the simplest precautions in the amputation
of large limbs. Wherever we go in the country, orchard
trees may be seen with trunks disfigured by unsightly protu¬
berances and yawning cavities. Yet projecting dead stumps
such as have assisted in bringing the trees to this condition
are periodically left by the hand of the bungling pruner, who
will continue in this course until he has completed the ruin
already begun. Such trees are monuments to the ignorance or
negligence of those who have had them in charge. Intelligent,
capable men, careful of their other material interests, continue
year after year to “ butcher” their trees in this outrageous
manner, as their fathers did before them, even though the
results of such work are constantly before their eyes.

The growth of many orchard trees has been badly directed.
They have been pruned “ up into the air,” so that their long,
tall, slender limbs have been unable to withstand the fury
of the gale or support the loads of ice which form on them
during winter storms. Weakened as such trees are by decay,
the action of the wind has sent their greatest branches crash¬
ing down in ruin. The ice storm of Nov. 5, 1894, which
visited the eastern part of this Commonwealth, destroyed
hundreds of apple trees by breaking down most of their
lai ’ge branches ; yet avc have not seen a sound, vigorous,
well-nourished and properly pruned tree that Avas materially
injured by that storm. Neither was it always the older trees
which succumbed, for some of the oldest, having had irood

7 O O

174

THE GYPSY MOTH.

care and therefore not being weakened by the almost univer¬
sal decay, upheld their loads, survived the storm’s fury and
were not seriously injured.

It is far better never to prune at all than to prune in an
unscientific manner. Native forest and fruit trees never
pruned by the hand of man grow to maturity in better con¬
dition than those in many orchards. In the forest, trees
are pruned by nature. As they grow upward, the dense
shade formed by their tops kills the lower branches by de¬
priving them of the sunlight. These branches decaying drop
oft' or are torn away by the wind. Little or no damage to
the resinous coniferous trees results from this process. As
the branches usually break oft* close to the trunk, and the
wood is so filled with resin as to exclude water and parasitic
fungi, the wounds heal readily and the trunk remains per¬
fect. More injury is likely to follow to deciduous trees
from this operation, especially when the branches are large,
yet wounds caused by broken branches are often healed.
The breaking is most likely to take place during the winter
storms, when there is less danger of injury to the trunk and
bark. Yet serious injury is often done and the wreaker trees
are frequently killed or their shape is ruined by this process
of natural pruning. Such pruning as is required for the pur¬
poses of the gypsy-moth work will assist in forming healthy
growth rather than retard it.

That many apple trees are in ruins before they are fifty
years old is almost entirely due to neglect or the ruinous
policy pursued in their handling. Such trees well cared
for might continue to bear fruitfully for a century.* A
knowledge of vegetable physiology and the practical applica¬
tion to tree culture of its laws is greatly needed by those
who have the care of trees. A knowledge of the causes of
diseases of trees and the means of their prevention is also
essential to the farmer, orchardist and forester.

It is the function of roots to fix the plant in the soil and to
absorb from it water and the soluble organic and inorganic
crude material which is needed for growth and development.
It is now believed by botanists that this fluid, which we will

* Apple trees in an orchard planted in Medford by Gov. John Brooks soon after
the Revolutionary War have borne fruit within a few years.

BAD PRUNING.

175

call crude sap, charged with material for the upbuilding of
the tree, is absorbed from the soil by the roots and is forced
upward, flowing through the trunk and branches to the
leaves, where it is elaborated by the evaporation of water
and the absorption of carbonic acid gas from the air. It
then finds its way throughout the whole tree, even to the
roots, passing through the soft bast cells of the inner bark
just outside the cambium layer, forming, as it goes, the new
wood and bark.

It may be stated as a general rule that there can be no
perfect circulation of the sap and no long-continued growth
of new wood or bark on any branch or stump which supports
no leaves. It would appear, then, that roots, trunk and
branches have no inherent power of themselves to continue
growth and extension, but must depend upon the action
of the leaves to furnish that elaborated nutriment without
which their continued growth and development is impossible.*
If the new wood is formed by the sap in its descent from the
leaves, it evidently follows that if the projecting stump of
an amputated branch is left without leaves so
placed as to draw the sap to its farthest ex¬
tremity, there to be elaborated and returned,
it must die.f

Effect of Bad Pruning. — The cut, Fig.

13, represents a stump left on a street tree
by the workmen employed in pruning trees
under the direction of the city forester of
one of our Massachusetts cities. Around

, , . , . . , . , Fig. 13. Stump of a

such an unprotected stump the ram and branch left by bad
other atmospheric influences soon begin the pluuing"
work of decay between the bark and the wood. The cam¬
bium layer, lacking circulation, dries up; insects enter;

* It is well known that the roots will for a time perform their functions without
the assistance of the leaves, and that growth of different parts of the tree occurs at a
time when there are no leaves upon it. But this growth is made by the absorption
of water by the roots and by the use of reserve material. If a tree is continually
deprived of its leaves until its reserve material is exhausted, it will die.

f It is well known that there are some exceptions to this rule. Certain vigorous
trees will push out shoots from latent buds near the end of the amputated branch,
and leaves are formed, which by their functions enable the tree to cover the wound.
Willow trunks and branches deprived of their leaves and left upon the ground have
thrown out foliage and roots and grown into vigorous trees.

176

THE GYPSY MOTH.

the bark becomes loosened, warping away from the wood
and finally falling oft’. This condition, so familiar to ob¬
serving people, may be seen by reference to Fig. 14, which
represents an extreme case. Nevertheless, in pruning,
such stumps are commonly (we might say usually) left,
not only by farmers and orchardists, but also by the em¬
ployees of city street departments and park commissions
and even by the workmen employed in
public forest reservations. The stump
left exposed to sun, rain and the action
of the frost cracks. Water enters and
decay sets in which gradually extends
through the wood cells down into the
trunk. Therefore each stump left pro¬
jecting eventually produces decay in that
part of the tree with which it connects.
fig. 14. The stump dies Fig. 15 shows a short section of the trunk

back, injuring the trunk. „ . , . ■. , . . ,

ot a tree on which such a stump has been
left. The stump shown at the right indicates the remark¬
able effort made on the part of the tree to cover the wound ;

yet in the course of years the wood has
been eaten away by rot and the wound
has never healed. Decay has entered
the heart of the tree and is fast de¬
stroying it. Had the branch been cut
even with the surface of the trunk and
the wound properly treated, it might
have been covered with new growth of
wood, and decay might have been pre¬
vented.

Wounds on vigorous trees caused by
by the removal of small branches in this
bad pruning. manner sometimes heal over because of
the small size of the branches and the comparative short¬
ness of the stumps. But as the stump often decays be¬
fore the wound heals, injury to the tree results, and in
any case an awkward protuberance is formed on the
trunk. From such misshapen parts shoots or suckers usu¬
ally spring. Another section of a trunk is here shown.

Fig. 15. A trunk

METHOD OF PRUNING.

177

If the wound is

Fig. 16. Excrescence
caused by bad pruning.

(Fig. 16.) The wound has nearly healed, yet decay has set
in and an unsightly excrescence has been formed on the
trunk of the tree in the effort of healing,
well covered by the new growth of wood
before injury has been done by the rot,
the progress of decay is stopped. In
order to heal readily, a wound caused
by the removal of a branch should be so
made that the sap on its way to the roots
may come in contact with the entire edge
of the wound without deviating from a
direct course.

The Proper Method. — -Evidently, then,
no portion of the amputated branch should
be left, but the cut should he made close to
and perfectly even with the outline of the
trunk or limb from which the branch is removed , without regard
to the size of the wound thus made. When this is done,
the elaborated sap flows over the wound from the edges,
forming callus first at the top and sides, and gradually
covers it with healthy, straight-grained wood. The wound
is thus healed over and the decay of the trunk is pre¬
vented. This healing is gradual and may require years
for accomplishment, especially if the limb removed is large
and the tree old and not vigorous. The annual wood-ring
being thickest on a young tree, wounds made on such a tree
will heal more quickly than on an old tree. Wounds made
near the top of a growing tree heal more readily than those
near the base, for the reason that the annual wood-ring is
thickest at the top. If the wound is left exposed to the sun
and wind during the time required for healing, its surface
invites decay. To prevent this we must protect the wound
at once by applying shellac or coal tar to its entire surface.
The use of grafting wax or other thick coatings for such a
purpose is not recommended, as they are likely to be cracked
or pushed off by the growth of the new bark and thus leave
the wood comparatively unprotected. A solution of shellac
and alcohol, such as is commonly used by painters, is an ex¬
cellent wood preservative, as it closes the wound, prevents

178

THE GYPSY MOTH.

the exudation of crude sap, commonly called “bleeding,” and
is not open to the objection which applies to grafting wax.
Paint is often used. Thick mineral paint mixed with linseed
oil has given satisfactory results at the Massachusetts Agri¬
cultural College at Amherst, and is recommended by Prof.
S. T. Maynard. Coal tar has been long used in Europe
as the best substance known for this purpose. It needs
no preparation aside from an occasional warming in cold
weather, and may be readily applied with a painter’s brush.
This substance will not injure the wood, but, on the con¬
trary, is one of the most perfect wood preservatives known.
If pruning is done with discretion at the right season,
the trunk being not already decayed, and if the tar is
applied at once on the removal of the branch, the wood
will remain sound, and, except in the case of very old
and feeble trees, the new growth will in time cover the
wound. Decay may be prevented or delayed even in old
trees by such treatment. Coal tar should be used with some
caution on cherry and plum trees, as it may injure the tree
if applied to the bark. Wounds on the maple and elm,
which often “bleed,” may need more than one application
of coal tar to stop the “bleeding.” In such cases the first
coat of tar should be well rubbed off before the second
application.

The two most essential rules in regard to removing limbs
are followed in the pruning done in the gypsy-moth work.
Although known and practised in this country at the begin¬
ning of the present century, they have been ignored by most
American writers on tree pruning. Yet Wm. Coxe of
Burlington, N. J., wrote in 1817 : —

In cutting off a branch, it should be done as close as possible,
never leaving a stump, for the bark cannot grow over it, and
disease in the wood will inevitably follow. If the wound produced
by the separation be very large, cover it with tar or thick paint.*

The principles of pruning were ably set forth in 1861 by
De Courval, as practised with perfect success for more than
forty years in the forest of his vast estate of Pinon (Aisne),

* Coxe on “ Fruit Trees,” 1817, page 41.

RULES FOR PRUNING.

179

France. Later in 18<14 the Baron Des Cars published an
able treatise, describing a thorough, practical system of
forest-tree pruning, based on the principles laid down by
De Courval. The American edition of this work (trans¬
lated from the seventh French edition) with an introduc¬
tion by Dr. Chas. S. Sargent, professor of arboriculture in
Harvard University, is the most comprehensive work on this
subject that has ever appeared in the English language.*
The publication of the American edition of this work was
made possible by the trustees of the Massachusetts Society
for the Promotion of Agriculture, an old and honored asso¬
ciation, which has done much for the improvement of agri¬
culture in this Commonwealth. The book should be in the
hands of every person wTho has the care of trees.

Season for Pruning. — Writers on horticulture differ as
to the best season for pruning. Each urges the advantages
of pruning at certain seasons to increase wood growth or
the development of fruit. Objections are frequently made
to pruning in the winter, on account of real or supposed
danger to the tree from exposing large wounds to the extreme
cold. Similar objections are sometimes urged to pruning in
the early spring and late fall, when the newly cut surfaces
are exposed to the influence of sudden and severe frosts.
It is frequently said by orchardists that if a tree is pruned
in the spring, when the sap is flowing copiously, and the
crude sap is allowed to flow down from the wound, it will
poison the bark below and produce decay of the trunk of
the tree.

Such examinations as we have been able to make of the
results of spring pruning indicate that the injury is due to
entirely different causes, viz., the crushing of the bark and
consequent killing of the cambium layer at the base of the
wound or the separation of the bark from the trunk. Such
injuries are likely to occur unless great care is used in prun¬
ing. The danger of a separation of the bark from the trunk
below the wound and the consequent running of the crude
sap into the cavity thus formed is always greatest during the

* “ A treatise on pruning forest and ornamental trees,” by A. Des Cars, translated
from the seventh French edition, with an introduction by Dr. Chas. S. Sargent.
Boston, 1884.

180

THE GYPSY MOTH.

time of the year when the bark peels most readily. In ex¬
planation of this, we cannot do better than to quote Prof. It.
Hartig of the University of Munich, whose pathological work
is a model of thoroughness and scientific accuracy : —

At the time when the cambium is active, it is quite impossible
to prevent the cortex being loosened, the friction of the saw being
sufficient to account for it. But the main cause is to be traced to
the fact that, ill order to prevent the cortex being torn off, a cut is
first of all made underneath, and during the sinking of the branch
the lower edge of the wound is subjected to severe pressure. The
cortex of the lower edge of the wound forms a pivot round which
the sinking branch turns, and, although the effects may not be
immediately visible, still, the crushing and tearing at that point
kills the cambium for an inch or two from the edge of the wound.
Of course in such a case the new growth — namely, the callus — is
not formed at the edge of the wound, but at a considerable dis¬
tance from it, where it is covered by the cortex. The result is
that the cortex, which was originally in intimate contact with the
wood, becomes detached, so that a cavity is formed beneath the
Avound between the wood and the dead tissues. This caAdty acts
like a gutter to catch the rain-water that Aoaa’s OArer the surface of
the wound, as A\Tell as all the organisms that it may contain. This
forms a specially suitable place for the germination of the spores
or parasitic fungi, and it is from here that wTater containing the
soluble products of decomposition finds its way by means of the
medullary rays into the interior of the wood. This caAfity is a
gutter in every sense of the term, and at the same time the point
of attack for fungi. EA’en although the surface of the wound may
haA'e been coated Avith tar immediately after pruning, this spot
remains unprotected, and indeed it is only formed after the cortex
has been separated from the Avood by the advancing callus. It is
in fact the Achilles’ heel of the branch wound. In pruning, the
main object must be to preATent its formation ; but this is possible
only if pruning be confined to autumn and winter, when growth
is at a stand-still, and when the cortex is less liable to be detached
from the wood. If one also takes the precaution to support the
branch during sawing, and at the moment of separation to push it
clear of the wound, danger is reduced to the minimum.*

* “ Tbe Diseases of Trees,” by Trof. R. Hartig, pages 255-257. English edition by
Dr. H. Marshall Ward, London, 1894.

SEASON FOR PRUNING.

181

An examination of injurious results of spring and summer
pruning indicates that the injury sometimes extends down¬
ward and serious harm is done.

There is a danger from the running of sap which occurs
when pruning is done in spring or summer, aside from any
possible harm resulting from the drain on the vitality of the
tree. Warmth and dampness are particularly favorable for
the germination of parasitic fungi and the progress of decay.
Though decay may occur without the presence of these
organisms, its progress is more rapid when they are pres¬
ent. Therefore, wounds wdiich are constantly kept wet in
warm weather by the flow of crude ) sap are most likely to
decay.

There are reasons also why pruning in summer is likely
to be weakening to the tree : —

If the term, winter pruning, is given to any removal of shoots
during the resting period of a woody plant, we may say generally
that winter pruning is strengthening, while summer pruning is
weakening.

If any portion of the shoot system is taken away after it has
passed through one summer, the structure and activity of the
root system — that is, its power of absorption and of forcing up
water — is such that it can nourish all the branches. At the
beginning of the next period of activity, by cutting away some
branches the water-consuming area is diminished. The same
amount of pressure has therefore a reduced field of action,
and consequently the effect on the remaining branches must be
increased.

By pruning in the summer we remove soft shoots with only
recently developed leaves. The latter have yet their chief work
to perform ; for at the commencement they are developed at the
cost of the reserve material which is stored up in the branch, then
comes a period at which the young leaf requires all the substance
it assimilates from without for its own growth, and only after
its full development does it begin to work for the benefit of
the branch. If, thei’efore, a soft shoot is taken away, the older
portions of the branch are robbed of the materials which were
used in the unfolding of the leaves, without receiving anything in
return from the leaves they have developed. This causes, there¬
fore, a loss to the general economy of the plant ; but, with the

182

THE GYPSY MOTH.

increased productiveness of our cultivated plants, such a slight
weakening may be overlooked, if any other special advantage is
gained.*

Tarring the wounds gives the most satisfactory result when
pruning is done late in the autumn or in winter, for it is
then that the tar is best absorbed by the surface of the
wound. When branches are cut off in spring or summer,
the tar fails to penetrate the surface of the wound because
of the flowing sap, and its thin superficial layer does not
prevent the cut from drying later. In drying, cracks are
formed, into which water and the spores of fungi may gain
entrance. For this reason it is often necessary to apply two
or more coats of tar to the wound.

Having considered some of the objections to removing
limbs in summer, it is plain that the late winter is the most
favorable time for such pruning as is here advocated. There
is then less exposure to extreme cold to be considered. It
is known that certain trees have a considerable flow of sap
in winter. It is said that the Indians were accustomed to
draw the sap from the sugar maples in November, when
good sap days frequently occur, f It may be better to prune
such trees in the spring or summer. The results of pruning
native deciduous and coniferous trees at different seasons
of the year have never been fully observed with scientific
accuracy, and there is much to be learned.

Removal of Dead or Broken Branches. — Dead branches
may be removed at any time of the year, if proper precau¬
tions are taken to avoid injuring the bark or trunk of the
tree in the operation. If these branches are left upon the
tree until they decay and drop off or are torn away by
the winds, the bark loosens and forms a harboring place for
the gypsy moth and certain other insects, which hide beneath
it and oviposit there. Their eggs being out of sight, they
hibernate in comparative safety until the following spring,
when the larvae hatch and attack the foliage, thus weakening
the tree. If dead branches are not removed, they are some-

* “A popular treatise on the physiology of plants,” by Dr. Paul Sorauer. English
edition by Prof. F. E. Weiss, pages 137, 138.

f “The Circulation of Sap in Plants,” by W. S. Clark. Annual Report of the
Massachusetts State Board of Agriculture, 1873-74, page 162.

REMOVING DEAD BRANCHES.

183

times broken off* by the wind, leaving a long stump project¬
ing from the tree. The ragged surface of the break offers
perfect conditions for the beginning of decay, and the seams
of the stump communicate it rapidly
to the trunk. Fig. 17 shows a section
of a tree trunk bearing the broken
stump of a dead branch. The tree,
being vigorous, has pushed forward
callus on the branch and partially
covered it with new wood and bark.

This attempt at healing might have
been successful had the branch been
broken close to the tree ; but in this
case the effort of the tree to heal the „

Fig. 17. Decaying branch left on

wound was of no avail. The neoieet the trunk of u-ee.

O

to remove these dead branches is often indirectly the cause
of cavities in tree trunks. When living branches are broken
by the wind, heavy loads of fruit or other causes, the stumps
should be removed. Such ragged and broken snags offer
points of attachment for parasitic fungi ; and if the break
occurs in summer, when the sap is flowing, the conditions
are particularly favorable for the propagation of these fungi,
and the extension of wound rot.

The decay of a tree trunk resulting from improper pruning
and the neglect to remove broken branches is shown in Fis:.
18. Such rotting away of the wood of the tree as is shown
here will not occur immediately, but is
the result which will inevitably, in the
course of years, follow such a policy. If
pruning is begun on the young fruit tree
by nipping off buds and directing shoots
so as to form a symmetrical head, and is
carried on with good judgment as the tree
grows, there will be no need of the ampu¬
tation of large limbs, except such as are
broken by accident or die from other causes.

Amputations of the large lower branches
of shade trees are often necessary in pruning
for beauty and utility. In orchards bad .pruning often neces¬
sitates later the removal of large, decaying hollow limbs, lest

i IT

Fig. 18. Sectional view
of a trunk, showing the
result of neglect and
bad pruning.

184

THE GYPSY MOTH.

they break down and split off a portion of the trunk, which
in such case is frequently hollow. The removal of such
limbs in time may prevent injury to the trunk. These am¬
putations when necessary are merely a question of surgery ;
and if they are performed at the right season and in the
proper manner, and the wound is properly treated, there is
little danger of injury to an otherwise sound tree. Where
injury to such a tree results from the process, it is usually
from ignorance of correct methods or carelessness in their
use. Still, it is well to hear in mind that when a surgical
operation is to be performed, the result depends not only on
the skill of the operator but also on the age and vigor of the
subject.

The death of old decaying trees is sometimes hastened by
the amputation of large and hollow branches. The shock
caused by the removal of several large branches, together
with the reduction of leaf surface, which makes it difficult
for the tree to heal the wounds, will often kill such trees.*
The proper method for treating the cavities of such trees will
be spoken of later.

Removing Large Limbs. — In this process great caution
must be exercised : (1) not to injure the tree by the unneces¬
sary removal of too many large branches in one season ; (2)
to avoid injury of the tree by the breaking down or falling
of the branch; (3) to guard against accidents to work¬
men. The old rule for removing large branches was to
cut the stump across its diameter near its base, never mak¬
ing a cut larger than the diameter of the branch. This
practice has already been shown to be pernicious, as the
tree has great difficulty in covering the lower part of the
wound with a new growth of bark. Where a large limb
is removed in this manner, the lower part of the stump
never becomes entirely covered, and finally decays. In saw¬
ing off a branch the first cut should never be made from
above, as the limb is likely to split and tear away from
the trunk. The result of such an accident as is shown in

* If an old tree with sound trunk whose branches appear to be dying is “headed
down ” by the removal of most or all of its large branches, it may revive, throw out
shoots and form a smaller and more vigorous head.

REMOVING LARGE LIMBS.

185

Fig. 19 may prove very serious to a tree. Whenever it is
necessary to amputate a large or long branch, a cut should
be made from the under side of the
branch, at a distance of two or three feet
from the trunk, and should extend half
way through its diameter, as in Fig. 20, K!\t , ...
line A; another cut, B, should then be
made farther out, extending down into ; p ‘ i/j
the branch until it falls. The first cut ( i
will prevent the limb from breaking fiu. 19. Limb breakine down
and splitting off and the bark from tear- 11 m cut "Iunol> made'
ing down on the tree. The stump may then be removed
close to the trunk on the line C, cutting first from below,
and supporting the stump so that crushing or tearing of
the bark may again be avoided. This
method will prevent injury to the tree
and guard against serious accidents which
sometimes occur when the limb is first
cut too close to the tree. In such cases
the outer end of the branch striking the
ground has sometimes caused the inner
fig. 20. The proper method end to rebound and strike or throw down
of removing a large limb. the workman. Whatever method is em¬
ployed, the wound should be made perfectly smooth and even
with the outline of the trunk by cutting or planing its sur¬
face, which should then be immediately
covered with coal tar.* On fruit trees,
however, it is well never to remove a
large excrescence or shoulder (such as is
sometimes formed at the base of a limb)
if the wood is sound, but to cut the
limb at its junction with the shoulder.

Large wounds are often made in the
tree trunk by the teeth of horses, the
breaking down of large limbs or in other
accidental ways. When such an acci¬
dent occurs as is shown in Fig. 21, it should receive innne-

Fig. 21. A trunk injured by
the breaking of a large limb.

* If the roughened surface left by a saw-cut is smoothed, it lessens the danger
of decay; and if the edges of the wound are trimmed down to the outline of the
tree, the wound is more readily covered by the occluding callus.

186

THE GYPSY MOTH.

Fig. 22. A cavity
caused by the tearing ,

away of a large limb, scribed IS SnOWll ill Fig. 23.

cliate attention. It is necessary to cut away the stump
which is left and to remove as much of the wood as will be
required to make an even surface ; also to cut away all the
bark which has been loosened below the wound. Otherwise
such a wound will in time present an appearance similar
to that shown in Fig. 22, and the injury may continue to
extend. If such wounds are not immediately treated and
covered with coal tar, their inner surface often
becomes decayed, threatening the life of the
tree. If the decayed wood is carefully cut
away and the exposed surface thoroughly
covered with coal tar, the tree will remain
healthy. Though the new wood and bark
may never entirely cover the wound, there
will be no further decay.

A cavity treated in the manner above de-

Decay has been
stopped, and the new bark and wood have entiVely covered
the edges of the wound, leaving the tree in a healthy condi¬
tion. The directions given by Des Cars
for the use of coal tar on trees are so ad¬
mirably stated that we give an extract
from them : —

Coal tar has remarkable preservative prop¬
erties, and may be used with equal advantage
on living and dead wood. A single application
Fig. 23.' A cavity properly without penetrating deeper than ordinary paint

treated; decay arrested forms an ifn pervious coating to the wood cells,
and healing begun. .

which would without such covering, under ex¬
ternal influences, soon become channels of decay. This simple
application, then, produces a sort of instantaneous cauterization,
and preserves from decay wounds caused either in pruning or by
accident. The odor of coal tar drives away insects, or prevents
them, by complete adherence to the wood, from injuring it. After
long and expensive experiments the director of the parks of the
city of Paris finally, in 1863, adopted coal tar in preference to
other preparations used for covering tree wounds, as may be seen
in all the principal streets of the capital. . . .

One coat of coal tar is sufficient for wounds of ordinary size ;
but when they are exceptionally large, a second coat may after
a few years be well applied. In warm countries, like the south

TREATING HOLLOW TREES.

187

of France, the great heat of summer renders coal tar so liquid that
it is impossible to properly treat wounds made at that season.
In such cases another coat should be applied during the following
winter.*

Removing Shoots and Suckers. — Many street trees, espe¬
cially elms, which have suffered from the effects of bad
pruning, send forth shoots or suckers from many points of
the trunk. These shoots are believed to be detrimental
rather than beneficial to the tree, impairing the development
of its top and larger branches. So long as suckers are
allowed to remain, many of the gypsy-moth caterpillars
will seek shelter among them during the day in preference
to going to the burlap. If suckers are carefully removed,
no injury to the tree will result.

Treating Hollow Trees. — When the trunks and larger limbs
of trees are riddled with holes caused by neglect or bad
pruning, another mode of treatment becomes necessary.
Thousands of gypsy caterpillars which feed upon the foliage
at night will retire through the holes to the interior of
the hollow trunks and branches, where they secrete them¬
selves during the day, emerging at night to continue their
destructive work under cover of the darkness. The clos¬
ing of such cavities by filling, covering or sealing them is
an important auxiliary to the other means of extermination.
It prevents the caterpillars from hiding and the moths
from ovipositing within the hollow trunks and branches,
and drives them to the burlap for shelter. If the holes
are carefully covered in the winter, many eggs are en¬
closed within. When they hatch in the spring, the young
caterpillars are prevented from leaving their hiding-places
and are thus buried alive, as it were, in the tree trunks. This
work must be very thoroughly done to prevent the escape
of the minute, newly hatched caterpillars.

During the work of the first gypsy moth commission
many holes were filled with hydraulic cement. If the hole
was large, it was packed with stones and a coating of cement
put on the face of this filling at the mouth of the hole. If
the hole treated was in a large and otherwise sound trunk,

* “ Tree Pruning,” by A. Des Cars, pages 58 and 59.

188

THE GYPSY MOTH.

the cement, provided it was properly mixed and applied,
remained intact for years. Small holes surrounded by sound
wood were also tilled to advantage in this manner. The
cement may be held effectively if laid on a strong iron wire
netting nailed across and just within the mouth of the hole.
Whenever cement is used on growing trees, it should be
faced up within the growth of new bark and
wood, so that the latter may grow over and
hold it tightly. (See Fig. 24.) When the
callus has already formed on the edge of
the cavity, it should be cut away. This
cutting will stimulate new growth, and if
the cement is properly faced up within
the mouth of the cavity, the callus will
eventually cover it. If the hole is so filled
that the cement laps over the edge upon

Fig. 24. Cemented cavity . ... 01

the bark, it is likely to prove worse than
useless, as the growing bark beneath the cement will throw
it off from the tree, leaving a space as a hiding-place for the
caterpillars. Hard cement must be carefully applied by an
experienced man, otherwise it is likely to prove worthless,
and by crumbling and cracking leave the cavity in a worse
condition than before.

This cement cannot be used during the colder months of
the year, as the action of the frost may cause it to crack.
Neither can it be used effectively to stop cracks or cavities,
the sides of which may be moved independently of each
other by the action of the wind on the branches. Experi¬
ments in closing such cavities with plaster of Paris, mineral
wool, Purcell’s elastic cement, Webster’s elastic
cement, Portland cement and Roslindale cement
were made in the winter of 1891-92. None of
these materials gave satisfactory results. Tarred
burlap or canvas has been used for this purpose
wTith some success. If three thicknesses of bur¬
lap are closely and strongly tacked over the
opening to a hollow in a tree trunk and after¬
ward thoroughly soaked with coal tar (Fig.
25) the covering will remain intact and imper¬
vious to the weather for several vears. Oiled cloth will also

Fig. 25. Bur-
lapped cavity.

COVERING HOLES IN TREES.

189

answer the same purpose. These fabrics are not materially
affected by the movements of the tree, and if well tarred are
not often bored through by insects, as the tar is repugnant
to them.

In many cases such cavities as are exposed by the sawing
off of large hollow stumps of broken branches may be covered
to advantage with tin or zinc, which must be tacked closely
over the cavity and afterwards painted or tarred. (See Fig.
26. ) If these coverings are applied in the win¬
ter, it may be necessary to use in connection with
them some such substance as the insect lime, in
order to prevent the escape of the young cater¬
pillars in the spring. This substance may be
smeared around the edge of the tin or burlap in
such a manner as to close every crevice commu¬
nicating with the cavity. It has also been used
to stop small holes in trees, and will answer the Tinned cavlty-
purpose temporarily, but it must be occasionally smoothed
over, as it shrinks and cracks in a short time.

Scraping Trees and JR emoving Loosened Bark.

Scraping the loose outer bark from old trees facilitates
the discovery of the eggs, larvae and pupae, of the gypsy
moth. Such scraping leaves the surface of the trunk and
larger branches in a comparatively smooth condition, and
deprives the caterpillars of their places of refuge, causing
them to crawl down and seek shelter under the burlaps.

If in dealing with fruit trees the loose bark only is scraped
off and burned, the main object is accomplished. Such scrap¬
ing benefits orchard trees by the removal of mosses and
lichens and the eggs and hibernating forms of injurious
insects.

An implement modelled after the scuffle hoe is useful for
this work. (Fig. 27.) Its blade being double-edged, it may
be used with both the upward and downward motion, and by
means of a long handle the trunk and branches of the fruit
trees may be reached to a height of from twelve to eighteen
feet from the ground. The ordinary “three-cornered”
scraper is also much used. It is believed that this loose
outer bark forms a protection to the tree from the cold of

190

THE GYPSY MOTH.

winter. Objections to its removal based on this belief are
obviated by scraping in the spring before the opening of
the leaves, when the tree no longer needs protection against
the cold. If the loose bark of apple trees is scraped olf
about April 15 and caught upon cloths spread beneath the
trees and the scrapings afterward burned, many injurious
insects are likely to be destroyed.

Fig. 28. Barb shave.

Fig. 27. Long handled scraper,

If we go further, and without cutting too deeply remove
some of the outer bark, double benefit to the tree ensues.*
Its growth is stimulated, a great flow of crude sap occurs,
a luxuriant growth of foliage is thrown out and an unusual
supply of elaborated sap for the upbuilding of the tree is
returned from the foliage and flows into the liber or inner
lining of the bark, killing or driving away the bark borers
(scolytidce) . These beetles are among the most dangerous
enemies of trees. For bark cutting a shave (Fig. 28) in¬
vented by Mr. G. W. McKee, one of the special inspectors
employed by the Board, has been found very effective.

Dr. Packard says that perhaps the best method of pre¬
venting or stopping the work of bark beetles is that of a

* Elms which have had the outer bark removed in this manner in November have
developed an unusually vigorous growth of dark green foliage in the ensuing sum¬
mer. Trees treated in this manner have shown great vigor also in healing wounds
on their trunks.

SCRAPING TREES.

191

Frenchman, M. Robert, as described in the “Gardener’s
Chronicle” and referred to by Miss Ormerod. He gives the
quotation from Miss Ormerod as follows : —

The best remedy appears to be that adopted with great success
in France by M. Robert, after careful observation of the circum¬
stances which stopped the operations of the female beetle when
gnawing her gallery for egg laying, or which disagreed with or
destroyed the maggots, and is based in part on similar observa¬
tions of the effect of flow of sap to those noticed in England by
Dr. Chapman.

It appeared on examination that the grubs died if they were not
well protected from the drying action of the air ; on the other
hand, if there was a very large amount of sap in the vegetable
tissues that they fed on, this also killed them ; and it was observed
that when the female was boring through the bark if a flow of sap
took place she abandoned the spot and wrent elsewhere. It was
also noticed that the attack (that. is, the boring of the galleries
which separates much of the bark from the wood) is usually under
thick old bark, such as that of old elm trunks, rather than under
the thinner bark of the branches. Working on these observations,
M. Robert had strips of about two inches wide cut out of the bark
from the large boughs down the trunk to the ground, and it was
found that where the young bark pressed forward to heal the
wound and a vigorous flow of sap took place many of the maggots
near it were killed, the bark which had not been entirely under¬
mined was consolidated and the health of the tree was improved.

Working on from this, M. Robert tried the more extended
treatment of paring off the outer bark, a practice much used in
Normandy and sometimes in England for restoring vigor of growth
to bark-bound apple trees, and noted by Andrew Knight as giving
a great stimulus to vegetation. M. Robert had the whole of the
rough outer bark removed from the elm (this may be done con¬
veniently by a scraping knife shaped like a spoke shave). This
operation caused a great flow of sap in the inner lining of the bark
(the liber), and the grubs of the Scolytus beetle were found in
almost all cases to perish shortly after. Whether this occurred
from the altered sap disagreeing with them, or from the greater
amount of moisture around them, or from the maggots being more
exposed to atmospheric changes, or any other cause, was not
ascertained, but the trees that were experimented on were cleared
of the maggots. The ti’eatment was applied on a large scale, and
the barked trees were found, after examination by the commis¬
sioners of the institute at two different periods, to be in more

192

THE GYPSY MOTH.

vigorous health than the neighboring ones of which the bark was
untouched. More than two thousand elms were thus treated.

This account is abridged from the leading article in the “ Gar.
dener’s Chronicle and Agricultural Gazette” for April 29, 1848,
and the method is well worth trying in our public and private
parks. It is not expensive ; the principle on which it acts as
regards vegetable growth is a well-known one, and as regards
insect health it is also well known that a sudden flow of the sap
that they feed on, or a sudden increase of moisture around them,
is very productive of unhealthfulness or of fatal diarrhoea to
vegetable-feeding grubs.

A somewhat similar process was tried by the Botanic Society, in
1842, on trees infested by the Scolytus destructor in the belt of
elms encircling their garden in the Regents’ Park, London. “ It
consists in divesting the tree of its rough outer bark, being careful
at the infested parts to go deep enough to destroy the young larvae,
and dressing with the usual mixture of lime and cow dung.” This
operation was found very successful, and details with illustrations
were given in a paper read in 1848 before the Botanic Society.*

No injury to trees which have been scraped in the course
of the work on the gypsy moth has been observed, although
this practice has been continued for three years and more than
nine thousand trees have been scraped. Apple trees and elm
trees treated in this way have shown an immediate increase
of foliage area and growth, presenting a marked contrast to
trees near by which have been left untreated. Whether a re¬
action will set in in future years remains to be seen. As yet
no serious reactionary effect has been noted. Trees which
have been scraped have exhibited remarkable vigor in healing
wounds. In the gypsy-moth work large elms are frequently
met with which cannot be cleared of the moth without shav¬
ing off their outer bark. This bark often overgrows small
cavities in the trunk in such a manner that hiding-places for
the moth are formed which it is impossible to discover until
the rougher portion of the outer bark has been removed.
While that is being done, it is not difficult to expose these
hiding-places and to destroy any form of the moth found
within.

* Fifth report of the United States Entomological Commission, 1886-90, pages 31, 32.

PLATE XXXIV. Clearing infested brushland.

BURNING RUBBISH HEAPS.

193

. The Destruction of Rubbish.

The gypsy moth, like many other insects, shows a liking
for a rubbish pile. Brush heaps, old stone walls and fences
overgrown with bushes and vines, dumping grounds, old
piles of lumber, tin cans, rags, paper and other debris all
furnish many hiding-places for the caterpillars, retreats for
pupating and places where the moth can deposit its eggs.

It is remarkable kowT many absolutely filthy rubbish heaps
accumulate in the back yards of some tenement-houses.
These deposits of rubbish are especially noticeable in certain
districts of the larger towns and smaller cities. Not only
are all sorts of *waste material from all parts of the house
from cellar to garret thrown into the back yard, but refuse
from the kitchen is also frequently deposited there, together
with a collection of empty but unclean cans, such as are orig¬
inally used for “ canned goods.” Old shoes, broken bottles
and earthen ware, cast-off articles of apparel, corn husks and
the withered tops of vegetables in all stages of decay, bones,
fish heads, lobster and oyster shells are also common con¬
stituents of these rubbish piles. Such heaps of rubbish,
often overgrown with weeds and bushes, would form an in¬
structive spectacle for local boards of health.* Even the
grounds of the wealthy are not always exempt from accumu¬
lations of rubbish, which may be found occasionally about
the corners of back fences or in the rear of stables.

Amid such associations the gypsy moth delights to dwell.
In the many places of shelter offered by such rubbish heaps
the larvte can safely hide during the day, sallying forth at
dusk to destroy the foliage in the vicinity.

One of the first steps, then, toward exterminating the
gypsy moth from any locality is to clear up the ground ;
burn rubbish, old lumber, wood, brush, rags and dead leaves ;
bury or melt up old tin cans ; tear down or remove stone
walls and old fences ; and leave the premises as clean as pos¬
sible. Cremation is a cleansing process ; bonfires mark the
progress of civilization. Such work will not only aid in

* There has been much improvement in respect to the accumulation of rubbish in
yards in our cities and large towns since the slight cholera scare of 1893.

194

THE GYPSY MOTH.

disposing of the moth but will remove harboring places
for other insects and render the locality more healthful and
wholesome. The agents of the Board of Agriculture have
found it necessary to remove, burn or bury many of these
accumulations of debris in order to secure the destruction of
the moth.

Destroying Pupae and Moths.

As the eggs of the gypsy moth hatch in the months of
April, May and June, the larvae feed in the latter part
of April and during the months of May, June, July and
August. In July and August all forms of the moth may
be found together in the same locality. Pupae and moths
are found upon the same trees, under the same burlaps and
in the same rubbish heaps with the larvae ; therefore no
special measures are taken to destroy these forms of the
insect. They are searched for in all the hiding-places which
shelter caterpillars, and are destroyed by the same means.
The white female imagoes are especially noticeable when
resting on the bark of trees. They may be found in July
and August, and, as they do not fly, they may be readily
captured.

A Summary of the Methods most Useful to the

Farmer.

Unless sufficient appropriations are made to exterminate
the gypsy moth or to hold it in check where it now is, its
rapid increase and spread over this and other States will
probably follow. In case of the permanent cessation of
public exterminative or preventive work, the labor of hold¬
ing the gypsy moth in check or of repressing its destruc¬
tive outbreaks will devolve upon the citizen and especially
upon the farmer.

In considering the methods most useful to the farmer for
the destruction of the gypsy moth, it is well to inquire, first,
what class of farming crops are most liable to injury by the
pest. As the gypsy moth feeds by preference on trees, shrubs
and foliaceous plants, those farmers who devote themselves
entirely to dairying or grain raising will be likely to suffer
least. Market-gardeners have less to fear from the gypsy

METHODS FOR THE FARMER.

195

moth than the general farmer or fruit grower. The well-to-
do market-gardener who raises little or no fruit has few trees
on his land to care for ; his methods of cultivation are inten¬
sive, and he is obliged to employ a number of held hands
in his business. He is therefore better able to protect his
crops against the attacks of an insect like the gypsy moth
than is the general farmer or the small farmer wTho has to
depend largely on his own labor. There would be less
danger to the interests of the agriculturist in thickly settled
districts where market-gardening is carried on than in thinly
settled sections where farms are larger and less highly culti¬
vated, where much wood is grown and where there are many
orchards. In such regions the waste and wooded land, where
the moth might breed and where little could be done by the
owners to check it, greatly exceed in area the cultivated
land, where its ravages would do the greatest injury.

In considering, then, the means most useful to the farmer
for controlling or exterminating the moth, we must choose
those most readily available to the general farmer of moder¬
ate means.

Burning the eggs or killing them by means of creosote or
other oils are the methods which can be used most effectually
by most farmers. The work can be done during the late
fall, winter and early spring, — a time of the year when
most farmers are not overburdened with the labors and cares
incidental to planting and harvesting. If this is thoroughly
done in an orchard, there need be no fear of the fruit crop
being destroyed in the ensuing summer by the gypsy moth
unless the orchard is invaded from without by caterpillars
which have bred in the woods or upon shade trees.

If shade trees are near the orchard, all the orchard trees
cleared of eggs should be banded with insect lime or supplied
with tree protectors, either of which will go far toward
protecting them from the inroads of migrating caterpillars.
But if there is a tract of badly infested woodland near the
orchard, the bands will be of little use in protecting the
trees against the invasion of the multitude of caterpillars.
In such cases the most economical plan would be to cut
down all the infested woods and burn over the ground. Few
farmers can afford to attempt to keep the pest out of wood-

196

THE GYPSY MOTH.

land, as the cost of the labor would be more than the value
of the wood. If precautionary measures have been neg¬
lected, and the caterpillars appear in swarms, they may strip
the trees before arriving at an age when they will seek the
burlap.

When small caterpillars are very numerous upon the trees,
spraying with arsenate of lead at the rate of thirty pounds
to one hundred and fifty gallons.of water will destroy most
of them. If arsenate of lead is not at hand, two or three good
sprayings with Paris green in May will greatly lessen their
numbers. The trees may be afterwards burlapped, and the
caterpillars killed as they gather day by day under the bur¬
laps. A small burning tank with a cyclone burner might be
used to stay the march of an invading host of these cater¬
pillars, and would check them anywhere. (See Plate XX.)
The care of trees and the general cleanliness of grounds will
do much toward rendering an orchard an unfit dwelling-place
for the gypsy moth, and will facilitate the moth’s destruction.

The Annual Inspection.

The inspection and egg-killing in the infested district and
the inspection in the towns in its vicinity during the late fall,
winter and early spring are the chief means of preventing
the dissemination of the moth, and the first and most impor¬
tant steps toward extermination. It is by examining the
trunks and the lower surfaces of large limbs of trees during
this search that most of the conspicuous egg-clusters are
found. In this way most of the colonies of the moth have
been discovered.* It is for the prosecution of this work
that the most efficient and experienced men are retained.
The inspection goes on through the winter months, except
when interrupted by severe storms, deep snow or the ex¬
haustion of the appropriation.

So long as there are moths in the district at present in¬
fested, just so long will there be danger of their distribution
throughout that district and to adjacent towns ; the danger

* Webster defines a colony (under the head of natural history) as a number of
animals or plants living together beyond their usual range. In the gypsy-moth work
the word “ colony ” has been applied to the moth when it has been found isolated
from others of its kind by a belt of uninfested country.

THE ANNUAL INSPECTION.

197

increasing or decreasing, according to the increase or reduc¬
tion of the number of the moths, especially along highways
or in cultivated lands and woodlands most frequented by
man.

Each autumn, as soon as the foliage is well off the trees,
the most experienced employees of the Board are organized
into squads, which are set to work examining such territory
within the infested towns as has not been recently inspected.
Many colonies have thus been found by careful search within
the region known in 1891 to be infested. Much time and
money have been spent in this search, but money enough
has not been provided in any year to make the search
thorough and complete. To provide against the spread of
the moth, more or less of this kind of work has been done
each year in the towns outside of the infested region. In
this outside search considerable time and money have been
expended, and only a few small colonies of the moth have
been found. These were all at a short distance outside
the boundary of the region known in 1891 to be infested.
Though this search does not at first sight appear to have
furnished results proportionate to the expense incurred, yet,
had the colonies not been found and stamped out of exist¬
ence, any one of them might have increased and spread
like the original Trouvelot colony.

As the prevention of the spread of the moth and its exter¬
mination are the objects contemplated by the statute author¬
izing the work, this search of towns adjacent to the infested
region must continue so long as the region continues to be
infested; otherwise, there can be no absolute assurance that
the moths are not spreading beyond the limits of the region
in which the work is carried on.

As the search extends farther away from the centre of the
infested region, the territory to be examined becomes greater,
increasing the expense, while the likelihood of its being in¬
fested diminishes. Therefore, in towns next outside those
immediately adjacent to the infested region the search is
confined to those places which experience has shown are
most likely to become infested, mainly the villages and bor¬
ders of highways. Especial attention is paid to all points
which by reason of the character of the business of the resi-

198

THE GYPSY MOTH.

dents appear to have been particularly exposed to infesta¬
tion.

Beyond these towns only the borders of railways, certain
highways, the centres of villages and such estates as are
believed to have been exposed to a possibility of infestation
are inspected. A few cities which are centres of trade and
travel form an exception to this rule. They have been more
thoroughly inspected. The following cities and towns have

been more or less thoroughly looked over.

Some have been

visited only once,

but most of them have been inspected

several times durin

g the last five years.

In none of them

has any trace of the

moth been found : —

Bedford.

Ipswich.

North Andover.

Boxford.

Lincoln.

Quincy.

Billerica.

Lowell.

Rowley.

Brookline.

Middleton.

Sudbury.

Concord.

Manchester.

Topsfield.

Dedham.

Milton.

Tewksbury.

Essex.

Newton.

Wilmington.

Georgetown.

Newbury.

Wayland.

Gloucester.

Newbury port.

Weston.

Hamilton.

North Reading.

Wenham.

Hull.

Measures for

the Information of

the Public.

The Board of Agriculture has from the first believed that
success in the work of preventing the spread and securing
the extermination of the gypsy moth could not be hoped for
without the intelligent co-operation of the public. Every
effort, consistent with the letter and meaning of the statute
under wdiich the work has been carried on, has been made
to diffuse information in regard to the identity and character
of the pest and the laws enacted and regulations made for
its destruction. The rules and regulations of the gypsy
moth committee have been frequently advertised in the daily
papers. Every facility has been offered to the daily and
weekly press in regard to the publication of illustrated arti¬
cles upon the gypsy moth. Cuts of the moth have been
loaned many newspapers, and have had a wide circulation.
Information has been frequently given to the agricultural
press.

DISTRIBUTING INFORMATION.

199

The prejudice existing against the spraying and other feat¬
ures of the work, which was expressed in the local press
in 1890, continued to find some expression in 1891. The
papers, however, gave the work of the Board of Agriculture
a wide publicity. We can do no less than acknowledge the
spirit of fairness of the press of the State, and the willing¬
ness manifested to publish everything in regard to the work
which would be of interest to the people. Yet false reports
as to the appearance of the gypsy moth in various places at
a distance from the infested region have been frequently and
widely circulated. These appear to originate not with the
newspapers themselves but with citizens who, believing that
they have discovered the gypsy moth on their premises, can¬
not wait to notify the Board, but immediately rush into print
and so give the alarm. In all such cases it has been found
upon investigation that the injury noticed was caused by some
other insect. Yet these local ‘ ‘ scares ” have assisted in arous¬
ing the interest of the people, and leading them to further
investigation of the appearance and character of the moth.

Early in 1891 arrangements were made with an artist for
drawings of the gypsy moth to be reproduced for illustra¬
tion. A colored plate (Plate I. of this report) was prepared
and printed in the first annual report of the State Board
of Agriculture on the extermination of the gypsy moth.
Ten thousand copies of this report were printed and dis¬
tributed throughout the Commonwealth, especially in and
near the infested district. Fifteen hundred extra copies
of the plate were also printed, to be used in connection
with other material and for posting in public places, such
as post-offices, schools, libraries and museums. One hun¬
dred and fifty glass-covered cases, containing specimens
of the different forms of the gypsy moth, preserved, mounted
and labelled, were prepared for exhibition in the infested
district, as well as for museums and other public places in
the State. A bulletin of information was also prepared, and
five hundred copies were printed in large type and framed.
In the centre of each frame was placed one of the colored
plates representing the different forms of the gypsy moth ; a
printed explanation accompanied the plate. These frames
were placed in promiuent positions in post-offices, mostly

200

THE GYPSY MOTH.

in eastern Massachusetts. A large frame containing in addi¬
tion to the bulletin a photograph of the moth’s ravages, and
having a specimen case attached, was placed in the main post-
office of each city or town in the infested district.

In 1891 a bulletin of information in regard to spraying for
the gypsy moth and other insects was printed in pamphlet
form and distributed through the infested district. Some
fifty thousand copies of the law of 1891, providing for the
extermination of the gypsy moth, together with the rules and
regulations under which the work is conducted, have been
printed and distributed among the people of the infested
district and in towns near by. The law and the rules and
regulations were also printed in poster form and posted in
many public places. Many placards containing certain sec¬
tions of the law were also printed and posted. Each season
from twenty thousand to twenty-five thousand copies of the
annual report on the gypsy moth (each with a colored plate
of the insect) have been printed for distribution, in addition
to the nine hundred copies annually printed for the use of the
Legislature. Circular letters, calling the attention of citizens
to the threatening danger from the invasion of the moth,
have been printed and sent with or without the reports to
newspapers and citizens throughout the State. Lectures on
the gypsy moth and the means of its extermination have been
given by the secretary of the Board of Agriculture, the ento¬
mologist and the director. Other speakers have frequently
spoken on the same subject at farmers’ institutes and other
meetings.

When the Massachusetts exhibit at the W orld’s Columbian
Exposition at Chicago was being prepared, the committee
in charge requested the Board of Agriculture to prepare an
exhibit for the exposition. This was done, and the exhibit
occupied a central place in the Massachusetts building at the
fair. It consisted of a glass case seven feet in height, contain¬
ing a representation of an apple tree denuded of its leaves
by the gypsy-moth caterpillars, and exhibiting on its trunk
and branches all forms of the moth, together with many of
the vertebrate and invertebrate enemies of the moth, includ¬
ing birds, fowls, predaceous beetles and parasites. Pho¬
tographs showing the destructiveness of the moth were

FALSE ALARMS.

201

exhibited. A large amount of printed matter in regard to
the moth was distributed at the fair.

In October, 1895, in response to a request received from
the Massachusetts Charitable Mechanic Association, this ex¬
hibit was sent to the fair held in the Mechanics building,
Boston, where it was exhibited together with another case
containing sections of tree trunks and other objects on which
the egg-clusters of the gypsy moth had been laid. There was
also a collection of bromide enlargements of photographs,
showing the moth as in nature, its ravages and the means of
destroying it. At the request of L. O. Howard, entomolo¬
gist of the United States Department of Agriculture, dupli¬
cates of some of these bromides were also sent to the Cotton
States and International Exposition at Atlanta, Ga., where
they were exhibited as a part of the entomological exhibit of
the United States Department of Agriculture.

The measures taken to inform the public have succeeded
in arousing public interest to such an extent that many
citizens of the State immediately report to the Board any
injurious insects which appear to them to be gypsy moths.
Such reports are sometimes received from other States.
Many false alarms of the moth’s presence have been sent in,
and all have been investigated. Reports of the appearance
of insects which were wrongly supposed to be the gypsy
moth have been received from the following places : —

Places from which False Alarms have been received.

Massachusetts.

Brockton.

Georgetown.

Acton.

Brookfield.

Gloucester.

Andover.

Bourne.

Grafton.

Ashburnham.

Chester.

Groton.

Athol.

Concord.

Holden.

Abington.

Charlton.

Hopedale.

Amesbury.

Carlisle.

Haverhill.

Auburn.

Clinton.

Holliston.

Billerica.

Dedham.

Hyde Park.

Berlin.

Duxbury.

Hingham.

Braintree.

Easton.

Hudson.

Bedford

Fall River.

Hull.

Bolton.

Foxborough.

Ipswich.

Boxford.

Fitchburg.

Lincoln.

Brookline.

Framingham.

Lowell.

Bridgewater.

Gill.

Lawrence.

202

THE GYPSY MOTH.

Places from which False Alarms have been received — Concluded.

Massachusetts — Con.

Rehoboth.

Connecticut.

Marlborough.

Scituate

Fairfield.

Marshfield.

Southborough.

Glastonbury.

Merrimac.

Sterling.

Ridgefield.

Milford.

Sutton.

Methuen.

Sudbury.

Maine.

Manchester.

Springfield.

Cape Porpoise.

Maynard.

Templeton.

Sabbatus.

Milton.

Tewksbury.

Monson.

Townsend.

New Hampsh

Newbury port.

Tyngsborough .

Barnstead .

Newton

Uxbridge.

Center Harbor

Needham.

W eymouth.

Haverhill.

Newbury.

Wenham.

Kensington.

Northbridge.

West Bridgewater

Kingston

Norwood.

Wilmington.

Lakeport.

North Andover.

Weston.

Portsmouth.

North Brookfield.

Westborough .

Pratts.

North Reading.

West Newbury.

Seabrook.

Pittsfield.

Wellesley.

Pepperell.

Wayland

Iowa.

Plymouth.

Wrentham.

Fort Madison.

Princeton.

Worcester.

Quincy.

Vermont.

Randolph.

Bhode Island.

Green River.

Rowley.

Providence.

Rockport.

Pawtucket.

In all cases the damage reported was caused by some
other insect. The many reports thus received are gratify¬
ing, indicating as they do a public interest in the work,
and a desire to aid as far as possible in stamping out the
pest. The investigations in other States have been made
mainly to prove or disprove the claim that the gypsy moth
is confined in America to a limited district in Massachusetts.
This is the theory on which the work of extermination has
so far proceeded, and no proof has ever been given that it
has been found outside of this district.

PLATE XXXV. Baltimore orioles and nest.

NATURAL ENEMIES.

203

Natural Enemies of tiie Gypsy Moth.

Insect-eating Birds.

Since the work of preventing the spreading and securing
the extermination of the gypsy moth in Massachusetts was
placed in the hands of the Board of Agriculture in 1891,
particular attention has been paid to the natural enemies of
the moth. All persons employed in the work have been
instructed to watch for enemies or parasites, and keep a
record of all observations made. In accordance with these
instructions, voluminous notes now covering many hundred
pages have been made. Many enemies of the moth have
been studied both under natural conditions and in confine¬
ment. Search has been made through European literature
for information in regard to the enemies of the moth abroad.
Much information bearing upon the subject has also been
obtained by foreign correspondence. In apportioning the
preparation of the report on the natural enemies, the task of
preparing a report on the birds was assigned to me. My
colleague, Professor Fernald, will treat of tlie other enemies
of the moth.

The Usefulness of Birds as Insect Destroyers.

The subject of birds versus insects is a most important
one. The influence of birds on the agriculture of a country
is incalculable. The protection or destruction of native birds
and the introduction of foreign species are subjects worthy
of the most thoughtful consideration of the agricultural
department of any government.

Land birds fulfil their part in many ways in preserving
the balance of nature, but chiefly by doing much toward
holding in check the increase of the insect world, which, if
unrestricted, would swarm over and devastate the earth.

Birds are among the most highly organized of vertebrate
animals. In them we find the greatest activity and the
highest temperature of the blood. To maintain this tern-

204

THE GYPSY MOTH.

perature and supply the tremendous waste of the tissues
caused by this activity a great quantity of food is necessary.
Excellent provision is made by nature for the rapid digestion
and assimilation of a great amount of food. In August,
1895, two young crows were confined at the experiment
station in Malden, and observations were made on their feed¬
ing habits. The time from the entrance of the food into the
mouth to the first voiding of excreta containing remains of
the food eaten was usually about one and one-half hours. It
is probable that digestion is still more rapid in the smaller
insect-eating birds.* * * § The common titmouse or chickadee
( Parus atricapillus ) is one of the smaller birds of New Eng¬
land, yet the good accomplished by it in destroying the eggs
of insects injurious to orchard and forest trees is almost
beyond belief. I have given elsewhere an estimate, based
on careful observations and dissections, that in twenty-five
days one of these birds will destroy 138,750 eggs of the
canker-worm moth (Anisopteryx pometarici) . f

Prof. Samuel Aughey, who fed confined plovers on in¬
sects, found that they would eat on an average 202 locusts
and other large insects per day.J

Professor Treadwell fed to a young robin in twelve hours
forty-one per cent, more than its own weight in worms. The
same bird consumed nearly half its own weight of beef in a
day.§

At this rate a man would eat daily about seventy pounds
of meat. Because of their enormous appetites, birds are
most potent factors for good or ill. It is well known that
crows and blackbirds destroy vast quantities of grain for a
short season when they swarm upon the fields ; but their
services in destroying injurious insects are not generally
recognized.

* According to Maynard the indigestible remains of food are excreted by the cedar-
bird in one-half hour after eating. (See “ Birds of Eastern North America,” C. J.
Maynard.)

t Bulletin on “ Birds as protectors of orchards,” Massachusetts Crop Report,
July, 1895, published by the Massachusetts State Board of Agriculture.

% First report United States Entomological Commission, 1877, page 343.

§ “Birds of New England,” by E. A. Samuels, page 159. The paper on this
subject was originally read by Professor Treadwell before the Boston Society of
Natural History.

USEFULNESS OF BIRDS.

205

The activity of birds, as shown in running, climbing trees,
hopping or flying, together with their powers of vision,
renders them particularly adapted for searching out, over¬
taking and destroying insects. Birds often assemble where
insect outbreaks occur, and assist in checking great insect
invasions.

In a search through agricultural, entomological and orni¬
thological literature, we find many instances on record in
both hemispheres where birds have been instrumental in
saving crops or forests by destroying injurious insects.
Samuels states that in 1847, as an immense forest in Pom¬
erania was on the brink of being utterly ruined by caterpil¬
lars, it was suddenly and very unexpectedly saved by a flock
of cuckoos, who established themselves in the place for a
few weeks and thoroughly cleaned each tree.*

During the great locust invasions in the West the investi¬
gations of Professor Aughey, as published in the first report
of the United States Entomological Commission, showed
that birds were among the greatest enemies of locusts, and
that in many instances when the farmers had given up the
battle against the “grasshoppers,” the crops were saved by
the flocks of birds that descended upon the fields, destroying
immense numbers of the feeding locusts. f

Many instances are on record where a great increase of
insect pests has followed the destruction of birds. George
Kearly, in the “Entomologist’s Weekly Intelligencer,”
speaks of an outbreak of insect pests in a park at Brussels,
in which the gypsy moth was one of the chief offenders, hav¬
ing stripped well-nigh all the trees of their foliage. He says
this great increase of insects followed soon after and was
caused by the destruction of sparrows and other birds in the
park, by order of the authorities.:}: In a letter recently
received from J. O. Clercy, secretary of the Society of
Natural Sciences, Ekaterinburg, Russia, he states that the
ravages of two species of cutworms and some ten species

* E. A. Samuels, in report of Massachusetts State Board of Agriculture, 1865-66,
page 117.

f Report of the United States Entomological Commission, 1877, page 338.

X The “Entomologist’s Weekly Intelligencer,” 1858, Vol. 4, page 192.

206

THE GYPSY MOTH.

of locusts contributed, together with the want of rain, to
starve the inhabitants in that region in 1891 and 1892.
One of the causes, he says, which permitted such a numer¬
ous propagation of insect pests was the almost complete de¬
struction of birds, most of them having been killed and
sent abroad by wagon loads for ladies’ hats. A law for the
protection of birds has now been enacted, and, says Clercy,

‘ ‘ the poor little creatures are doing their best to reoccupy
their old places in our woods and gardens. This reoccu¬
pation, however, does not go on as rapidly as did their
destruction.”

Many species of water birds, the gulls and terns especially,
are useful as insect destroyers. In 1848 the crops of the
Mormons in Utah were attacked by the Western cricket (Ana-
brus simplex) , which came down in great armies from the
highlands about Salt Lake. These crickets had already
destroyed a considerable portion of the crops, when great
flocks of gulls appeared and ate the crickets. Hon. George
Q. Cannon says: “Black crickets came down by millions
and destroyed our grain crops ; promising fields of wheat
in the morning were by evening as smooth as a man’s hand,
— devoured by the crickets. Sea gulls came by hundreds
and thousands, and, before the crops were entirely destroyed,
these gulls devoured the insects so that our fields were
entirely freed from them.” *

This occurrence is well authenticated and testified to by
many eye-witnesses. f

While some ornithologists regard birds as by far the most
important natural enemies of injurious insects, many ento¬
mologists believe that insect and vegetable parasites are more
useful in this respect than birds ; yet some of the most
eminent economic entomologists, who have had occasion to
observe the insect-eating habits of birds in connection with
great outbreaks of insect pests, have been among the first to

* “ Insect Life,” Vol. 7, No. 3, page 275.

f See the nineteenth annual report of the secretary of the Massachusetts Board
of Agriculture, 1871, page 76; the report of the United States Commissioner of Ag¬
riculture, 1871, page 79; also the second report of the United States Entomological
Commission for 1878 and 1879, relating to the Rocky Mountain locust, page 166,
A. S. Packard, Jr.

MOTH-EATING BIRDS.

207

give public expression to their appreciation of the value of
birds as destroyers of noxious insects.*

A study of the food of insect-eating birds leads to the belief
that if in any way their numbers and efficiency can be aug¬
mented, an increase in agricultural products will be secured.

Birds seen to feed upon the Gypsy Motii.

Thirty-eight species of birds have been identified when

feeding upon the gypsy
They are as follows : —

moth in one or more of its forms.

Yellow-billed cuckoo, .

. Coccyzus amcricamis. (Linn.)

Black-billed cuckoo,

. Coccyzus erythrophthalmus. (Wils.)

Hairy woodpecker,

. Dryobales villosus. (Linn.)

Downy woodpecker,

. Dryobates pubescens. (Linn.)

Pigeon woodpecker,

. Colnptes cmratus. (Linn.)

King bird, ....

. Tyrannus tyrannus. (Linn.)

Great-crested flycatcher,

. Myiarchus crinitus. (Linn.)

Phrebe, .

. Sayornis plioebe. (Lath )

Wood pewee,

. Contopus virens. (Linn.)

Least flycatcher, .

. Empidonax minimus. Baird.

Blue jay, ....

. Cyanocitta cristata. (Linn.)

Crow, .

. Corvus americanus. Aud.

Baltimore oriole, .

. Icterus galbula. (Linn.)

Purple grackle or crow blackbird, Quiscalus quiscula. (Linn.)

Chipping sparrow,

. Spizella socialis. (Wils.)

Chewink, ....

. Pipilo erythrophthalmus. (Linn.)

Rose-breasted grosbeak,

. Habia ludoviciana. (Linn )

Indigo bird, ....

. Passerina cyanea. (Linn.)

Scarlet tanager, .

. Piranga erythromelas. Vieill.

Red-eyed vireo,

. Vireo olivaceus. (Linn.)

* Townend Glover, first entomologist of the United States Department of Agri¬
culture, wrote in 1871 : “ Insectivorous birds are the best allies of the farmer, and
were they all destroyed there is little doubt that it would be almost impossible to
raise certain crops.” (Report of the United States Commissioner of Agriculture,
1871, page 71.)

He also wrote: “ A knowledge of their nature and habits is of as much impor¬
tance to the farmer and fruit culturist as is the science of entomology.” (Report of
the United States Commissioner of Agriculture, 1865, page 36.)

Prof. C. V. Riley, late entomologist of the Department of Agriculture, has testified
to the utility of birds as follows : “ Few injurious insects can be well and fully
considered without reference to their liability to be devoured by various natural
enemies, and especially birds.” (Report of the United States Commissioner of
Agriculture, 1885, page 210.)

Prof. John B. Smith, State entomologist of New Jersey, in an address to the
farmers of New Jersey, said: “Take care of your natural friends! Among these
the birds rank highest.” (“Insecticides, and how to apply them,” seventeenth
annual report of the New Jersey State Board of Agriculture, 1889-90, pages 294, 295.)

208

THE GYPSY MOTH.

Yellow-throated yireo, .
White-eyed vireo,
Black-and-white warbler, .
Yellow warbler, .
Chestnut-sided warbler,
Black-throated green warbler,
Oven bird, ....
Maryland yellow-throated w
bier, . .

American redstart,

Catbird, ....

Brown thrasher, .

House wren, ....
White-breasted nuthatch,
Chickadee, ....
Wood thrush,

American robin, .

Bluebird, ....
English sparrow, .

Vireo flavifrons. Vieill.

Vireo noveboracensis. (Gmel.)
Mniotilta vctria. (Linn.)
Dendroica cestiva. (Gmel.)
Dendroica pensylvanica. (Linn.)
Dendroica virens. (Gmel.)
Seiurus aurocapillus. (Linn.)

war-

Geotlilypis trichas. (Linn.)
Setophaga ruticilla. (Linn.)
Galcoscoptes carolinensis. (Linn.)
Hatporhynchus rufus. (Linn.)
Troglodytes cedon. Vieill.

Siita carolinensis. Lath.

Paras atricapillus. Linn.

Tardus mustelinus. Gmel.

Merula migratoria. (Linn.)

Sialia sialis. (Linn.)

Passer domesticus. (Linn.)

Birds which feed on the Larvae, Burpee and Imagoes.

It is generally believed by entomologists (judging from
their writings) that hairy caterpillars have a certain immu¬
nity from the attacks of birds. In Europe this appears to
be true to some extent of the larvae of the gypsy moth. A
writer in the “ Annales de lTnstitut Horticole de Fromont”
says that in twenty years of observation he has not seen a
bird bring one of the caterpillars to its young.*

Iveppen, writing of the gypsy moth in Russia, says that
the cuckoo is the only bird which takes them. Grimm
noticed about Saratov that birds had completely forsaken the
places where the caterpillars were usually numerous. This
is said to have taken place also iu the district of Kirsanov in
the province of Tambov, f Grimm thinks this is owing to

* “ Annales de l’Institut Horticole de Fromont,” Yol. 5, page 311, Paris, 1833.
t This does not agree with the experience of the forest authorities in Bavaria
during the recent invasion occasioned by the spruce moth or “nun” ( Liparis
monaeha) , 1889-91. This insect is closely allied to the gypsy moth and was
formerly placed iu the same genus. The caterpillars are provided with hairs sim¬
ilar to those of the gypsy caterpillars. The flight of starlings collected in one
locality alone was credibly estimated at 10,000, all busy feeding on the caterpillars,
chrysalides and moths, not to mention enormous flights of titmice and finches sim¬
ilarly engaged. The attraction of starlings to such centres became so great that
market-gardeners felt their absence seriously in distant parts of the country.

“ Protection of Woodlands,” by Hermann Farst, English edition; translated by
John Nisbet, 1893, page 126.

OBSERVATIONS ON BIRDS.

209

the fact that the body of the caterpillar is covered with small
hairs, which become detached, and, piercing somewhat the
skin of persons and animals, cause great itching.*

I have found very little evidence in the writings of Euro¬
pean authors that birds other than the cuckoo and the tit¬
mice destroy the larvae of the gypsy moth, although several
species are said to destroy the eggs . f In this country, how¬
ever, the reverse appears to be true. Few birds seem to
eat the eggs, while many attack all other forms of the moth.
In the season of 1891 my attention was first called to the fact
that certain birds were devouring large numbers of the larvae.
The accuracy of the reports received was soon verified by
my own observations. Several species of birds were seen
busily engaged in eating the insects wherever they were
numerous. The inspectors were directed to record all
observations made on birds which were feeding on the cater¬
pillars.

Unfortunately, there were at that time only eleven observ¬
ers on the force who could accurately identify birds in the
field. These men were also perfectly familiar with the dif¬
ferent forms of the moth. The notes made by them indi¬
cated that thirteen species of birds were feeding on the
moth in one or more of its forms. The observations begun
in 1891 have been continued during a part of each succeed¬
ing summer. Although as a rule they have been made inci¬
dentally in connection with the work in the field, one or
more men have been detailed at times to disprove or confirm
reports that have been made, or to watch some particular
species of bird, so that some points in regard to its value as
a moth destroyer might be settled. Where the caterpillars
are very numerous, they cluster in masses on trees. Cer¬
tain birds habitually visit these swarms either to eat the
caterpillars or to take them as food to their young. If the
observer remained quietly at his post, he was able to view
them at a distance of a few feet or yards. Each observer was

* Translated from “ Injurious Insects ” by Theodore Keppen, 3d Vol., special
part.

f In a recent letter Dr. Ebermayer of Munich names starlings, crows, titmice and
tree creepers among the enemies of the gypsy moth but does not say what form of
the moth they destroy.

210

THE GYPSY MOTH.

supplied with an opera glass, by means of which he could
determine at a greater distance whether or not the birds were
feeding on the caterpillars of the gypsy moth. Few birds
were shot and few dissections made as compared with the
number of birds reported as feeding on the caterpillars.
This might serve to discredit the accuracy of the observa¬
tions, were they not made at close range, and when the
caterpillars were large enough to be readily identified. No
birds were shot except where it was absolutely necessary to
determine whether it was the gypsy moth caterpillar or
some other upon which they were feeding. No observations
were accepted as conclusive unless the observer was known
to be careful in his work and conservative in his statements,
or unless ample corroborative evidence was obtained. While
there is some possibility of error in field observations, there
is also a possibility of error in stomach examinations. Di¬
gestion in birds is so rapid that it is impossible to specifi¬
cally identify some portions of their insect food unless the
bird is killed within a very few minutes after the insects are
eaten. When birds are feeding on larvce, a large proportion
of the stomach contents is often unrecognizable.*

Birds do not always swallow hairy caterpillars whole. In
many cases they tear them open, eating only some of the
internal parts which are unrecognizable upon dissection of
the stomach. Other birds appear to kill wantonly many
caterpillars and moths. Woodpeckers, jays and chickadees
have been seen to snap them up and then drop them to the
ground, sometimes uninjured but often mortally hurt.
Sparrows and other birds have been seen to kill many moths
which they do not eat.

The Most Useful Birds.

The records of the observations made on birds comprise
one hundred and fifty typewritten pages. A glance over
these pages shows that the greater number of observations
have been made on less than a dozen species, and indicates
that these are probably the birds most useful in destroying

* Considering the possibility of error in records made from either observation or
dissection, it would seem that one should be used as a supplement to and a check
on the other.

MOST USEFUL BIRDS.

211

the gypsy moth. It cannot be stated with certainty which
species is of most value in this respect, as the birds ob¬
served vary both in numbers and usefulness with the locality
and season. From observations made eleven species are
known to be very useful. In the apparent order of their use¬
fulness they are : yellow-billed cuckoo, black-billed cuckoo,
Baltimore oriole, catbird, chickadee, blue jay, chipping spar¬
row, robin, red-eyed vireo, yellow-throated vireo and crow.

Fig. 29. Yellow-billed cuckoo.

The cuckoo is the only bird that I have found mentioned
in European literature as feeding commonly on the larvae
of the gypsy moth. Altum says the cuckoo is efficient
especially in local ravages of the moth.* Appearances in¬
dicate that the cuckoos lead the rest of the American birds
in destroying the gypsy moth. Yet it must be considered
that as these cuckoos are comparatively large birds, seeking
by preference the larger larvae, their feeding is readily ob¬
served. As the larvae are usually swallowed whole by the
cuckoo, their remains are readily recognized in the dissected
stomach. It is difficult to identify with certainty the smaller
larvae when they are eaten by small birds. If these small
birds consume the smaller larvae in numbers equal to those
of the larger ones eaten by the cuckoo, they are more benefi¬
cial, as the destruction of the larvae when young will prevent
the injury they might do to vegetation before the cuckoo
would be likely to attack them.

* “ Forstzoologie,” Vol. III., page 96,

212

THE GYPSY MOTH.

Yellow-billed Cuckoo. — In 1891 yellow-billed cuckoos
were observed in several of the worst infested localities,
where they remained nearly all day, feeding on the gypsy
larvae or carrying them from time to time to their young.
This habit of feeding on hairy larvae seems to be quite con¬
stant with the cuckoos. They seem to prefer the gypsy
larvae even to the pupae.

Mr. F. II. Mosher, an inspector in the employ of the
Board, who observed this species in 1895, says that it will
go to a bunch of pupae and search for larvae, pulling out the
molts or casts, and will take pupae only when larvae are not
to be found. This was noticed in different individuals of
this species and in different localities. Some of the cuckoos
would take no pupae at all, but would continue their search
for larvae until they found them.

That the yellow-billed cuckoos feed their young quite con¬
stantly on these larvae is evident from the observations made.
The stomach of one young cuckoo when examined contained
a number of partly digested larvae and the heads of sixteen
others. Ninety per cent, of the stomach contents consisted
of these larval remains. When the young birds were able to
fly, the parents would lead them to the worst infested spots
and feed them frequently with caterpillars.

Mr. C. E. Bailey, an agent of the Board and a field orni¬
thologist of much experience, says that the yellow-billed
cuckoo is very fond of the gypsy larvae, sometimes eating
nine or ten full-grown ones in less than a half hour. He
also states that he has observed that it eats more caterpillars
than the black-billed cuckoo.

Black-billed Cuckoo. — The black-billed cuckoo is probably
nearly if not quite as useful as its congener in destroying
hairy caterpillars, and appears to be almost equally destruc¬
tive to the gypsy moth larvee. From personal observation,
as well as from reports of the observations of others, I am
led to believe that this bird does not feed as rapidly as the
yellow-billed cuckoo, and spends more time in beating the
caterpillars, perhaps for the purpose of killing them, or pos¬
sibly to divest them of their hairs before eating them. In
the end, however, the caterpillar is swallowed whole. Like
the yellow-billed cuckoo, this species feeds the caterpillars
to its young.

MOST USEFUL BIRDS.

213

Neither species of the cuckoo is very numerous in the
infested region, but both are fairly common and both are
attracted by the gypsy moth to badly infested orchards or to
the edges of badly infested woodland. Five cuckoos have
been seen at a time in an infested tree. In some infested
places they may be found at times in considerable numbers,
and the number of larvae they destroy is astonishing. They
frequently take larvae from under the burlaps.

Baltimore Oriole. — The oriole, like the cuckoo, is a well-
known destroyer of the tent caterpillar ( Clisiocampa Ameri¬
cana) and other hairy larvae. Several observers have seen
this bird taking gypsy larvae from the burlaps. In 1894 in
an orchard in 'Winchester four orioles were seen to follow
along the rows of trees, flitting from burlap to burlap, and
taking the larvae from under the cloth. The birds would
hang to the burlap while turning up the edges and running
their bills beneath. The young orioles frequently enjoy a
gypsy moth diet, and the adult birds have been seen day
after day feeding their young with these insects.

Only three orioles’ stomachs have been dissected. One
contained four nearly full-grown gypsy moth larvae, another
two, and one was empty. These dissections probably did
not fairly indicate the value of these birds as caterpillar de¬
stroyers, as the orioles have been seen to kill caterpillars of
which they ate only a small portion.

Catbird. — Where the gypsy moth has penetrated into
thickets, the catbird feeds on
the larvae, and, as the season
advances, destroys many of
the pupae, taking both these
forms of the moth to its
young. That this habit is
quite constant is evident, as
the catbird was seen feeding:
on the larvae in 1891, and
almost daily through a con¬
siderable portion of the sum¬
mer of 1895 by observers in several different towns. The
catbird has been seen to take larvae of all sizes to its young.
It is one of the birds that frequent badly infested localities.

214

THE GYPSY MOTH.

Fig. 31. Chickadee.

Chickadee. — The chickadee, though a small bird, feeds
quite constantly on the gypsy moth larvae, “skinning” or

tearing to pieces the larger larvse
which it cannot swallow. On cap¬
turing a large specimen the bird
usually stands on the caterpillar,
striking it w ith its bill until the
skin is torn open, when it pro¬
ceeds to eat the vital parts.
Sometimes the chickadee eats
nearly all of a large larva. This
bird is also fond of the pupae,
usually breaking them open and
eating a small portion of the
body tissues and juices. Chick¬
adees have been seen to feed on
the female moths.

Blue Jay. — In infested woodlands or in orchards near its
favorite haunts the blue jay is most useful as a caterpillar
hunter. Mr. M. J. Flood, formerly in the employ of the
Board, who wTas stationed in 1891 at a badly infested locality
in Arlington, where he watched the gypsy moth larvae for
forty-eight hours, reported that he saw hundreds of the
larvae picked up by this bird. During the day he saw six¬
teen blue jays eating the larvae and pupae, which he could
see very distinctly as the birds held them in their bills.
These birds are known to be regular visitors to badly in¬
fested trees, yet they are so wary that it is difficult to observe
them closely. The prying nature of the blue jay stands it
in good stead in searching out hidden larvae. It pecks
them from the crevices of the bark or from under the bark
on dead limbs, and searches every hole. It frequently visits
burlaps on infested trees, thrusting its bill under the burlap
and raising it enough to draw out the hidden larvae beneath.
Mr. Mosher reports having seen the blue jays feeding larvae
and pupae to their young. The jays have been frequently
seen carrying the larvae in their beaks, probably with the
intention of feeding them to their young. Sometimes they
pinch or hammer the larvae, killing them in wanton sport or

MOST USEFUL BIRDS

215

maiming them and dropping them upon the ground. This
habit of killing and dropping larvae has been observed else¬
where.*

' ' Wrm

Fig. 32. Blue jay.

Chipping Sparrow. — Though the chipping sparrow does
not rank high among insectivorous birds, and feeds largely
upon seeds during certain seasons of the year, it nevertheless
destroys very many in¬
sects, especially lepi-
dopterous larvae, which
are injurious to trees
and garden plants. It
is often seen chasing
flying gypsy moths. It
appears to be fond of
gypsy moth caterpillars,
and I have frequently
observed it in badly
infested spots catching
and killing large larvae,
and dissected contained a nearly full-grown larva of the
gypsy moth, which had been swallowed head first.

In 1891 Mr. E. P. Felt confined (for experimental pur-

Fig. 33. Chipping sparrow.

A young chipping sparrow shot

* Dr. C. M. Weed in the Ninth Annual Report of the Ohio Agricultural Experi¬
ment Station, 1890, p. lv.

216

THE GYPSY MOTH.

poses) a number of gypsy moth caterpillars in nets on the
branches of apple trees. It was found almost impossible to
complete the experiments, as many of the caterpillars dis¬
appeared from the nets. An examination of the nets showed
that they had been broken open in some unknown way. I
watched one of the nets and saw a chipping sparrow break
through the netting and secure one of the larger larvae. As
these birds were frequently seen about the nets, it is probable
that they were responsible for the abduction of many larvae
which disappeared. Mr. Felt says in his notes that sixty
per cent, of the larvae used in the experiments were taken
by birds which broke into the nets. There were very few
of these larvae in the vicinity, except those confined in the
nets.

Robin. — The robin has been reported by several observers
as feeding upon the larvae of the gypsy moth, and by one as
feeding upon the pupae. One observer believes the robin to
be the most useful bird of all ; but the notes on this bird are
lacking in detail. I can say nothing from personal observa¬
tion in regard to its habits of feeding on the gypsy moth,
except that it has been often seen feeding on the ground
about apple trees frequented by the gypsy moth, or upon the
lower branches of such trees, also in trees in badly infested
woodland.

Red-eyed Vireo. — This bird has been seen by many observ¬
ers to feed on the gypsy moth larvae. It probably feeds its
young quite regularly on the larvae. The vireos are known

to be caterpillar hunters, but
are believed to prefer smooth¬
skinned species. They, how¬
ever, frequently break open
the nests of the tent cater¬
pillar to get at the hairy
larvae within. This bird usu¬
ally places the gypsy moth
larva on a limb, and pulling
it to pieces eats the pieces
separately ; yet it has been
seen often to eat the larva
whole and also to feed it alive to the young birds.

O .1 O

Fig. 34. Red-eyed vireo.

MOST USEFUL BIRDS.

217

Yellow-throated Vireo. — Mr. C. E. Wood, an inspector
in the employ of the Board, writes that he saw a yellow-
throated vireo take a large larva, alight on a limb with it,
and, placing one foot on it, peck its head oft’ and give the
body to a young full-fledged bird which was waiting to be
fed. The young bird took the body of the larva, placed it
on the limb under one foot, and, pecking off a few small
pieces swallowed the rest whole. The yellow-throated vireo
has been seen by several observers to catch and eat the
larvae, and is probably nearly as useful in this respect as
the red-eyed vireo.

Ci 'Oiv. — The crows in the infested region are so shy that
it is difficult to get near enough to them to observe care¬
fully their feeding habits. It was not until 1895 that they
were actually seen to feed upon the gypsy moth, though it
had been noted that they sometimes frequented badly infested
places. They had also been seen to take their jmung to in¬
fested localities, where they were apparently feeding them
with the larvae or pupae. In the summer of 1895 the prob¬
ability of their feeding upon the gypsy moth was made a
certainty by the observations of Mr. Mosher, whose work
in observing birds has been done with the most painstaking
and patient care.

The prying, inquisitive habits of the family are well illus¬
trated by the crow when searching for gypsy moth larvae and
pupae. Dead bark is torn off from branches, clumps of
bushes are penetrated, and rubbish on the ground is over¬
hauled by the bird in its search for the insects. Mr. Mosher
watched a crow which alighted within thirty feet of him on
a branch above his head, and fed upon the gypsy larvae with¬
out noticing his presence.. By using an opera glass all the
motions of the crow in searching for and capturing its prey
were readily seen. The crows will alight upon the branches
and search the under sides, where the gypsy moth caterpil¬
lars crawl or cluster. They are apparently quite fond of the
pupae, and will also eat the female moths. The young crows
kept at the insectary were fed almost exclusively for two or
three days upon these insects. Although they ate them at
first with avidity, they soon refused them and would not
touch them so long as other food could be obtained ; neither

218

THE GYPSY MOTH.

would they capture and eat the larva?. When the first moths
were placed in the cage, they caught and ate them eagerly.
The larger crow ate eighty-three and the smaller thirty-three.
On the second trial, crow number one ate fifty-eight moths
and crow number two twenty-three, thus together destroying
eighty-one. On the third trial they would have none of them.
At first, the birds, being apparently quite hungry, devoured
them whole. Later they rejected the thorax with the wings
and other appendages, and took the soft abdomens only.
The birds were at first so eager for the moths that they
would snatch them from each other. A curious fact about
their eating was that they swallowed the moths hind end
first, while grasshoppers were always swallowed head first.
It would appear from this limited experiment that the crows
soon became tired of a gypsy moth diet. It is quite prob¬
able that unconfined crows would tire of the moth as food
were no other food available. Yet from the frequency of
the crow’s visits to the infested spots, the size and capacity
of the stomach, and the number of different forms of the
moth eaten, it may be inferred that this species is quite use¬
ful in destroying the gypsy moth.

Other Useful Birds.

Bluebird. — In 1891 the bluebird was often seen feeding
on the larvae and pup® of the gypsy moth, but this was not
noticed in the ensuing years, and in 1895 no bluebirds were
seen during the summer in the infested region. When blue¬
birds breed in or near an infested orchard, they will no doubt
destroy many of these insects.

Warblers. — Although certain warblers have been seen
occasionally to capture many of the gypsy caterpillars and
moths, it is difficult to determine by observation or dissection
how useful they are in this respect. Owing to their activ¬
ity, and the small size of the larvae usually taken by them,
it is often impossible to learn the species or the number of
insects which they eat. The great vernal flights of warblers
through the infested region occur in May, at a time when
the larvae of the gypsy moth are very small, and are either
feeding or resting upon or underneath the leaves. The birds
migrating northward restlessly move from tree to tree, and

OTHER USEFUL BIRDS.

219

accurate observation of their feeding habits is then difficult.
As warblers glean much of their food from the twigs and
foliage, it is highly probable that the mortality among the
small caterpillars is partly caused by these birds.

Observations on the feeding of the warblers were made
when the spring migrants had gone north and the sum¬
mer residents were breeding. The warblers which breed in
the infested districts do not appear to feed habitually on the
gypsy moth. Both observations and dissections indicate that
most of them prefer the small, smooth, geometrid larvae. All
of them appear to have a particular fondness for the canker-
worms, and a few eat the tent caterpillar. Yet some of the ob¬
servations made show that certain species of warblers destroy
many of the larger gypsy caterpillars. These species also
destroy moths, both male and female. Mr. Bailey saw a yel¬
low warbler take two large gypsy moth larvae, tear them
open and eat out the body contents, leaving the skins upon
the tree. He saw a black-and-white creeping warbler just
from the nest capture and eat seventeen gypsy moth cater¬
pillars. All of them were pecked open.

Mr. I. C. Green, a former employee of the Board, consid¬
ers the redstart the most useful of all birds in destroying the
gypsy moth, but does not give the details of his observations.
This species has been seen by other observers to feed espe¬
cially on the male moth, which it often captures in flight.

The oven bird is mentioned by several observers as feed¬
ing on larvae and moths. The other warblers in the list
have seldom been seen to take any form of the moth.

Sparrows. — Though the towhee bunting or chewink was
not seen preying on the gypsy moth prior to 1895, the
observations of Mr. Mosher give ample proof of its useful¬
ness in this respect, especially in woodland or in sprout-
land where it is a common bird. It eats readily all forms of
the moth excepting the eggs, and this habit has been fre¬
quently observed. The rose-breasted grosbeak and indigo
bird occasionally eat the larvae.

Flycatchers. — All the flycatchers which breed in the dis¬
trict are given in the list of birds which destroy the moth.
Though most of them kill a great many moths, they proba¬
bly are not as useful as most other birds on the list, as they

220

THE GYPSY MOTH.

pursue mainly the quick-flying male moths. Experience in
trapping male moths has shown that ordinarily their capture
has little effect on the number of fertile egg-clusters in a badly
infested spot. This is partly because most of the male moths
find their mates close at hand, and so fertilize females before
taking any extended flight ; and partly because the male
being polygamous, each one that escapes the birds may fer¬
tilize several females. Yet as very many of the males are
caught by flycatchers, this may account for the scarcity of
males and the number of infertile egg-clusters sometimes
found in badly infested localities. As many males emerge
before the females, and as the moth lives but a few days

in the perfect form, most of
the males usually die before the
females all emerge, and males
are comparatively scarce late
in the season even in a badly
infested locality. If at this
time the flycatchers and their
young frequent an infested lo¬
cality, they still further reduce
the number of surviving male
moths. This scarcity of male
moths late in the season, which
is in part caused by the flycatchers and other birds, may
prevent the fertilization at that time of many eggs. Yet the
good done in this way by the flycatchers may be counteracted
by their destruction of liymenopterous parasites of the moth.
Of these parasites the ichneumon flies appear to be the
most useful, yet even they have not proved at all effectual
in reducing the numbers of the gypsy moth, even under the
most favorable circumstances. Mr. Kirkland has seen a wood
pewee dart down and capture an ichneumon fly, apparently
Theronia melanocephalct. This fly sometimes attacks gypsy
caterpillars, and has been frequently seen searching over
trees infested by them. Occasionally a flycatcher wTill pick
up a spinning larva as it hangs swraying in the wind by
its thread from the tree, but there seems to be no reason to
believe that this is a habit. Though the flycatchers confine
their feeding on this insect mostly to the male moths, they

OTHER USEFUL BIRDS.

221

frequently take females, and doubtless destroy many in the
aggregate during a season. The king bird appears to be the
most useful flycatcher in this respect, and has been seen to
eat very many of the females. This bird may thus render
efficient service to the farmer by preventing the deposit of
many thousands of fertilized eggs. Its comparative value
as a gypsy moth destroyer depends largely upon the number
of female moths that it kills.

Woodpeckers. — Of these most useful birds the three resi¬
dent species have all been seen feeding upon the caterpillars
or pup:e of the moth.

The flicker has also been seen carrying caterpillars to its
young. Mr. W. C. Colt, an inspector in the employ of the
Board, says that he watched a female flicker take nearly full-
grown larvae to its young. The bird made regular trips to
its nest at intervals of from three to flve minutes. The
downy woodpecker was observed by Mr. Bailey to eat a few
caterpillars, and to peck many others and afterward drop
them from the tree to the ground.

From what is known of the habits of woodpeckers, it was
expected that they would be found to feed on the gypsy
moth pupae. The downy and hairy woodpeckers are known
to feed in winter to a greater or less extent on the hibernat¬
ing pupae of many insects. Yet the hairy woodpecker only
has been observed to peck into the pupae of the gypsy moth.
This bird is not at all common in the district, but both
old and young birds have been seen feeding upon the pupae
by Mr. Mosher.

There is much difference of opinion among observers as to
the comparative usefulness of certain species of birds in
destroying the gypsy moth. This is to be expected, as each
is prone to regard his own observations as conclusive in
respect to all the species which he observes. In drawing
conclusions from observations on the food of birds a great
deal must be allowed for their individual preferences and
acquired tastes. For example: several observers report the
red- eyed and yellow-throated vireos as feeding eagerly on
gypsy moth caterpillars. Mr. Henry Shaw notes that in
one infested locality the red-eyes appeared to be living on
them, eating them constantly. Mr. C. E. Wood has seen

222

THE GYPSY MOTH.

the yellow-throat go from burlap to burlap, drawing out the
larvce from beneath. Yet Mr. Bailey reports that he has
seen individuals of these species search a tree over for hair¬
less larvae before they would eat one of the caterpillars of
the gypsy moth, of which there were thousands on the tree.

I do not question the correctness of any of these observa¬
tions. Certain fowls or flocks of fowls in the infested
region ate the caterpillars with avidity, while other individ¬
uals or flocks would not touch them. The same individual
preference was noticed among toads.

It appears that the presence of a great number of hair¬
less larvae has the indirect effect of lessening the number of
gypsy moth caterpillars destroyed by birds. When canker-
worms are plentiful, the birds eat comparatively few of the
hairy caterpillars until the canker-worms have disappeared.
Although many gypsy moth caterpillars were eaten very
early in the season of 1895 by the orioles, vireos and other
birds, these caterpillars received very little attention later,
when the growing canker-worms became more noticeable.
Most of the birds then devoted their attention to the canker-
worms. About June 10, when the canker-worms had mostly
disappeared, the birds again attacked the gypsy moth larvae
and continued to feed upon them for some time. Their appe¬
tites for these insects appeared finally to wane, having been
apparently cloyed by an excessive diet of hairy caterpillars.
It has been noticed that sometimes birds tire of a monotonous
diet, and that they will even cease to feed for a time upon a
favorite insect prey. This may partially account for the fact
mentioned by Grimm, that the birds forsook the Russian
forest which had been devastated by the gypsy moth. Yet
this would not be a sufficient reason to account for a continued
absence, as birds often return to feast again after a change of
diet. But the lack of shade, water and green food, all of
which together make a region unfit for the habitation of wood
birds, may have driven them for a time from the devastated
forest. In the infested district in Massachusetts forest birds
will not remain constantly through the hot summer days in
woodland which has been stripped by the gypsy moth, but
will betake themselves to shaded glades and brooksides, mak¬
ing frequent sallies into the bare, infested woods to feed on
the pest.

BIRDS FEEDING ON TIIE MOTH.

223

Birds attracted to Infested Localities.

The attraction of birds to infested localities and the num¬
bers of gypsy moths destroyed by them there may be best
realized by visiting a badly infested spot at a season when
all forms of the insect are to be found upon the trees. At
such a time the birds which feed upon the moth may be
observed to the best advantage. For this purpose one
should rise before daybreak and be on the ground before
sunrise, as many birds are in active pursuit of insects at that
time.

Upon approaching at dawn a badly infested spot in wood¬
land, the stroke of a flitting wing, the rustle of dead leaves,
an occasional shower of scattering dewdrops, a chirp or alarm
note heard here and there, all denote the presence of birds in
the woods. Their forms are still hidden or only dimly visible
in the uncertain, growing morning light. The infested spot
has the appearance of an opening or clearing. We emerge
in what appears to be a dead forest. The trees wear no foli¬
age. The pines, oaks, birches, poplars and wild cherries are
stripped and bare. The few leaves which still hang upon the
young maples and walnuts only accentuate the general naked¬
ness. There are sounds, not of the wind or storm, and yet
akin to these, pervading the woods, — sounds as of dry
leaves stirred by a rising breeze, mingled with those of the
tine pattering raindrops of sudden showers. These are caused
by the hosts of gypsy caterpillars which have devastated the
woods. The sound of their feeding is in the air, their
excreta rattle like raindrops on the dead leaves. As the
rising sun throws level beams across the hillside, the tracery
of the bare, interlacing branches and twigs is reproduced
upon the barren upright rocks of a rugged ledge. There is
little or no summer green, except the moss on the stones
along the stream, and a few small shrubs which have not
yet been wholly stripped. Upon the bare trees, especially
those near the edges of the defoliated tract, hundreds of
thousands of hairy caterpillars swarm. Many of them are
now hurrying down the trunks and crawling away to places
of concealment, seeking shelter from the sun’s rays. Many
more, having been travelling perhaps throughout the night

224

THE GYPSY MOTH.

in search of food, are still crawling in search of it, either on
trees or upon the ground. Masses or swarms of caterpil¬
lars are clustered in every sheltered place ; thousands are
feeding on the leaves of trees near the borders of the deso¬
lated area. The pupae hang in bunches under the limbs
and in the crevices of the larger trees. Many female moths
are just emerging from the chrysalides, and others are drying
their wings. This is the appearance presented by a wood¬
land colony of the gypsy moth on a July morning.

Seated here, somewhat screened b}^ the remaining herbage
on the borders of the stripped tract, we may observe the
struggle for existence between the moth and other forms

oo

of life. From the harsh semi-conversational notes heard,
first solemn and wary, then growing animated and cheerful,
we judge that a crow is feeding its fledged young in the
vicinity. Soon the crows are seen flying near. They alight
about forty yards away by the brook, and the old bird, go¬
ing to a clump of bushes, feeds her young time after time
with something she takes from among the stems. With
a glass we can see her take the larvae and pupae and put
them into the open beaks of her eager young. The old bird
now finds a female moth and passes it to one of the brood.
Soon becoming alarmed by some movement on our part, they
fly away to some pines, where in the high branches they
resume their feeding. An examination of the bushes they
have just left shows that the old crow has taken nearly all
the larvae, pupae and moths from the clump, leaving only a
few moult skins and spun threads to mark the recent ex¬
istence of the moth there.

A family of chickadees now appear. Flitting about
among the trees, they begin to catch and eat the larvae. One
picks up a large caterpillar, places both feet upon it and eats
out the viscera, leaving the head and skin. Another pecks
a caterpillar into small pieces and apparently eats most of the
pieces. Number one now flies some ten yards with a large
larva which it has just seized. Alighting on a convenient
limb, the bird hammers its prey awhile and finally drops it,
mutilated and dying, to the ground. Another bird tears a
female moth in pieces, eating only the contents of the abdo¬
men. All devote more or less time to killing the pupae, eat-

BIRDS FEEDING ON THE MOTH.

225

ing only a small portion of each. Thus with cheery chirp
and call they flit about through the woods, killing and eat¬
ing as they go. A red-eyed vireo alights on a branch within
six feet of us, and, picking three half-grown larvae from the
leaves, swallows them head first and flies away towards the
brook. Something is scratching in the leaves a few yards
away. With the glass we can see four towhees scratching
and digging like chickens. They are searching for the pupae
which they greedily eat. If a male moth flies low overhead,
one of these birds will leap from the ground and capture it.
They search about upon the ground and among the small
shrubs and seize the newly emerged females, beating them
on the ground and finally swallowing them. A lone cuckoo
whose dismal notes we have just heard now comes down
from a near-by tree, alights on a small sapling and proceeds
to breakfast. It picks off fourteen caterpillars, one by one,
hammers the larger ones a little and then swallows them
whole. A family of brown thrushes is busy by the brook.
With the glass one of them can be plainly seen in the act
of taking pupae from the stem of one of the larger bushes.
A family of five black-and-white creeping warblers come in
sight. They run and climb about on the trunks and branches
of the stripped trees, picking up the smaller larvae of the
gypsy moth and other insects, and now and then darting into
the air after flying male moths or pecking at the females.
These females they rarely eat and sometimes do not mate¬
rially injure, though they knock many of them off the trees.
One female which falls is snapped up by a towhee which
springs from the ground to take it in the air. A single
Baltimore oriole flies in, looks about as if out of its element,
catches several larvae and disappears in the direction of the
highway. The harsh cries of the blue jays have been ring¬
ing for some time through the woods. One at a time, five
jays pass among the trees. With the glass we can see two
of them taking the large larvae from a tree trunk. They
fly with them to branches or to the ground, and eat them
there. You can plainly see the jays as they take the cater¬
pillars in their bills, but they are so shy that they will not
remain long within our range of vision. Now the chicka¬
dees are back again. One of them takes twelve pupae in

226

THE GYPSY MOTH.

succession, carries each one to a limb, pecks it open and
drops it upon the ground.

As the sun grows warmer the number of male moths in
zigzag flight increases. It is now six o’clock, and the snap¬
ping of bills heard on all sides tells us that the flycatchers
are in the woods. Seven king birds are hunting the male
moths. They catch scores of them, and occasionally they
pick off a female or capture a falling larva. One of these
birds comes in over the tree tops and hangs suspended on
hovering wings. Suddenly dropping toward the earth, it
picks up a fluttering female moth, and, flying to a limb, with
a single snap of the bill divests the insect of both wings and
swallows it. The bird then looks to right and left, flies from
its perch, catches a male moth in mid-air, returns to its perch,
swallows the moth and calls cheerily to its mate. The other
king birds are all busy in like manner. As they seem to have
settled down to remain for some time, we will keep tally of
such moths as we can actually see them take at close range.
Several chipping sparrows now appear hopping about on the
ground. Now and then one picks up a half-grown larva.
They are pecking and eating the female moths. They also
chase and capture a low-flying male moth. Two catbirds
are searching the thicket along the brook. They are taking
pupae from the ground and dead leaves and also from the
leaves and twigs of the low bushes, but we can see this only
occasionally, as most of the time the birds are hidden from
view. The crows went when the king birds came, but the
flycatchers are still hawking about. As the reflected heat
of the summer sun is radiated from the earth, the newly
emerged male moths gain life and vigor from its warmth,
and fly in large numbers through the woods. Three least
flycatchers, two pheebes and several wood pewees are in sight
and pursue the moths most of the time.

At half-past nine the king birds have disappeared. Our
tally sheet shows that we have seen them take seventy-nine
male and twenty-four female moths. They were watched
only a portion of the time, but were feeding quite constantly.
It is safe to say that between 6.15 and 9.30 they have killed
two hundred and fifty male moths. The number of females
taken cannot be so readily estimated.

BIRDS FEEDING ON TIIE MOTH.

227

One chipping sparrow has been seen to take five females ;
six least flycatchers, thirty-one males and nine females ; two
wood pewees, twenty-two males and seven females. These
birds were most of the time at a considerable distance from
the point of observation, and it was only now and then when
they approached quite near that their actions could be dis¬
tinctly seen. The phcebe appears to have taken male moths
only. The towhees took eighteen moths, male and female,
while on the ground. They then went into the trees, and
while there moved on and were lost to view. A male yellow
warbler appeared and was seen to eat a larva and a female
moth. The oriole came again, taking four larvae. Redstarts,
creeping warblers and chickadees come and go, feeding on
the moth, but it is impossible to follow them and also watch
the other birds. It is now eleven o’clock. The birds have
nearly all left the hot and barren land of the defoliated hill¬
side, and are resting or feeding quietly in the shade among
the leaves, where they cannot be so readily watched.

Let us now go to an infested orchard a mile away, where
not all the trees have been stripped by the caterpillars. Here
we find some species of birds represented that were seen in
the morning in the woods, but the catbird, the towliee, the
creepers, the redstart, the wood pewee and the crow are
absent. Yet we find here the robin, bluebird, yellow-
throated vireo, flicker and house wren, all of which feed
more or less upon the moth. As the afternoon advances,
seven black-billed and four yellow-billed cuckoos are seen
feeding on the larvae and pupae. There are yellow warblers,
chickadees, half a dozen orioles, several chipping sparrows
and other birds in the orchard. The few infested orchard
trees appear to be much better protected by birds than the
woodland, and the moth has not made so much progress
here.

In the waning summer afternoon we return to the woods,
where, as the shadows lengthen, the birds again are busy.
The kiug birds and other flycatchers and the chickadees are
especially diligent. The king birds are now eating many
of the female moths. A solitary scarlet tanager hammers
a female moth upon a branch, shearing off its wings and
then eating its abdomen. In the advancing shadows of the

228

THE GYPSY MOTH.

approaching night many sparrows are seen hopping along
the ground, where they find their evening meal. Although
the birds are quite silent and it is impossible to make out the
species as they move among the shadows, the white female
moths can be plainly seen as the birds pick them up in their
bills. Some fifty birds are seen busily feeding on the moth
as we walk through the stripped woodland once more before
leaving for the night.*

Birds which destroy the Various Forms of the Moth.

The birds which have been found preying upon the gypsy
moth may be classified as follows : —

Birds feeding on the larvte — chickadee, downy wood¬
pecker, wood thrush, yellow-billed cuckoo, black-billed
cuckoo, yellow warbler, rose-breasted grosbeak, scarlet tana-
ger, black-and-white creeping warbler, red-eyed vireo, chip¬
ping sparrow, oriole, blue jay, yellow-throated vireo, crow,
catbird, black-throated green warbler, redstart, wood pewee,
robin, English sparrow, least flycatcher, wren, Maryland
yellow-throat, chestnut-sided warbler, brown thrush, purple
grackle, oven bird, white-eyed vireo, bluebird, flicker.

Birds feeding on the pupae — yellow-billed cuckoo, black¬
billed cuckoo, chickadee, yellow-throated vireo, towhee, hairy
woodpecker, scarlet tanager, crow, catbird, oriole, blue jay,
phcebe, English sparrow, brown thrush, king bird, wood
pewee, bluebird, yellow warbler.

Birds feeding on the male moths — king bird, chickadee,
oriole, redstart, yellow warbler, towhee, wood pewee, yellow-
throated vireo, red-eyed vireo, great-crested flycatcher, black-
and-white creeping warbler, least flycatcher, phoebe, brown
thrush, oven bird, English sparrow, chipping sparrow, blue¬
bird, indigo bird.

Birds feeding on the female moths — king bird, chicka¬
dee, towhee, great-crested flycatcher, phcebe, black-and-white
creeping warbler, red-eyed vireo, crow.

Birds which possibly eat the eggs — downy woodpecker,
chickadee, white-breasted nuthatch, blue jay, English spar¬
row.

* This description of the feeding of birds upon the gypsy moth is taken from
notes made in the field.

BIRDS FEEDING ON THE MOTH.

22 9

Do Birds feed on the Eggs of the Moth?

The field agents employed in the gypsy moth work have
often noticed egg-clusters of the moth which appeared to
have been pecked open by birds. A large number of egg-
clusters in the woods presented this appearance. Occasion¬
ally a bird was seen apparently pecking or eating the eggs.
A single species which would feed on the eggs during all the
winter months would be far more useful than many feeding
on the caterpillars during the summer. The eggs are so
minute that a bird feeding on them would destroy in one day
more individuals of the species than another could in one
hundred days by feeding on the large caterpillars. It could
find these eggs for nine months of the year, whereas the cat¬
erpillars are to be found for less than five months. The de¬
struction of the eggs also prevents all injury to vegetation
by the caterpillars, while if the eggs are allowed to hatch,
the caterpillars may do considerable damage before they are
killed.

Wishing to do all possible toward protecting and fostering
egg-eating birds, I determined to learn by accurate observa¬
tion and dissection whether any of our native birds were
destroying any considerable number of the eggs. For this
purpose Mr. Bailey was requested to watch birds during a
part of the winter of 1894-95. He selected several stations
for observation, one in an orchard and others in the woods of
the Middlesex Fells. The stations in the woods were chosen
because of the abundance of the egg-clusters of the gypsy
moth in the vicinity of each. The station in the orchard
was surrounded by a high board fence, built to prevent in¬
terference from without, and several hundred egg-clusters of
the gypsy moth were exposed on a single tree. At all these
stations bait was hung upon the trees for the purpose of
attracting birds. Pieces of beef bone, suet, waste meat and
grain were used to attract the different species. Crows, jays,
nuthatches, titmice, kinglets, woodpeckers and tree creepers
soon found the bait and made frequent visits to the infested
trees.

The birds soon became so accustomed to the presence of
the observer that they would feed within a few feet of him.

230

THE GYPSY MOTH.

The chickadees became so tame that they would sometimes
alight upon his hat or coat sleeve. They would come like a
flock of chickens to be fed, and some would feed on limbs
within three feet of his face. Occasionally one would even
take food from his hand. In a short time chickadees, nut¬
hatches, creepers and downy woodpeckers became so tame
that their feeding habits could be closely watched. Then
observations were begun. A downy woodpecker was seen
to strike an egg-cluster, scattering the eggs over the snow ;
yet the bird did not eat any of them. On close examination
it was seen that the eggs as well as some of the bark on
which they rested had been removed by the bird to get at
the larva of some insect which happened to lie under this
bark. The birds which came to the bait on the infested trees
were there many times each day for about three months, yet
the eggs were seldom molested. Daring all this time, how¬
ever, the birds were feeding daily on eggs and other hibernat¬
ing forms of other injurious insects, of which they destroyed
large numbers. Thirty-eight visits were made in one after¬
noon by birds to one tree on which were sixty-five gypsy
effgf-clusters. The birds all came within three or four feet

ou

of these eggs ; two of them even perched on egg-clusters,
but they did not eat or even notice the eggs. Whether the
result would have been the same had there been no meat for
them to feed on, we cannot say ; yet, as they were constantly
destroying the eggs of other insects, and as they occasionally
pecked the egg-clusters of the gypsy moth but did not eat
the eggs, it is fair to assume that they will not do so unless
perhaps when driven to it by extreme hunger. As from
observations made on birds in confinement it seemed prob¬
able that the hairs with which the egg-clusters are covered
were disagreeable to the birds, an experiment was made to
see if they would eat the eggs when the hair was removed.
For this purpose some hundreds of eggs denuded of hair
were glued upon a twig or stick in close proximity to the
meat. The birds attacked the bait as usual, but if they
ate any of the eggs it was not observed, although a few
were knocked or pecked off. They would not eat the eggs
even when they were cleaned of hair and distributed over
the meat. No birds were actually seen to eat any of the

BIRDS FEEDING ON THE MOTH.

231

eggs. One hundred and ninety-one egg-clusters were put
upon a tree to which from ten to thirty chickadees came
daily. Only seventeen of these clusters were pecked open.
In each case the bird was seen in the act. The eggs were
pecked off or taken in the beak and dropped to the ground.
A few blows would generally suffice to knock off most of
the eggs. Ten birds which were pecking at the eggs were
shot, but in no case were either the eggs or any portions of
them found in the stomach or intestines.

The observations showed that the egg-clusters were some -
times pecked oft* by nuthatches, either in a search for hiber¬
nating larvae or pupae hidden beneath the clusters, or to
secure the larvae of predaceous insects which bore into the
egg-clusters and feed upon the eggs. No bird has actually
been proved to feed upon the eggs except the English spar¬
row. One of these birds which was kept in confinement ate
a few of these eggs from time to time when deprived of
other food, but did not appear to relish them. It appears
that very little can be expected from our native birds in this
respect, unless they acquire a taste for the eggs. Yet many
egg-clusters have been found which appear to have been
pecked open or eaten by birds. The cause of this appear¬
ance was sought, and it was seen that squirrels and wood¬
peckers when climbing about on the trunks and branches
of trees frequently tore oft* the eggs in running or climbing
over them, so that they presented much the same appearance
as those actually pecked into by birds. The gray and red
squirrels were seen in the act, as well as several species of
birds. Chickadees have frequently been seen by men em¬
ployed in the woods to peck these egg-clusters, and several
observations seemed to indicate that birds were feeding on
them. The woodpeckers occasionally knocked them oft’ the
trees. Considering the prying, thieving nature of the jays,
it is quite probable that they may peck into the egg-clusters
and eat the eggs. Though the eggs are so tough that the
smaller titmice might have difficulty in breaking their shells,
the more powerful beak of the jay would easily accomplish
this.

In Europe, woodpeckers, creepers and titmice are said to
perform great service by eating the eggs of the gypsy moth.

232

THE GYPSY MOTH.

Altum says that in the year 1848 endless numbers of the
larvte of the gypsy moth had eaten every leaf from the trees
of Count Wodzicki. In the fall all the trunks and branches
were covered with the egg-clusters. Having recognized the
uselessness of the attempt to remove them by hand, he finally
gave up all his endeavors, and prepared to see his beautiful
trees die. Toward winter numerous flocks of titmice and
wrens came daily to the trees. The egg-clusters disap¬
peared. In the spring twenty pairs of titmice nested in the
place, and the caterpillar plague was noticeably reduced. In
the year 1850 the birds had so cleared his trees that he saw
them during the entire summer iu their most beautiful
verdure.*

Reaumur says that the larvae of the gypsy moth were very
numerous in 1826 on the lines of the Allee Verteat Brussels.
Many of the trees were stripped, and if one-half the eggs
which were deposited that year had hatched, scarcely a leaf
would have been left the next season, either there or in the
park, where the eggs were numerous also ; yet two months
afterward hardly one was to be seen. This destruction of
the eggs he attributes to titmice, tree creepers and other
small birds. f

The Introduction of European Birds.

If it is true that these European birds are so very useful
in this respect, the comparative immunity of many European
regions from the attacks of the gypsy moth may be due in a
measure to their efforts. If such be the case, their introduc¬
tion into Massachusetts may well be thoughtfully considered.
If introduced into a new country these feathered egg hunters
might thrive and multiply exceedingly, and if the eggs of
the gypsy moth are to them a familiar food, they would
probably seek these eggs here in preference to the unfamiliar
insect eggs which they would find. Such birds might in this
way prove as useful as a small army of men. Yet what com¬
pensation would they exact for this service ?

* “ Forstzoologie,” Vol. II., page 324, 1880.

t “An Introduction to Entomology,” by Kirby and Spence, Philadelphia, 1846,
page 152.

INTRODUCTION OF FOREIGN BIRDS. 233

When the introduction of any bird or other animal from a
foreign country is proposed, great care should be exercised to
study thoroughly all phases of the subject. Often, when
such importations have been made without careful scientific
investigation, they have proved very expensive mistakes.
The importation of the rabbit into Australia, the mongoose
into Jamaica, and the sparrow into America and Australia,
are familiar examples. The English sparrow was introduced
here for the express purpose of suppressing such native
pests as the larvae of the canker-worm moths. If previous
to its introduction its habits had been carefully studied in
Europe by a competent man appointed for the purpose by the
United States government, its introduction might have been
prevented. This exotic species, the value of which is doubted
in its native home, was brought here to perform a task which
native American species might have accomplished much bet¬
ter had they been protected and encouraged in our parks as
the sparrow was.

There are in Europe at least six different species of titmice.
All of them are found in some of the countries where dispar
is native. They are all recognized as eminently beneficial,
and are regarded by foresters, entomologists and ornitholo¬
gists as among the most useful species in controlling noxious
insects. Could they be successfully introduced here, they
might do a vast amount of good not only in destroying the
eggs of the gypsy moth but the larvae also, as well as the
eggs of many other injurious insects. It is difficult to imag¬
ine that any harm could come from the introduction of these
insectivorous birds, unless they should change their habits
in some way or drive out our native species, especially the
black-cap titmouse or chickadee, and fail to eat the females
and eggs of the canker-worm moths which the chickadee
devours in such quantities.* If that should happen, it
would indeed be a catastrophe, as the chickadee is one of
the most useful of all our native birds.

No importation of birds should be blindly attempted. An

* The great titmouse (Parus major) has been known to attack other birds
and break open their skulls, eating their brains. Some species of European tit¬
mice are believed to do some injury to plantations of young trees by destroying
buds or leaves.

234

THE GYPSY MOTH.

exhaustive study of their food habits should first be made
in their native home, and all the possibilities of their intro¬
duction should be well considered.

The English Sparrow and the Gypsy Moth.

The English sparrow has been seen to feed on all forms
of the gypsy moth ; yet this bird in its relations to dispar
is injurious rather than beneficial to man. That its name
appears so frequently in the records of observations is due to
the fact that it has been for years the most common bird in
villages and cities of the infested region, and that it is known
to many observers who would be unable to identify most
other birds.

The sparrow was introduced into Boston Common in 1868.
It is recorded that in 1871 it had reached Somerville, and
in 1873 Lynn and Cambridge. It undoubtedly appeared in
Medford about the same time, as Somerville adjoins both
Medford and Cambridge, while Lynn is some ten miles east
of Boston.*

While it is no doubt true that native birds were a great
factor in holding the moth in check during the first eight or
ten years of its existence in this country when its numbers
were few, it is equally true that the rapid distribution and
increasing numbers of the English sparrow later from 1875
to 1885 in the region infested resulted in driving out many
native birds. The bluebirds, wrens, house swallows and
martins were the first to leave, for as the sparrows multiplied
they took by force the bird houses and cavities formerly occu¬
pied by these birds, compelling them to seek nesting-places
elsewhere. As the sparrows further multiplied, their quarrel¬
some disposition impelled them to attack and drive away other
birds found around their nesting-places. What they could
not do singly they accomplished by force of numbers, until
comparatively few native birds were able to breed in the
immediate vicinity of the towns and villages. It is undoubt¬
edly true that the sparrow did something toward compensat-

* See “ The English sparrow in America,” United States Department of Agricult¬
ure, 18S9, page 21. I am informed by Mr. Walter Wright of Medford that his
father, Elizur Wright, liberated several pairs of sparrows in Medford about that
time.

THE ENGLISH SPARROW.

235

ing for this exile of insect-eating birds by destroying some
of the smaller gypsy caterpillars and occasionally killing
some moths or even eating a few moth eggs ; but it was
noticeable that wherever the sparrow was most plentiful in
the infested region, there also the gypsy moth became most
numerous. This was due partly to a distribution of both
species along the same highways and partly to the indirect pro¬
tection extended by the sparrow to the moth in driving away
the latter’s enemies among native birds. The caterpillars used
the bird boxes occupied by the sparrows as a place of retreat,
and the female moths deposited their eggs in these boxes.
Sparrows and caterpillars formed a sort of happy family in
the bird houses, which swarmed with both birds and insects.
By driving the native birds away the sparrow became in a
measure responsible for the phenomenal increase of the gypsy
moth in numbers and its consequent destructiveness in Med¬
ford. The increase of some other injurious insects has been
noticed wherever the sparrow has become so plentiful as to
banish native birds.* The trees in Boston and some of the
towns in its vicinity have often suffered injury from invasions
of the Orgyia teucostigma, or white-marked tussock moth,
caused indirectly by this sparrow. The sparrow, having
driven away the native birds, fails to make good their loss
by destroying the hairy caterpillars.

The ravages of leaf-feeding beetles ( Chrysomelci sccdaris )
have also become noticeable upon elm trees in localities most
frequented by the sparrow. The imported elm-leaf beetle
( Galeruca xanthomelcena ) has also been most injurious in
cities where the sparrow is abundant.

The Distribution of the Moth by Birds.

The dissemination of the moth in woodlands seems to indi¬
cate that it is distributed more or less by birds. This theory
is substantiated by our observations. Isolated colonies of
the moth are sometimes found in the vicinity of the nests
of the larger land birds, such as crows, jays and robins.
Occasionally birds flying to their nests with food for their

* Second report on the “ Injurious and other insects of the State of New York,”
by J. A. Linter, Albany, 1885, pages 80-82.

236

THE GYPSY MOTH.

young drop caterpillars or other insects. We have a few
instances on record where the gypsy moth caterpillars have
been dropped in this way, and in one case at least the cater¬
pillar was not materially injured.

Inspector Sanderson saw a wood thrush take a large cater¬
pillar from a tree and Hy off with it. The caterpillar wrig¬
gled in the bird’s bill and finally fell when the bird had flown
a few yards. The bird did not come back for it.

On July 6, 1895, Mr. Bailey saw a blue jay flying over the
woods in Saugus. It was flying about thirty yards from the
earth, and appeared to be making quite a long flight. As it
came near him he observed that it was carrying something
in its beak, and he immediately shot at it wTith his revolver,
not with the intention of killing the bird, but to make it
drop what it was carrying. It dropped a large gypsy moth
caterpillar, very nearly full grown. Mr. Bailey picked up
the caterpillar, which appeared to be uninjured. He had,
watched the bird’s flight for some distance, and thought it
came about half a mile. The bird continued its flight north¬
ward, carrying the remainder of the food in its bill. Mr.
Bailey kept and fed the larva, which pupated on July 12.
A female moth emerged from the pupa on July 29, appar¬
ently in fine health.

It is not an uncommon occurrence for birds when suddenly
frightened to drop food, and when carrying several larvae
in the beak at once, the one nearest the end of the beak
would be the one most likely to be dropped and also the one
least liable to injury by the beak. Birds sometimes carry in¬
sects a short distance without any apparent purpose. Mr.
Bailey saw a chickadee take seven larvae from a tree and fly
away with them, dropping them ten feet or more from the
tree. Three of these larvae were not injured. He also saw
a least flycatcher carry away three female moths, only one of
which it ate. One was dropped at a distance of twenty-five
yards from the tree from which it was taken.

There is another way in which the caterpillars may be dis¬
tributed by birds. They are often hatched in holes of trees
and in bird houses frequented by birds, especially by the
English sparrow. When first hatched in such places, they
are likely to spin down on their threads, and bird houses

BIRDS DISTRIBUTING THE MOTH.

237

and hollow trees have been found in which these spinning
caterpillars were very numerous. The caterpillars may be¬
come attached to the feathers of birds which pass to and fro,
and in this way may be carried short distances. Yet the
danger of distribution by the accidental dropping of cater¬
pillars by birds in flight does not appear to be so great as
that resulting from the dropping of caterpillars at the nest.
It occasionally happens that hairy caterpillars wriggle out of
the mouths of the young birds and are dropped into or below
the nests.

Mr. Bailey saw an oriole take to its young a caterpillar so
large that the latter could not eat it. The young bird placed
its foot upon the caterpillar, and drawing backward ejected
and dropped it upon the ground. The old birds occasionally
dropped food at the nest. Mr. Bailey watched a pair of
chickadees bringing food to their young. They appeared to
fly about half a mile to an orchard infested with the canker-
worm, returning to the nest about once in twelve minutes
with food. These birds dropped a few of the canker-worms
just outside the nest. A new colony of moths was discov¬
ered in Cambridge not far from a badly infested locality.
The appearance of the colony indicated that it was started
by crows, as the larvae were scattered all about in the vicinity
of the crows’ nest. If several caterpillars of the same species
are dropped in this way, there is a strong probability of a
colony being formed in the vicinity of the nest. A bird may
overlook a few caterpillars near its nest, preferring to go
where caterpillars are plentiful rather than to search for them
where they are scarce. It is probable, then, that the bird
which is most useful in destroying caterpillars and which
feeds the largest number to its young will be the most likely
to aid in the distribution of the moth. The danger of dis¬
tribution would probably be greater in the case of the larger
species of birds, were it not that a caterpillar seized in the
bill of a crow would be more likely to be seriously injured
than one taken in the bill of a small bird. The danger of
distribution to distances of much more than half a mile by
birds in this way does not seem to be great.

Mr. Bailey watched a catbird taking food to her young.
She flew back and forth about four times an hour. He

238

THE GYPSY MOTH.

could see her go and come for at least a thousand yards.
She flew about twenty- five yards from the earth, going
straight from the locality in which her nest was situated to
the locality from which she procured the food. Other small
birds have been known to fly an equal distance to secure
food for their young.

The distribution of caterpillars by birds goes to prove the
rule that nature does not usually work for the extermination
of species. While the birds are very useful as assistants in
the work of extermination by destroying the gypsy moths,
they hinder the work to some extent by distributing the
larvae and the female moths.

No appreciable distribution of caterpillars by birds will
occur, however, except when caterpillars are present in large
numbers, for then only will birds go to a distance to secure
caterpillars as food for their young. Probably no other
form of dissemiuation of caterpillars bv birds will materially
extend the moth’s distribution even under the most favorable
conditions. Wherever the caterpillars are present in large
numbers in a settled country, they will be carried much far¬
ther and scattered abroad more widely by man and domestic
animals than by birds. In -woodlands remote from civiliza¬
tion, birds might be the principal factor in diffusing the
moth to a short distance from badly infested spots, but the
distribution of the moth in such places is not of so much
moment as in cultivated and settled regions. If the moth
were allowed to increase and spread over the whole State,
we may infer that all possible distribution by birds would
be of little importance as compared with the good they
would do in checking the increase of the moth.

In towns where the moths are few and where most of them
have been already destroyed, and especially in small isolated
colonies, birds are very useful allies in the work of extermi¬
nation. In such localities they take the caterpillars only
when they come in their way, and rarely carry them to their
young unless the nests are quite near the infested spot.
Undoubtedly in many such cases birds have contributed as
much toward the extermination of the moth as have the men
employed in the work of extermination. Where the cater¬
pillars are few, therefore, birds render efficient assistance in

BIRDS DISTRIBUTING THE MOTH.

239

the work of extermination. As this work progresses, birds
become more and more useful as destroyers of the moth and
less dangerous as disseminators of the insect.

There appears to be little if any danger of the distribu¬
tion of fertile female gypsy moths by birds, for, though birds
have frequently been seen to carry the female moths a few
feet or yards, the observations of five years have not afforded
an instance of their carriage to a greater distance. The per¬
fect moths are to be found only in midsummer and later, a
time when all of the larger and most of the smaller birds
have no young in the nest.

It is not probable that the birds distribute the eggs of the
moth to any appreciable extent, though they undoubtedly
scatter them somewhat by pecking egg-clusters from the
trees. As it was known that many of the scattered eggs
hatch, when denuded of their hairy covering, it seemed im¬
portant to determine whether birds would break the egg
shells in feeding on the eggs, and whether unbroken eggs
would pass through the digestive tract of a bird without in¬
jury to the shell and hatch if left exposed under natural
conditions. Birds might thus distribute the moth as widely
as they are known to distribute certain plants by scattering
undigested seeds. A confined sparrow was fed upon the
eggs of the moth, and it was found that most of them were
broken by the bird’s bill, or in the process of digestion ; yet
some were passed entire. A similar experiment was made
with the crow. As the crows would not eat the eggs of the
moth unless disguised in food more to their taste, these
eggs were inserted in the bodies of grasshoppers and other
large insects, and while thus covered were swallowed by the
crows. A small proportion of these eggs were passed with
the shell unbroken, but the life of the eggs appears to have
been destroyed, as they are now drying up. This indicates
that there is no danger of a distribution of living eggs to a
distance by egg-eating birds.

Although, as has been shown, certain species of birds
undoubtedly assist in the distribution of the moth by carry¬
ing the caterpillars about, birds do much to prevent distribu¬
tion not only by reducing the numbers of the caterpillars,
but by capturing male moths in search of isolated females.

240

THE GYPSY MOTH.

thereby preventing the fertilization of scattered females and
the establishment of new colonies of the moth. Under the
most favorable circumstances in open country and with favor¬
ing wind and weather the male will occasionally find a female
at a distance of half a mile. It is probable that in orchards
or woodlands the scent of the female does not travel so far.
In any case a male flying some distance to a female would
wander about a good deal before finding its mate. In the
mean time it must run the gauntlet of the flycatchers, spar¬
rows, warblers and all the birds which so frequently capture
flying males. It is to these birds a shining mark, and,
although its flight is swift and eccentric, they readily follow
and easily capture it. When flying low in the open land
male moths are often pursued and captured by sparrows.
They may also be captured by swallows, but this has never
been observed. Experiments made in trapping male moths
by attracting them to females have often failed because of
the number of these moths captured by birds. Birds will
sometimes capture every male moth before it reaches the
trap. Therefore certain species do much in this way to
compensate for the injury which they or others may do in
distributing the moth.

Birds versus Useful Insects.

In their destruction of gypsy moths birds sometimes
destroy parasites of these insects. The parasites within the
caterpillars and pupge are eaten together with their hosts.
Yet the immediate destruction of caterpillars by birds is
of more importance to man than the lingering death which
is caused by the parasite. The larvae of hymenopterous
parasites feed almost exclusively on the fatty portions of the
insects which they attack, thus allowing them to live, feed
and grow, and do as much damage to vegetation as if they
were not parasitized. When the caterpillar has finished
feeding, or later when it has pupated, the parasite, having
eaten the greater portion of the fatty substance, eats out
the vitals, thus killing its host. The bird, on the contrary,
snaps up the caterpillar at once, thus preventing further
injury to the tree. The question then arises, would the
parasite unhindered be more effectual in checking the rav-

BIRDS VERSUS INSECTS.

241

ages of its host than the bird ? It is possible that, should
predaceous birds, insects and other enemies be insufficient
in holding the moth in check, the conditions in the course
of years, after great damage had been done, would be so
favorable for the multiplication of insect parasites that they
might check for a time the ravages of the moth. Experience
in many countries shows that, where other enemies of a
pest fail to hold it in check, insect parasites, starvation and
epidemic diseases sometimes put an end for the time being
to the plague. In addition to the destruction of parasites,
together with the host, some ichneumons and tachinid
Hies are captured in the imago form by the hycatohers.
Birds also destroy some of the predaceous insects. This
is especially true of robins, jays and crows. Yet Pro¬
fessor Forbes has shown that the destruction of such insects
by birds is not necessarily an evil.* The bugs which appear
to be most useful in the destruction of the moth are believed
to have some immunity from the attacks of birds by reason
of their pungent secretions. Crows, however, destroy cer¬
tain of these bugs.

Conclusions.

Our present knowledge of birds as enemies of the gypsy
moth in Massachusetts points to the following conclusions : —

At least a dozen species are very useful in this respect ;
probably twenty-five others are more or less useful, when
the moths become very numerous, or when other species of
insects which these birds prefer are scarce.

Birds destroy larger numbers of the gypsy caterpillars
when the canker-worms or other hairless larvae are scarce
than when they are plentiful.

Although birds gather in localities infested by the moth
for the purpose of feeding on the caterpillars, they do not
flock to such infested localities in such numbers as they do
to regions infested by migrating locusts or by hairless cater¬
pillars.

Birds are particularly useful in preventing the increase of
small colonies of the moth, and in this respect are allies to

* Bulletin No. 3, Illinois State Laboratory Natural History, November, 1880,
page 83.

242

THE GYPSY MOTH.

man in the work of extermination. A few cases are noted
in which such colonies appear to have been exterminated by
birds. They are also useful in checking the increase of the
moth in large colonies.

More species of birds are found attacking the moth in
orchards than in woodlands, though woodland birds often
visit orchards situated near their usual haunts, and orchard
birds visit badly infested colonies in woodlands.

While birds are very useful in restraining local ravages of
the moth, it is probable that should the moth be allowed to
spread over the whole State, its increase would so outrun the
numbers of birds that they would have no appreciable effect
in checking its most serious outbreaks.

The injury done by birds in distributing the moth and
destroying parasites and other useful insects appears to be
of little importance when compared with the good they do
in destroying the moth.

If laws for the protection of birds were enforced, and if
birds were fostered, encouraged and protected generally by
citizens, there is no doubt that their efficiency as insect de¬
stroyers could be greatly increased. The most important
service that could be rendered by birds in the case of the
gypsy moth would be the destruction of the eggs. This
service, supplemented by that of destroying the other forms
of the moth in summer, would be of very material benefit.
As no American birds appear to eat the eggs to any extent,
it would be well to investigate thoroughly the habits of
European egg-eating species, with a view to their introduc¬
tion into Massachusetts, if this should be found desirable.

The Protection of Birds.

It is quite evident that by pursuing a policy for the pro¬
tection of birds, the number of birds in the region infested
by the gypsy moth and their efficiency as insect police could
be greatly increased. While the present laws for the pro¬
tection of insectivorous birds are wise in the main, no
adequate provision is made for their enforcement, and they
are consequently a dead letter to certain classes of people.
A great many birds are killed and many nests broken up
by boys. In the fall the country swarms with gunners.

PROTECTION OF BIRDS.

243

Thousands of birds are killed for the milliners. The camps
of Italians, where employees engaged in public works are
quartered, furnish many of these gunners. These men will
shoot birds of any kind, anywhere and on any man’s premises.
Everything that wears feathers is considered by them as fair
game.

The appointment of officers to enforce the bird laws might
assist much in bird protection. Children in the public schools
should be taught the usefulness of birds, and it should be
generally considered a crime to destroy insect-eating birds.
The farmer might as well allow men to steal his fruit and
grain as to shoot the insect-eating birds on his premises.
The number of birds destroyed by cats is astonishing. I
have known a single cat to break up the nests of six pairs of
birds in a day, destroying all the young and one of the old
birds. Many wild and vagabond cats roam the woods and
orchards and destroy thousands of birds. Outside the cities
cats probably do enough injury by killing birds to much
more than counterbalance all the benefit derived from them
in the way of destroying rats and mice. A few traps prop¬
erly attended by a bright boy will do more towards clearing
a place of rats and mice than half a dozen average cats.

The number of such birds as nest in boxes or hollow trees
can be increased by putting up boxes in which they may
breed, and protecting them as far as possible from the English
sparrow and other enemies. If evergreen hedges and patches
of shrubbery are provided as retreats for birds to which they
can fly when pursued by hawks, and if plenty of wild and
cultivated fruit is grown in the vicinity, such a locality will
be much frequented by birds.

Birds may be attracted to infested localities in the winter
or summer by supplying them with food and safe nesting-
places. A people who protect and foster insectivorous birds
cannot fail to add materially to the prosperity of agriculture.

THE GYPSY MOTH.

2U

The Progress oe Extermination.

The extermination of the gypsy moth was begun by the
Commonwealth under a misapprehension of the facts. When
the first great outbreak of the pest was brought to the atten¬
tion of the Legislature in 1890, it was believed that the moth
was confined to cultivated lands in the town of Medford.
This infested district was not supposed to exceed one-half
mile in width and one and one-half miles in length. The
difficulty and expense of extermination were consequently
underestimated. An appropriation was made for the pur¬
pose of exterminating the moth in this small tract and
preventing its spread to other parts of the State. In the
attempt to exterminate the moth, the experience of the first
year showed that the insect was not confined to Medford, and
the commission of 1890 reported that fifty square miles were
more or less infested. The experience of the second year
proved that the moth was distributed over an area of over
two hundred square miles, not only in cultivated lands but
in waste and wood lands as well. The magnitude of the task
undertaken by the Commonwealth then became apparent.

Circumstances favoring Extermination.

There are certain circumstances connected with the habitat
of the moth, which, taken together with known facts in its
life history, encourage the attempt to secure its extermina¬
tion.

Limited Area Occupied. — The experience of five years
confirms the belief that the moth is confined to a limited area
on and near the coast line.

Favorable Location. — The infested region is bounded on
the east and south-east by the ocean, which prevents the
spread of the moth in those directions. Much of the territory
along the coast consists of salt marsh, in which the gypsy
moth cannot live.

The infested region is in the most populous portion of

EXTERMINATION.

245

the State ; therefore the extermination of the moth directly
interests a large number of people. This fact assures the
intelligent co-operation of many individuals.

The original centre of infestation in the district was situated
on a short line of railroad ending in Boston, and thus the
danger of distribution by rail was not great.

The Infested Area has been reduced. — As a result of the
work of extermination, the region now occupied by the gypsy
moth is considerably less than that occupied by it five years
ago, when the work was begun.

SIovj Spreading. — The female moth does not fly. On
this fact rests the principal hope of preventing the spread of
the insect, and finally securing its extermination. Could
the female moth fly, as does the male, the species would
probably have been distributed long since over all eastern
Massachusetts and adjacent parts of New England, if not
farther. The moth occupied twenty years from the time of
its introduction in spreading over the territory infested by
it in 1891.

The I Loth hibernates in the Egg. — It remains in that
form during most of the fall, the winter and early spring.
The eggs are conspicuous, and an opportunity is thus given
for inspecting the territory and discovering the colonies of
the moth during the fall and winter months, while the trees
are leafless and the insect is doing no damage. It is more
feasible to exterminate an insect pest which may be attacked
in the winter, when it is stationary for a fixed period, than
to exterminate a species that can be reached only during
the summer months, at which time its distribution is being
effected.

Obstacles to Extermination.

Though there are many encouraging circumstances in
connection with the problem, there are also serious obstacles
tQ success.

Enormous Reproductive Capacity of the lloth. — Its won¬
derful reproductive powers and its remarkable tenacity of
life provide for a rapid increase and redistribution in an in¬
fested locality in the inspection of which a few moths may
have been overlooked.

246

THE GYPSY MOTH.

Many Food Plants. — Where the moth is abundant, it is
found on nearly all plants of economic value. In inspecting
a region in search of the moth it is necessary to examine all
species of trees. It is therefore much more difficult and
expensive to locate all the colonies than it would be were
the insects confined to a few food plants.

Other Obstacles. — The infested region being densely pop¬
ulated, the danger of local distribution and reinfestation by
man and animals constantly passing and repassing infested
centres is much greater than it would be were the district
thinly populated.

No one method can be depended upon for exterminating
the moth. Nature often defeats an attempt to exterminate
by a single process at a particular season of the year.
The most approved methods applied singly frequently fail.
Exterminative work must proceed day after day throughout
the year, to insure success. Though every effort was made
in 1891 to exterminate the moth from the region most in¬
fested, the inspection of 1892 gave abundant evidence of the
impossibility of extermination in one year’s time. In 1891
the destruction of the eggs was depended upon for extermi¬
nation. Yet caterpillars were found in 1892, even in those
parts of the infested territory where the work had been most
carefully done, and where the greater part of the eggs had
been destroyed. Many of these came from eggs which had
been scattered on the ground in the previous fall and winter
before the work of destroving the clusters was begun. Eggs
are sometimes thus scattered by the wind and rain, by
people picking fruit or pruning or cutting trees, by birds
and animals, or by various other causes. The female moth
occasionally drops a few eggs upon the ground or in crevices
of the bark, where they will escape the most thorough
search. Spraying, as ordinarily done, will destroy only a
small portion of the caterpillars. Bands of insect lime and
other tree protectors merely prevent most of the caterpillars
from ascending trees which have been first cleared of eggs.
If thus kept out of trees, they will betake themselves to
other plants. While the burlap bands afford a means of
disposing of most of the caterpillars, there can be no cer¬
tainty of taking them all by this method.

PLATE XXXVI. Men at work on the Dexter elm, Malden. From a

photograph.

EXTERMINATION.

247

The Success of Local Extermination.

The work of extermination was begun on the principle
that, if the moths could be exterminated from one tree, they
could be eradicated from any number of trees, providing the
same kind of work that cleared the first tree could be carried
on simultaneously over a large area. It was soon found that
the moth could be cleared from trees of ordinary size by
honest, thorough, intelligent labor. Yet many doubters
asserted that it was impossible to clear the larger trees.
Medford, being one of the oldest towns in the State, had
many very large elms. This was also true of Malden. It
was believed by some of the residents that it would be im¬
possible to clear the moths from these trees except by the
aid of a balloon. The largest tree in the infested region was
selected for trial of the possibility of extermination. This
tree is situated on the property of the Messrs. Dexter of
Malden, and stands in front of the old Dexter mansion.
The tree lias been owned by this family for more than two
hundred yeafrs. If not the largest tree in the State, it is
one of the largest.* Early in 1891 an attempt was made
to clear the moths from the tree, and a gang of four men,
who had had some experience, went to work upon it to
destroy the eggs of the moth. After working for several
days upon the tree they reported it cleared. Another gang
of men was put at work upon the tree, and six hundred
additional egg-clusters were discovered. Notwithstanding
this, caterpillars appeared in the spring upon the tree. It
was then sprayed thoroughly, an extension ladder sixty-five
feet in length being used, together with several additional
ladders placed in various parts of the tree. Later in the
season all the holes in the limbs were covered or filled, and
the few egg-clusters found were treated with creosote oil.
In 1892 the tree was banded with tarred paper, which was
kept constantly moist with a mixture of tree ink, tar and
oil. A few caterpillars were found, however, on the tree,
having hatched probably from scattered eggs left in the

* The Dexter elm has the following dimensions : circumference at base, 29 feet;
circumference six feet from ground, 21 feet; height, 110 feet; spread from north¬
east to south-west, 104 feet. Some of the branches of the tree are 3 feet in
fliameter.

248

THE GYPSY MOTH.

crevices of the bark. In 1893 no caterpillars appeared,
and no form of the moth has been found since 1892 upon the
tree. In the inspections of the tree every care has been
taken to go over it thoroughly, from its highest branches to
the base of the trunk. The dead limbs have been removed
and holes have been covered, but no other work has been
necessary at the regular inspections. Plate XXX VI. shows
men at work in the inspection of the tree.

The extermination of the moth from many orchards was
accomplished without much difficulty. Plate XXXVII. shows
apple trees which were seriously injured during the season
of 1891 by the gypsy moth. They were cleared of the moths
and so treated that in 1892 they regained a large part of
their foliage (Plate XXXVHI. ) . They have borne very little
fruit, however, since 1891.

Having learned that it was possible to clear the moth
from any tree, it remained to be proved whether the creat¬
ure could be cleared from orchards or entire estates.
Although in 1891 many estates appeared to have been
cleared, there was still some doubt that the moths were
exterminated from them. But the estates were examined
again and again in succeeding years, and no moths were
found except in a very few instances. The number of
infested estates from which the moths had been cleared
increased annually. Not only were estates cleared, but
infested localities consisting of many estates were entirely
freed from the moth.

More than a thousand colonies in the infested region, some
of them covering many estates, have been entirely cleared
of the moth and have remained clear, until it has become an
established fact that wherever the moths are found in open
and cultivated lands, they can be exterminated. The diffi¬
culty of exterminating the moth in woodland has been found
to be much greater. Yet, despite all obstacles, some of
which at first seemed insurmountable, the moths have been
cleared from certain infested localities in the woods. The
destruction of all vegetation by fire will accomplish exter¬
mination in woodlands. But much of this infested woodland
is retained by the Commonwealth for park purposes, and the
destruction of the trees is out of the question, however much

PLATE XXXVII. Apple trees stripped by caterpillars of the gypsy moth,
Swampscott. From a photograph taken Aug. 5, 1891.

PLATE XXXVIII. View of the same trees in Swampscott a year later,
after the moths had been cleared from the locality by the agents
of the Board of Agriculture. From a photograph
taken in July, 1892.

EXTERMINATION.

249

the exigencies of the case might seem to warrant such a course.
Therefore burlapping, banding, spraying and other means,
less expeditious and in the end more expensive than fire,
have been resorted to. These means call tor larger appro¬
priations than have yet been made, and without such appro¬
priations, promptly granted, the extermination of the moth
can never be accomplished. Though a continual advance in
the work of extermination has been made annually in the outer
towns of the infested district, though some of them appear
quite and others nearly cleared of the moth, there is a section
of woodland in the inner towns which is probably in a worse
condition than it was in in 1891.

Larger Appropriations Needed.

While the agents of the Board have been engaged in pre¬
venting the spreading of the moth and prosecuting the work
of extermination in the outer towns of the infested region,
they have been unable to do much more with the means pro¬
vided than to check the moth’s annual increase in the central
towns. This partial policy, the inevitable consequence of
the inadequate appropriations, has necessitated in the inner
towns an annual repetition of the work and expense with¬
out any considerable advance towards extermination in those
towns. As a result, while extermination has been success¬
ful over large areas, principally in the outer towns, the
moths have increased in the comparatively neglected wood¬
land in the central towns. The Board is required by law
to do all possible toward preventing the spread and securing
the extermination of the gypsy moth in this Commonwealth.
All possible with the means at hand has been undertaken.
All the evidence obtainable goes to show that the spread of
the moth into territory outside the region infested in 1891
has been prevented, and that extermination has been accom¬
plished both locally and over a considerable area, greatly
reducing the infested territory. Our only hope of prevent^
ing the spreading of the moth lies in doing everything possible
to exterminate it. Therefore, whatever imperils the success
of extermination, renders the prevention of the moth’s dis¬
semination less certain. The expense of extermination has
been greatly augmented and success retarded and gravely

250

THE GYPSY MOTH.

imperilled by inadequate resources and repeated delays in
making the annual appropriations. Unless ample appropri¬
ations are promptly granted, failure is certain.

To continue the past policy of inadequate and belated ap¬
propriations may result sooner or later in the escape of the
moth from the territory to which it is at present confined and
its final distribution over the whole country. In such a case
it might injure the agricultural interests beyond calculation.
If the gypsy moth should be allowed to spread over the
United States, the average farmer would be powerless, under
the conditions prevailing in this country, to protect his or¬
chard, woodland or garden against the ravages of .this insect.
Whatever affects the prosperity of the farmer affects the
prosperity of the whole people. Knowing as we do that the
moth feeds on nearly all forest and orchard trees and garden
plants, knowing also the injury done in Europe within the
past century by this insect, having* learned by experience the
greatly increased destructiveness of European insects when
introduced here, and considering the annual damage now done
to agriculture by insects in this country (estimated by an em¬
inent authority at three hundred and eighty million dollars),
we can but view with alarm the possibility of the spread of
this insect over the United States.

There is no doubt in the minds of those acquainted with
the facts that the gypsy moth can be held in check where it
now is and that it can be exterminated if sufficient resources
can be secured and vigorous measures taken. It would seem,
then, that the general government should seize the opportunity
now presented to stamp out the pest which Massachusetts
undertook to exterminate as soon as it was publicly known
that it was within her borders, reducing its numbers and the
area of its dissemination by local extermination and thus far
holding it in check. The policy of control or extermination
of insect pests by governmental commissions, which has been
so successful in certain European countries, might be applied
to advantage in this case by the government of the United
States. There are those who believe that neither the State
nor nation should appropriate money for the extermination
of this insect, but that land owners should be left to protect
their own property from its ravages. According to Professor

EXTERMINATION.

251

Fernald, this would prove to be the worst possible policy,
as after the moths had spread over the State, the expense to
land owners would be enormous as compared with the expense
of the work as carried on by the State in the present re¬
stricted territory. He makes the following comparison in
his report on the work of 1895, made to the gypsy moth
committee of the State Board of Agriculture : —

“The value of the taxable property in this State is
$2,429,832,966, and an appropriation of $200,000 is a tax
of less than one-twelfth of a mill on a dollar. A man having
taxable property to the amount of $5,000 would have to pay
a tax of only 41 cents and 6 mills. This beggarly sum of
money would make but a small show in the work of clearing
the gypsy moth caterpillars from an infested $5,000 farm,
while in the uninfested parts of the State the land owners
would be paying an exceedingly small premium to the State
to insure them against the ravages of the gypsy moth. This
premium on a $1,000 farm would be 8^ cents, and for fifty
years it would amount to only $4.16§. This protection
would extend not only to farmers and owners of forest lands,
but also to residents in villages and cities who own lands
with trees and shrubs on them, and to vegetation wherever
grown within the limits of our Commonwealth.”

The expense of this work, if undertaken by the United
States government, would be infinitesimal to the individual
citizen and would be an economical insurance against the
ravages of the moth on his property and that of his posterity.

THE GYPSY MOTH.

PORTHETRIA DISPAR (L.).

I * A ll T II.

G. TT. FERHALD.

Plate 39.

Insects mistaken for the Gypsy Moth

■W'y.

EXPLANATION OF PLATE 39.

Drawn in colors by Ella M. Palmer.

It has seemed desirable to present colored figures of the following insects since
in some of their forms they are the ones most commonly mistaken for the gypsy
moth.

1. Eggs of Euvanessa antiopa (Linn.) (Vanessa

butterfly) .

2. Caterpillar of Euvanessa antiopa.

3. Chrysalis “ “ “

4. Imago “ “ “

5. Egg-cluster of Clisiocampa a7tiericana Harr.

(tent caterpillar).

6. Caterpillar of Clisiocampa americana.

7. Cocoon “ “ “

8. Male imago of “ “

9. Female imago of “ “

10. Caterpillar of Orgyia antiqua (Linn.).

1 1 . Male imago “ “ “

1 2 . Egg-cluster of Orgyia definita Pack.

13. Caterpillar “ “ “

14. Male imago “ “ “

15. Egg-cluster of Orgyia leucostigma (S. and A.)

(the white marked tussock moth).

16. Caterpillar of Orgyia leucostigma.

17. Male imago of “ “

18.

u it

Female imago of

THE GYPSY MOTIT.

Porthetria disjiar (L.).

This species was first described by Linnaeus, in 1758, in
the tenth edition of his “ Systema Naturae,” Yol. I, page 501,
under the name of Phalcena (Bombyx) dispar , the specific
name being given because of the marked difference or dis¬
parity between the sexes. In 1801, Schrank, in his “Fauna
Boica,” placed this species under his genus Laria ; but this
generic name had been previously used by Scopoli in the
beetles, and thus, being preoccupied, could not properly be
used for the moths. In 1810, Ochsenheimer, in the third
volume of his “ Schmetterlinge von Europa,” established the
genus Liparis and put dispar under it ; but Liparis is also
preoccupied, and cannot be used. Hiibner, in his “Yer-
zeichniss bekannter Schmetterlinge,” page 100, published
about 1822, placed dispar in his genus Porthetria with three
exotic species, and therefore dispar, being the only European
species, has been taken as the type. In the same work, page
158, Hiibner established the genus Ocneria with rubea Fab.
as the type, but Staudinger and some others, believing that
rubea and dispar should be in the same genus, placed them
with their allies under Ocneria.

In 1829, Stephens, in his “Illustrations of British Ento¬
mology,” Haustellata, Yol. II, page 55, established the genus
Hypogymna and placed dispar under it. He also proposed
this name in his catalogue the same year. In accordance
with the laws of priority, almost universally accepted by
zoologists, it is necessary to adopt the oldest tenable generic
name which is not preoccupied ; and therefore Hlibner’s genus
Porthetria, with dispar as the type, was given by Kirby in
his recent “Catalogue of Lepidoptera Heterocera,” and has
been adopted by Comstock and Dyar in this country.

256

THE GYPSY MOTH.

The question whether dispar shall remain under the genus
Ocneria depends on whether it has the same generic charac¬
ters as rubea. If it has, then it should remain with rubea ,
otherwise it should be placed under the genus Porthetria.
To settle this question to my own satisfaction, I sent to
Europe and obtained specimens of Ocneria rubea , and, after
a critical study of the structure, I am convinced that the two
insects are not congeneric, and must be placed under differ¬
ent genera. On showing the insects to Prof. J. B. Smith,
he agreed with me in my conclusions, and in a letter from
Prof. A. R. Grote of Bremen, Germany, I learned that he
had independently reached the same conclusion. I therefore
feel obliged to adopt the name Porthetria dispar, given by
Htibner over seventy years ago. In all our previous pub¬
lications, however, the name Ocneria dispar has been used,
following Staudinger’s catalogue.

Common Names.

The following are some of the common names which have
been given to this insect in different European countries. We
have adopted the common name “gypsy moth,” because it is
the one most frequently used in England, and has already
come into very general use in this country. This name was
first given to it, so far as I can learn, by Wilkes, in 1741 ;
and Humphreys, in his “British Moths,” says that “the
popular name of the gypsy was no doubt suggested by the
brown, tanned kind of color of the male.”

Schwammspinner : Fungus-spinner. The egg-cluster resembles a
small tree fungus.

DiCKKOPr : Thick-head. The head of the caterpillar is unusually
large.

Rosenspinner : Rose-spinner. They feed on rose bushes.

Apricosenspinner : Apricot-spinner.

Stamjipiulj:ne : Stem-moth. The moths rest on the trunks of
trees.

Grosskopf : Great-head.

Baumraupe : Tree-caterpillar.

Schwammraupe : Fungus-caterpillar.

Grosse Schwammraupe: Great fungus-caterpillar.

Schwammmotte : Fuugus-moth.

Stammraupe : Stem-caterpillar.

Grosskopfspinner : Great-head spinner.

COMMON NAMES AND BIBLIOGRAPHY. 257

Ungleicher Spinner: Dissimilar spinner. The sexes are very
unlike.

Ungleicii Nachfalter : Dissimilar nocturnal-moth.

Zweifach: Two-fold.

Grosskopfbar : Great-head bear.

Dickicopfiger Bar : Thick-headed bear.

Le Bombyx dissemblable : The dissimilar bombyx.

Le Bombyx disparate : The dissimilar bombyx.

La Spongieuse: The spongy (moth).

La Chenille commune : The common caterpillar.

Le Zig-Zag.

The Gypsy Moth.

The Brown Arches.

Literature on the Gypsy Moth.

All the works in this list have been examined except those
marked with an asterisk.

Goedart, Histoire des Insectes, vol. I, pp. 118, 142, pi. 63, 16G2.

Merian, Erucarum Ortus, etc., part I, pi. 18-31, 1679.

Merian, Erucarum Ortus, etc., part II, pi. 19, 1683.

♦Blankaart, Schauplatz der Raupen, p. 25, pi. 6, figs. A-C, 1690.

Frisch, Beschreib. von Ins., vol. I, p. 14, pi. 3, figs. 1-9, 1720.

Frisch, Beschreib. von Ins., suppl., vol. XIII, p. 28, 1722.

Merian, Erucarum Ortus, folio edition, pi. 183, 1730.

La chenille h oreilles, Reaumur, Memoires, vol. I, p. 110, pi. 3, figs. 1,
3-5; p. 19, pi. 4, figs. 1-4, 6-8; p. 352, pi. 22, figs. 5, 6, 8-10; p.
359, pi. 24, figs. 1-4; p. 609, pi. 45, figs. 1-13; p. 614, pi. 46, figs. 1-7,
1734.

La chenille a oreilles, Reaumur, Memoires, vol. II, p. 63, pi. 1, figs. 11-15;
p. 433, pi. 34, fig. 3, 1736.

♦The Gipsey Moth, Wilkes, Twelve New Designs of English Butterflies,
1741-42.

Roesel, Insecten Beliistlgung, part I, p. 17, pi. 3, figs. 1-7, 1746.

Schreber, Samml., vol. XIII, p. 153, 1750.

Baumraupe, Schaeffer, J. C., Nachricht von einer Raupe, etc., 1752.
Fhalaena (Bombyx) dispar, Linn. Syst. Naturae, ed. 10, vol. I, p. 501,
1758.

Schaefler, J. C., Der Wunderbare Eulenzwitter, etc., 1761.

*Poda, Insecta Musei Graecensis, p. 86, 1761.

Fhalaena Dispar, ScopolR Ent. Carniolica, p. 197, 1763.

Le Zigzag, Geoff., Hist. Abreg6e des Ins., vol. II, p. 112, No. 14, 1764.
♦Gronovius, Zoophylacium, vol. II, p. 208, 1764.

Schaeffer, J. C., Abh. von Ins., vol. II, p. 315, pi. 1, figs. 1-8, 1Y64.
Schaeffer, J. C., Icon. Ins. Ratisb., part I, vol. I, pi. 28, figs. 3-6, 1766.
Phalaena (Bombyx) dispar, Linn. Syst. Nat., ed. 12, vol. I, p. 821, 1766.
♦Bombyx Dispar, Hufnagel, Berl. Mag., vol. II, p. 406, pi. 3, No. 16, 1766.
♦Bombyx Dispar, Hufnagel, Berl. Mag , vol. Ill, p. 8, No. 2, 1767.

Merian, Hist. Generale des Ins. d’Eur , ed. 3, vol. II, p. 5, pi. 18, 1771.
Bombyx dispar, Wilkes, English Moths and Butterflies, pi. 42, 1773.

258

THE GYPSY MOTH.

Phalaeua dispar, Gleditsch, Forstwiss., vol. I, p. 310; voL II, pp. 45, 81,
227, 739, 1775.

The Gipsy, Harris, Aurelian’s Pocket Companion, pp. 29, 30, 1775.

Phalaena dispar, Christmann, Onomatologia Nat. Hist., vol. VI, p. 350,

1775.

Bombyx dispar, Fab., Syst. Ent., p. 570, No. 49, 1775.

Phalaena dispar, Fuessl., Verz. Schweiz. Ins., p. 35, No. 660, 1775.
Bombyx Dispar, Denis and Schiffermiiller, Syst. Verz. Schm., p. 52, No. 6,

1776.

Grosskopf, Mueller, O. F., Zool. Dan. Prod., p. 665, pi. 16, figs. 2-11, 1776.
Phalaena dispar, Mader, Raupenkalender, p. 99, No. 282, 1777.

Phalaena dispar, Fischer, J. B., Natur. gesch. von Livland, p. 151, 1778.
Phalaena dispar, Fuessl., Mag. fur Liebhaber der Ent., vol. II, p. 286, 1778.
Phalaena Bombyx dispar, De Geer, Abhl. Gesch. der Ins , vol. II, p. 293,
1778.

Phalaena Bombyx dispar, Goeze, Ent. Beit. Ritter, part III, vol. II, p.
331, 1779.

Phalaena dispar, Leske, Anfangs. Handb. Nat. Gesch., p. 460, No. 8, 1779.
Eichen und Ulmraupe, Glazer, Abhl. von schiidl. Raupen, p. 39, 1780.
Phalaena dispar, Rimrod, Naturforscher, vol. XVI, p. 130, 1781.

Bombyx dispar, Fab., Species Insectorum, vol. II, p. 183, 1781.

Bombyx dispar, Lang, Verz., p. 86, No. 661-664, 1782.

Phalaena Bombyx Dispar, Esper, Schmett., vol. Ill, p. 197, pi. 38, figs.
1-6, 1782.

*Bombyx Dispar, Martin, Vade-Mecum, Pom. Trees, No. 44, 1785.

Le zigzag, Ernst, Pap. d’Europe, vol. IV, p. 106, pi. 138, fig. 186, a-g, 1785.
Phalaena dispar, Bock, Versuch. Nat. Gesch., etc., vol. V,pp. 29-32, 1785.
*Fourc., Entomologia Parisiensis, p. 261, No. 14, 1785.

Bombyx dispar, Fab., Mantissa Insectorum, vol. II, p. 117, 1787.
Borowski, Naturgeschichte Theirreichs., vol. VII, p. 97, 1786.

Borowski, Ifhturgeschichte Theirreichs., vol. VIII, p. 77, 1787.

*De Villers, Ent. Linnaei, vol. II, p. 144, 1789.

Bombyx dispar, Vieweg, Tab. Verzeichniss, vol. I, p. 54, 1789.

Bombyx dispar, Lodi, Opuscol. scelt., vol. XII, p. 183, 1789.

Bombyx Dispar, Borkh., Eur. Schm., vol. Ill, p. 312, No. 118, 1790.
Bombyx disparate, Oliv. Ency. Meth., vol. Ill, p. -59, 1790.

Rossi, Fauna Etrusca, vol. II, p. 170, 1790.

Phalaena Bombyx Dispar, Preyssler, Verz. bomischer Insecten, p. 41,
1790.

Sepp, Nederlandische Insecten, vol. Ill, p. 5, pi. 2, 3, 1791 (?).

Phalaena Bombyx Dispar, Schwarz, Raupenkalender, pp. 60, 224, 377, 1791.
Phalaena Bombyx dispar, Brahm, Ins. Ival. II, p. 517, No. 378; p. 739, No.
24, 1791.

*Hennert, Raupenfrass und Windbruch, 1791.

Bombyx dispar, Borkh., Rhein. Mag., vol. I, p. 334, 1791-94.

Bombyx dispar, Fab., Ent. Syst., vol. Ill, part I, p. 437, 1793.

Phalaena Bombyx Dispar, Pezolds, Mitteldie uns SchikL, etc., vol. II, fig.
8, 1794.

Bombyx dispar, Panzer, Fauna Germ., vol. II, pp. 22, 23, 1794.

Phalaena Dispar, Berk., Synop. Nat. Hist., Gr. Brit, and Ire., vol. I, p. 136,
1795.

BIBLIOGRAPHY.

259

Phalaena Dispar, Don., Nat. Hist. Br. Ins., vol. V, p. 67, pi. 163 (Gipsey
Moth). 1796.

Bombyx Dispar, Hub., Sarninl. Bomb., p. 121, pi. 19, figs. 75 male, 76
female, 1800 (?).

Bombyx Dispar, Illiger’s edition, Wien Verz., vol. I, p. 75, 1801.

Laria dispar, Schrank, Faun. Boica, vol. II, part 1, p. 256; part 2, p. 151,
1801-02.

var. (?) a, Bombyx disparina, von Mueller, Fauna Silesiaca, part III, vol.
I, 1802.

♦Phalaena Bombyx dispar, Stewart, Elements of Nat. Hist., vol. II, p. 160,
1802.

Bombyx disparus, Haworth, Lep. Brit., p. 88, 1803.

Phalaena dispar, Blumenbach, Manuel d’Histoire Nat., vol. I, p. 465, 1803.

Stammphalane, Goeze, Naturgeschichte der Europais., vol. IX, p. 569,
1803.

Phalaena Bombyx Dispar, Bechstein, Forstinseckten, p. 369, pi. 6, fig. 1,
a-e, 1804.

Bombyx dispar, Panzer, Syst. Nomen., p. 40, 1804.

Bombyx dispar, Latreille, Hist. Nat. des Crust, et Ins., vol. XIV, p. 185,
1805.

Bombyx Dispar, Linn., Syst. Nat., Turton edition, vol. Ill, p. 207, 1806.

Bombyx Dispar, Hub., Ges. Europ. Schm., pi. 37, fig. 2, a, b, c, 1806-18.

Liparis Dispar, Ochs., Schm. Eur., vol. Ill, p. 195, 1810.

Phalaena Dispar, Blumenbach, Abbild. Nat. Hist. Gegenstand, p. 370, 1810.

Bombyx disparate, Latreille, Crustaces, Arach. et Ins., pi. 8, fig. 2, 1810.

Laria Dispar, Leach, New Edinburgh Ency., Article Entomology, p. 721,
1815.

Phalaena Dispar, Salisbury, Hints to Propr. of Orchards, p. 67, pi. 1, figs.
10, 11, 1816.

Sericaria dispar, Latreille, Le Regne Animal, vol. II, p. 269 ; Atlas, pi. 152,
1817.

Bombyx disparate, Latreille, Le Regne Animal, vol. Ill, p. 568, 1817.

Liparis Dispar, Zincken, Germar’s Mag. der Ent. , vol. Ill, p. 431, 1818.

Liparis dispar, Samouelle, Ent. Com., p. 246 (Gipsey Moth), 1819.

Liparis Dispar, Godart, Hist. Nat., vol. IV, p. 256, pi. 25, figs. 1, 2, 1822.

Porthetria Dispar, Hub., Verz. bek. Schmett., p. 160, 1822 (?).

Bombyce disparate, Dumeril, Considerat. General., pi. 45, fig. 3, 1823.

♦Laria dispar, Meig., Handb. fur Schm., p. 122, pi. 47, 1827.

Hypogymna dispar, Daudville, Ann. Soc. d’Hort. Paris, vol. Ill, p. 98,
1828.

Hypogymna dispar, Daudville, Ann. Soc. d’Hort. Paris, vol. V, pp. 204,
324, 1829.

Bombyx dispar, J. M., Gardener’s Mag., vol. V, p. 204, 1829.

Hypogymna dispar, Steph., Ill. Br. Ent. Haust., vol. II, p. 56, 1829.

♦Liparis dispar, Ivlug., Verhandl. deGesell, Naturf. Freunde, pp. 363, 369,
pi. 1, fig. 20, 1829.

Hypogymna dispar, Steph., Cat. Ins. Haust., p. 50, 1829.

Hypogymna dispar, Rennie, Libr. ofEntert. Ivnowl., vol. II, pp. 79-82,1830.

Sericaria dispar, Latreille, Animal Kingdom, vol. IV, p. 201, 1831.

Liparis dispar, Bdv., Coll. Icon, et Hist, des Chenilles d’Eur., pi. IX, figs.
3, 4, 1832.

260

THE GYPSY MOTH.

Bombyx dispar, Brown, Book of Butterflies, vol. I, p. 52, 1832.

* Liparis dispar, Dup. et Guen., Icon, de l’Hist. Nat. Chenilles, vol. II, pi.
8, figs. 2-6, 1832.

Liparis dispar, Godart, Icon, des Chenilles, les Bombycites, pi. 8, 1832.
*Hypogymna dispar, Rennie, Conspectus of Butterflies and Moths, p. 39,
1832.

Phalaena Bombyx dispar, Anon., Ann. de l’lnst. Hort. Fromont, vol. Y,
p. 311, 1833.

Liparis dispar, Silb., Revue Entomologique, ser. I, vol. I, p. 80, 1833.
Liparis Dispar, Bouch6, Nat. Gesch. der Ins., Lieberung I, p. 106, 1834.
Liparis dispar, Burm., Manual of Entomology, p. 313, 1836.

Hypogymna dispar, Duncan, Naturalist’s Library, vol. IV, p. 206, 1836.
Liparis dispar, Lacordaire, Manual of Entomology, p. 312, 1836.

Bombyx dispar, Sepp, title-page, vol. V, aberr. male, 1836.

Liparis dispar, De Selys, Cat. Lep. de la Belg., p. 28, 1837.

Liparis dispar, Krause, Arbeit. Schles. Gesell. f. vaterl. Kultur, p. 110, 1837.
Liparis dispar, Boie, Naturhistorisk Tidskrift, vol. I, p. 522, 1837.

Liparis dispar, Audouin, Naturhistorisk Tidskrift, vol. II, p. 304, 1838.
Liparis dispar, Lacordaire, Intro, a l’Entomologie, vol. II, pp. 371, 383,

1838.

*Bombyce disparate, Debia, Rec. Agr. Soc. Dept., p. 156, pi. 1, 1838.
Hypogymna dispar, Curt., Br. Ent., vol. XVI, p. 767 (Gypsy Moth), 1839.
Bombyce disparate, Lamarck, Animaux sans Vei’tebres, vol. Ill, p. 77,

1839.

Bombyx dispar, Dejean, Ann. Soc. Ent. France, vol. VIII, p. 41, 1839.
Bombyx dispar, Reichenbacka, Galerya, Obr. Zvvier. Hist. Nat., vol. II,
p. 302, 1839.

Bombyx (Liparis) dispar, Nordl., Stett. Ent. Zeit.,vol. I, p. 266, 1840.
Bombyx (Liparis) dispar, Kollar, Inj. Ins., English ed., p. 26, 1840.
Phalaena Bombyx dispar, Ratz., Forst. Ins., vol. II, p. Ill, pi. 5, figs.
IF, IF', IK, 1L, 1C, 1840.

Liparis dispar, Schultze, Stett. Ent. Zeit., vol. I, p. 49, 1840.

Hypogymna dispar, Westw., Int. to Modern Classif. Ins., p. 384, 1840.
Bombyx dispar, Fonscol., Mem. de 1’Acad. de Sci. Agr. Arts, etc., vol. V,
p. 85, 1840.

Liparis Dispar, Hering, Stett. Ent. Zeit., vol. Ill, p. 9, 1842.

Liparis dispar, Joly, Revue Zoologie, vol. V, p. 115, 1842.

Porthetria dispar, Humphrey and Westw., Br. Moths and their Transf.,
vol. I, p. 17, figs. 1-3, 1843.

Liparis Dispar, Duponchel, Cat. Methodique, p. 68, 1844.

Liparis Dispar, Eversmanu, Fauna Lep. Volgo-Ural, p. 142, 1844.

Liparis Dispar, Ilerrich-Schaefler, Eur. Schm., vol. II, p. 135, 1845.
Liparis dispar, Villa, Memoria deg Insetti carnivori, p. 59, 1845.

Liparis dispar, Ratz., Stett. Ent. Zeit., vol. VII, p. 37, 1846.

Liparis dispar, Bellier, Ann. Soc. Ent. France, vol. XVI, p. 98, 1847.
Bombyx dispar, Johnson, Diet, of Modern Gardening, p. 92, 1847.
Bombyx dispar, Nordl., Stett. Ent. Zeit., vol. IX, p. 266, 1848.

Liparis dispar, Bellier, Bull. Soc. Ent. France, ser. II, vol. VII, p. 173,
pi. 6, 1849.

Liparis dispar, Guen., Hist. Nat. Nocturnes, vol. II, pi. 8, fig. 2, a, b, 1849.
Liparis dispar, Bellier, Bull. Soc. Ent. France, ser. II, vol. X, p. 73, 1852.
Liparis dispar, Filippi, Stett. Ent. Zeit., vol. XIII, p. 263, 1852.

BIBLIOGRAPHY.

261

Liparis Dispar, Speyer, Stett. Ent. Zeit., vol. XIII, p. 318, 1852.
Lymantria dispar, Walk., Cat. Lep. Het., part IV, p. 872, 1855.

Borabyx dispar, Sepp, title-page, vol. VIII, aberr. male, 1855-60.

Liparis dispar, DeSelys (?), Ann. Soc. Ent. Belg., vol. I, p. 52, 1857.
Hypogymna dispar, Stainton, Manual, vol. I, p. 130, 1857.

Hypogymna Dispar, Humphrey, Gen. Br. Moths, p. 27, pi. 10, figs. 1-10,
1858.

Ocneria dispar, Speyer, Die Geograph. Verbreit. Schm., part I, p. 401,
1858.

Hypogymna Dispar, Ivearley, Ent. Weekly Intelligencer, vol. IV, p. 192,
1858.

Rosenspinner, Hermann, Der Raupen und Schmetterlingsjager, p. 81, 1859.
Liparis dispar, Hagen, Stett. Ent. Zeit., vol. XXI, p. 34, 1860.

Liparis dispar, Leunis, Zoologie, p. 543, 1860.

Hypogymna dispar, Batty, Ent. Weekly Intelligencer, vol. VIII, p. 141,
1860.

Hypogymna dispar, Stanley, Ent. Weekly Intelligencer, vol. VIII, p. 187,
1860.

Schwammspinner, Pueschl., Kurzgefasste Forst. Ency., Leipzic, pp. 186,
298, 1860.

Liparis dispar, Mulder, Tijdschrift voor Ent., ser. I, vol. II, p. 2, 1860.
Liparis dispar, Goreau, Ins. Nuis. aux Arbres Fruitiers, p. 89, 1861.
Liparis dispar, Hagen, Stett. Ent. Zeit., vol. XXII, p. 59, 1861.

Liparis Dispar, Ratlike, Stett. Ent. Zeit., vol. XXII, p. 238, 1861.

Bombyx dispar, Siebold, Stett. Ent. Zeit., vol. XXII, p. 443, 1861.

Liparis dispar, Ddbner, Zool., vol. II, p. 345, 1862.

Ocneria dispar, Speyer, Die Geog. Verbreit. Schm., part II, p. 287, Nach-
trage, 1862.

Liparis dispar, Keller, Stett. Ent. Zeit., vol. XXIII, p. 284, 1862.

Liparis dispar, Prittw., Stett. Ent. Zeit., vol. XXIII, p. 382, 1862.

Liparis dispar, Newm., Proc. Ent. Soc. Lond., pp. 70, 77, 1862.

Ocneria dispar, Jaggi, Bull. Soc. Ent. Suisse, vol. I, p. 313, 1862-65.
Liparis dispar, Bremer, Lepidopteren Ost-Siberiens, p. 41, 1864.

Liparis dispar, Bdv., Journ. Soc. Hort. France, p. 447, 1864.

Sericaria dispar, Mulder, Tijdschrift voor Ent., ser. I, vol. VII, p. 125,

1864.

Liparis dispar, Keppen, Horae Soc. Ent. Rossicae, pp. 81, 257, 287, 294,

1865.

Ocneria dispar, Tieffenbach, Berl. Ent. Zeit., vol. IX, p. 413, pi. 3, fig. 8,

1865.

Bombyx dispar, Samuels, Agriculture of Mass., p. 116, 1865-66.

Bombyx dispar, Ratz., Die Waldverderbniss, vol. I, pp. 113, 226, 1866.
Ocneria dispar, Maurissen, Tijdschrift voor Ent., ser. II, vol. IX, p. 176,

1866.

Liparis dispar, Brehm and Rossmassler, Die Thiere des Walden, vrol. II,
p. 107, fig. 11; p. 108, figs, a-cl, 1866-67.

Ocneria dispar, Pfutzner, Berl. Ent. Zeit., vol. XI, p. 199, 1867.

Liparis dispar, Westwood, Proc. Ent. Soc. Lond., pp. 44, 49, 1867.
Ocneria dispar, de Gavere, Tijdschrift voor Ent., ser. II, vol. X, p. 200,

1867.

Bombyx dispar, Rudzky, Horae Soc. Ent. Rossicae, vol. V, p. 12, 1867.
♦Ocneria Dispar, var. Disparina, Snell., Vlind. Nederl. Macro., p. 175, 1867.

262

THE GYPSY MOTH.

Liparis dispar, Bdv., Essai sur l’Entomologie Horticole, 1867.

Bombyx dispar, Ratz., Die Waldverderbniss, vol. II, pp. 12-151, etc.,

1868.

Bombyx dispar, Berce, Bull. Ent. Soc. France, ser. Ill, vol. VIII, p. 61,
1868.

Liparis dispar, Dorfmeister, Stett. Ent. Zeit., vol. XXIX, p. 183, 1868.
Liparis dispar, Charault, Bull. Soc. Agr. Sci. Arts, vol. XI, pp. 688, 697,
1868.

Bombyx dispar, Senft, Systematische Bestimm. Deutsch., p. 77, pi. 1, 2,
3, 5, 1868.

Liparis dispar, Girard, Bull. Soc. Ent. France, ser. Ill, vol. IX, p. 69,

1869.

Liparis dispar, Bull, della Soc. Ent. Italiana, vol. I, p. 69, 1869.

Bombyx dispar, Bull, della Soc. Ent. Italiana, vol. I, pp. 78-81, 1869.
Liparis dispar, Charault, Bull. Soc. Agr. Sci. Arts of Sarthe, vol. XII,
p. 316, 1869.

Liparis Dispar, Ivieferstein, Stett. Ent. Zeit., vol. XXX, p. 229, 1869.
Ocneria dispar, Speyer, Stett. Ent Zeit., vol. XXX, p. 246, 1869.

Phalaena Bombyx dispar, Ratz., Die Waldverderber, p. 184, pi. 5, flg. 1,

1869.

Liparis dispar, Newm., British Moths, p. 37, 1869.

Ocneria dispar, Jaggi, Bull. Soc. Eut. Suisse, vol. Ill, p. 100, 1869-70.
Hypogymna dispar, Riley, Annual Rep. Missouri, vol. II, p. 10, 1870.
Hypogymna dispar, Riley, Am. Ent., vol. II, p. Ill, 1870.

Liparis dispar, Bargagli, Bull, della Soc. Ent. Italiana, vol. II, pp. 208,
262, 279, 1870. •

Bombyx dispar, Bazin, Bull. Soc. Hist, de l’Yonne, ser. I, vol. XXIV, pp.
11-20, 1870.

Ocneria dispar, Tratman, The Ent., vol. V, p. 172, 1870.

Ocneria dispar, Spiller, The Eut., vol. V, p. 183, 1870.

Ocneria dispar, Davidsou, The Eut., vol. V, p. 213, 1870.

Ocneria dispar, Button, The Ent., vol. V, p. 393, 1870.

Ocneria dispar, Bowyer, The Ent., vol. V, p. 452, 1870.

Ocneria dispar, Hylaerts, Tijdschrift voor Ent., ser. II, vol. XIII, p. 148,

1870.

Ocneria Dispar, Kirby, Cassell’s Eur. But. and Moths, p. 110, pi. 25, figs.
a-c, 1870 (?).

Liparis dispar, Briggs, Proc. Ent. Soc. Lond., p. 9, 1871.

Liparis dispar, Dohrn, Stett. Ent. Zeit., vol. XXXII, p. 29, 1871.

Liparis dispar, Dei, Bull, della Soc. Ent. Italiana, vol. Ill, pp. 75, 360,

1871.

Ocneria dispar, Hylaerts, Tijdschrift voor Ent., ser. II, vol. XIV, p. 38,

1871.

Bombyx dispar, Siebold, Bull, della Soc. Ent. Italiana, vol. IV, p. 121,

1872.

Liparis dispar, Plateau, Bull, della Soc. Ent. Italiana, vol. IV, p. 197, 1872.
Liparis dispar, Vinercati, Bull, della Soc. Ent. Italiana, vol. IV, p. 302,
1872.

Liparis dispar, Ghiliani, Bull, della Soc. Ent. Italiana, vol. IV, p. 365,
1872.

Liparis dispar, Lelievre, Feuilles des Jeunes Naturalistes, vol. Ill, p. 77,
1872.

BIBLIOGRAPHY.

2G3

Ocneria dispar, Hagen, Stett. Ent. Zeit., vol. XXXIII, p. 389, 1872.
Ocneria dispar, Nickerl., Verb. z. B. Wien., vol. XXII, p. 729, 1872.
Pbalaena Bombyx dispar, Kauschinger, Die Lehre vora Walds., p. 65, fig.
13, 1872.

Liparis dispar, Greville, The Ent., vol. VI, p. 190, 1872.

Liparis dispar, Clifford, The Ent., vol. VI, p. 289, 1872.

Liparis dispar, Standish, The Ent., vol. VI, p. 364, 1872.

Psilura dispar, Frey and Wullsch., Bull. Ent. Soc. Suisse, vol. IV, p. 258,
1873-76.

Ocneria dispar, Rigg.-Stehlin, Bull. Ent. Soc. Suisse, vol. IV, p. 597,
1873-76.

Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. V, p. 164, 1873,
Ocneria dispar, Dihrik, Stett. Ent. Zeit., vol. XXXIV, p. 114, 1873.

Liparis dispar, Kaltenbach, Die Pflanzenfeinde, pp. 74, 158, 185,205, 217,
429, 1874.

Ocneria dispar, Kaltenbach, Die Pflanzenfeinde, pp. 537, 548, 569, 594,
613, 626, 634, 640, 651, 1874.

♦Liparis dispar, Barrett, Trans. Norwich Soc., suppl., p. 14, 1874.

Liparis dispar, Plateau, Recherches sur Digestion, etc., p. 84, 1874.
Bombyx (Liparis) dispar, Tasch., Ent. f. Giirt. und Garten, p. 219, figs.
58-61, 1874.

Liparis dispar, Targ. Tozz., Bull, della Soc. Ent. Italiana, vol. VI, p. 86,

1874.

Liparis dispar, Dubois, Lep. de Belgique, vol. II, p. 170, 1874.

Ocneria dispar, Lelievre, Feuilles des Jeunes Naturalistes, vol. V, pp.
97-100, 1874.

Liparis dispar, Girard, Bull. Soc. Ent. France, suppl., vol. IV, p. 129, 1874.
Liparis dispar, Girard, Bull. Soc. Ent. France, suppl., vol. V, p. 114, 1875.
Liparis dispar, Gaschet, Bull. Ent. Soc. France,. ser. V, vol. V, p. ccxiii,

1875.

Chenilles it oreilles, Ernst, Pap. de l’Europe, vol. IV, p. 106, pi. 138, 1875.
Liparis dispar, Villa, Lo. Studio Insetti in Lombardia, 1876.

Bombyx dispar, Blanchere, Rav. des For. et Arbres d’ Align., pp. 178, 853,
figs. 92, 93, 153, 154, 155, 156, 1876.

Ocneria dispar, Weithofer, Verh. ver Briinn., vol. XV, p. 39, 1876.

Liparis dispar, var. b, bordigalensis or disparoides, Mab. and Gascli., Bull.

et Ann. Soc. Ent. France, ser. V, vol. VI, pp. 9, 521, 1876.

Liparis dispar, Mabille, Bull. Soc. Ent. France, suppl., vol. VI, p. 9, 1876.
Ocneria dispar, Bettoni, Considerazioni sopra casa, etc., p. 121, 1876.
Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. VIII, p. 129,

1876.

Liparis dispar, Brehm, Thierleben, vol. IX, p. 15, 1877.

♦Bombyx dispar, Bouche, Schwammraupe, Schwammspinner, vol. IV, p.
410, 1877.

Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. IX, p. 55, 1877.
Liparis dispar, Depuisset, Les Paps., p. 248, pi. 24, fig. 2, a-c, 1877.
Ocneria dispar, Christoph., Stett. Ent. Zeit., vol. XXXIX, p. 408, 1878.
Ocneria Dispar, Cassel, Die Makrolep. der Amgegend Cassels, p. 113, 1878.
Ocneria dispar, Brants, Tijd. Ent., vol. V, p. 22, 1878.

Liparis dispar, Locard, Soc. Agr. Sci. and Arts of Lyons, 1878.

Ocneria dispar, Enock, The Ent., vol. XI, p. 170, 1878.

Ocneria dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. X, p. 22, 1878.

264

THE GYPSY MOTH.

Ocneria dispar, Turati, Bull, della Soc. Ent. Italiana, vol. XI, p. 171, 1879.
♦Dickkopfspinner, Horamerliug, Isis, Russ., vol. IV, p. 86, 1879.

♦Liparis dispar, Szalkay, Termeszet, Fuzetek, vol. IV, p. 105, 1879.

Liparis dispar, Pearce, The Ent., vol. XII, p. 229, 1879.

Bombyx dispar, Altum, Forstzoologie, vol. II, p. 321, 1880.

Psilura Dispar, Freyer, Lep. der Schweiz., p. 91, 1880.

♦Liparis dispar, Slosarski, Der Polnische Gartner, vol. II, pp. 69-92, 1880.
Liparis dispar, Wilson, Larvae of the Brit. Lep., p. 68, pi. 12, fig. 8, 1880.
Ocneria dispar, Fiori, Bull, della Soc. Ent. Italiana, vol. XII, p. 211, 1880.
Ocneria dispar, Maassen, Stett. Ent. Zeit., vol. XLI, p. 168, 1880.

Ocneria dispax% Heriug, Stett. Ent. Zeit., vol. XLII, p. 331, 1881.

Ocneiia dispar, Staudinger, Stett. Ent. Zeit., vol. XLII, p. 106, 1881.
Bombyx (Liparis) dispar, Schm-Gobel, Die Schiidlichen Foi-stinseckten,
part I, p. 99, fig. 95, 1881.

Bombyx (Liparis) dispar, Schm-Gobel, Die Schiidlichen Foi’stinseckten,
part II, p. 96, 1881.

Bombyx dispar, Altum, Forstzoologie, vol. II, p. 321, 1881.

Liparis dispar, Goossens, Bull. Ent. Soc. Finance, vol. I, p. 232, 1881.
Liparis dispar, Lucas, Bull. Ent. Soc. France, vol. I, p. 118, 18S1.

Lipai’is dispar, Girai'd, Bull. Ent. Soc. Fx-ance, vol. II, 1882.

Ocneria dispar, Gauckler, Katter’s Ent. Naclitrichten, vol. VIII, p. 271,
1882.

Liparis dispar, Altum, Forstzoologie, vol. Ill, p. 91, 1882.

Ocneria dispar, Teich., Stett. Ent. Zeit., vol. XLIV, p. 171, 1883.

Ocneria dispar, Keppen, Injurious Insects, vol. Ill, p. 19, 1883.

Ocneria dispar, Mina, Natui’alista Sicil. Giorna. Sci. Nat., vol. Ill, p. 51,
1883.

Ocneria dispar, Oudemans, Tijd. Ent., vol. XXVII, p. 16, 1881.

Ocneria Dispar, Ilomeyer, Stett. Ent. Zeit., vol. XLV, p. 121, 1881.
Ocneria dispar, Tasch., Bi’ehm’s Thierlebeu, Inseckten, p. 395, figs. 1-3,
1881.

♦Ocneria dispar, Kalchberg, Naturalista Sicil. Giorna. Sci. Nat., vol. IV,
p. 55, 1881-85.

Hypogymna dispar, Wood, Animated Creation, vol. Ill, p. 423, 1885.
Ocnei’ia dispar, Bull, della Soc. Ent. Italiana, vol. XVII, p. 156, 1885.
Ocneria dispar, Raynor, The Ent., vol. XVIII, p. 213, 1885.

Ocneria dispar, St. John, The Ent., vol. XIX, p. 250, 1886.

Ocneria dispar, Adkin, The Ent., vol. XIX, p. 281, 1886.

Ocneria dispar, Blaber, The Ent., vol. XIX, p. 281, 1886.

Ocneria dispar, Hall, The Ent., vol. XIX, p. 282, 1886.

Ocneria dispar, Buckler, Lai'vae of Brit. Butterflies, vol. Ill, p. 37, 1886.
Liparis dispar, Brocchi, Traite de Zoologie Agricole, p. 151, 1886.

Ocneria dispar, ab. semiobscura, Thierry, Le Naturalist, vol. VIII, p. 237,
1886.

Ocneria dispar, ab. erebus, Thierry, Le Naturalist, vol. VIII, p. 237, 1886.
Ocneria dispar, ab. semiobscui-a, Meig., Le Naturalist, vol. VIII, p. 237,
1886.

Ocneria dispar, ab. erebus, Meig., Le Naturalist, vol. VIII, p. 237, 1886.
♦The Gypsy Moth, Dictionary of Gardening (Insects), vol. II, p. 182, 1887.
Ocneria dispar, Edwards, The Ent., vol. XX, p. 275, 1887.

Liparis dispar, Goossens, Bull. Ent. Soc. France, ser. VI, vol. VII, p. 166,
1887.

BIBLIOGRAPHY.

265

Liparis dispar, Bellier, Bull. Ent. Soc. Erauce, ser. VI, vol. VII, p. 182,
1887.

Ocneria (Liparis) dispar, Hess, Der Forstsclmtz., ed. II, vol. II, pp. 70-75,
lig. 53, a-d, 1887.

Ocneria dispar, Theile, Berl. Ent. Zeit., vol. XXXI, p. 23, 1887.

Ocneria dispar, Mina, Naturalista Sieil. Giorn. Sci. Nat., vol. VII, p. 225,

1887- 88.

Ocneria Dispar, Graeser, Berl. Ent. Zeit., vol. XXXII, p. 125, 1888.
Ocneria Dispar, Ziegler, Berl. Ent. Zeit., vol. XXXII, p. 23, 1888.

♦Liparis dispar, Oliv , Rev. Sci. Bourb., vol. I, p. 210, 1888.

Ocneria dispar, Bock, Ent. Nachr., vol. XIV, p. 56, 1888.

Ocneria dispar, Jackson, The Ent., vol. XXI, pp. 235, 322, 1888.

Ocneria dispar, Walk., Ent. Mon. Mag., vol. XXV, p. 65, 1888.

Lymantria dispar, Leech, Proc. Zool. Soc. Loud., vol. LVI, pp. 30, 63,

1S88.

Liparis dispar, Platner, Biol. Centralbl., vol. V, p. 521, 1888.
♦Schwammspinner, Ivatzer, Zum Frasse des Schwammsp. in Kroatien,

1888- 89.

-Bomb3rx (Liparis) dispar, Fiirst, Ivaucliinger’s Lehre von Walds., ed. 4,
pp. 140, 141, pi. 3, 1889.

Liparis (Ocneria) dispar, Targ. Tozz., Bull, della Soc. Ent. Ital., vol.
XXI, pp. 113, 272, 1889.

Ocneria dispar, Cune, Act. Soc. Esp., vol. XVIII, p. 77, 1889.

Ocneria dispar, Berge, Schmett., p. 63, pi. 26, fig. 2, a-c, 1889.

Ocneria dispar, Porcliinsky, Ins. Inj. to Fruit Gardens, Crimea, pp. 14-20,
1889.

Liparis dispar, Tunley, The Ent., vol. XXII, p. 259, 1889.

Ocneria dispar, Hall, The Ent., vol. XXII, p. 161, 1889.

Ocneria dispar, St. John, The Ent., vol. XXII, p. 162, 1889.

Ocneria dispar, Arkle, The Ent., vol. XXII, p. 186, 1889.

Ocneria dispar, Fernald, Mass. Hatch Exp. Station, Special Bulletin, 1889.
Hypogvmna dispar, Buck, Larvae Brit. Moths, pi. 37, figs. 6, 6a, 1889.
Ocneria dispar, Howard, Proc. Ent. Soc. Wash., vol. I, p. 264, 1889.
Ocneria dispar, Dei, Bull, della Soc. Ent. Ital., vol. XXII, p. 276, 1890.
Ocneria dispar, Wingelmuller, Mem. III. Garten Zeitung, p. 269, 1890.
Liparis Dispar, Raspail, Bull. Soc. Zool. France, vol. XV, p. 94, 1890.
Liparis dispar, Montillot, Amateur d’lnsectes, p. 252, 1890.

The Gypsy Moth, Rep. Mass. Bd. Agr., p. 58, 1890.

Ocneria dispar, Ent. Record, vol. I, p. 225, 1890.

Ocneria dispar, Ent. Record, vol. II, p. 24, 1890.

Ocneria dispar, Pack., Rep. U. S. Ent. Com., vol. V., p. 138, 1890.

The Gypsy Moth, Sargent, Garden and Forest, vol. Ill, p. 150, 1890.
Gypsy Moth, Jack, Garden and Forest, vol. Ill, pp. 273, 277, 1890.
Ocneria dispar, Riley and Howard, Ins. Life, vol. II, pp. 86, 208, 262, 1890.
Ocneria dispar, Riley and Howard, Ins. Life, vol. IIT, pp. 41, 78, 126, 1890.
Ocneria dispar, Riley and Howard, Ins. Life, vol. Ill, pp. 200, 297, 364,
368, 381, 472, 474, 491, 1891.

Ocneria dispar, Lintn., Rep. Ins. N. Y., vol. VII, pp. 302, 304, 335, 357,
1891.

Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 289, 1891.
Ocneria dispar, Butler, Ins. Life, vol. Ill, p. 277, 1891.

Ocneria dispar, Weir, Ins. Life, vol. IV, p. 138, 1891.

266

THE GYPSY MOTH.

Tlie Gypsy Moth, Jack, Garden and Forest, vol. IV, p. Ill, 1891.

The Gypsy Moth, Fernow, Garden and Forest, vol. IV, p. 142, 1891.

The Gypsy Moth, Smith, Garden and Forest, vol. IV, p. 153, 1891.
Bombyx (Liparis) dispar, Demaison, Bull. Eut. Soc. France, vol. LX, p.
14, 1891.

Liparis dispar, Bezzi, Bull, della Soc. Eut. Ital., vol. XXXIII, p. 74,

1891.

Ocneria dispar, de Muro, Bull, della Soc. Ent. Ital., vol. XXXIII, p. 328,

1891.

Ocneria dispar, Ent. Record, vol. Ill, pp. 53, 183, 1891.

Ocneria dispar, Fernald, Mass. Hatch Exp. Sta., Bull. 19, p. 109, 1892.
Ocneria dispar, Fernald, Can. Ent. vol. XXIV, p. 87, 1892.

Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 259, 1892.
Ocneria dispar, Henshaw, U. S. Dept. Agr., Bull. 26, p. 75, 1892.

The Gypsy Moth, Jack, Garden and Forest, vol. V, p. 75, 1892.

The Gypsy Moth, S., Garden and Forest, vol. V, p. 81, 1892.

The Gypsy Moth, Nutter, Garden and Forest, vol. V, p. 119, 1892.

Ocneria dispar, Riley and Howard, Ins. Life, vol. IV, pp. 227, 356, 1892.
Ocneria dispar, Riley and Howard, Ins. Life, vol. V, pp. 54, 194, 1892.
Ocneria dispar, Hertwig, Text Book of Embryology, translated by Mark,
p. 34, 1892.

Ocneria dispar, Bethune, Rep. Ent. Soc. Out., vol. XXIII, p. 86, 1892.
Gypsy Moth, Beddard, Animal Coloration, p. 272, fig. 36, 1892.

Ocneria dispar, Ent. Record, vol. Ill, pp. 699, 869, 1892.

Ocneria dispar, Ent. Record, vol. IV, p. 204, 1892.

Porthetria Dispar, Kirby, Cat. Lep. Het., vol. I, p. 475, 1892.

Ocneria dispar, de Carlini, Bull, della Soc. Ent, Ital., vol. XXIV, p. 86,

1892.

Ocneria dispar, South, The Ent., vol. XXV, p. 259, 1892.

Ocneria dispar, Hodkinson, The Ent., vol. XXyi, p. 20, 1893.

Ocneria Dispar, tfofman, Die Raupen der Gross-Scljmett. , p. 57, pi. 16,
fig. 13, 1893.

Ocneria dispar, Eckstein, Die Kiefer, vol. I, p. 22, pi. 13, figs. 4-9, 1893.
Bombyx (Liparis) dispar, Fiirst and Nisbet, Prot. of Woodlands, Eng. ed.,
pp. 126, 207, pi. 3, fig. 19, 1893. . A

Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 263, 1893.
Ocneria dispar, Lintn., Rep. Ins. N. Y., vol. IX, pp. 422, 433, 440, 1893.
Liparis dispar, Judeich and Nitsche, Lehrbuck der Mit.-Europ. Forstin-
seckt., vol. Ill, 1893. - ^

Ocneria dispar, Seitz, Stett. Ent. Zeit., vol. LIV, p. 369, 1893.

Ocneria dispar, Riley and Howard, Ins. Life, vol. VI, pp. 53, 235, 338,

1893.

Ocneria dispar, Skinner, Ent. News, vol. IV, p. 158, 1893.

Porthetria dispar, Dyar, Proc. Bos. Soc. Nat. Hist., vol. XXVI, p. 155,
1893.

Ocneria dispar, Weed, Am. Nat., vol. XXVII, p. 750, 1893.

Ocneria dispar, Kingsley, Am. Nat., vol. XXVII, p. 1070, 1893.

Ocneria dispar, Nicholson, Ent. Record, vol. V, pp. 236, 310, 1893.
Ocneria dispar, Weed, N. H. Coll. Ag. Exp. Sta., Bull. 23, p. 30, 1894.
Hypogymna dispar, Barrett, Lep. Brit. Islands, part XX, p. 303, 1894.
Ocneria dispar, Furneaux, Butterflies and Moths, p. 227, 1894.

Ocneria dispar, Kulagin, Ins. Inj. to Gard. and Orchards in Russia, 1894.

DISTRIBUTION IN THE OLD WORLD. "267

Oeneria dispar, Rudzky, Ins. Useful and Inj. to Fruit Trees, pp. 9-13,

1894.

Oeneria dispar, Kane, The Ent., vol. XXVII, p. 15, 1894.

Oeneria dispar, South, The Ent., vol. XXVII, p. 25, 1894. £

Oeneria dispar, Turner, The Ent., vol. XXVII, p. 153, 1894.

Oeneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., 1894.

The Gypsy Moth, Ent. Record, vol. VI, p. 314, 1895.

The Gypsy Moth, Ent. Record, vol. VII, p. 146, 1895.

Oeneria dispar, Mocsary, Termeszet. Fuzetek, vol. XVIII, pp. 67, 72,

1895.

Portlietria dispar, Comstock, Manual for the Study of Insects, p. 312, flg.

378, 1895. *

Oeneria dispar, Fletcher, Rep. Ent. Soc. Ont., vol. XXV, p. 67, 1895.

The Gypsy Moth, Fletcher, Trans. Royal Soc. Can., vol. I, p. 14, 1895.
Oeneria dispar, Meyrick, Handbook of British Lepidoptera, p. 175, 1895.

Distribution in Other Countries.

>

The gypsy moth has a wide distribution in the old world.
Speyer, in “ Die Geographische Verbreitung der Schmetter-
linge,” published in 1858-62, Vol. I, page 401, and Vol. II,
page 287, informs us that it extends over the entire region,
from the lowlands to the highlands, through middle and
southern Europe, western Asia and northern Africa, reach¬
ing from Stockholm on the north to Algiers on the south,
England on the west, the Altai Mountains and the Caspian
Sea on the east. It extends also into eastern Asia, including
Japan ; and the tropics, Neitner having found it in Ceylon.

Bremer, in his “ Lepidopteren Ost-Siberiens,” published
in 1864, reported it in south-eastern Siberia. Staudinger,
in his “Catalog der Europieischen Faunengebiets,” published
in 1871, gives for the distribution of the gypsy moth the
entire territory, except the northern countries, including
southern Sweden and England. He also doubtfully includes
Livonia. Gra?ser states that the young caterpillars of this
species were very common in the early part of June, 1881,
near Vladivostock, Siberia. He further states that the qater-
pillars in Amoor have a very different appearance from those
in Europe, the prevailing color being yellow ; but all the
moths bred from these caterpillars were entirely like those
of Europe, “Berlin Ent. Zeits.,” Vol. XXXII. In 1861,
Homeyer reported the gypsy moth on the Island of Majorca
in great abundance, destroying both deciduous and evergreen
trees. In the “Entomologist’s Monthly Magazine,” Vol.

268

THE GYPSY MOTH.

XXY, page 65, 1888, Mr. J. J. Walker reported that he
found this insect in great abundance in southern Spain, near
the village of Los Barrios. In a work on ‘‘Injurious In¬
sects,” by Theodore Keppen, published in Russian and trans¬
lated for me by Dr. F. B. Stephenson, U. S. X., it is stated
that this insect occurs in the central and southern parts of
Russia, in the Caucasus and all southern Siberia, but it does
not occur in the vicinity of St. Petersburg. He further states
that, according to Xolken, it does not appear in the Baltic
Provinces, but has been found occasionally in Livonia, and,
on the authority of Albrecht, it is very common in the
vicinity of Moscow. Romanoff, in the sixth volume of his
“ Memoires sur les Lepidopteres,” reports it in North China,
and I have in my collection three male gypsy moths from
Pekin, China, received from Dr. O. Staudinger. In a letter
from Dr. Ritzema-Boz of Holland, dated Sept. 3, 1895, he
writes, “This insect is common in Holland and also in all
western Europe.”

The Gypsy Moth in England.

The earliest information that I have found of the presence
of the gypsy moth in England, is given by Wilkes, in his
work entitled “Twelve New Designs of English Butterflies,”
published in London in 1741-42, with twelve plates, but with¬
out text. Plate X, Fig. 2, represents the insect under the
name “TheGipsey Moth.”

Harris described it in his “ Aurelian’s Pocket Companion,”
published in 1775. Donovan, in his “Natural History of
British Insects,” Yol. V, published in 1796, figures this insect
on Plate CLXIII, and describes it on pages 67-69, calling
it the “Gipsey Moth.” In his account he says : “That the
Phalena Dispar was not uncommonly scarce about fifteen
years ago, is evident from this circumstance, few collections
of British insects that were in the hands of eminent collec¬
tors are without an English specimen, which was procured
about that time.” From his further account we infer that
he considered it a rare insect in England. Haworth, in his
“Lepidoptera Britannica,” page 88, published in 1803, calls
it Bombyx disparus, and for a common name “The Gipsy,”
and says it is very rare. Salisbury, in his “Hints to Pro-

THE GYPSY MOTH IN ENGLAND.

269

prietors of Orchards,” published in London in 1816, gives
the fullest and most complete account of the gypsy moth that
I have seen in English up to that date. He states that this
caterpillar is common in gardens and woods, where it does
considerable damage.

Stephens, in Yol. II, page 56, “Illustrations of British
Entomology,” Haustellata, 1829, says it is not common near
London, but appears to abound in the fens of Huntingdonshire.
He also refers to the statement that it was introduced into
Britain by eggs imported by Mr. Collinson, but says that the
abundance with which it occurs near Whittlesea, and the dis¬
similarity of the indigenous specimens (which are invaria¬
bly paler, with stronger markings) to the foreign, sufficiently
refute the opinion.

Curtis, in his “British Entomology,” Yol. XYI, 1839,
alludes to the scarcity of this species in the time of Donovan,
and speaks of linding them in considerable numbers, when a
boy, in the marshes at Horning, in Norfolk. Mr. Stainton,
in his “Manual of Butterflies and Moths,,” Vol. I, page 130,
1857, says, “It is found plentifully in fenny districts, but is
not generally common.” George Kearley, in the “Ento¬
mologist’s Weekly Intelligencer,” Yol. IY, page 192, 1858,
speaks of the gradual disappearance of the gypsy moth in
England, and states that it was claimed by some to have
actually become extinct in that country. Mr. Richard South,
in the “Entomologist,” Yol. XXY, page 259, 1892, states
that entomologists in 1870 seem to have been a little troubled
about the right of the gypsy moth to be considered a British
insect, referring, of course, to those caterpillars or imagoes
which were then found at large. He further says, after speak¬
ing of specimens having been found from time to time, that
there is no reasonable doubt that this species is extinct in
England; “that somewhere about the fourth decade of this-
century, the species began to decrease in numbers, and that
toward the end of the fifties it had practically ceased to exist
as a wildling in this country.”

Numerous attempts have been made to introduce this insect
into England again, but they do not appear to have been
successful. Many entomologists have bred it in confinemeitf,
continuing until it can now be regarded only as a semi-do-

270

THE GYPSY MOTH.

mesticated species in England ; and complete degeneration of
the stock, by the process known as “in-and-in breeding,” is
possibly averted by the periodical introduction of eggs from
the Continent.

The late Mr. J. Jenner Weir, in a letter to “ Insect Life,”
Yol. IV, page 138, 1891, said that the gypsy moth had been
unintentionally exterminated in England, and further writes,
“ I think the gypsy moth must have been destroyed simply
by collectors.” Mr. C. G. Barrett, in his “ Lepidoptera of
the British Islands,” Yol. II, page 303, 1894, gives a very
good history of the occurrence of this moth in England and
of its probable disappearance, but without assigning any
cause for such disappearance.

Mr. C. Nicholson read a paper on the life-liistory of the
gypsy moth, before the City of London Entomological and
Natural History Society, Sept. 18, 1894, in which he pro¬
posed for discussion, among others, the question why this in¬
sect had become extinct in England. Mr. J. W. Tutt gave it
as his opinion that it was because the insect was not a native.
“ Its whole history proved it to be an imported species, even
when it first became known. Thousands of specimens in all
stages had been set loose in various parts of the country,
but, with the exception of an odd specimen here and there,
no specimens were taken wild. Its abundance in the fens for
a year or two simply pointed to the care with which it was
put out, and to the temporary existence of favorable condi¬
tions. There are thousands of acres of land, to all intents
and purposes fitted for its establishment here, but it — pos¬
sibly the agriculturists would say fortunately — will not
establish itself.”

The history of the gypsy moth in the United States does
not seem to lend force to the view taken by Mr. Tutt, as
much as we wish it might prove true, for it seems to thrive
as well here as in any part of the old world. America is
indebted to Europe for a long list of insect pests, many of
which are far more injurious, because of their unrestricted
increase, than in their native country ; notable among these
are the currant saw-fly ( JVematus ribesii), the larch saw-fly
( Nematus erichsonii ), the cabbage butterfly ( Pieris rap fa) ,
the Buffalo carpet-beetle (Anthrenus scrophularica) and many

THE GYPSY MOTH IN ENGLAND.

271

others, none of which show any indications of a decline, in a
foreign country. The idea of Mr. Weir, that they wrere de¬
stroyed in England by collectors, hardly seems worthy of
consideration. I will not attempt to express an opinion as to
the cause of their extinction in that country, but it seems
to me that it must be due to causes not yet understood ; and
if the profound thinkers in entomological matters, of whom
England has so many, have not satisfactorily settled this
question, it would be folly for me to express any decided
opinion on the subject. I wish, however, to call attention
to one or two points. Great Britain, because of its insular
position, the prevailing winds and the currents in the sur¬
rounding ocean, has a far different climate from that of
Massachusetts or the interior of Europe and other parts of
the old world, where this insect is usually most abundant.
I noticed, when in England, that the foliage of all vegetation
seemed darker than in this country, or, at least, than in the
eastern part of it ; and it occurred to me that this might be
due, in part, to the larger amount of moisture in the atmos¬
phere, especially as quite similar conditions of climate, with
darker foliage occur in British Columbia, as I have been in¬
formed by my colleague, Mr. E. H, Forbush, who also states
that the arboreal animals of that region are much darker than
those in the eastern parts of the United States. Some years
ago, while in England, my kind friend, Mr. C. G. Barrett,
gave me a very complete series of British Tortricids, and
I never look at my collection without noticing how much
darker these insects are than the same species from Germany
and other parts of Europe. It seems to me that this dark¬
ening may have resulted from natural causes, operating
through a very long period of years. When these insects
first made their way into the British forests and fens, with
their darker surroundings, the lighter colored individuals,
contrasting the most with the objects on which they rested,
naturally fell a prey to their enemies more readily than the
dark-colored individuals ; the darker ones were left to propa¬
gate the species, and, in time, a dark race was formed. I
am well aware that I am now trespassing on ground which
is far better understood by my English brethren, but I trust
that I may be permitted to call attention to this matter for

272

THE GYPSY MOTH.

the purpose of considering the bearing of environment and
climate on the gypsy moth.

If we suppose that the native home of this insect was in
central Europe or south-western Asia, and that it was de¬
veloped from some progenitor in which the sexes were of the
same Color, possibly not very unlike the males of the present
time, we may well suppose that, as the females developed
a larger number of eggs, rendering them so heavy that they
flew but rarely, and, in time, not at all, their wings, not being
used, would grow weaker and less useful as organs of flight,
as we now find them. Under these circumstances, suppose
them to be inhabiting trees and shrubs, the bark of which is
of light color, as birch, their enemies, the birds, etc., could
readily distinguish these strongly contrasting females on the
trunks of the trees and destroy the darker forms, leaving
the lighter examples to propagate the species ; and, as this
went on, in time permanently light-colored females would be
produced.

The males fly actively during the day, and are captured,
while on the wing, by insectivorous birds ; but in this case
slight variations in color would not be apparent to the birds,
and no discrimination would be made in favor of such vari¬
ations. For this reason the males have probably retained
more of their primitive color and appearance, while the
females have made a most remarkable change ; and, as a
result, this insect furnishes a most striking illustration of
what is called sexual dimorphism.

Another reason for thinking that the males have changed
far less than the females, and that the changes made were
perhaps in a different direction, is the fact that they more
nearly resemble the males of allied species than they do the
females of their own. Compare Figs. 3 and 4, on Plate I.,
with Figs. II, 14 and 17, on Plate 39, and also with Figs. 1
and 2, on Plate I. The three species of Orgyia just referred
to have wingless females (one of which, O. leucostigma , is
represented on Plate 39, Fig. 18), which are so heavy that
it would be impossible for them to fly with wings of ordinary
size. It is probable, however, that the remote ancestors of
these insects were winged in both sexes, and that, as the female
developed a larger reproductive system and more eggs, she

INJURIES IN THE OLD WORLD.

273

became too heavy for flight, and at last abandoned all at¬
tempts, just as the gypsy moth is now doing, and that by dis¬
use these organs became atrophied, and nothing now remains
but mere rudiments of the wings. A similar fate possibly
awaits the gypsy moth. Two of the species of Orgyia ,
figured on Plate 39, Figs. 14 and 17, are so-called natives
of this country; while the other, Fig. 11, is a native of
Europe, and has been in this country probably a compara¬
tively short time, not long enough, at any rate, for the new
environment to produce any noticeable change. Since the
introduction of O. dejinita (Fig. 14) and 0. leucostigma into
this country, whenever and in whatever way that may have
happened, the three species have been in an environment
which has produced marked changes in the males, while the
wingless females have probably changed far less. The two
American species have changed so little from each other that
O. dejinila, for a long time, was not recognized as a distinct
species. It may have branched otf from the stem of leucos¬
tigma at a comparatively recent date.

If, in comparatively recent times, the gypsy moth made its
way into England, by the help of man or otherwise, may not
the darker color of the foliage and other surroundings have
rendered the female moths more conspicuous objects to their
enemies, so that, “ in the struggle for existence,” this species
was exterminated before it had time to take on the darker
colors, as may have been the case with the British Tortri-
cids? It may be thought that the warm, damp climate of
England would favor fungoid plants which are destructive to
insect life ; but, if this caused the extermination of the gypsy
moth in England, why has it not also caused the extermi¬
nation of numerous other species with more or less similar
larval habits? If any of the above conditions caused the
extinction of this moth in England, we have little to hope
for in America, since so very little of our territory has any
such climatic conditions as England.

Injuries in the Old World.

There are many accounts, in the older books, of extensive
damage done by insects at different times in various parts
of Europe, some of which was probably caused by the gypsy

274

THE GYPSY MOTH.

moth ; but it is impossible to be quite sure what insects may
have been referred to in these old accounts for the reason
that only local common names were used before 1758, when
Linnaeus introduced the custom of giving a scientific name
to each insect, by which it should be known in all countries.

In a work entitled “ Beschreibung von allerlei Insecten in
Teutschland,” by J. L. Frisch, published in Berlin, 1720,
Yol. I, page 14, is a brief notice of a garden and forest
caterpillar which is evidently the gypsy moth. Plate III
represents a male, a female laying her eggs, a caterpillar,
the anterior and posterior ends of a caterpillar and a male
antenna. He writes of this insect as follows: “This cat¬
erpillar, in the third part of the copper-plate, Fig. 1, is
called Bunt-Knopffig, on account of the light violet-blue
and purple-red tubercles on its back, and also Garten und
Forstraupe (garden and forest caterpillar), because it not
only destroys all the leaves of the fruit-bearing trees of the
orchard, but also does not hesitate to attack forest trees,
especially the oaks, on which it is found every year. In this
year, 1720, this caterpillar entirely stripped every tree of
the double row of lindens along the road from Neustadt to
Berlin.” In the appendix to this work, published later, is a
statement that a certain injurious caterpillar (possibly the
gypsy moth), in 1721 and 1722, ravaged not only the fruit
trees throughout Germany, but also oaks and other forest
trees, and even killed many of them.

Thomas Brown, in the “ Book of Butterflies,” Yol. II, page
52, published in London in 1832, states that in 1731 the
caterpillars of the gypsy moth committed terrible havoc
among the cork oaks of France.

In 1761, J. C. Schaeffer published a work on the gypsy
moth, the first edition of which appeared in 1752. He states
that in this last year the trees in the orchards and gardens,
the bushes in the fields, and even whole forests, not only in
many places in Saxony but also in Altenburg, Leitz, Nauin-
burg, Sangerhausen and many other regions, were entirely
stripped of their leaves. The branches and twigs were
densely covered with caterpillars, instead of leaves, and they
also crawled over the ground in great numbers. An exam¬
ination proved that they all belonged to this one species, and

INJURIES IN THE OLI) WORLD.

275

that they had been more or less abundant for three years in
succession. The first year there were not very many, the
second they were comparatively numerous and the third year
they were present in overwhelming numbers. Some of the
common people thought that the caterpillars grew out of the
ground, like the grass ; others thought that they were cre¬
ated by the evil one ; still others assured the author that they
had seen with their own eyes thousands of the caterpillars
brought by the wind ; and, finally, there were many who
thought these caterpillars were sent by Cfod as a punishment
for their sins. The author states that about eleven years be¬
fore, he saw this same species in Saxony, after having stripped
the leaves from every tree and shrub in the vicinity, feed on
grass and grain.

In the “ Naturforscher,” Vol. XVI, page 130, 1781, Pas¬
tor C. J. Rimrod gave a long and very good account of the
gypsy moth, and wrote of two invasions at his home in Quen-
stedt, one in 1760-61 and the other in 1781.

Preyssler, as stated by Bechstein, in his “ Yollstandige
Naturgeschichte der schadlichen Forstinsekten,” page 372,
1804, says that the gypsy moth was once very common at
Prague, and stripped the leaves from the fruit trees, so that
they bore no fruit. Bechstein, in the same place, says that
this is a formidable insect, against which very active meas¬
ures must be taken, for, because of its large brood and great
voracity, the damage done by the caterpillars may be easily
understood. Linnaeus and Fabricius call it the pest of the
fruit garden.

Panzer, in his “Faunae Insectorum Germanic®,” Yol. II,
page 22, 1794, says the caterpillars of this insect appeared for
many years in frightful numbers, and destroyed the fruit trees
to the great injury of their owners. In 1818, the cork-oak
forests extending from Barbaste to Podenas, in south-western
France, were devastated by innumerable hosts of gypsy moth
caterpillars. After having devoured both the leaves and the
acorns, they attacked the maize, millet, fodder and all the
fruits. They even invaded the dwellings in the neighborhood
of the trees, to the extreme annoyance of the occupants.

Godart says, in his “ Iconographie des Chenilles, Lcs Bom-
bycites,” published in 1832 : “This caterpillar lives on nearly

276

THE GYPSY MOTH.

every species of tree, and, as it is as common as voracious,
it often causes great damage to orchards of fruit trees as well
as in the parks and forests, and, together with other cater¬
pillars, often completely defoliates them.” This same author,
in his “Histoire Naturelle,” Yol. IY, page 256, states that in
1823 the trees in the forest of Senart in Fontainebleau were
entirely defoliated by the gypsy moth, so that the trees were
as bare as in winter. Finding nothing further to devour,
the caterpillars crawled over the ground in all directions,
seeking food. M. Daudeville, writing in the “Annales de
la Societe d’Horticulture de Paris,” Yol. Ill, page 98, 1828,
after referring to this caterpillar and the descriptions that
had been given of it, said that the pest extended from the
west to the north-east of the city of Saint Quentin, for a
distance of more than sixty miles, and had completely dev¬
astated the trees, so that they were entirely bare. These
insatiable insects not only devoured the buds, leaves and
flowers, but even the small twigs of fruit trees. For three
years, in an orchard of three hundred apple trees, they had
not left a leaf intact, and the gradual decay and death of
several of the trees were attributed to these insects. In the
same journal it was stated that Yiscount Hericart of Thury,
in a journey which he had just completed, observed that the
apple trees in the departments of Calvados, the Eure, Eure-
et-Loir, the Seine-Inferieur, Seine-et-Oise, the Oise, the
Somme and the Aisne were entirely ravaged by this insect.

Mons. N. Joly, in the “ Revue Zoologique,” Yol. Y, page
115, 1842, says that during the years 1837, 1838 and 1839,
there appeared in the forests around Toulouse in France an
innumerable quantity of the gypsy moth. The caterpillars
of this insect attacked the oaks with such avidity as to
strip them completely of their foliage, so that after the first
onslaught the trees appeared as they do in winter. The
caterpillars were so numerous that persons passing through
the woods could hear them eating, and might easily believe
themselves in the midst of a menagerie. These devastating
insects occupied an area of more than twenty-five square
leagues.* On their approach to Toulouse they attacked

An area nearly as large as the infested territory in Massachusetts.

INJURIES IN THE OLD WORLD.

277

the willows, which they damaged much less, because of the
ability this tree possesses of putting on new foliage. In
the “ Stettiner Entomologische Zeitung,” Vol. IX, page 266,
1848, it is stated that Riegel in 1838 saw about eight acres
of oak woods entirely stripped of leaves by the gypsy moth.
Ratzeburg, in “Die Waldverderbniss,” published in 1868,
Yol. II, page 154, says the gypsy moth, ten }Tears before,
had spread, in a space of three years, from Brandenburg to
the zoological gardens. On page 189 he says that the size
and voracity of this caterpillar (gypsy moth) and the vast
numbers in which they sometimes appear make the results
for the beech, as well as for the elm, frightful in the extreme.
In the zoological gardens at Berlin the beeches are said to
have been severely attacked. A very competent observer,
Dr. Gerstacker, as an eye-witness, stated that in 1852 many
beeches became dry and dead. In that year all the cater¬
pillars transformed, but in 1853, not having sufficient food,
many died of starvation. On page 339, in speaking of the
ravages of different species of caterpillars, he says that
Bombyx dispar (the gypsy moth) may be mentioned first as
being the largest and most ravenous, and further says that
he knew of a devastation by which was caused the weakening
and death of many trees. This author states (page 185) that
in the great devastation which occurred in the zoological
gardens at Berlin, in 1851-53, these caterpillars attacked
not only the native but also the foreign trees and shrubs
cultivated there, no species being entirely avoided by them.

Bazin, in an article on “ The Ravages upon the Oaks by
Bombyx dispcir,” published in “Bulletin de la Societe des
Sciences historiques et naturelles de l’Yonne,” pages 11-20,
1870, speaks of the abundance of this species everywhere.
Before the middle of June, 1868, “ there were spots in the
woods that every day spread like spots of oil on the water,
where not a leaf remained on the trees or shrubs.” The oaks
were attacked first, and after they had been stripped the
birches, aspens, elms and even pines and larches were com¬
pletely denuded. In the fields a large number of apple trees
were defoliated by this caterpillar, and the apples themselves
were sometimes eaten into to such an extent that they became
malformed. In the same article M. Bazin states that it was

278

THE GYPSY MOTH.

reported that caterpillars of this species had occasioned the
death of children who had eaten strawberries upon which
these caterpillars had rested, and that, as a consequence, the
sale of strawberries had been prohibited in certain regions.
It did not seem possible that the story of the death of the
children from this cause could be true, or even that any
derangement of the digestive system could have occurred.
To test the statement, M. Bazin put four gypsy moth cater¬
pillars in a wide-mouthed bottle with twelve strawberries
and a strawberry leaf. At the end of twenty-four hours they
had eaten a very little of the leaf and also a little of the
strawberries, but had not eaten them with the avidity that
they do other kinds of food. They had been in contact with
the strawberries more completely, however, than they would
if they had been at liberty, for they had crawled over the
berries again and again, and, if they had the power to impart
to them any injurious properties by contact, they must have
done so under these conditions. M. Bazin then ate four of
these strawberries, and, a little later, feeling no inconvenience
from these, ate the remaining eight, without the slightest
disturbance in the stomach. As the opinion prevailed more
or less widely that cows and other animals that had eaten
these caterpillars had been made sick, he caused a dog to
swallow some of them, but the animal gave no indication of
inconvenience.

In reviewing Dr. E. L. Taschenberg's “ Entomoloo-ie fiir
Gartner,” etc., in the “ Stettiner Entomologische Zeitung,”
Yol. XXXII, page 167, 1871, Dr. Dohrn, in speaking of
the gypsy moth, says that from his experience the active
caterpillars, after escaping from the eggs, can crawl about
for eight or ten days without food. He states that on May
3, 1854, he was in Glogau, and noticed gypsy moth cater¬
pillars crawling on his own clothing as well as on that of
others. Under the roof of the shed, near which they sat,
thousands of caterpillars which had hatched that day were
crawling about. They had let themselves down by threads,
and thus dropped upon the clothes of the people. Threads
from many more caterpillars had become entangled into long
chains, which waved in the almost imperceptible breeze, and
from which hung, so far as he could judge, about a thousand

INJURIES IN THE OLD WORLD.

279

oaterpillars. In another village he saw, some time later on
a fine day, caterpillars of this same species swaying on long
threads from apple trees in an orchard, and which, although
there was no wind, were directed towards a neighboring
orchard which the owner had always kept carefully cleared
of caterpillars and egg-clusters, and who had often com¬
plained of the laziness and ill-will of his neighbor. On the
highway in Ilerms village, in Glogau, the same summer, a
large apple tree was eaten almost bare of leaves, and the fe¬
male moths were laying their eggs on the trunk. Later in the
season Dohrn states that he saw the tenant carefully scrap¬
ing off the egg-clusters, even from the highest branches, and
he expected the tree would be quite free from these caterpil¬
lars the next year ; but to his astonishment, in the following
July, it was full of gypsy moth caterpillars, and eaten bare.
The tenant said he would do nothing more in future, since
all his work was of no avail ; but, upon questioning him as
to whether he had burned the eggs, he replied that such a
thing had not occurred to him. He had simply trodden all
the egg-clusters and scrapings into the ground, where they
had been preserved, and the caterpillars, hatching out the fol¬
lowing year, found their way up into the tree.

In an article in the “ Bullettino della Societa Entomoloodca
Italiana,” Vol. Ill, page 360, 1871, published in Florence,
Italy, Apelle Dei has an article on the “Ravages of Insects
in the Senesian Country,” in which he mentions the gypsy
moth, stating that it had ravaged the oak forests of the high
Chianti for many years, and during the year 1871 they had
stripped the forests of Chianti to an extent and with a sever¬
ity that was frightful, and that many of the oaks had been
destroyed. Dubois, in his “ Lepidopteres de Belgique,”
Vol. II, published in Brussels in 1874, states that in 1858,
Brussels and its neighborhood suffered very much from the
ravages of the gypsy moth, notably the boulevards and park.

Porchinsky, in his work on “Insects Injurious to Fruit
Gardens in the Crimea, Russia,” published in St. Petersburg
in 1889, states that the gyps}' moth caterpillar appears in the
Crimea not unfrequently in enormous quantities. This hap¬
pened in 1842, and also in the early sixties and seventies.
Especially during 1871 were the gardens of the Crimea nearly

280

THE GYPSY MOTH.

destroyed. In 1884 these caterpillars were so numerous that
they covered the railroad tracks so that trains were moved
with difficulty. Again, in 1885, they occurred in great num¬
bers along the southern shore. Observations in the Crimea
show, however, that the gypsy moth rarely continues in the
same locality in large quantities for more than three years.
Thus in 1861, an unusually large number of caterpillars was
noticed in the Crimea, and they continued to increase until
1863, when their highest number was reached. Although
the greater part of the caterpillars succeeded in forming
cocoons, yet very many of them were diseased, as was shown
by their soft and withered condition, and, when broken open,
there flowed out from some of them a dark-brown liquid
mass. In 1864, there were decidedly less caterpillars than
durimr the previous year, while only occasional individuals
were met with in 1865.

In a work on “ Insects Injurious to Gardens and Orchards
in Central and Xorthern Russia,” by X. Kulagin of the Uni¬
versity of Moscow, published in St. Petersburg in 1894, it
is stated that the gypsy moth is very widely distributed. It
is found in all the central provinces of Russia, in the Cauca¬
sus and in southern Siberia. Besides injuring fruit trees,
the caterpillars destroyed the leaves of forest trees over an
extent of territory comprising from one thousand to three
thousand dessatines (2,860 to 8,580 acres).

In a work on “ Injurious Insects,” by Theodore Keppen,
published in Russia in 1883, Yol. Ill, commencing on page
49, it is stated, in speaking of the gypsy moth, that these
caterpillars often appear in countless numbers. In 1852, in
the vicinity of Kishenev, eighty-three miles north-west of
Odessa, they occurred by millions in the gardens and forests.
Havino- destroyed all the leaves, they attacked the bark
of the young shoots and completely ruined a large number
of different kinds of trees. In 1842, and also in the early
sixties and seventies, Georg Seopru states that they were
exceedingly injurious to the fruit trees in the Crimea. Ac¬
cording to the statements of Professor Eversmann, the for¬
ests of oak and aspen, in the province of Orenboorg, were
stripped of their leaves, presenting the same appearance
as in winter. In 1852, the caterpillars laid waste the forests

Explanation of Plate 40.

Drawn in colors by Ella M. Palmer.

1. Showing the feeding and spinning habits of gypsy moth cat¬

erpillars of different ages. The bark on the lower part
of the apple twig has been eaten by the young cater¬
pillars early in the season.

2. Showing the method of feeding upon a young growing shoot

of white pine ( Pinus strobus ) .

3. Red oak (Quercus rubra ) leaf attacked by a nearly full-

grown gypsy moth caterpillar.

Plate 40.

Feeding habits ofGypsy Moth Caterpillars.

INJURIES IN THE OLD WORLD.

281

of oak, linden and beech in the province of Kazan, but sub¬
sequently these trees put out a new set of leaves.

The late V. E. Graft’ reported that the oak suffered greatly
in the province of Yekaterin. In 1856, the gypsy moth was
observed in great abundance in the province of Riazan. In
1857, the forests near the province of Tambov were visited
by vast masses of these caterpillars. The trunks of the wild
apple and cherry trees were wrapped about with a felt-like
substance formed by the covering of the eggs. During 1863,
these caterpillars were seen in vast numbers on the oak in
various fores’ts in the province of Kazan. Here, as stated
by Tideman, the trees injured most were the oak, linden,
maple, elm and birch, while the mountain-ash and hazel-nut
did not suffer so much. In 1867, the caterpillars were seen
in other districts, and in 1868, their numbers became fright¬
ful to contemplate throughout the whole province of Kazan.
In 1867 to 1869, the gypsy moth caterpillars were very de¬
structive in the province of Samara, and Rudzky states that
they were very abundant at the same time in all parts of the
province of Penza. During June, 1867, all the trees on
many estates were entirely stripped of their leaves, and the
forests in many cases to the extent of several hundred des-
satines* appeared as they do in the winter. The caterpillars
seemed to prefer the oak and linden, but after defoliating
these they attacked other trees and shrubs, and finally de¬
stroyed the grass. In the forests near the city of Penza the
dead caterpillars formed such putrid masses that the police
were obliged to take measures to destroy the decaying heaps.
An incalculable quantity of eggs were laid on the trunks of
both deciduous and evergreen trees. In 1869 and 1871, the
gypsy moth caterpillars appeared in great quantities in the
Kupiansk district of the province of Kharkov.

In more recent times, 1879-80, these caterpillars multiplied
in frightful numbers and spread over an immense territory,
beginning in the province of Kiev and Poltava and extend¬
ing through Kharkov, Voronezh, Tambov, Saratov, Sim-
beersk into Kazan. f Owing to defective reports concerning

* One dessatine is equal to 2.86 acres.

t A territory about equal to all our Atlantic States, and in nearly the same lati¬
tude as Labrador.

282

THE GYPSY MOTH.

this unusual appearance of Porthetria dispar , it is hard to
say where the calamity began. Considering the time of their
appearance, it is supposed that they first appeared en masse
in the province of Kharkov. According to Yaroschev, the
caterpillars were seen in threatening numbers in the district
of Zmiev during 1877-78. The insect may have spread
westward in the province of Poltava and eastward in the
province of Voronezh, and from these to more distant parts.
The simultaneous appearance in different places so widely
separated, led to the opinion that there were various places
of origin from which the insect was distributed. Yaroschev
states that the caterpillars were so abundant in the vicinity
of Zmiev, in 1878, that in going from one forest to another
they literally covered the walls of the houses lying in the
way. They fed on all sorts of plants, except ash ( Fraxinus
excelsior ) and wild pear.

Anderson gives interesting details of the presence of the
caterpillars in the forest of Shipov in the province of Voro¬
nezh. They first attacked the so-called winter oaks ( Quer-
cus pedunculata, vav. fardi flora) , and, after destroying the
leaves as soon as they appeared, they devoured the leaves of
the lime tree, aspen, hawthorn, spindle tree, hazel and others,
and finally the numerous grasses were destroyed. Early in
June they began to pupate, and by the middle of the month
they were all in this stage. About 3,500 dessatines (10,010
acres) of the forest were laid bare, and detached trees in
other parts of the woods were stripped of their leaves. By
the middle of July the moths had emerged and laid an enor¬
mous number of eggs.

According to Gazen, vast quantities of these caterpillars
were seen in the district of Kirsanov in the province of Tam¬
bov, in April, 1879. Having eaten all the leaves on the trees
and shrubs, the caterpillars descended to the ground and lit¬
erally covered it in all directions. In the district of Volsk,
in the province of Saratov, the caterpillars of the gypsy moth
appeared in vast numbers in April, 1879, eating the leaves
of all sorts of trees, though preferring the birch and oak,
and finally they attacked the pine. By the end of May,
10,000 dessatines (28,600 acres) of forest were completely
denuded of their leaves. After this they devoured the

INJURIES IN THE OLD WORLD.

283

grass, and, coming to a field of grain in their march, they
destroyed that also. In 1880, they appeared in force in the
forests of the provinces of Simheersk and Kazan.

In a letter from Professor Henry of the School of For¬
estry, Nancy, France, dated July 27, 1895, he says : “ Liparis
dispar (the gypsy moth) is well known to French foresters.
This caterpillar is a plague to fruit trees, oaks, chestnuts,
lindens, elms, poplars and other trees, on all of which it
thrives. In 1868, more than 60 hectares (148jt acres) of oak
woods were entirely stripped by it. It was so common in
1880, ®n the sides of Mt. Ventoux near Avignon, that the
legions of caterpillars covered the ground and entirely de¬
stroyed vegetation. In Savoy it made an invasion in 1887
upon the chestnuts and fruit trees. There is not a year
passes, comparatively speaking, in which the caterpillars do
not show themselves in our territory, if not in one place
then in another.” In a letter from Dr. J. Ritzema-Boz, from
Amsterdam, Sept. 3, 1895, he writes that this insect is com¬
mon in Holland and also in all western Europe, but the
ravages of the caterpillar are very much more common in
the eastern parts of Europe. In Holland the ravages of the
gypsy moth are very rare indeed. In 1848, it stripped the
leaves from the oak ( Quercus pedunculata ) over 50 hectares
(123^7g acres) near Lutphen in the Dutch province of Gelder-
land, and then attacked the other trees. In 1887 it was very
abundant on oak near Wymegen in the province of Gelder-
land. In 1880 these caterpillars destroyed the leaves on a
large number of hectares of oaks near Yeenendeal in the
province of Utrecht.

In a letter from N. Nasonov, of the University Museum of
Zoology, in Warsaw, Poland, dated Aug. 7, 1895, he writes
that he had the opportunity of knowing personally of an
immense number of the caterpillars of the gypsy moth in
the orchards of the government of Warsaw during the years
1891 and 1892, and also on the deciduous trees in the
government of Moscow in 1894. In 1892, the leaves of
the fruit trees in Warsaw were eaten by these caterpillars
to such an extent that they bore no fruit. According to
the information received from the central Russian govern¬
ment, the caterpillars of the gypsy moth have this summer

284

THE GYPSY MOTH.

(1895) nearly defoliated the forests in the government of
Kalonga.

Notwithstanding the general damage to all kinds of vege¬
tation in Europe, the greatest complaint comes from the
fruit-growing districts, where this insect shows a preference
for the foliage of fruit trees.

Methods of Destroying the Gypsy Moth in Europe.

The natural enemies of the gypsy moth, as the birds,
parasites and predaceous insects, are relied upon to a great
extent to keep it in check in European countries, except in
localities where it is very abundant, and the outbreaks very
frequent. It should be borne in mind that the European
methods are not for the purpose of exterminating or even
preventing the spread of this insect ; for, as has already
been stated, it is more or less common everywhere. The
extermination of this pest in Europe by artificial means
would probably be an absolute impossibility, and, therefore,
all that is attempted is to destroy it wherever it appears in
great abundance.

The usual methods are to scrape otf the egg-clusters and
burn them, or cover them over with raupenleim or other
materials in the fall, winter or spring before they hatch,
applying the substance by means of a brush on a long
pole to those egg-clusters that are too far above the ground
to be reached in any other way. Later in the season the
trees are protected from those caterpillars that hatch from
egg-clusters laid on the ground or elsewhere, by banding
with raupenleim. The caterpillars are destroyed whenever
found, generally by crushing them as soon as they hatch,
and while they are still clustering on the egg-mass, form¬
ing the so-called “spiegel.” The pupae are destroyed by
hand, and also the female moths before they have laid their
eggs.

Dr. N. Xasonov, of the "Warsaw University Museum of
Zoology, in the letter previously cited, writes that, in Po¬
land, the principal measures used in combating these in¬
sects are to destroy the eggs, band the trunk of the trees
with raupenleim and gather the caterpillars and pupae by

REMEDIES IX EUROPE.

285

hand. In a Russian work* by A. F. Rudzky, is given the
following : “The eggs are laid on the trunks of the trees in
large masses. These may be easily scraped off with a knife
during ten entire months in southern Russia. If the egg-
clusters are not scraped off’, it is necessary to destroy the
caterpillars as soon as hatched, and while still clustering in
groups. When the caterpillars have spread over the whole
tree, it is as impossible to destroy them as the separate
moths. When they have eaten the foliage from one tree,
they go in a mass to another ; but this may be, in a measure,
prevented by putting the so-called ‘ catch bands ’ on the tree
trunks. The cheapest of these bands are made of wadding,
five or six inches in width, and bound on tightly, leaving an
upper and lower edge, which is to be roughed up, so that
the caterpillars may become entangled in the uneven sur¬
faces. The wadding may be made fast to the trunks with
strings, or glued together in bands. Where a large number
of these bands are needed, it is advisable to paste the wad¬
ding (during the winter) on coarse paper, one side of which
is smeared with tar. Bands of pitch or tar are frequently
used, but these soon become dry. In the Crimea, a mixture
of two parts of boiled tar and one part of rape oil, thoroughly
heated together, is used ; also a mixture of ten pounds of
lard, twenty pounds of hemp-seed oil and eighty pounds
of coal tar. This is applied directly to the tree and needs
renewing twice a year. Labodsky recommends this same
ointment, and says that, when well prepared, it will retain
its sticky qualities an entire autumn.”

Theodore Beling, inspector of forests at Seesen, wrote
July 21, 1895, that the methods adopted there were to kill
the caterpillars, puprn and moths, but that the most impor¬
tant method was to destroy the egg-masses on the tree trunks
by scraping them off and burning them, or by covering them
with raupenleim, or with a mixture of four parts of wood
tar and one part of petroleum. I)r. Richard Hess, in “Der
Forstschutz,” published in Leipzig, 1887 and 1890, gives
the following concerning the gypsy moth: “Prevention:
Protection of its enemies, bats, cuckoos, starlings, crows,

* “ Insects Useful and Injurious to Fruit Trees.”

28(5

THE GYPSY MOTH.

titmice, tree-creepers, etc., ichneumons and tachinids are
especially to be noted. Orchard trees should be smeared
with a thin mixture of lime, black-soap, potash and cow-
dung. Killing : Destruction of the egg-masses, from August
to April, by scraping them off and burning them, or by
smearing them with wood-tar thinned with petroleum or
raupenleim. Killing the ‘ spiegel ’ in May, and crushing the
caterpillars when clustering on the trunks and branches of
the trees, from the end of May through June ; gathering the
pupae in July and August.” In a letter from Dr. Ebermayer,
professor in the University of Munich, dated July 22, 1895,
substantially the same methods are recommended.

J. Porchinsky, in his work on “Insects Injurious to Fruit
Gardens in the Crimea,” says: “The eggs should be de¬
stroyed in the winter season, when time and circumstances
permit. The egg-clusters should not be crushed, as this
might allow some of them to escape ; but they should be
carefully scraped off and burned. The eggs having been
destroyed, the tree should be protected from caterpillars that
might come from neighboring trees by ‘catch bands’ (pre¬
ventive bands). These preventive bands are almost the only
means with which to combat insects of all classes most injuri¬
ous to orchards ; and, therefore, their consideration is of the
first importance ; but it is not so easy to find a paste that
will, under all conditions of weather, retain the peculiar
qualities desired. The most simple of these ‘ catch bands ’
is a belt of tar put around the trunk of the trees, on thick
paper, smeared with tar and made fast to the trunks.

“In the Crimea, axle grease is placed about the tree
trunks in belts from three and a half to seven inches in
width, and about twenty-eight inches above the level of the
ground. This ointment often retains its sticky qualities a
long time, yet it is far from satisfactory.

“ The experiments of Klausen, in which he used wadding
as a catch band, are of importance in connection with the
question of prevention. A large number of these bands of
cotton were put around the trunks of trees, the upper and
lower borders being well spread out, for, the more fluffy and
open the cotton, the more easily the caterpillars become
entangled. In the course of two hours a large number of

REMEDIES IN EUROPE.

287

caterpillars became entangled, and by evening were dead.
After a rain these bands should be replaced.”

By the advice of Prof. B. E. Fernow, of the Department
of Agriculture, Washington, D. C., I wrote the following
letter to Professor Altum : —

Amherst, Mass., U. S. A., Jan. 21, 1895.

Prof. Dr. Bernard Altum.

Dear Sir : — I send you by post some papers which contain an
account of the introduction and spread of the “ Schwammspinner”
( Ocneria dispar L.) in this country, and of the efforts that have
been made to exterminate this insect. You will see by an exam¬
ination of these papers that the insect has proved more destructive
here than it usually does in Europe, while in England it has be¬
come extinct from unknown natural causes.

We have already found several parasitic and predaceous insects
preying on 0. dispar, as you will see mentioned in the reports
which I send to you ; but I very much wish to learn whether you
think it would be wise for us to attempt to introduce the European
parasites into this country ; and, if so, what parasites would it be
desirable for us to introduce, and where and how can they be best
obtained? We have been advised to introduce some of the Euro¬
pean predaceous beetles, as Calosoma sycoplianta (L.), Calosoma
inquisitor (L.) and Silplia quadrijmnctata L. Others have told
us that Calosoma sycoplianta is so large and conspicuous that
insectivorous birds would destroy it to such an extent that it would
prove of little assistance in destroying the “ Schwammspinner.”
Will you be so kind as to give me your advice on this subject, and
also any information you may have of the methods used in Europe
for the destruction of this insect? I have your valuable wrork on
“ Forstzoologie,” but from all I can learn this insect is more
troublesome and destructive in southern Europe than in Germany.
I shall be very grateful for any information that you may be able
to give me.

Very respectfully, your obedient servant,

C. H. Fernald.

In reply to the above letter Professor Altum wrote as
follows : —

I have never known of a devastation in Germany equal in severity
and extent to that in your country. So far as I know, all of the
devastations of dispar in this region have occurred on limited
areas, and have always quickly disappeared.

288

THE GYPSY MOTH.

An importation of predaceous insects to oppose this destructive
dispar , e. g., Calosoma sycophanta , etc., cannot possibly be of
any industrial importance. These work in no noteworthy degree
even in our far smaller dispar calamities. There are small para¬
sitic insects, especially the species of Microgaster, and even mi¬
crobes (bacteria), which are valuable. But these cau only be
collected and sent away when they appear in multitudes, and I do
not know at present of a single case in which there is such an
appearance.

I can only recommend a single successful artificial remedy,
namely, painting or moistening the egg-clusters with liquid fat
(oil, petroleum, train oil) or with thin liquid wagon grease, raupen-
leim, etc. With brushes having long handles, and also by the use
of ladders, most of the egg-clusters can be reached. As a rule,
these egg-clusters stand out visibly from the darker green bark of
the trunks and branches, the under side of which may be cleaned
with a brush attached to a pole. This work can be doue from
September to April, and has always been a complete success here ;
but with such an enormous and extensive development as dispar
presents with you, the successful execution of the above method
of destruction does not seem possible ; moreover, no other artificial
method is of value. You will, therefore, for the present, make
use of this method where the insect appears in small numbers, or
as single individuals beyond the area being destroyed, and also
where the first colonies or gathering points appear, that is to say,
where a great development of the insect is feared. Here the in¬
sects are in such numbers that it is possible to destroy them, and
are, for the most part, to be found on the lower portion of the
trupks of the trees, where they can be easily reached by the hand
or with short-handled brushes. These later central poiuts of the
invasion usually have a small area and definite borders, and such
a method of destruction must be adopted and carried on with all
possible energy, for the protection of the surrounding territory.
It is needless to say that the caterpillars, pupae and female moths
should be destroyed.

The Eggs.

The eggs (Plate I, Figs. 9 and 10) are nearly globular,
slightly flattened on the lower side, and generally flattened
or depressed on the upper side. They are about one-twen¬
tieth of an inch (1.5 mm.) in lateral diameter, and of a dark
salmon color when first laid ; but when fertile they change
to a darker color, owing to the development of the embryo,
which is quite fully formed in about three weeks. The egg

PLATE 41. Mass of pupa-cases and egg-clusters under a fence rail.

_ _

THE EGGS.

289

appears to be smooth, when examined with a lens, but if the
shell be very carefully removed and examined under a half¬
inch objective, or a higher power, it exhibits somewhat
irregular hexagonal marks over the entire surface, except at
the centre of the depression above, which is occupied by the
micropyle with its surrounding rosette. This consists of
three rows of somewhat pear-shaped cells, each row over¬
lapping a part of the next outside of it (Plate 58, Figs.
11 and 12). The most successful method found for ren¬
dering the micropyle and surface markings visible was to
remove the contents of the egg and mount the shell dry.
When mounted in Canada balsam, glycerine or glycerine
jelly, all the markings were obliterated. It was impossible
to obtain any better, or even as good, results by first stain¬
ing the shells in hgematoxylin, eosin, aniline red, aniline
blue, picro-carmine or methyl green. This last stain, how¬
ever, gave better results than any of the others.

The eggs are laid in the summer, soon after the emergence
of the moths, in oval or rounded clusters (Plate I, Fig. 8),
usually containing from four hundred to five hundred eggs,
but clusters have been found which contained one thousand
eggs. These egg-clusters vary in size from one-half an inch
to one and one-half inches in length, and from one-third of
an inch to one inch in width. The average dimensions of
fifteen clusters were found to be 21^| mm. long, 11 1 mm.
wide and 5| mm. deep. The female covers the eggs, as
she deposits them, with the yellowish hairs from the under
side and end of the abdomen, which cause the cluster to re¬
semble a small piece of sponge in general appearance (Plate
I, Fig. 8). In time, however, they fade, and more nearly
resemble the eggs of the white marked tussock moth (Plate
39, Fig. 15). The female deposits her eggs in every con¬
ceivable place, as on the branches and trunks of trees (Plate
55), often below the surface of the ground when this has
shrunken away from the tree ; in cavities in trees or other
concealed places ; under bark which has separated from dead
branches ; under bands of tarred paper or cards tacked upon
the trees ; in stone, walls ; under stones and in cavities in the
ground ; in old tin cans, on dead leaves or other rubbish
near the infested trees; under fence rails (Plate 41) or the

290

THE GYPSY MOTH.

loose boards or timbers of barns or out-buildings ; in birds’
nests, and many other places, occasionally on leaves on the
tree and sometimes on the fruit ; but undoubtedly the trunks
and branches of the trees (Plate 42) are the most natural
places. As a rule, the eggs on the limbs are laid on the
under side, although in a few instances they have been found
on the upper side, but more or less concealed. In one case
an egg-cluster was found on a piece of old rope hanging from
a tree, and another on a thermometer hanging against the
outside of a chimney. It is not an uncommon thing to find
them in tent caterpillars’ nests, and one was found deposited
on a spider’s web on a fence.

The typical form of an egg-cluster is elongated and slightly
narrowed at the end last laid. This form is subject to all
imaginable variations, according to the conditions under
which the mass of eggs is laid. In one instance, six appar¬
ently complete egg-clusters were observed that had been laid
nearly on top of each other ; and in another, a female that
appeared to have died on her egg-cluster was nearly half
covered with eggs deposited by a second moth while laying
close by. Eggs laid by unfertilized females are usually
poorly covered with hair, and crippled females, as well as
those which have trouble about emerging, often leave a large
part of the hair of the abdomen in the pupal case. Eggs
laid by such females are usually stuck together in a loose
mass, poorly covered and easily separated. The adhesive
substance by which the eggs are attached to each other and
to the surface upon which they are deposited, as well as that
which causes the hairs of the abdomen to adhere to them, is
insoluble in dilute or absolute alcohol, chloroform or spirits
of turpentine.

Scattered Eggs.

In nearly every case where a fertilized female was confined
in a box, she was found to scatter eggs while laying. The
eggs were dropped accidentally, the moth being unable to
attach them to the surface on which she rested. Frequently
a considerable number were dropped before she succeeded in
attaching a single egg ; but after a small number had been
securely deposited, fewer eggs were scattered, although occa¬
sionally they were dropped throughout the entire process of

PLATE 42. Mass of egg-clusters on the trunk of a large elm.

SCATTERED EGGS.

291

laying. The most marked cases of egg-scattering were those
where the moth did not first form a hairy area on which to
deposit eggs. Observations made on the egg-scattering of
fifteen gypsy moths, ten in the insectary and five on trunks
of trees in the field, showed that all of them scattered eggs,
some of which were dropped before the moth mated and
others afterwards. The number of eggs scattered by these
insects ranged from one to thirty-four, the average being
nine and three-fourths. Male moths, when numerous, in
attempting to mate with females while they are laying, often
disturb them to such an extent as to cause them to drop or
scatter eggs. Eggs scattered by fertilized females have
proved to be fertile. Observations made in the field show
that many eggs are scattered by the moths when laying
under the most natural conditions. In one colony in Sau¬
gus, in 1894, the greatest number of egg-clusters were on
the rough bark of pine trees, and many scattered eggs were
found at the base of these trees among the pine needles.
Nearly all of these eggs were naked, and in many cases they
were loose, though some were attached to pine needles or to
fragments of bark at the base of the trees. Scattered eggs
were also found in crevices of the rough bark below the
clusters. Eighty-five per cent, of the scattered eggs taken
at this place proved to be fertile. This scattering of eggs
doubtless explains why caterpillars occur in places where
the eggs on the trees have been destroyed the previous
winter, and indicates the value of burlapping as a supple¬
ment to the work of egg destruction.

Resistance of Eggs of the Gypsy Moth to the Action
of the Elements.

In January, 1895, a number of egg-clusters were thor¬
oughly broken up, so that the eggs were entirely separated,
and as much of the hair removed as possible. The eggs
from each cluster were then placed in a small paper box
which was covered with two thicknesses of thin, open cheese¬
cloth. Six of the clusters were placed underneath the store¬
house, where they were sheltered from storms, but otherwise
wholly exposed to all climatic changes ; and, to determine
the effect of the actual out-door exposure, six more egg-

292

THE GYPSY MOTH.

clusters were taken from trees, and, after being prepared in
the same manner, were placed in exposed positions on the
ground, in the centre of a colony. The tops of the boxes
were placed uppermost, so as to give free access to rains,
and the localities marked, so that they might be readily found.
The boxes were allowed to remain here through all the cold
weather and storms of the season, sometimes being bare, and
sometimes covered by the ice formed from the melting snow.

On the 4th of April, all of these egg-clusters, as well as
those from underneath the storehouse, were collected and
placed in the hatching-boxes. Those from the colony were
more or less covered with debris which had been carried into
the box by the action of rain or of thawing ice. All of the
egg-clusters hatched from April 16 to April 20, and, judging
from the small number of eggs remaining unhatched, pro¬
duced as many caterpillars as similar clusters which had been
kept intact, either in cold storage or out of doors, during
the winter.

From this it is evident that, although the hairy covering
of the egg-cluster may serve in a measure as a protection to
the eggs, yet it is not essential to their successful hiber¬
nation. Certain European writers recommend scraping the
eggs from the trees, and state that when this is done their
vitality is destroyed by the severity of winter. This cer¬
tainly is not true in Massachusetts, even if it be so in
Europe.

Effect of Extremes of Temperature on the Eggs of
the Gypsy Moth.

During the spring of 1895, considerable time was devoted
to studying the effect of heat and cold, in extreme degrees,
upon the eggs of the gypsy moth, with a view of obtaining
a better knowledge of the capabilities of this insect to resist
such extremes, which fact has a bearing in showing whether
sudden climatic changes would aid in holding the insect in
check.

The experiments with extremes of heat were conducted by
use of a hot- water oven, the necessary degree of heat being
obtained by means of a small oil stove, and the temperature
of the interior being indicated by a small thermometer.

EXPERIMENTS ON EGGS.

293

To obtain extremes of cold, the eggs were placed in vials
and enclosed in a small can, which was then placed in an¬
other can containing a freezing mixture (composed of equal
parts of coarse granulated snow and salt, and in some cases
one which v7as composed of four parts of snow and five parts
of calcium chloride). The degree of cold was indicated by
a thermometer placed in the freezing mixture, and so ar¬
ranged as to be easily read through a glass window in the
side of the can.

Effect of Heat on Eggs.

On April 3, ten egg-clusters of the gypsy moth were ex¬
posed for thirty minutes to a temperature of 80° F. They
were then placed in the hatching-boxes, where the temper¬
ature w^as normal, and daily observations made until April
16, wdien all the egg-clusters were found to have hatched.
April 3, ten egg-clusters wTere exposed for thirty minutes
to a temperature of 90°, and w7ere then placed in hatching-
boxes ; all of the clusters had hatched April 16. April
3, ten egg-clusters were exposed for thirty minutes to a
temperature of 100°, and then placed in hatching-boxes ; by
April 17, all had hatched. April 3, ten egg-clusters were
exposed for thirty minutes to a temperature of 110°, and
then placed in hatching-boxes; on the 17th of April all of
these egg-clusters had hatched. March 26, three egg-clusters
were exposed for thirty minutes to a temperature of 120°,
and then placed in hatching-boxes ; one of these hatched
April 7 and the other two on April 9. On April 3, ten egg-
clusters were exposed for thirty minutes to a temperature of
130°, and then placed in hatching-boxes; on April 12, all
of these egg-clusters commenced hatching. Having obtained
this result, they were further experimented with by being
placed in a cold box surrounded by ice and salt, and ex¬
posed for thirty minutes to a temperature ranging from zero
to 8° below7 ; none of the egg-clusters hatched after this
treatment. April 15, ten egg-clusters were exposed for a
period of fifteen minutes to a temperature of 140°; none
hatched. April 16, six egg-clusters were exposed to a tem¬
perature of 150° for a period of fifteen minutes, and then
placed in the hatching-boxes ; none hatched.

294

THE GYPSY MOTH.

From the above experiments we conclude that a temper¬
ature of at least 140° is necessary to destroy the vitality of
the developed embryo in the egg. In March, 1895, the
effect of the naphtha torch flame was tried upon egg-clus¬
ters, exposing them to the action of the flame for various
short periods of time. This apparatus is sometimes used for
destroying eggs laid in cavities in trees. Of thirty-one egg-
clusters treated in this manner none hatched.

Effect of Cold on Eggs.

Experiments in rapidly changing egg-clusters from a high
to a low temperature were conducted with the following re¬
sults : March 22, 1895, four egg-clusters were changed in
twenty minutes from a temperature of 80° above zero to 5°
above, and left over night in a freezing mixture of calcium
chloride and snow. Two of the egg-clusters hatched April 9
and two April 11. Apparently these egg-clusters hatched
as well as the average ones in the field, and the caterpillars
from them fed and grew in as satisfactory a manner as
normal caterpillars. March 26, two egg-clusters were ex¬
posed for some time to a temperature of 80° F. They were
then packed in a mixture of calcium chloride and snow, and
in fifteen minutes reduced to a temperature of 20° below
zero, a fall of 100°. They were kept at this temperature for
thirty minutes, and then taken out and placed in the hatch¬
ing-box. By the 16th of April all had hatched.

Date of Hatching.

The eggs of the gypsy moth hatch in the spring, from the
last of April to the middle of June, depending on the weather
and the places in which they are deposited, those eggs which
are laid in warm, sunny places hatching the earliest, while
those that are laid in cold places, being protected from the
heat of the sun, hatch much later. The earliest recorded
date of hatching in the field was April 1, 1892, in Medford,
and on May 14 of the same year a large part of the eggs in
warm, sunny places had hatched. The latest date noted was
June 17.

The embryo develops very rapidly, especially in a warm
temperature. Eggs laid Aug. 10, 1894, showed well-de-

SECOND BROOD.

295

veloped embryos August 26, and eggs were found in the
field, Aug. 18, 1894, that contained mature embryos 1.4 mm.
long. Notwithstanding this early development of the em¬
bryo, up to this year no eggs were found to have hatched
in the fall, though a careful watch was kept for them. In
Europe fall hatching is reported in at least one instance.
Ratzeburg, in “ Die Forst-Insecten,” Yol. II, page 112, says :
“ Here they remain [on the branches] much like a long mass
of fungus until the next April or May, or by exception they
hatch in the autumn, as I have seen them myself on the
5th of September, 1836.”

A Second Brood.

In the early part of September, 1895, many of the gypsy
moth egg-clusters were found to be hatching at the “Win¬
ning” colony, in Woburn, where the caterpillars had com¬
mitted serious depredations during the summer months.
The second brood, which appeared only in this particular
colony, seemed to have hatched because of peculiar condi¬
tions of location and temperature. The colony is situated
on the side of a hill, sloping towards the south, which is
covered with a dense growth of medium-sized oak trees.
When this colony was discovered, in the early part of the
summer, the caterpillars were much larger and more nearly
ready to pupate than in any other colony, and this led to the
opinion that the eggs must have hatched much earlier than
in other localities. Many of the moths emerged and laid
their eggs at this place before the caterpillars in other colo¬
nies, where the conditions for rapid development were not
as favorable, had commenced to pupate.

While embryonic development in this insect appears to be
more rapid in warm weather, a limited number of experi¬
ments performed in 1893 and 1894, seem to indicate that a
certain degree of cold is probably necessary to mature the
embryo. In the latter part of August on several nights the
temperature fell quite low in the eastern part of the State,
and on one night a frost occurred in some places. At this
time a part of the eggs in the “ Winning’” colony had been
deposited from four to six weeks, which was sufficient time
for the development of the embryo. This cool weather was

296

THE GYPSY MOTH.

followed by a hot wave, during which a thermometer, ex¬
posed to the direct rays of the sun at Malden, reached a
temperature of 112° F. This extremely hot weather caused
a part of the eggs in this colony to hatch, thus giving rise to
a second brood, although in no case was the hatching com¬
plete, as only a few eggs (one to twenty-five) hatched from
a cluster. Eggs brought to the insectary, and kept at an
average temperature of 70°, gave rise to a few caterpillars,
from time to time, for more than a month.

A number of the caterpillars from this second brood were
collected and sacked in on a small red oak tree, and others
were taken to the insectary and fed daily. At the time of
this writing (Dec. 5, 1895) a part of the latter have pupated.
Careful observations were made upon the caterpillars sacked
in on the tree, and also upon those which were feeding under
natural conditions in the colony. In neither case were they
found to thrive in a normal manner, and with cooler weather
and frosty nights they gradually died, until none were left.
Those which survived longest had nearly all entered the
second molt. The caterpillars reared at the insectary did
not show as much strength and vigor as those which hatched
normally in the spring, and over seventy-five per cent, of
them died before reaching the fifth molt.

While this is the only positive record of a second brood
of the gypsy moth in this country, it is presumably true that
in some cases egg-clusters may have partly hatched in the
fall of previous years. Any egg-cluster taken in the field,
which possesses marked peculiarities, is usually sent to the
insectary for examination, and many of the clusters thus sent
in during the winter and spring ot 1894-95, were found to
contain empty egg-shells. The size and appearance of the
holes in the shells indicated that it was not the work of mites,
since they eat out a ragged, irregular opening, while the hole
left by the exit of the young caterpillar has a more regular
outline, and varies from a small circular aperture to a nar¬
row band eaten around the entire periphery of the shell.
After studying a number of these egg-clusters during the
spring of the present year, Mr. Kirkland suggested that
fall hatching would best explain the occurrence of the empty
egg-shells ; but at that time there was no positive evidence

HATCHING OF THE EGGS.

297

that such hatching had actually taken place in the infested
district. In the light of our present knowledge, however,
it seems probable that fall hatching may have occurred occa¬
sionally during previous years, and also that, under the most
favorable conditions, this insect shows a tendency to be¬
come double-brooded, like the related species of the genus
Orgyia.

The death of the caterpillars of the second brood, feeding
in the field, was to be expected, since the season was not long
enough to permit them to reach maturity. Even if they had
matured it is doubtful if the caterpillars would have seriously
injured trees which had retained their foliage throughout the
summer.

On the softer and more delicate foliage of those trees
which had leaved out a second time, after being stripped
early in the season, the caterpillars fed with great avidity,
and, had the length of the season permitted, such trees might
have been injured to a considerable degree.

Hatching of the Eggs.

The majority of the eggs hatch during the warm part of
the day, from 10 a.m. to 2 p.m., and continue hatching for
several days. It is apparent that, when hatching, the cater¬
pillar first eats a hole through the side of the egg-shell, the
flattened surfaces representing the top and bottom of the
egg, and then eats more or less of a band around the shell
on the side, often leaving only the upper and lower surfaces
of the egg. Sometimes the caterpillar emerges from the
egg by a single hole in the side, but usually it eats a band
around the side of the egg, leaving only the upper and lower
disks remaining.

Number of Caterpillars from Single Egg-clusters,
and Time required for Hatching.

From one egg-cluster that had been kept in a warm room at
the insectary during the winter of 1893-94, 1 egg had hatched
Feb. 23, 1894, at 9 a.m. ; at 10 a.m., 49 more; at 11 a.m.,
13 more ; and at 5 p.m., 50 more, making 113 which hatched
the first day.

298

THE GYPSY MOTH.

February 24, at noon, 80 more eggs had hatched; at 5
p.m., 43 more from the same cluster, or 123 on the second
day.

February 25, at 10 a.m., 20 more eggs had hatched; at
1.15 p.m., 47 more; and at 6.15 p.m., 6 more, making 73
eggs which hatched on the third day.

February 26, at 7.30 a.m., 87 more had hatched; at 1.30
p.m., 172, and at 5 p.m., 16 more, or 275 on the fourth day.

February 27, at 7 a.m., 39 more had hatched; and at 5.40
p.m. , 43 more, making 82 for the fifth day.

February 28, at 7 a.m., 2; at noon, 26 ; at 5 p.m., no
more had hatched, making 28 eggs which hatched on the
sixth day.

March 1, at 7 a.m., 2 more eggs had hatched ; at noon, 5 ;
and at 5 p.m., 2 more, making 9 for the seventh day.

March 2, at 7.20 a.m., 1 more egg had hatched; and at
5 p.m., 1 more, making 2 that hatched on the eighth day.

March 3, at 7.45 a.m., 1 more egg had hatched. No other
eggs hatched from this cluster. The total number of eggs
hatched from the cluster, in nine days, was 706. From
another egg-cluster, kept under similar conditions, 997
hatched in eleven days.

To gain further information concerning the actual number
of caterpillars which may hatch from one egg-cluster, and the
time required for hatching, a number of egg-masses which
had been taken from the field were brought into a warm
room and placed in boxes, April 25, 1895. The caterpillars
were counted and then removed as soon as hatched. From
egg-cluster No. 1, 250 caterpillars were hatched in 2 days and
22 hours. From egg-cluster No. 2, 408 caterpillars were
hatched in 3 days, 17 hours and 10 minutes. From egg-
cluster No. 3, 708 caterpillars were hatched in 3 days, 17
hours and 15 minutes. From egg-cluster No. 4, 679 cater¬
pillars were hatched in 3 days and 1 hour. From egg-
cluster No. 5, 393 caterpillars were hatched in 3 days, 22
hours and 30 minutes. From egg-cluster No. 6, 438 cater¬
pillars were hatched in 4 days, 16 hours and 45 minutes.
The whole number of caterpillars from the six egg-clusters
was 2,876, an average of 479 to each cluster. The average
time in hatching was 3 days, 20 hours and 6| minutes.

the caterpillar.

299

From studies made on a large number of egg-clusters in
the insectary, supplemented by observations in the held, it
was discovered that in many cases some part of the eggs
composing an egg-cluster did not hatch. Seven large egg-
clusters which had hatched were found to contain on an
average 124 unhatched eggs, the smallest number being 43,
the largest 224. A small number of unhatched eggs is found
in nearly all the old nests taken in the held.

The Larva or Caterpillar.

Relative Vitality of Caterpillars hatching at Different Times
from the Same Egg-cluster.

The following observations were made under my directions
by Messrs. Minott and Mosher, both careful and reliable
observers : —

From a large cluster of eggs, laid by a single female
gypsy moth, and kept in a warm room, 4 hatched late in the
afternoon of March 11, 1894; at 10 a.m., March 13, 333
more eggs had hatched ; at 5.20 p.m., 194 more had hatched ;
March 14, 233 had hatched; March 15, at 4.35 p.m., 48
more eggs had hatched; March 19, 10 more hatched; March
20, 3 ; and on the 21st, 6 more eggs hatched, making 831
eggs hatched from this cluster. The caterpillars were re¬
moved as soon as hatched.

Fifty caterpillars were selected, as follows: 10 of those
hatched on the second day, 10 of those hatched on the third
day, 10 of those hatched on the fourth, 10 of those hatched
on the eighth and 5 of those hatched on the ninth and tenth
days, making 6 sets of caterpillars taken from those which
hatched at different times. Each caterpillar was fed on let¬
tuce, in a box by itself, and under as nearly similar con¬
ditions as possible, careful records being made, for the pur¬
pose of learning whether there was any difference in the
vitality of caterpillars hatched at different times, from the
same egg-cluster ; the period of rest before and after each
molt, and the time between each molt. No perceptible dif¬
ference was noticed in the vitality of those hatched at differ¬
ent times. It was observed that they all ate equally well
and appeared equally healthy, and that all their transforma-

300

THE GYPSY MOTH.

tions agreed very closely, except that those which hatched
latest did not require as many days in their molts, and there¬
fore reached the adult stage as soon as the others, although
marked variations occurred among the individuals of each
hatch (Plate 43). Some grew faster than others, while some
appeared to eat about the same amount as others and yet did
not grow as rapidly.

Description of the Larva or Caterpillar.

The following descriptions were prepared from the study
of from twenty-five to fifty caterpillars in each stage : —

First Larval Stage. — The larva, when first hatched, is
3.6 mm. (about fourteen hundredths of an inch) in length, and
the head is .6 mm. (about twenty-three thousandths of an inch)
in width and somewhat thicker than the body, shining black,
with a few (about forty) pale-yellow hairs scattered over the
surface, the longest of which are not quite equal to the width
of the head. There are a few additional hairs on the mouth
parts. The body is more or less cylindrical, slightly taper¬
ing toward the posterior part which is blunt and rounded.
When first hatched they are a pale brownish-yellow, with a
brown spot on the forward side of segments four to twelve
inclusive, on the subdorsal line of each side, but the ground
color stows darker within a few hours. The subdorsal tuber-
cles of the second segment (first after the head) are elon¬
gated laterally and joined at the dorsal line. These are of
a dark-brown color. The lateral tubercles of this segment
are fused, forming one very large lateral tubercle on each
side, which extends obliquely out and forward. The third
and fourth segments have three tubercles on each side, one
subdorsal, one lateral and one stigmatal. The remaining
segments, except the last, have large subdorsal and lateral
tubercles, the latter being so large as to fuse more or less
completely with those above them. There are three nearly
equal-sized tubercles on each side of the last segment, so
arranged as to form an arched row around the posterior end
of the animal.

The insect at this stage has two kinds of hairs arising
from the tubercles, the first of which (Plate 48, Fig. 8) is
about as long as the thickness of the body, of a pale-brown

PLATE 43. Variation in size of caterpillars of the same age.
Fifty caterpillars hatched from the same egg-cluster
were reared separately on lettuce leaves, all receiving
exactly the same treatment. When the caterpillars were
five weeks old, the two extremes in size, together with
a caterpillar of medium size, were photographed. The
smallest caterpillar as here shown has not molted. The
medium caterpillar has molted twice. The largest has
molted four times and is approaching the fifth molt.

THE CATERPILLAR.

301

color, smooth throughout, with a sharp point at the outer
end ; and at the basal third they have an inflated globule,
the diameter of which is three times as great as that of the
hair. The walls of this globule are delicate, and when the
insect is alive they are fully distended, probably with air or
gas ; but when dead they collapse more or less completely,
often causing the hair to be bent at this place. The first
and second rows of tubercles on each side have only hairs
of this kind on them. Similar hairs occur on the larva of
the nun moth ( Lymantria monacha ) before the first molt,
and have been called aerostatic hairs by Wachtl and Kor-
nauth, and the globules aerophores. These authors believe
that these inflated globules have the effect of small balloons,
and aid in transporting the young caterpillars to a consid¬
erable distance when the wind blows. The other kind of
hairs (filiform hairs) (Plate 48, Fig. 9) arise from the two
lateral rows of protuberances, and are unusually long, some
of them being longer than the body of the caterpillar ; and
they have several longitudinal rows of minute barbs extend¬
ing the entire length.

Later the caterpillar changes color, the tubercles becoming
black, the body reddish-brown with a row of dull reddish
spots along the middle of the back, one each on the fifth
to the eleventh segments inclusive. There are no retractile
tubercles in this stage.

The time between hatching and the first molt, of twelve
caterpillars bred in confinement, in an unheated room, was
from eight to twelve days, the average being nine and one-
fourth days. The temperature very materially affects the
time before molting, for, when caterpillars were kept in
breeding cages near warm steam pipes, they molted in five
days ; while others, from the same egg-cluster, kept in a
cool part of the room, molted in seven days.

Second Larval Stage. — Length, 7 mm. (about twenty-
seven hundredths of an inch), and the head is 1 mm. (about
thirty-nine thousandths of an inch) in width, shining black,
with numerous fine, pale-yellow hairs scattered over the sur¬
face. Body, dark brown, with the tubercles black, and a
somewhat triangular yellowish spot on the top of segments
nine, ten and eleven, in the middle of which, on segments ten

302

THE GYPSY MOTH.

and eleven, there is an orange-colored retractile tubercle, and
also one on each side of the dorsal line, near the front edge
of segments live, six, seven and eight, of the same color, but
much smaller. There are four rows of tubercles on each side,
which, named from above, may be called the subdorsal, the
lateral, the stigmatal and the substigmatal row, each with one
tubercle on each segment after the head. The tubercles of
the subdorsal rows on the second segment (first after the
head), on the front lndf of the segment, are subquadrate in
form, and but slightly separated from each other by the dorsal
line. The subdorsal tubercles of the third and fourth seg¬
ments are smaller, and nearly elliptical in outline, while
those on the remaining segments are larger and more nearly
circular. The tubercles of the lateral row are smaller than
those above, and on segments five to thirteen inclusive they
are partially fused with those of the stigmatal row ; but as
they are a little further forward than those below, the fusion
gives an obliquely elongated tubercle. To effect this fusion
the tubercles of these two rows are brought towards each
other. The tubercle of the stigmatal row, on the second seg¬
ment, is large, somewhat produced, and directed obliquely
forward. The substigmatal row consists of medium-sized
tubercles, lying directly above the legs and prolegs, and
about half-way between them and the stigmatal row. A little
below, and behind these tubercles, on segments seven to
eleven inclusive, is a very small tubercle, and on segments
five, six, eleven and twelve there are two small tubercles on
each side beneath, the inner ones being much the smaller.
The tubercles of the subdorsal and lateral rows are armed
with black, pointed spines and a few pale-yellow hairs, while
the remaining tubercles are armed with longer pale-yellow
hairs. On each side of the dorsal line, near the subdorsal
tubercles, on segments three to twelve inclusive, is a very
small tubercle, with one black spine and occasionally a few
pale-yellow hairs.

Third Larval Stage. — Length, 10 mm. (a little less than
one-half of an inch), immediately after molting, and the
head is 1.8 mm. (about seven hundredths of an inch) in
width, shining black, with numerous pale-yellow hairs scat¬
tered over the surface. The general color of the body is

THE CATERPILLAR.

303

dark brown and very much broken, giving the appearance
of a large spot on each segment. The lateral lines are dull
yellowish-white. Arrangement of tubercles, bristles and
hairs as in the last stage.

Fourth Larval Stage. — Length, 13 mm. (about half an
inch), immediately after molting, and the head is 2.8 mm.
(about eleven hundredths of an inch) in width, pale brown¬
ish-white, mottled on the sides and above with dark brown,
and there is a dark-brown vertical stripe on each side of the
clypeus and numerous pale-yellow hairs scattered over the
surface. The body is dark brown, finely mottled with yel¬
low ; while the dorsal line is pale ochre-reddish, enlarged
into small grayish spots on the middle of the sixth, seventh
and eighth segments, and on the ninth, tenth and eleventh
segments there are larger orange-colored spots. The lat¬
eral line is pale yellow, and below this the surface is ashy,
mottled with dark brown. The tubercles, spines and hairs
are as in the preceding stage.

Fifth Larval Stage. — Length, 23 mm. (about nine-tenths
of an inch), immediately after molting. The head is 3.6 to
4.4 mm. (about fourteen to seventeen hundredths of an
inch) in width, or about the same width as the following
segments without the lateral tubercles. The ground color
is cream-white, and there is a vertical, velvety-black stripe
on each side of the clypeus, outside and above which, the
surface is sprinkled more or less thickly with velvety-black
dots, which are more or less confluent. The labrurn and
mandibles are of a watery, whitish color, and the mouth
parts beneath are dull reddish. Scattered over the surface
are numerous pale-yellow setaceous hairs, varying in length
from the width of the head to half that length. The upper
surface of the body is cream- white, marked wdth black in
minute, irregularly formed spots, giving a general dark-gray
color, but leaving the dorsal line of a lighter color. The
subdorsal tubercles, on segments two to six inclusive, are
blue, and those on segments seven to twelve inclusive, are
red. All the tubercles and retractile tubercles are of the
same form, and arranged the same as in the last two stages ;
the spines and hairs are also like those in the preceding
stage. The fleshy, retractile tubercles on the dorsum of

304

THE GYPSY MOTH.

the tenth and eleventh segments usually have a convex cap
of hardened reddish fluid, which may be removed with the
point of a needle, and beneath which the tubercle is hollow
to the depth of three or four mm., and filled with a reddish
fluid, which has an agreeable odor, but I am not able to state
what it is like.

Sixth Larval Stage. — Length, 30 mm. (about one and
eighteen hundredths inches), immediately after molting.
The head is from 5.5 to G mm. (about twenty-two hun¬
dredths of an inch) in width, dull or yellowish white, and
more or less mottled with black or brown over the top and
sides, with a vertical black or brown stripe on each side of
the clypeus. There is a great variation in the ground color,
and also in the amount of black or brown on the surface of
the head. Fine yellow hairs are scattered over the surface,
and the color and markings are as in the preceding stage.

Seventh Larval Stage. — Length, from 35 to 40 mm.
There is no marked difference in appearance, in this stage,
from the preceding, except in size, and all caterpillars that
we have bred to this stage have transformed into female
moths. Only a comparatively small proportion of the cater¬
pillars reach this stage before pupating.

First and Last Appearance of Larvae.

The newly hatched caterpillars of the gypsy moth have
been found in the field as early as April 20, and as late as
June 17. In the summer of 1893, Mr. H. N. Reid found a
caterpillar which did not begin to pupate until September 6.
The feeding period of the caterpillar generally extends from
the first of May, to about the middle of July, but varies
somewhat with the season, and, in a less degree, with the
locality of the colony, those near the sea-shore being some¬
what slower in development than those farther inland.

Molts.

In the latter part of the winter of 1893, Miss Carrie Gor¬
don, one of the assistants at the Malden office, observed the
molts of several caterpillars of the gypsy moth, taken from
egg-clusters which had been kept in a warm room, and thus

MOLTING.

305

caused to hatch earlier than they otherwise would have done.
The caterpillars were fed on the leaves of lettuce, and four
of them completed their transformations, — two males and
two females, — while three more died in pupating. The
males molted five times and the females six times. Wishing
to determine whether there would be any difference between
these caterpillars, hatched out of season, and those reared
under normal conditions, twelve newly hatched caterpillars
of the gypsy moth, each in a separate box, were given to
Miss Rose Davis, one of my assistants, early in May, 1893.
These were fed on apple leaves, and each molt carefully
noted. Of this lot, seven females molted five times, one
female molted four times and four males molted four times.
As these results differed so materially from those of Miss
Gordon, I took fifty-five newly hatched caterpillars in May,
1894, fed each on apple leaves, in a separate box, and care¬
fully observed the molts myself. Fifty-two of these cater¬
pillars completed their transformations, with the following
results : one female molted six times, twenty-nine females
molted five times and nine females molted four times ; seven
males molted five times and six males molted four times.
These ‘results showed that in all probability no mistakes
were made by the other observers, and also that the process
of forcing the caterpillars makes no difference in the number
of molts, though the small number carried through by Miss
Gordon fails to make this point as conclusive as might be
desired.

The time between the hatching of the eggs, which occurred
Feb. 3, 1893, and the first molt, and also between the
remaining molts, is as follows, according to Miss Gordon’s
observations : —

From the time of hatching till the first molt, 6 days.

From the time of the first till the second molt, 7, 8 and 9 days.

From the time of the second till the third molt, 6 and 7 days.

From the time of the third till the fourth molt, 5, 6 and 7 days.

From the time of the fourth till the fifth molt, 6, 7 and 8 days.

From the time of the fifth till the sixth molt, 8 days.

According to Miss Davis’ observations, the time between
the hatching of the eggs, which occurred May 7 and 8, 1893,

The records of fifty caterpillars, hatched April 3, 1895, and reared at the insectary, are given below in tabulai

306 THE GYPSY MOTH.

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MOLTING

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308

THE GYPSY MOTH.

and the first molt, and also between the remaining molts, is
as follows : —

From the time of hatching till the first molt, 8, 9, 10 and 11
clays.

From the time of the first till the second molt, 7 and 8 days.

From the time of the second till the third molt, 7 and 8 days.

From the time of the third till the fourth molt, 6, 7 and 8 days.

From the time of the fourth till the fifth molt, 7, 8 and 9 days.

According to my own observations, the time between the
hatching of the eggs, which occurred April 28 and 29, 1894,
and the first molt, and also between the remaining molts, is
as follows : —

From the time of hatching till the first molt, 9, 10 and 11 days.

From the time of the first till the second molt, 11 days.

From the time of the second till the third molt, 5, 6 and 7 days.

From the time of the third till the fourth molt, 10 and 11 days.

From the time of the fourth till the fifth molt, 8, 9 and 10 days.

From the time of the fifth till the sixth molt, 13 days.

The Process of Molting.

When preparing to molt the young caterpillars remain
quiet for twenty-four hours or more. The head is withdrawn
from the old head covering, giving the caterpillar the appear¬
ance of having a very small head. The skin behind the head
covering is ruptured, and the caterpillar crawls out of it, the
whole process occupying not more than two minutes. Imme¬
diately after molting the long hairs of the body are curled up
considerably, but gradually straighten out in about an hour.
At intervals of about five minutes the caterpillar twists about,
bringing the head to the right and left and upwards and
backwards, nearly to the posterior end of the body, as if
stretching itself or trying its muscles. The head grows per¬
ceptibly darker, even within an hour from the time of molt¬
ing, and in a few hours the head becomes black and shining
and the caterpillar commences feeding.

The approach of the molting period, in the later molts, is
indicated by the development of a light-colored area, which
forms behind the head during three or four days preceding

PROCESS OF MOLTING.

309

molting. This area, which is but a narrow transverse line at
first, gradually widens and extends down each side of the
posterior margin of the head. It is widest on the dorsal line,
and is formed by the separation and projection forward of
the old chitinous covering of the head, while below and
beneath, the new light-colored head covering becomes visi¬
ble. The light-colored area is apparently the top of the head
drawn back from the old covering, and protected by the
tightly stretched integument of the annulation.

The caterpillar stops feeding usually from twenty- four to
forty-eight hours before molting, and rests quietly except for
occasional spasmodic twistings of the body. When the time
for molting arrives, the integument splits on the ventral part
of the annulation between the head and second segment and
partly up the sides. The caterpillar clings by means of its
prolegs to the surface on which it rests. It elevates the
middle segments, depresses segments four and five and ele¬
vates the head and segments two and three. Its contortions,
at this stage, somewhat resemble the travelling movements
of a geometrid caterpillar, and, as the band over the light-
colored area behind the head is very tenacious, the caterpillar
bends itself nearly double ; the feet are then withdrawn by
a series of successive movements ; with a few more con¬
tortions of the body sufficient force is developed to burst the
band in the rear of the head, and the dorsal surface of the
thoracic segments is molted. This stage requires about five
minutes from the first separation of the integument. The
head covering generally remains attached.

By alternately contracting and expanding, the remaining
segments are molted one after another. The last three seg¬
ments are generally molted in rapid succession, and the molt¬
ing, with the exception of the head, is completed in about
fifteen minutes. After resting a few minutes the caterpillar
begins to rid itself of the firm head covering. This is done
by bending down the anterior segments, and then rubbing the
top, front and sides of the head upon the surface to which the
caterpillar clings. Finally, the top of the head covering is
loosened and pushed off. This process of molting the head
requires from fifteen minutes to half an hour, and the whole
process is completed in less than an hour. After molting

310

THE GYPSY MOTH.

the caterpillar raises its head and swings it from side to side,
resting at intervals, and begins feeding in about twenty-four
hours. The increase in the size of the body over that of the
preceding molt, is more plainly noticed after the caterpillar
has taken its first meal, but the increased size of the head is
apparent at once. When first emerged from the molted skin
the head is nearly cream- white, with faint darker markings,
and all the colors of the body are light, but after a few
hours they darken to the normal shades. The dorsal retrac¬
tile tubercles are very prominent immediately after molting,
but regain their normal size in a short time.

Caterpillars attracted to Light.

When caterpillars hatch in hollow trees or other dark
places, they invariably find their way out in a short time,
being attracted, as it is supposed, towards the light. To
determine how strongly the light influenced them in their
movements, May 6, 1895, twenty-five newly hatched cater¬
pillars were placed in small pasteboard boxes which had a
small hole in each end. One end of each box was placed in
the bright sunlight, while the other end was shaded. In
an hour and a half all the caterpillars had emerged through
the holes in the ends exposed to the sun.

Distance Young Caterpillars are able to Travel.

For the purpose of ascertaining how far from the egg-
cluster a newly hatched caterpillar can travel without feed¬
ing, seven were placed on a large sheet of white paper on a
table. Their movements were traced by following them
with the point of a pencil on the paper as they crawled,
and these lines were carefully measured after the death of
the caterpillars. In their movements it was observed that
they showed a strong tendency to crawl towards the window
during the day, and towards the light of the lamp during the
night ; but in no case were they observed to be attracted
towards food, however near it was placed, provided it did
not touch their hairs. The distance travelled by each cater¬
pillar before it died was as follows : No. 1 travelled 904
feet; No. 2, 93 feet; No. 3, 143 feet; No. 4, 85 feet; No.
5, 36 feet; No. 6, 46£ feet; and No. 7, 144 feet; aver-

CATERPILLAR TRAPS.

311

age, about 91 feet. These observations have a bearing on
the question of how far the trees around a colony should be
burlapped.

Caterpillar Traps.

In the summer of 1895, at the suggestion of Mr. For-
bush, several attempts were made to capture the caterpil¬
lars of the gypsy moth by means of traps, constructed with
reference to their habit of seeking out cracks, crevices, etc.,
for shelter during the day. Different styles of traps were pre¬
pared, all made with small openings, closed by a fringe of
hair-cloth or felt, through which the insect might enter but
could not return. These traps were attached to the trunks
of badly infested trees ; and, while they caught and retained
a small number of caterpillars, as a whole they were not a
success.

When a number of old tin cans are placed along an
infested hedge or wall, at the time the caterpillars are
pupating, it has been found that they will enter them in
large numbers and pupate. Females, emerging in these
cans, deposit their eggs there ; and by frequent examination
of the cans a large number of pupae and egg-clusters can be
destroyed.

Feeding Habits.

In genera], it may be said that the gypsy moth caterpillar
is almost omnivorous so far aa foliage is concerned, and its
ability to adapt itself to nearly every food plant is one of
the chief obstacles to its extermination. For this reason,
also, it is capable of committing far greater depredations
than any of our common native insects. A list of food
plants attacked by the gypsy moth is given on succeeding
pages, and, since the ravages of the insect on fruit and
forest trees have been so fully described in Part I. of this
report, we pass to a more detailed account of the feeding
habits. The feeding habits of caterpillars of different ages
are shown on Plate 40.

Time and Manner of Feeding.

To determine the time and manner of feeding of the cater¬
pillars, a series of observations was made by Mr. Minott in

312

THE GYPSY MOTH.

1893, and repeated by Mr. Kirkland in 1894. Many obser¬
vations had been made by different members of the force,
but none were so extensive or complete as those made by
these gentlemen, yet all agreed more or less in regard to
the habits. To enable one to make observations on cater¬
pillars, on trees in the field or forest, it was necessary to
have some system of marking ; and for this purpose water-
colors were found to be excellent, and in no way injured the
insects ; though, in the case of caterpillars which were to be
continuously observed during the entire larval stage, it was,
of course, necessary to reapply the color after each molt.
Several different colors were used, especially those which
contrasted strongly with the ground color of the caterpil¬
lars.

From these observations it appears that the caterpillars
remain on the egg-cluster, after hatching, from one to five
or more da3's, according to the weather, when they wander
off to the leaves and commence feeding. The first food
is the leaf hairs, and, unless one observes very carefully,
he might suppose that they do not feed until they are four
or five days old ; from this time on, however, one can see
where they have eaten the tissues, making small holes
through the leaf, though occasionally they eat from the
edge ; but they are extremely irregular in their manner of
feedinof. Between the third and fourth molts their method
of feeding is about equally divided between eating holes
through the leaf and eating along the edge (Plates 40 and
44). From the fourth molt till they are ready to pupate,
they eat almost entirely from the edge of the leaf, though
there are occasional exceptions to this.

Mr. Kirkland’s observations on full-grown caterpillars
were made on the nights of July 7, 8 and 9, 1894. A me¬
dium-sized infested elm tree was selected, and all small twigs
and branches that might interfere were removed. A band of
burlap had been put aromid the trunk, about four feet from
the ground. Twenty caterpillars, some partly and some
fully grown, were under the burlap. Eight of these cater¬
pillars were marked with water-colors, in such a manner that
they could be distinguished from each other as well as from
those not marked. The caterpillars were numbered, and

1

PLATE 44. Oak leaves eaten by the caterpillars of the gypsy moth.
Taken from an infested tree, Saugus, July, 1894.

TIME AND MANNER OF FEEDING.

313

observations made every ten minutes, from 6 o’clock in the
afternoon till 5 the next morning. At 7.30 p.m., caterpillar
No. 4 began to grow uneasy, and moved about under the bur¬
lap or on the trunk below it. At 8.20 the first one, No. 2,
started up the tree from the burlap, and soon all the rest
were on the move. Some of the caterpillars, after climbing
up the trunk several feet, descended for a short distance and
then ascended again ; and they often stopped to rest on their
way up or down the tree trunk. At 9.50 No. 3 had reached
the leaves, sixteen feet from the burlap, and begun feeding.
Others reached the leaves later, and fed during the night
with intervals of rest. At about 3 a.m. they ceased feeding
and descended the trunk, and at 4.25 all were at rest under
the burlap or in crevices in the bark. One caterpillar about
to molt and one about to pupate remained quietly under the
burlap all night. It was further observed that the smaller
caterpillars, as a rule, fed on the lower branches, while many
of the larger ones went to the extreme tips of the upper
limbs.

Mr. Minott’s observations were made on the nights of
July 26, 27, 28 and 29, 1893 ; and the results were sub¬
stantially the same as in Mr. Kirkland’s observations, except
that the caterpillars started from their places of concealment
to ascend the trees a little earlier in the evening. The
observations of Mr. Kirkland, on a single caterpillar, will
illustrate fairly well the operations of the insect during the
night, though others varied slightly in their work : —

P.M.

7.40.

Caterpillar came out from under the burlap and

began

moving up the tree.

7.50.

Ascended the trunk, twelve feet from the burlap.

8.00.

Reached a leaf fifteen feet from burlap and commenced

feeding.

8.10.

Still feeding.

8.20.

Had three feeding spells between 8 and 8.15, with

short

rests between.

8.30.

Feeding.

8.40.

Moving.

8.50.

Feeding.

9.00.

Feeding.

314

THE GYPSY MOTH.

P.M.

9.10.

Feeding. It began at the base of the leaf, clasping the
petiole and twig with feet and prolegs, eating the base
of the leaf close to the midrib, then, raising its head,
worked out toward the margin of the leaf, making a
crescent-shaped cut, then started from the midrib

9.20.

9.30.

9.40.

again.

Feeding.

Resting, after having eaten steadily twenty-five minutes.
Feeding (began at 9.31). The caterpillar then fed
steadily until 11 p.m.

11.00.

Resting a few seconds, after feeding one and one-half
hours.

A.M.

12.10.

Feeding. Has fed continuously since 11.10; has eaten
the w hole of one side of a leaf and is now working
upon the tip.

12.20.

Feeding upon the tip of the remaining half of the leaf.
It begins at the midrib, actually eating it, then takes
a strip square across the leaf to the margin, then
begins eating again at the midrib. Sometimes it
reverses this movement, and feeds from the margin
to the midrib.

12.30.

12.40.

12.50.

Feeding.

Feeding.

Left the remains of its leaf, having eaten nearly all
through it, and started at once upon the second. The
caterpillar then fed without interruption until 3.20

A.M.

3.20.

Stopped feeding, crawled out to the end of the twig,
turned back and crawled down the main branch.

3.30.

3.40.

3.50.

4.00.

4.10.

Slowly descending (daylight approaching) .

Descending.

Descending, about four feet above the burlap.
Descending.

Crossed the burlap, crawled under it, and at once became
quiet.

Weather during the night, fair, cool and starlight.

Summary .

Detailed observations made on twenty-five caterpillars
may be summarized as follows : —

PLATE 45. Hornbeam and other trees stripped by the caterpillars
of the gypsy moth, Swampscott, 1891.

AMOUNT OF FOOD.

315

1. The large caterpillars leave the burlap or other places
of concealment for their places of feeding between 7 and 8
o’clock in the evening, or sometimes a little later.

2. They proceed by easy stages, resting frequently,
from their places of concealment to the places of feeding,
though some of them wander up and down the trees more
or less.

3. When the distance is short, they proceed directly to
the leaves and begin feeding immediately.

4. They feed and rest alternately, at frequent intervals
during' the night.

5. As a rule, they go to the same feeding place each
night and return to the same place of concealment, though
they will accustom themselves to a new feeding place,
especially in the younger stages.

6. They cease feeding at daylight (between 3 and 4
o’clock in the morning), but when it is cloudy they feed
later. It would seem that the first indication of daylight
is the signal for them to return to their places of con¬
cealment.

Amount of Food consumed by Caterpillars.

To learn the amount of food hungry caterpillars of dif¬
ferent ages would consume in twenty-four hours, the follow¬
ing experiment was made during the summer of 1895 : a
known quantity of food was supplied to the caterpillars,
and at the end of a specified time the remains of the leaves
were carefully soaked in water and then measured. May
10, at 4.30 p.m., three caterpillars, between the first and
second molt, were placed in a breeding jar with 6 square
inches of lettuce leaf. At 7.30 a.m., May 11, 4 square
inches were added, making a total of 10 square inches.
May 11, at 7.30 a.m., the refuse was removed, and equalled
2 square inches, thus giving 8 square inches as the amount
consumed by the three caterpillars, or 2| square inches per
caterpillar for twenty-four hours. May 10, at 4.30 p.m.,
three caterpillars, between the second and third molt, were
supplied with 9 square inches of lettuce leaf. The next
morning 4 square inches were added, and at 1.30 p.m.

316

THE GYPSY MOTH.

'2 square inches. The refuse, which was removed at 4.30
p.m., measured 3 square inches, making 12 square inches
which had been eaten by the three caterpillars, or 4 square
inches per caterpillar. May 10, at 4.30 p.m., three cater¬
pillars, between the third and fourth molt, were supplied
with lettuce as follows : May 10, at 4.30,9 square inches;
May 11, at 7.30, 4 square inches; and at 1.30 p.m. 4 square
inches: total, 17 square inches. The refuse was removed
May 11. and measured 3 square inches, leaving 14 square
inches as the amount consumed, or 4| square inches per
caterpillar. Three caterpillars, between the fourth and fifth
molt, were supplied with 18 square inches of lettuce at the
same date and hour, and on May 11, at 7.30 a.m., 9 square
inches were added ; and at 1.30 p.m. 9 square inches more.
The refuse, removed at 4.30 r.M., May 11, measured 5
square inches, leaving 31 square inches the amount con¬
sumed by all, or 101 square inches per caterpillar. June 20,
three caterpillars, between the last molt and pupation, were
given 20 square inches of lettuce leaf at 7 a.m., and at
5 r.M., 20 square inches more were added. At 7 a.m., June
27, the refuse was removed and soaked out. It then
measured 5 square inches, making 33 square inches that had
been eaten by the three caterpillars, or 11| square inches
per caterpillar.

These figures give evidence of the food capacity of the
caterpillars, but it should be borne in mind that lettuce does
not offer so much resistance to the jaws (mandibles) of the
caterpillar as do the harder leaves of the apple, oak and
others.

Food Plants.

A series of experiments was conducted during the part of
the season of 1895 that the gypsy moth was in the caterpillar
stage, for the purpose of determining so far as possible all
the plants this insect will feed upon. For this purpose col¬
lectors brought in specimens of all the plants met with in the
fields and forests of the infested territory. To Mr. H. L.
Frost, a careful student of botany as well as entomology,
was assigned the work of determining these plants and carry¬
ing out the details of the experiment. While the plants were

FOOD PLANTS.

317

still fresh they were placed in eight-ounce glass jars, and four
caterpillars, in the fourth or fifth molt, were placed upon them.
This number was about all that could feed without crowd¬
ing, and at the same time give appreciable results before the
plants wilted. The jars were covered at the top with thin
cloth, to prevent the escape of the caterpillars and at the
same time to allow ventilation. They were numbered, and
the numbers, with the names of the plants, were booked at
the time the caterpillars were placed on the food, the jars
being kept in a place sufficiently cool to prevent undue evap¬
oration, but at a temperature at which the caterpillars fed
readily. Observations were made every twenty-four hours,
and, if at the end of three days the caterpillars showed an
unwillingness to feed on the plant, the experiment was re¬
peated with a fresh stock of caterpillars on a fresh supply of
the same food. If they did not attack it at the second trial,
in view of their accustomed readiness to feed on nearly all
plants, it was assumed that they would not feed on the plant
in question. The flora of the region about Malden is mari¬
time rather than inland, and some of the common plants
of the central and western parts of the State do not occur
there.

Attention is called to the fact that the caterpillars of
the gypsy moth feed readily on common water plants,
such as Nymph/m odorata, Pontederia cor data and Alirraa
planlago. Experiments performed this year proved that
some of the caterpillars will live for several days floating
on the water and without food. These two facts in connec¬
tion may help to explain the distribution of this insect along
streams.

In the following lists both the common and scientific
names are given, as far as possible. The nomenclature is
that of Gray’s “Manual of Botany,” 1889, for the wild
plants, and Wood’s “Botany” of 1889, for the cultivated
plants. An asterisk before a name denotes that the cater¬
pillars fed on the plant only when forced to do so by
starvation. It will be noticed that about twenty-one per
cent, of the plants in the following list are of economic
value.

318

THE GYPSY MOTH.

Plants upon which the Gypsy Moth Caterpillar has been known to feed
in Massachusetts.

Virgin’s bower ( Clematis Virginiana).

♦Wind flower ( Anemone Virginiana).

White water crowfoot ( Ranunculus
aquatilis, var. trichophyllus) .

Small-flowered crowfoot ( Ranunculus
abortivus) .

Hooked crowfoot ( Ranunculus recur -
vatus ) .

Bulbous crowfoot ( Ranunculus bulbo-
sus).

Wild columbine ( Aquilegia Canaden¬
sis).

Peony (Pceonia officinalis).

Umbrella tree ( Magnolia umbrella).

* Magnolia Soulangeana.

Tulip tree ( Liriodendron Tulipifera).

Siberian pea tree {Car ag ana arbor es-
cens).

Barberry (Berberis vulgaris) .

Holly barberry ( Berber is Aquifolium) .

White water lily (Nymphcea odorata).

Pitcher plant ( Sarracenia purpurea) .

Celandine ( Chelidonium majus) .

Poppy ( Papaver orientalis) .

♦Pale corydalis ( Corydalis glauca) .

♦Sweet alyssum (Alyssum maritimum) .

Horseradish ( Nasturtium Armoracia).

Hedge mustard ( Sisymbrium officinale) .

Black mustard ( Brassica nigra).

Turnip ( Brassica rapa , var. depressa).

Savoy cabbage ( Brassica oleracea, var.
bullata) .

Shepherd’s purse ( Capsella Bursa-pas -
toris) .

Wild peppergrass (Lepidium Virgini-
cum).

♦Sea rocket ( Cakile Americana).

Radish ( Raphanus Raphanistrum) .

Blue violet ( Viola palmata, var. cucul-
lata).

Primrose-leaved violet ( Viola primulce-
folia).

Lance-leaved violet ( Viola lanceolata).

Dog violet ( Viola canina, var. Muhlen-
bergii) .

Pansy ( Viola tricolor) .

Carnation pink ( Dianthus caryophyl-
lus).

♦Sweet William ( Dianthus barbatus).

Bouncing bet ( Saponaria officinalis).

Corn cockle ( Lychnis Githago).

Common chickweed ( Stellaria media).

Mouse-ear chickweed ( Cerastium vul-
gatum) .

Sand spurrey ( Buda rubra).

Purslane ( Portulaca oleracea).

St. John’s-wort ( Hypericum perfor¬
atum) .

Marsh St. John’s-wort ( Elodes campan-
ulata) .

Hollyhock (Altheea rosea).

Common mallow ( Malva rotundifolia) .
Indian mallow ( Abutilon vexillarium) .
♦Chinese hibiscus ( Hibiscus Rosa-Sinen-
sis).

Cotton plant ( Gossypiuni herbaceum) .
Basswood ( Tilia Americana).

European linden ( Tilia Europcea).

Wild eranesbill ( Geranium maculatum) .
Geranium ( Geranium sanguineum).
Yellow wood sorrel ( Oxalis corniculata ,
var. stricta).

Nasturtium (Tropceolum majus) .
Spotted touch-me-not ( Impatiens fulva) .
Fraxinella ( Dictamnus albus).
♦Shrubby trefoil ( Ptelea trifoliata).
♦Lemon ( Citrus Limonum).

Tree of Heaven ( Ailanthus glandulo-
sus) .

Black alder (Ilex verticillata) .

Climbing bittersweet ( Celastrus scan-
dens) .

European spindle-tree ( Euonymus
Europeeus) .

Grape ( Vitis vinifera) .

Northern fox grape ( Vitis Labrusca).
Virginian creeper ( Ampelopsis quinque-
folia) .

Ampelopsis veitchii.

Horse chestnut ( rEsculus Hippocas-
tanum).

Red buckeye ( JEsculus Pavia).

Sugar maple (Acer saccharinum) .
White maple (Acer dasycarpum) .
Cut-leaved maple (Acer dasycarpum ,
var. Weirii).

Red maple (Acer rubrum).

Sycamore maple (Acer Pseudo-Plat-
anus).

Box elder (Negundo aceroides).
Variegated box elder (Negundo acer¬
oides, var. variegata) .

Kceulreuteria paniculata.

Stag-horn sumach (Rhus typhina).
Smooth sumach (Rhus glabra).

Poison dogwood (Rhus venenata).
Poison ivy (Rhus Toxicodendron).
Rhus vernex.

FOOD PLANTS.

319

Plants upon which the Gypsy Moth Caterpillar has been known to feed
in Massachusetts — Continued.

Smoke tree ( Rhus Cotinus).

Milkwort (Poly gala poly gama).

Wild indigo (Baptisia tinctoria).
Yellow wood (Cladrastis lutea).

Dyer’s green weed ( Genista tinctoria ) .
Rabbit-foot clover (Trifolium arvense).
White clover (Trifolium repens).

Red clover (Trifolium pratense) .

Alsike clover (Trifolium hybridum).
Yellow clover (Trifolium agrarium).
Low hop clover (Trifolium procumbens) .
False indigo (Amorpha fruticosa) .
Locust (Robinia Pseudacacia) .
Wistaria ( Wistaria consequana) .

Tick trefoil (Desmodimn nudforum).
Common vetch ( Vicia sativa ) .

Beach pea (Lathyrus maritimus).
Ground-nut (Apios tuberosa).

Scarlet pole bean (Phaseolus multi-
forus).

Bush bean (Phaseolus nanus).

Red bud (Cercis Canadensis) .
Kentucky coffee tree (Gymnocladus
Canadensis) .

Honey locust (Gleditschia triacanthos) .
Chinese honey locust (Gleditschia Si-
?iensis) .

Coffee bean (Faba vulgaris).

Pea (Pisum sativum).

Cercidiphyllum Japonicum.

Beach plum (Prunus maritima).

Wild red cherry (Prunus Pennsylvan¬
ia a) .

Choke cherry (Prumis Virginiana).
Wild black cherry (Prunus serotina).
Damson plum (Prunus domestica) .
English cherry ( Prunus Avium) .

Peach (Prunus vulgaris).

Purple-leaved plum (Prunus Pissardi).
Prunus Davidii.

Apricot (Prunus Armeniaca) .

Japanese plum (Prunus Japonica).
Meadow sweet (Spircea salicifolia) .
Hardhack (Sjnrcea tomentosa) .

Spircea Thunbergii.

Purple flowering raspberry (Rubus
odoratus) .

Dwarf raspberry ( Rubus triforus).

Wild red raspberry (Rubus strigosus).
Thimbleberry (Rubus occidental is).
High blackberry (Rubus villosus).

Low blackberry (Rubus Canadensis).
*Avens (Geutn macrophyllum).
Strawberry (Fragaria Virginiana).

*Cinquefoil (Potentilla Norvegica).

Silvery cinquefoil (Potentilla ar gen-
tea).

Common cinquefoil (Potentilla Can¬
adensis) .

Shrubby cinquefoil (Potentilla fruti¬
cosa) .

Agrimony (Agrimonia Eupatoria).

Prairie rose (Rosa setigera) .

Dwarf wild rose (Rosa lucida).

Rose (Rosa nitida).

Crab apple (Pyrus coronaria).

Narrow-leaved crab apple (Pyrus au¬
gust folia) .

Choke berry (Pyrus arbutifolia) .

American mountain ash (Pyrus Amer¬
icana) .

Pyrus sambucifolia.

Pyrus pinnatifida.

Pyrus decata.

Pear (Pyrus communis) .

Apple (Pyrus Malus).

English hawthorn (Cratagus Oxyacan-
tlia).

Paul’s thorn (Crataegus coccinea, var.
Paulii) .

Cockspur thorn (Crataegus Crus-galli).

Shad bush (Amelanchier Canadensis).

Amelanchier alnifolia.

Quince (Cydonia vulgaris).

Japan quince (Cydonia Japonica) .

^Sweet-scented shrub (Calycanthus fo-
ridus) .

Mock orange ( Philadelphus coronarius) .

*Deutzia gracilis.

Hydrangea paniculata.

Common red currant ( Ribes rubrum) .

Black currant (Ribes nigrum).

Gooseberry (Ribes grossularia) .

English gooseberry (Ribes Uva-crispa).

Ditch stonecrop (Penthorum sedoides).

Garden orpine (Sedum Telephium) .

Witch hazel (Hamamelis Virginiana) .

Sweet gum tree (Liquidambar Styraci-
fiua).

Swamp loosestrife (Decodon verticil-
latus) .

Pomegranate (Punica granatum).

Great willow herb (Epilobium angusti-
folium) .

Slender willow herb (Epilobium lin¬
ear e).

Common evening primrose (CEnothera
biennis) .

320

THE GYPSY MOTH.

Plants upon which the, Gypsy Moth Caterpillar has been known to feed
in Massachusetts — Continued.

Evening primrose (( Enothera pumila).
Ladies’ eardrop ( Fuchsia coccinea ).
Squash ( Cucurbita verrucosa) .
Cucumber ( Cucumis sativus).

•Parsnip (Peucedanum sativum).

Zizia aurea.

Celery (Apium graveolens) .

Spotted cowbane ( Cicuta maculata).
Hercules’ club ( Aralia spinosa) .

Wild sarsaparilla (Aralia nudicaulis) .
Flowering dogwood ( Cornus Jlorida).
Cornus mas.

Common elder ( Sambucus Canadensis) .
Cranberry tree (Viburnum Opulus).
Arrowwood (Viburnum acerifolium) .
Downy arrowwood (Viburnum pubes-
cens) .

Arrowwood ( Viburnum dentatum) .
Viburnum tomentosum.

Sweet viburnum (Viburnum Lentago).
Black haw (Viburnum pruni folium) .
Wayfaring tree (Viburnum Lantana).
Snowberry ( Symphoricarpus racemo-
sus).

Trumpet honeysuckle (Lonicera sem-
pervirens) .

Bush honeysuckle (Diervilla trijida).
Wiegelia rosea.

Button bush (Cephalanthus occiden¬
tals) .

Partridge berry (Mitchella repcns).
Small bedstraw (Galium trifidum).
Rough bedstraw (Galium asprellum).
Joe pye weed (Eupatorium purpureum) .
Thoroughwort (Eupatorium perfolia-
tum) .

Golden-rod (Solidago rugosa).
Golden-rod (Solidago arguta).
•Golden-rod (Solidago Canadensis) .
Golden-rod ( Solidago lanceolata) .

Aster undulatus.

Aster cordifolius.

Aster leevis.

Aster puniceus.

Aster miser.

Horse weed (Erigeron Canadensis) .
Fleabane (Erigeron P hiladelphicus) .
Elecampane (Inula Helenium) .

Roman wormwood (Ambrosia artemis-
icefolia) .

Cone flower (Rudbeckia hirta).
Sunflower (Helianthus annuus).
*Helianthus decapetalus.

Artichoke (Helianthus tuberosus) .

Beggar ticks (Bidens frorulosa) .

Bur marigold (Bidens chrysanthe-
moides) .

May weed (Anthemis Cotula).

Yarrow (Achillea Millefolium) .

Ox-eye daisy (Chrysanthemum Leu-
canthemum) .

Chrysanthemum (Chrysanthemum Si-
nense) .

Tansy (Tanacetum vulgare).

Fireweed (Erechtites hieracifolia) .
Burdock (Arctium Lappa).

Common thistle (Cnicus lanceolatus) .
Tall thistle (Cnicus altissimus).

Canada thistle (Cnicus arvensis).

Dwarf dandelion (Krigia Virginica).
Chicory (Cichorium Intybus).

Fall dandelion (Leontodon autumnale) .
Rattlesnake root (Prenanthes altis-
sima) .

•White lettuce (Prenanthes alba).
Dandelion (Taraxacum officinale).
Lettuce (Lactuca sativa).

Common dahlia (Dahlia variabilis) .
French marigold (Tagetes patula).
Indian tobacco (Lobelia infiata).
Lobelia spicata.

Venus’ looking glass (Specularia per-
foliata) .

Dangleberry ( Gaylussacia frondosa) .
Black huckleberry (Gaylussacia resin-
osa).

Dwarf blueberry ( Vaccinium Pennsyl-

vanicum) .

Low blueberry ( Vaccinium vacillans) .
Swamp blueberry (Vaccinium corym-
bosum).

Leather leaf (Cassandra calyculata) .
Sheep laurel (Kalmia angustifolia) .
Clammy azalea (Rhododendron visco-
sum) .

Rhodora (Rhododendron Rhodora).
Great laurel (Rhododendron maximum).
Labrador tea (Ledum latifolium) .
Sweet pepperbush ( Clethra alnifolia) .
Prince’s pine (Chimaphila umbellata).
Shin leaf (Pyrola elliptica).

Pyrola rotundifolia.

Star flower (Trientalis Americana).
Steironema ciliatum.

Loosestrife (Lysimachia quadrifolia) .
Sweet leaf (Symplocos cratcegoides) .
White ash (Fraxinus Americana) .

Red ash (Fraxinus pubescens) .

FOOD PLANTS.

321

Plants upon which the Gypsy Moth Caterpillar has been known to feed
in Massachusetts — Continued.

Blue ash ( Fraxinus quadrangulata) .
Black ash ( Fraxinus sambucifolia) .
European ash ( Fraxinus excelsior).
Fraxinus Oregona.

Fraxinus rhycophylla.

Fraxinus Sag-Diana.

Fringe tree ( Chionanthus Virginica).
Privet ( Ligustrum vulgare).

Common lilac ( Syringa vulgaris).
Japanese lilac ( Syringa Japonica) .
Forsythia viridissima.

Dogbane f A pocynum androseemifolium) .
Swamp milkweed (Asclepias incarnata) .
Common milkweed ( Asclepias Cornuti) .
Poke milkweed ( Asclepias phytolac-
coides) .

Forget-me-not ( Myosotis arvensis).
Heliotrope ( Heliotropium Peruvianum) .
Morning glory (Ipomcea purpurea) .
Dodder ( Cuscuta Gronovii).

Bittersweet ( Solanum Dulcamara) .
Potato ( Solanum tuberosum).

Petunia nyctaginifolia.

Tomato ( Ly coper sicum esculentum).
Matrimony vine ( Lycium vulgare).
♦Virginia tobacco ( Nicotiana Tabacum) .
Nicotiana longiflora.

Mullein ( Verbascum Thapsus).

Toad flax ( Linaria Canadensis).

Butter and eggs ( Linaria vulgaris).
♦Monkey flower ( Mimulus ringens)
Water speedwell ( Veronica Anagallis) .
♦Purple gerardia ( Gerardia purpurea) .
Trumpet creeper ( Tecoma radicans) .
Catalpa ( Catalpa bignonioides) .

♦White vervain ( Verbena urticce folia) .
♦Blue vervain (Verbena hastata) .
Spearmint (Mentha viridis) .
Peppermint (Mentha piperita) .

Bugle weed (Ly copus Virginicus).
Catnip (Nepeta Cataria).

Self heal (Brunella vulgaris) .

Dead nettle (Lamium album).

Scarlet sage (Salvia splendens) .
Common plantain (Plantago major).
Seaside plantain (Plantago maritima).
Green amaranth (Amarantus retro-
flexus) .

Pigweed (Chenopodium album).

Coast blite (Chenopodium rubrum).
Spinach (Spinacia oleracea) .

Beet (Beta vulgaris).

Garget ( Phytolacca decandra) .

Patience dock (Rumex Patientia).

Swamp dock (Rumex verticillatus) .
Curled dock (Rumex crispus).

Sheep sorrel (Rumex Acetosella) .
Rhubarb (Rheum Rhaponticum) .

Coast knotgrass (Polygonum mariti-
mum).

Door weed ( Polygonum aviculare) .
Polygonum Pen nsylvanicum .

W ater persicaria ( Polygonum amphib-
ium) .

Polygonum Careyi.

Lady’s thumb (Polygonum Persicaria) .
Water pepper (Polygonum hydropiper-
oides) .

Smart weed (Polygonum Hydropiper).
Arrow-leaved tear thumb (Polygonum
sagittatum) .

Sassafras (Sassafras officinale).
Oleaster (Eleeagnus hortensis) .
Elceagnus Longipes.

Elceagnus umbellata.

Spurge (Euphorbia Cyparissias) .
Slippery elm ( Ulmus fulvus) .

White elm ( Ulmus Americana) .

Cork elm (Ulmus racemosa).

English elm (Ulmus campestris).
Scotch elm ( Ulmus montana) .

Common hop (Humulus Lupulus).

Red mulberry ( Morns rubra) .

Tartarian mulberry (Morus Tartarica).
Nettle (Urtica gracilis) .

N ettle ( Urtica dioioa) .

India rubber tree (Ficus elastica).
Sycamore (Platanus occidentalis) .
Butternut (Juglans cinerea).

Shell-bark hickory ( Cary a alba) .
White-heart hickory ( Cary a tomentosa).
Pignut (Cary a porcina).

Bay berry (Myrica cerifera).

Sweet fern (Myrica asplenifolia) .
Black birch (Betula lenta).

Yellow birch (Betula lutea).

White birch (Betula populifolia).
Paper birch (Betula papyrif era) .

River birch (Betula nigra).

Cut-leaved birch (Betula alba, var.

laciniata) .

Betula Danurica.

Speckled alder (Alnus incana).

Smooth alder (Alnus serrulata) .

Wild hazelnut (Corylus Americana).
Hop hornbeam ( Ostrya Virginica) .
White oak ( Quercus alba) .

Swamp white oak (Quercus bicolor).

322

THE GYPSY MOTH.

Plants upon which the Gypsy Moth Caterpillar has been known to feed
in Massachusetts — Concluded.

Red oak ( Quercus rubra) .

Scarlet oak ( Quercus coccinea) .

Black oak ( Quercus coccinea, var. tinc-
toria) .

Pin oak ( Quercus palustris) .

Scrub oak {Quercus ilicifolia) .

Barren oak ( Quercus nigra).

Chestnut ( Castanea sativa, var. Ameri¬
cana) .

Chinquapin ( Castanea pumila) .

Blue beech ( Carpinus Caroliniana) .
American beech {Fagus ferruginea) .
Purple beech {Fagus sylvatica, var.
purpurea) .

Crack willow {Salix fragilis) .

White willow {Salix alba).

Weeping willow {Salix Babylonica) .
Heart-leaved willow {Salix corclata).
White poplar {Populus alba).

American aspeD {Populus tremuloides) .
Large-toothed aspen {Populus grandi-
dentata) .

Balm of Gilead {Populus balsamifera,
var. candicans).

Black poplar ( Populus nigra) .
Lombardy poplar {Populus nigra, var.
dilatata).

"White pine {Pinus Strobus).

Pitch pine {Pinus rigida).

Scotch pine ( Pinus sylvestris) .

White spruce {Picea alba).

Norway spruce {Picea excelsa) .

Fir {Abies balsamea).

Hemlock {Tsuga Canadensis).

Larch {Larix Americana).

European larch {Larix Europcea).
Arbor vita; {Thuja occidentals).
Common juniper {Juniperus communis) .
Red cedar {Juniperus Virginiana).
♦Ginkgo {Juniperus Salisburia adianti-
folia) .

Ladies’ tresses {Spiranthes gracilis) .
Yellow fringed orchis {Rabenaria cili-
aris) .

Lady’s slipper ( Cypripedium acaule) .
Banana {Musa sapientum).

Canna {Canna Indica).

Blue flag {Iris versicolor) .

Blue-eyed grass ( Sisyrinchium angusti-
folium) .

Snowdrop ( Galanthus nivalis) .

Carrion flower ( Smilax herbacea) .
Common greenbrier {Smilax rotundi-
folia) .

Day lily {Remerocallis fulva) .

Adam’s needle ( Yucca Jilamentosa) .

Lily of the valley ( Convallaria majalis) .
Solomon’s seal {Polygonatum biflorum).
Asparagus {Asparagus officinalis).

False Solomon’s seal {Smilacina race-
mosa) .

* M aianthemum Canadense.

Bell wort ( Oakesia sessilifolia) .

Wood lily {Lilium Philadelphicum) .
Wild yellow lily {Lilium Canade?ise).
Tiger lily {Lilium tigrinum).

Indian cucumber root {Medeola Vir¬
ginia) .

Pickerel weed ( Pontederia cor data) .
Yellow-eyed grass {Xyris jlexuosa) .
Common cat tail {Typha latifolia).

Bur reed {Sparganium simplex).

Indian turnip {Ariscema triphyllum).
Arrow arum ( Peltandra undulata) .
Skunk cabbage {Symplocarpus fceti-
dus).

♦Sweet flag (Acorus Calamus).

Phyllodendron Amurense.

♦Water plantain {Alisma Plantago).
Arrow head {Sagittaria variabilis, var.
gracilis) .

Cotton grass {Eriophorum polystach-
yon).

Millet ( Panicum miliaceum) .

Finger grass {Panicum sanguinale) .
♦Barnyard grass {Panicum Crus-galli) .
Herd’s grass, Timothy {Phleum pra-
tense) .

♦Meadow foxtail {Alopecurus pratensis) .
Common oat {Arena sativa).

Eragrostis pectinacea.

Low spear grass {Poa annua) .
Kentucky blue grass {Poa jwatensis) .
Barley {Rordeum vulgar e).

Orchard grass {Dactylis glomerata).
Quitch grass {Agropyrum repens).
Bamboo {Bambusa arundinacea) .
Indian corn {Zea Mays).

Common horsetail {Equisetum arvense).
Common brake {Pteris aquilina).
♦Spleen wort {Asplenium ebeneum).
Shield fern {Aspidium Noveboracense) .
Sensitive fern {Onoclea sensibilis) .
Flowering fern ( Osmunda regalis) .
Osmunda Claytoniana.

Cinnamon fern ( Ostmmdacinnamomea) .
♦Ground pine {Lycopodium obscurum).
Selaginella apus.

FOOD PLANTS.

323

Plants upon which the Gypsy Moth

in the

Tulip tree ( Liriodendron Tulipifera).
Barberry ( Berberis vulgaris) .

Bass wood ( Tilia Americana).

European linden ( Tilia Europcea).
Northern fox grape ( Vitis Labrusca) .
Horse chestnut ( JEsculus Rippocasta-
num).

Sugar maple ( Acer saccharinum) .

White maple (Acer clasp carpum) .
Cut-leaved maple ( Acer dasy carpum,
var. IVeirii).

Red maple (Acer rubrum) .

Staghorn sumach (Rhus typhina).
Smooth sumach (Rhus glabra).

Foison ivy (Rhus toxicodendron).
Common locust (Robinia Pseudacacia) .
Cercidiphyllum Japonicum.

Wild red cherry (Primus Pennsylvan¬
ia) .

Choke cherry (Primus Virginiana) .

W ild black cherry ( Prunus serotina) .
Damson plum (Prunus domestica) .
Purple-leaved plum (Prunus Pissardi).
Wild red raspberry (Rubus strigosus).
Thimbleberry ( Rubus occidentalis) .

High blackberry (Rubus villosus) .

Low blackberry (Rubus Canadensis) .
Strawberry (Frag aria Virginiana).

Rose (Rosa nitida).

Dwarf wild rose (Rosa lucida).

Choke berry (Pyrus arbutifolia) .
American mountain ash (Pyrus Amer¬
icana) .

Pear ( Pyrus communis) .

Apple (Pyrus Malus).

Paul’s thorn (Crataegus coccinea, var.
Paulii) .

Shad bush (Amelanchier Canadensis).
Quince (Cydonia vulgaris) .

Arrow wood (Viburnum acerifolium).
Ox-eye daisy (Chrysanthemum Leu-
eanthemum) .

Burdock (Arctium Lappa).

Dangleberry (Gaylussacia frondosa) .
Low blueberry (Vaccinium vaciUans).
Swamp blueberry (Vaccinium corym-
bosum).

Plants upon which the Gypsy

Red baneberry (Act tea spicata, var.
rubra).

Rocket larkspur (Delphinium Ajacis).

Caterpillar has been found feeding
Field.

Clammy azalea (Rhododendron visco -
sum).

White ash (Fraxinus Americana) .
Common lilac (Syringa vulgaris).
Bittersweet '(Solatium Dulcamara) .
Mullein (Verbascum Thapsus).

Slippery elm (XJlmus fulva).

White elm (Ulmus Americana).

English elm ( Ulmus campestris) .
Sycamore (Platanus occidentalis).
Butternut (Juglans cinerea).

Shell-back hickory ( Cary a alba) .
White-heart hickory ( Cary a tomentosa) .
Pignut (Carya porcina).

Bay berry (Myrica cerifera).

American white birch (Betula populi-
folia).

Paper birch (Betula papyrifera) .

River birch (Betula nigra) .

Cut-leaved birch (Betula alba , var.
laciniata) .

Smooth alder (Alnus serrulata) .

Wild hazel nut ( Corylus Americana) .
White oak (Quercus alba).

Swamp white oak (Quercus bicolor).
Red oak (Quercus rubra).

Scrub oak ( Quercus ilicifolia) .
Chestnut ( Castanea sativa, var. Ameri¬
cana) .

Blue beech ( Carpinus Caroliniana) .
American beech ( Fagus ferruginea) .
Purple beech (Fagus sylvatica, var.
purpurea) .

White willow (Salix alba).

Weeping willow (Salix Babylonica) .
American aspen (Populus tremuloides) .
Balm of Gilead (Populus balsamifera,
var. candicans).

White pine (Pinus Strobus).

Pitch pine (Pinus rigida).

Common greenbrier (Smilax rotundi
folia) .

False Solomon’s seal (Smilacina race-
mosa) .

Kentucky blue grass (Poa pratensis) .
Common brake (Pteris aquilina).

Moth Caterpillar did not feed.

Bee larkspur (Delphinium elatum).
Great-flowered larkspur (Delphinium
grandiflorum) .

824

THE GYPSY MOTH.

Plants upon which the Gypsy Moth Caterpillar did not feed —

Winter cress ( Barbarea vulgaris).
Balsamine ( Impatiens balsatnina ) .
Myrtle ( Myrtus communis) .

Bur cucumber ( Sicgos angulatus).
Everlasting ( Antennaria plantagini-
folia).

Common everlasting ( Gnaph'alium poly-
cephalum) .

Common mugwort(^4r£emma vulgaris) .

Concluded-

Bluebottle ( Centaurea Cyanus) .
Rattlesnake weed ( Hieracium venosum) .
Indian pipe (Mo?ioti'opa unijlora) .

Red pepper ( Capsicum annuum).
Ground hemlock ( Tarns Canadensis).
Pogonia ophioglossoides.

Ground pine ( Lycopodium complana-
tum) .

Marsilia quadrifolia.

Cotton as a Food Plant.

The question was raised whether the gypsy moth would
prove destructive to the cotton plant in the South, should it
by any means escape from its present locality and Become dis¬
tributed in the cotton States. To decide this question, cotton
seeds were planted and two small plants were raised. When
one of these was about two inches high, gypsy caterpillars
were placed on it, and they devoured not only the leaves but
nearly all the stem, during a single night. The second plant
died before reaching the size desired for the experiment.

By correspondence with Mr. F. B. Carpenter of the agri¬
cultural experiment station at Raleigh, N. C., a dozen small
cotton plants were obtained, which were from two to two
and a half feet high. Although the plants were well packed,
they were badly wilted when they arrived. All but two were
set out in the ground in different places, in the hope that
some of the varied soils would prove congenial, but unfort¬
unately none of them lived. The leaves of one remaining
plant were taken off and put into ajar with ten caterpillars.
Notwithstanding the fact that the leaves were badly wilted,
the caterpillars on the second dav had eaten about one-fourth
of them, but at the end of this day the leaves had become so
dry that this experiment was discontinued. The remaining
plant, having been kept in water, had revived somewhat, and
on July 22 twenty caterpillars, of the fifth molt, were placed
upon it, the base of the plant being kept in water. The cat¬
erpillars at once began feeding heartily on the plant, appear¬
ing to prefer the fresh leaves at the top to the lower wilted
ones. They continued to feed till July 25, at which time
they had devoured the greater part of the plant, having eaten
leaves, tender petioles and half- developed boll. From this

PLATE 46. Oak branch attacked by gypsy moth caterpillars,
Saugus, July, 1894.

EUROPEAN FOOD-PLANTS.

325

experiment it seems evident that, if they were numerous in
a Southern cotton field, they might prove quite as destruc¬
tive as the cotton worm ( Aletia argillacea) .

Plants upon which the Gypsy Moth Caterpillar has been known to feed

in Europe.

Cabbage ( Brassica oleracea) .

Rock rose ( Cist us Laurifolius) .

Linden ( Tilia Europcea).

Spindle tree (Euonymus verrucosus) .
Sycamore (Acer Pseudo-Plantanus ) .
Tartar maple (Acer Tartaricum) .
White lupine (Lupinus albus).

Maple (Acer platanus) and other species.
Sainfoin ( Onobrychis sativa) .

Chinese wistaria ( Wistaria Sinensis) .
Pea vines (Pisurn sativum).

Honey locnst (Gleditschia triacanthos) .
Plnm (Prunus domestica) .

Prune (Prunus occidentalis ?).

Peach (Prunus Persica).

Apricot ( Prunus Armeniaca) .

Sloe (Prunus spinosa).

English cherry (Prunus Avium).

Laurel cherry (Prunus Laurocerasus) .
Black service berry (Prunus padus).
White thorn (Cratcegus Pyracantha) .
Hawthorn (Cratcegus Oxyacantha).
Quince (Cydonia vulgaris).

Mountain ash (Pyrus aucuparia) .
Apple (Pyrus malus).

Pear (Pyrus communis) .

European medlar (Mespilus German-
ica) .

Chinese medlar (Photinia serrulata).
Loquat tree (Eriobotrya Japonica) .
Strawberry (Fragaria vesca).

Rose (Rosa canina).

Rose (Rosa centifolia) .

Pomegranate (Punica granatum) .
Currant (Ribes alpinum).

Gooseberry (Ribes Ura-crispa) .
Cucumber (Cucumis sativus).

Spotted hemlock (Conium maculatum).
Water hemlock (Cicuta virosa).

Lettuce (Lactuca sativa) .

Heath (Erica Melaleuca).

Heather (Calluna vulgaris).

Azalea, various species.

Pimpernel (Anagallis arvensis ?).

Olive (Olea Europcea) .

Ash (Fraxinus excelsior).

Rhubarb (Rheum Rhaponticum) .

Elm ( Ulmus campestris) .

Elm ( Ulmus effusa) .

Elm (Ulmus pedunculata).

Elm (Ulmus subrosa).

Fig (Ficus Carica).

Plane tree (Platanus orientalis) .
Walnut (Jug Ians nigra).

Cork oak (Quercus suber).

Holm oak ( Quercus Ilex) .

Winter oak (Quercus pedunculata , var.
tardifiora) .

Oak (Quercus pubescens) and other
species.

Chestnut ( Castanea vesca) .

Beech (Fagus sylvaticus).

Hazel-nut (Corylus Avellana).
Hornbeam (Carpinus betulus).
Hornbeam ( Carpinus orientalis) .

Sweet gale (Myrica gale) .

Birch (Betula alba) and other species.
Alder (Alnus glutinosa) .

Speckled alder (Alnus incana).

Osier willow (Salix viminalis) .

White willow (Salix alba).

Brittle willow (Salix fragilis).

Poplar willow (Populus nigra) .

Aspen (Populus tremula) .

Willow (Populus alba) and other spe¬
cies.

Fir (Pinus Abies).

Scotch fir (Pinus sylvestris) .

Pine (Pinus Picea).

Larch (Larix Europcea).

Spruce (Abies excelsa).

Arbor vitae (Thuja occidentalis).

Savin (Juniperus Sabina).

Cypress (Cupressus sempervirens).

Lime tree (Cupressus Limetta).

Yew (Taxus baccata).

Grass, various species.

Grain.

An Experiment in Starving Caterpillars.

March 20, 1895, twenty-five newly hatched caterpillars,
and also the same number from each of the first, second and

326

THE GYPSY MOTH.

third molts, were placed in corked vials without food, and
kept in a normal temperature, in order to see how long they
would live under such conditions. Observations were made
on them at intervals of twenty-four hours. The following
table gives the number of caterpillars dying on the specified
dates : —

o .

U r->

§

March

22.

S

§

March

24.

t3

o .

i-> L~

§

March

26.

March

27.

March

28.

rj 'A

March

30.

O

H

Just hatched, .

-

_

5

8

12

-

-

-

-

25

First molt,

-

-

i

ii

13

-

-

-

-

-

25

Second molt, .

-

-

-

• 7

9

9

-

-

-

-

25

Third molt, .

_

-

-

9

7

3

1

3

-

2

25

This shows that caterpillars in the earlier stages will
readily live four days without food ; that an appreciable
number of second-molt caterpillars will live under the same
conditions for five days, while the third-molt caterpillars
may exist on starvation diet for nine days.

To gain further knowledge of the period of time it is
possible for gypsy moth caterpillars to live without food,
a number of them were placed in cold storage, and a few
removed from time to time and supplied with food. For
this work, which was carried on during the month of April,
1895, use was made of a double box packed with sawdust
and stored in a refrigerator, the temperature of which
averaged about 40° F. The caterpillars were kept in corked
vials and removed as needed. At the ordinary tempera¬
ture of the refrigerator the caterpillars became rigid and
inactive, and remained so throughout the time involved in
the experiment. April 3, 1895, a number of caterpillars in
each of the different molts, from those just hatched to those
between the fourth and fifth molt inclusive, were placed, with¬
out food, in corked vials in the refrigerator box. All of
those between the fourth and fifth molt died within a day
or two, possibly due to contact with the large quantity of
saliva which they ejected soon after being placed in the box.

EFFECTS OF TEMPERATURE.

327

At intervals of a few days several of the caterpillars of
the different ages were removed from the refrigerator and
placed on suitable food in a warm room ; and in this way the
length of time the caterpillars could exist without food, was
determined. None of the caterpillars between the third and
fourth molt were alive when removed from the box April 6.
Of those between the second and third molt, a single cater¬
pillar remained alive April 24, and this one, when supplied
with lettuce leaves, revived, fed and molted at the end of
nine days. April 12, a number of caterpillars between the
first and second molt were removed, and when supplied with
food revived and began feeding. Several of the newly
hatched caterpillars were found to be alive April 24, and
when supplied with food a number of them were able to feed,
and so reached maturity, after having been deprived of food
for a period of three weeks.

A nearly full-grown caterpillar, confined in a box July
30, 1894, without food, lived until August 9, but died the
night of that day. Lodi states that a caterpillar of this moth
in Europe went without food for twenty-seven days without
injury (“Opuscol. scelt.,” vol. XII, page 183, 1789).

Effect of Extremes of Temperature on Caterpillars of the

Gypsy Moth.

Effect of Heat. — Fifty caterpillars, in lots of ten, taken
from the different molts, from those just hatched up to and
including the fourth molt, were exposed for fifteen minutes
to a temperature of 110° F., and were then placed in jars
and supplied with food. Of those just hatched, only one
died ; of those of the first molt, three ; of the second molt,
three ; of the third molt, three ; and of the fourth molt,
three. The rest of the caterpillars survived and molted.
Fifty caterpillars, selected in the same manner as those of
the preceding experiment, were exposed to a temperature
of 120° for a period of fifteen minutes. Of those just
hatched, ten died ; of the first molt, ten ; of the second
molt, ten ; of the third molt, nine ; and of the fourth molt,
only one. April 4, fifty caterpillars were exposed to a tem¬
perature of 130° for a period of fifteen minutes. The cater¬
pillars used in this experiment comprised those just hatched

328

THE GYPSY MOTH.

and the various molts up to and including the fourth.
When taken from the oven, all but one were dead.

Effect of Cold. — Ten caterpillars just hatched, also ten
from each molt up to the fourth, were selected and placed in
vials, after which they were subjected to a temperature of
85° for a period of five minutes. They were then placed in
a cold box, where they were exposed to a temperature of 2°
above zero for a period of thirty minutes, at the end of which
time they were removed to a room where the temperature
was 70°, and examined. Only one caterpillar survived the
above treatment, but this one, after a few days, fed and grew
in a normal manner. Fifty caterpillars, in lots of ten, from
the different molts, were transferred from a normal tempera¬
ture of 70° and exposed to a temperature of zero for a period
of half an hour, when they were returned to the tempera¬
ture from which they were first taken. When removed, all
were dead. Fifty caterpillars in the various molts, up to
and including the fourth, were placed in vials (the mouths
of which were stopped with cloth instead of cork), and then
removed from a temperature of 82° to a cold box, where
they remained fourteen hours, exposed to an approximate
temperature of zero. All were dead when taken out.

A study of these experiments shows that, as a rule, the
small caterpillars possess the ability to resist a considerable
degree of cold but not of heat; while the larger caterpil¬
lars possess the ability to resist the heat better than the
cold. This is as one would naturally expect to find it,
since at the time of hatching the weather is usually cool,
while the increase in size of the caterpillars keeps pace
with the ordinary increase of temperature, so that by the
time the caterpillars are full grown we often have a con¬
siderable degree of heat.

Experiment in drowning Caterpillars.

In many places the gypsy moth infests the trees along the
course of streams, under such circumstances as to lead to
the impression that they were distributed by falling into
the water while in the caterpillar stage, and, drifting down
stream with the current, reached the shore, and, making

POSITION ON TREES.

329

their way to suitable food plants, passed their transforma¬
tions and thus established new colonies down stream.

To determine the actual resistance of these caterpillars to
water, the following experiments were made in July, 1895.
July 12, four jars were filled with water, and at 9 a.m. five
gypsy moth caterpillars of the fifth molt were placed in
each. In jar No. 1, half of the caterpillars were alive the
third day; the remainder died July 17. In jar No. 2, one
caterpillar died the first and two the second day ; the other
two lived until the morning of the fifth day. In jar No. 3,
one died the first and the rest the fifth day. In jar No.
4, one died the first and one the second day, the rest living
until the morning of the fourth day. These results show that
the gypsy moth caterpillars are al fie to live in water for two or
three days, during which time, if they should fall into swiftly
moving streams, they would be carried a considerable dis¬
tance, and in this manner some of the colonies found along
the shores of streams may have been established.

Position of Caterpillars on Trees.

To ascertain the normal position of the caterpillars of the
gypsy moth on trees, a tight board fence was built around a
medium-sized apple tree upon which a number of caterpillars
were feeding. The fence was five feet in height, and en¬
closed an area of eighteen by eighteen feet. At a height of
three feet from the ground a wide band of raupenleim was
placed around the fence on the inside, and at the base the
earth was banked up to the height of one foot, in order to
prevent the escape of the caterpillars. Careful observations
were made every morning by Mr. W. L. Tower, on the
location of the caterpillars and the places where they had
gone to rest after they stopped feeding. As the number of
caterpillars on the tree was not always the same, no tabu¬
lated list of their positions could be made ; yet the relative
number found each day, in the same place and position, was
more constant than could be expected. By adding the num¬
ber found in each location and the number found on the tree
every day, the percentage in each place was found to be
fairly constant.

330

THE GYPSY MOTH.

1894.

Number
under Burlap.

Number

on Trunk.

Number

on Branches.

Number

on Leaves.

Number

on Tree.

July 16, .

14

1

12

_

27

July 17, .

30

3

16

3

52

July 18, .

31

2

12

-

45

July 19, .

80

_*

47

7

134

July 21, .

75

38

-

113

July 23, .

100

Hf

28

-

139

July 25, .

74

7f

25

-

106

Total, .

Per cent.

404

6

178

10

616

(about), .

66

1

29

2

The average per cent, of the number under the burlap did
not vary much from sixty-six. The number found elsewhere
on the trunk and on the leaves of the tree together did not
constitute three per cent, of the whole.

In the early morning, before the rays of the sun struck
the burlap, the caterpillars were found under it on all sides
of the tree, but as the sun rose higher, the greater part
of them were on the west and northern sides, away from
the heat and light. As the sun went from east to west they
moved around the tree, keeping on the shady side. This
was true of the larger portion of the caterpillars, but in
some instances they have been found at mid-day resting
under the direct rays of the sun, with no covering whatever.
The caterpillars that were on the larger branches of the tree,
where the sun did not strike them, remained in the same
position all day unless disturbed, while those on the smaller
branches moved around, keeping on the shady side nearly
all the time.

Spinning Habits of Caterpillars.

The amount of silk a gypsy moth caterpillar is capable
of spinning has an important bearing on the distribution ot
these insects, since it is known that by spinning down upon
passing teams, etc., the caterpillars are carried from place to
place. The more silk a caterpillar is capable of spinning,

* Base of tree.

f Not counted in the results, as they were pupating.

SPINNING HABITS.

331

the greater are its chances of being carried into new localities.
To learn the quantity of silk that one of these caterpillars
can spin, a reel was made and mounted in a frame. Cater¬
pillars were taken on a soft brush and then jarred off into
space. This caused them to spin, when, by attaching the
end of the thread to the wheel and manipulating the cater¬
pillars carefully, the silk was reeled off and a record kept of
the number of revolutions of the wheel, until the caterpillars
could not or would not spin. It was found that they spun
best when a slight current of air was blown upon them. In
this manner caterpillars of known ages were experimented
with. Many of these experiments gave only negative results,
for the manipulation necessary in getting the thread started
often disturbed them so that they would spin only a few feet.
The following results were obtained from a number of the
experiments : —

March 22 : Four caterpillars, just hatched, were taken be¬
fore any of their store of silk had been drawn upon. The
first spun 4 feet and 6 inches, the second spun 9 feet and 1
inch, the third spun 38 feet and 2 inches, and the fourth spun
69 feet and 4 inches, — a distance greater than the height of
an average shade tree. March 14 : Of five first-molt cater¬
pillars, the first spun 53 feet and 2 inches, the second 24
feet and 2 inches, the third 3 feet and 2 inches, the fourth 6
feet and 4 inches and the fifth 7 feet.

April 23 : Three more caterpillars, of the first molt, were
experimented with, and the following results obtained : the
first spun 25 feet and 3 inches, the second 22 feet and G
inches and the third 47 feet and 9 inches. March 22 : Of
two second-molt caterpillars, the first spun 8 feet and the
second 2 feet. Other caterpillars, in the later molts, were
tried, but they could not be induced to spin. There seems
to be a decrease in spinning power as the caterpillar grows
older. Caterpillars of the second, third and fourth molt have
been seen spinning down to a considerable distance from trees
on which they were feeding, and in this manner they were
able to make the wind and passing teams aid them in finding
their way to suitable food plants.

The last thing before entering upon the rest previous to
molting is the spinning of a number of threads, forming a

332

THE GYPSY MOTH.

small silk mat. a little longer in diameter than the length of
the body of the caterpillar. When rocks have been burned
over, caterpillars have been seen spinning down to escape the
smoke and heat. They frequently spin threads from fences
to the neighboring trees. The insect also spins a scanty
cocoon for a shelter and support during the pupal stage.

The Process of Pupation.

Cocoon. — When the caterpillar is fully grown, it seeks
some sheltered spot (Plates 47, 49), and rests quietly for
about twenty-four hours. It then empties its alimentary
canal, the discharge being of a semi-fluid nature, and con¬
taining an abundance of chlorophyl, showing it to be, in
part at least, the remains of food. In about one hour after
this discharge, the caterpillar begins to spin a frail cocoon,
which is composed of a few coarse brown silken threads,
occasionally enclosing a leaf or other material. In spinning,
it first places its spinneret close to the surface on which the
cocoon is to be formed, and presses out a drop of the silk-
forming fluid, which serves as an anchor for the silk thread
which is then spun out. It first spins a few long threads,
which usually exceed the length of the cocoon when finished.
After a number of these long threads, which connect various
points and serve as a sort of frame, have been formed, the
caterpillar begins to spin more rapidly, and to place short
threads between the long ones, working always from the
inside, and changing at intervals from one side of the cocoon
to the other. Where the threads cross each other they are
fastened together by a drop of the fl-uid in much the same
manner as at the starting of the cocoon. In spinning, the
labial palpi and the feet are used to grasp the threads. As
a rule, the spinning is not completed at a single operation,
since the caterpillar rests several times, the rests ranging
from a few minutes to five or six hours. The actual time
spent in spinning is about six hours. After completing its
network of silk the caterpillar rests quietly, except for occa¬
sional spasmodic twitchings of the body, hanging head down¬
ward, and pupates at the end of about three hours.

Pupation. — When the process of pupation begins, the
skin commences to contract and wrinkle on the posterior

PLATE 47. Mass of pupae between the trunks of two trees. From a
photograph taken at the Winning colony, Woburn, July, 1895.

PLATE 48.

EXPLANATION OF PLATE 48.

[All figure* enlarged.]

Drawn by R. A. Cooley.

1. Ventral view of male pupa.

2. Ventral view of female pupa.

3. Dorsal view of female pupa.

4. Lateral view of female pupa.

5. Genital markings of male pupa.

6. Genital markings of female pupa.

7. Chitinized hook from cremaster of pupa,

greatly enlarged.

8. Aerostatic hair from newly hatched cater¬

pillar, greatly enlarged.

9. Normal hair from caterpillar, greatly enlarged.

THE PUPA.

333

segments of the caterpillar, showing that the pupa is being
withdrawn from that part. The pupa is pushed forward
by a vigorous use of the cremaster. In this manner the
skin on the posterior segments is pushed back, and the
pressure on the anterior segments becomes so great as to
nearly bend under that paid of the body. The insect takes
short rests at intervals during this process. Next, the skin
on the fourth segment splits along the dorsal line, the split
continuing forward and backward, and in a few seconds
extends from the base of the head to the annulation between
the fourth and fifth segments, the pupa, in the mean time,
forcing itself outward against the opening thus made. In a
few seconds more the movements of the pupa, aided by the
pressure from behind, which it is able to exert by means
of its cremaster, splits the head down on each side of the
clypeus to the mouth parts, and the pupa emerges by pass¬
ing outward through the opening, the whole process taking
about fifteen minutes.

The newly formed pupa is very soft and of a light color,
with the remains of the larval tubercles and markings
plainly visible, but these disappear and the pupa grows
harder and darker when exposed to the air. Caterpillars,
in their attempts to pupate, sometimes burst the thin pupal
skin and die from the escape of the fluids from the body.
In changing from the larval to the pupal stage, the insect
loses about thirty-five per cent, in size and nearly forty-five
per cent, in weight. A small part of the weight is left in
the larval skin and silk. How the insect, as a rule, fastens
itself to the silk in which it is enclosed, is not fully known.
In one case, however, a pupa was seen to emerge and fall
into the network of silk, when, by a wriggling motion, it
picked up the silk threads on its cremaster and then hung,
from gravity, head downward.

The maximum time spent in the pupal stage by one
hundred females was found to be 14 days, the minimum 7
and the average 10.65. The maximum time spent in the
pupal stage by eighty-eight males was found to be 17 days,
the minimum 9 and the average 13.41 days.

Pupa (Plate I, Fig. 5, and Plate 48). — The pupae of the
males vary in length from three-fifths to four-fifths of an inch,

334

THE GYPSY MOTH.

including the cremaster, or blunt spine at the end of the
abdomen, while those of the females vary from three-fifths to
one and two-fifths inches. Fig. 5, Plate I, was taken from
one of extraordinary size. The following description was
made from the study of thirty-nine males and one hundred
and twenty-one females : —

They vary in color from chocolate to dark reddish-brown,
and are cylindrical or fusiform, rounded anteriorly and taper¬
ing posteriorly to the cremaster, which is armed at the tip
with a cluster of minute hooks, one of which is shown at
Fig. 7, greatly enlarged. The covers to the various parts
of the body, as the wings, legs, antenna?, etc., are plainly
marked ; those of the wings are quite broad, and reach to
the posterior third of the fifth segment, while those of the
antennae are strongly curved, being much wider in the
males than in the females. At the front edge of the meso-
thorax, on each side, is an oval, dark reddish-brown velvety
spot, very distinct in some examples but nearly invisible in
others. Ochre-yellow hairs, arranged in groups, occur on
the eye, head and palpi covers, across the collar and thorax,
and in eight equidistant rows along the abdominal segments.
Some of the hairs in the groups across the collar and thorax
are dark brown. The abdominal segments are more or less
punctured, and the hairs arise in small circles. At the base
of the cremaster, on the ventral side, is an elliptical depres¬
sion, with curved ridges on each side. In the males, on the
middle of this segment, in front of the depression, is a small
raised tubercle, with a longitudinal slit on the top of it
(Fig. 5), while in the females this tubercle is wanting; on
the extreme front edge of this same segment, however, there
is a fine longitudinal slit, but the surface at this place is not
raised (Fig. 6).

Attached Pupce. — In order to determine the best plan for
raising the finest specimens of gypsy moths, a number of
experiments were made in the laboratory. In six of the ex¬
periments the pupae were fastened to the bottom of a small
pasteboard box, in which they were confined by means of a
pin put through the little bunch of silk at the end of the cre¬
master, and then into the bottom of the box. The moths all
emerged from these pupae, and were in good condition. In

PLATE 40. A stone has been rolled away from a lodge, exposing' the mass of pupee. From a
photograph taken at Arlington, Mass, July O, 1801.

PUPATION.

oojr

OO 0

two experiments a very tine pin was run through the cre¬
master, as near to the end as possible ; but it was found that
the pin injured the pupae, and consequently they died without
emerging. A very fine pin was run through the last seg¬
ment of a pupa, wdiich began to emerge, but died, being
unable to complete the process. In several other cases pupae
were stuck to the bottom of the box by means of a drop of
mucilage or a drop of sticky fly-paper gum. This was un¬
satisfactory, however, for the pupae, in wriggling about, got
themselves covered with the gum, and the few which did
emerge were in very poor condition.

Mass of Pupae. — When about to pupate, the caterpillars,
when numerous, collect in masses to spin their cocoons. On
the flat side of a rock one of these masses (Plate 49) was
found which measured eighteen inches in length and eight
inches in width, the whole being covered by one large net¬
work of silk. Beneath two partly eaten leaves of oak forty-
nine caterpillars had pupated, and another mass was found
in a groove between the trunks of two small trees (Plate
47), containing at least three hundred pupae and pupa-cases.

Pupation in the Field.

To learn the proportion of caterpillars which pupate on
trees and on the ground, as well as the per cent, of those
parasitized, a study was made of the “ Winning ” colony at
Woburn, in the latter part of July, 1895, the results of
which show that the larger part of the caterpillars pupated
in the trees. On the border of the colony, about forty per
cent, pupated above the burlap ; vPile in the centre, about
sixty per cent, were found to have pupated above it. These
facts confirm the generally accepted opinion that, when very
abundant, the per cent, of caterpillars pupating upon the
trees is somewhat increased.

Of the caterpillars which pupated elsewhere in the col¬
ony, the proportion wTas equally divided between those that
pupated on the ground and those which passed the pupal
stage on the trunks and under the burlaps on the trees.
All pupte which gave evidence of parasites, as well as the
empty pupa-cases from which parasites had apparently
emerged, were counted as parasitized. The per cent, of the

336

THE GYPSY MOTH.

sexes found to be parasitized was 9.7 per cent, of the males
and 7.5 per cent, of the females. This does not agree with
observations previously made, where the larger per cent,
parasitized were found to be females. The greater part of
the parasitized pupse were brought in, and many were found
to contain Dipterous larvae. In most cases no parasite ima¬
goes were obtained from these pupae, although some of the
Dipterous maggots have not yet transformed..

The Imago.

The Process of Emerging .

The emerging of the imago from the pupa is accom¬
plished as follows : when the insect is fully developed and
ready to come forth, it forces off the cap on the anterior
ventral part of the pupa, comprising the antennae, head- and
leg shields, and through the opening thus formed the antennae
appear, and then the first two pairs of legs are drawn out.
The cap is attached to the rest of the pupa at its apex, and
its larger anterior end is pushed away from the body by
means of the feet. The legs at first are stiff at the joints
between the tibiae and tarsi. Next, the juncture of the wing
covers on the top of the back splits, then the posterior
margin of the wing covers comes oft', and the insect crawls
up and out of the pupa-case, the hind legs coming out at the
same time as the wings. This process requires from five
minutes to five hours, according to the resistance of the pupa-
case and the vigor of the enclosed imago. When the moth
first emerges it is quite moist, but soon dries off. From
twenty minutes to two hours are required for the develop¬
ment of the wino-s.

Description of the Imago.

The following description was made from thirty males and
thirty-seven females. The males (Plate I, Fig. 3) measure
from 37 to 50 mm. (one and one-half to two inches) be¬
tween the tips of the expanded wings. The ground color
of all the wings is brownish yellow, varying in intensity in
different examples, but somewhat lighter beneath. The
head, thorax, antenme and upper side of the palpi are

THE IMAGO.

337

grayish brown, inclining to mouse color in some specimens.
The under side of the entire body, legs and palpi is some¬
what lighter than the under side of the wings.

The markings on the fore wings are dark brown, and are
as follows : the half line starts from the costa, near the base
of the wing, and extends half way across the wing. The
transverse anterior line arises from the basal fourth of the
costa and crosses the wing as a scalloped line. Just outside
of this line, on the cell, is the small orbicular spot. The
reniform spot is crescent shaped, and, resting on the outer
end of the cell, extends across its entire width. The median
shade is quite obscure, but is bent out around the end of the
cell, and toothed along the outside. The transverse poste¬
rior line arises from the outer fourth of the costa, is some¬
what curved and toothed on the veins, and terminates just
within the anal angle. The subterminal line, a little outside,
is similar to the transverse posterior line and parallel with
it. The terminal space is usually somewhat darker than the
rest of the wing, and all the cross lines are heavier on the
costa than elsewhere. The fringe is cut with dark brown
between the veins.

The hind wings have a faint discal lunule at the end of the
cell, and the terminal shade is darker brown than the rest of
the wing. The upper side of the abdomen is of the same
color as the upper side of the hind wings, and has a row of
brownish spots along the middle.

The outside of the third and fourth joints of the tarsi and
the ends of the femora on the upper side are brown ; the fore
and middle tibiae are pale mouse colored on the outside.

The females (Plate I, Fig. 1) measure from 37 to 62 mm.
(one and one-half to two and one-half inches) between the
tips of the expanded wings. The entire body and wings
above and beneath are yellowish white, except the abdomen
beneath and towards the end above, wdiich is pale yellow.
The markings of the fore wings are dark brown or nearly
black, but vary much in intensity in different specimens,
being almost entirely obliterated in some examples. The
half line at the base of the wing, the orbicular and reniform
spots, the costal end of the transverse lines and the black
spots in the cilia are quite pronounced. The form and

338

THE GYPSY MOTH.

position of the lines and spots are the same as in the males.
The fore wings are longer, narrower and more pointed than
in the males. The hind wings have a faint discal spot and
a subterminal line which is toothed along the outside on the
veins, and the cilia have black basal spots between the veins.
The antennts and legs are dark brown, but the hair on the
femora and tibiae is yellowish white.

The imago is subject to considerable variation in size.
The following table gives the dimensions of the largest and
the smallest imagoes of each sex, taken in the held : —

Expanse
of Fore
Wings.

Expanse
of Hind
Wings.

Length

of

Body.

Diameter

of

Thorax.

Diameter

of

Abdomen.

Largest male,

min.

46

mm.

37

mm.

18

mm.

5

mm.

3

Smallest male,

33

25

12

4

2

Largest female,

71

53

31

8

12

Smallest female,

44

34

16

5

6

Mr. J. H. Leech, in the “Proceedings of the Zoologi¬
cal Society of London,” Yol. LVI, page 630, expresses the
opinion that the Japanese gypsy moths, which have been
described as distinct species, do not differ from those of
Europe, except in size, and he regards them only as forms,
and not distinct species. He gives the extremes of size of
males and females in Japan and Corea as follows: “Ex¬
panse of wings of largest male, 71 mm. ; smallest male,
37 mm. ; largest female, 114 mm. ; smallest female, 48
mm.” Mr. Leech also gives the size of European examples
of the gypsy moth as follows: “Largest male, 54 mm.;
smallest male, 32 mm. ; largest female, 93 mm. ; smallest
female, 42 mm.” I have in my collection three males from
Pekin, China, which measure 46, 50 and 54 mm., respec¬
tively, in expanse of wings ; and several male examples
from Europe, the largest of which measures 43 mm. and
the smallest 37 mm. I can see no difference between the
examples from China and those from Europe, except in

size.

\

. * .

* ii

PLATE 50.

Explanation of Plate 50.

[All figures greatly enlarged.]

Drawn by C. P. Lounsbury.

1. Dorsal view of male moth.

2. Lateral view of genitalia.

3. Ventral view of genitalia.

4. Antenna of the male.

5. Single filament from antenna.

6. Section of antennal filament, showing insertion

of the finer lateral filaments.

HERMAPHRODITES .

339

Hermaphrodites .

Three specimens of the gypsy moth were taken in Med¬
ford, Mass., which are what Ochsenheimer would call perfect
hermaphrodites. One has the right half of the body, with
the wings and antenna of that side, of the form, color and
markings of the female ; while the left side of the body, with
its wings and antenna, is male. The second specimen is
male on the right side, and female on the left. In both of
these examples the frenulum is single on the male side, but
divided on the female. In the third specimen, the antenna
and both wings, on the left side, are female, while on the
right side, the antenna and both wings are male. The
abdomen is female in size and form, but the right side is
darker than the left, looking more like the male in color.

As the sexes of this moth differ so much in the form and
color of the wings and in the pectinations of the antennae,
an hermaphrodite is a remarkable insect in appearance, and
seems almost to suggest that it is a work of art. Hermaph¬
roditism in this species is occasionally met with in Europe,
several cases being on record in the European journals.

External Anatomy of the Motli.

The head is rather small, and joined by a very short neck
to the comparatively large thorax. This is followed by the
abdomen, which, in the male (Plate 50, Fig. 1), is medium
in size, gradually tapering to the last two segments. These
taper more rapidly to the genitalia or external genital or¬
gans, which consist of a genital hook and pair of clasps
(Plate 50, Figs. 2 and 3). The abdomen of the female is
enormously distended. The front is smooth and very slightly
rounded; the maxillae or sucking tube is rudimentary; the
palpi small, extended forward horizontally (Plate 51, Fig.
1 a), the basal and terminal joints being about equal in
length, while the middle joint is about three times as long
as either of the others, and covered with line hairs loosely
arranged over the surface, similar to those that cover the
surface of the head. There are no ocelli present. The
antennae are bipectinated very strongly in the male (Plate
50, Fig. 4), while in the female the pectinations are very

340

THE GYPSY MOTH.

much shorter aud stouter (Plate 51, Fig. 3). The pectina¬
tions of the male antennae (Plate 50, Fig. 5) are somewhat
curved, and taper slightly toward the outer end, where they
terminate in a tooth on one side and a much longer spine
on the other; there are numerous hairs, about twice as
long as the diameter of the pectinations, scattered over the
surface. Plate 50, Fig. 6, shows a portion of a pectination,
with the bases of four of these hairs, and still finer hairs,
scattered over the surface, which is thrown into very minute,
irregular longitudinal ridges, visible only under a high power
ot the microscope. The female antennse (Plate 51, Fig. 3)
have minute, elongated, tooth-like scales and bristle-like
hairs over the surface (Plate 51, Fig. 4), and the pecti¬
nations are cylindrical, stout and terminate obliquely in a
point at the outer end, near which, on the lower side, is a
short bristle. There are minute hairs sparsely scattered over
the surface, as shown in Plate 51, Fig. 4 b, and scattered be¬
tween these are minute pits, around the edge of which is a
row of minute hairs (Plate 51, Fig. 4 a).

The legs (Plate 51, Figs. 5, 6 and 7) are moderately
long and of medium size, with the first or coxal segment
somewhat conical in form ; the second segment (trochan¬
ter) much smaller, its length being about equal to the
thickness; the third and fourth segments (femur and tibia)
are of nearly equal length. The outer part of the leg (tar¬
sus) consists of five segments, the first of which is about the
length of the three following, and the last has a pair of di¬
verging claws at the end, with a fleshy organ (pul villus) be¬
tween them (Plate 51, Figs. 9 and 10). The claws have a
somewhat flattened under surface, with a row of small blunt
teeth along each side. The fore legs (Plate 51, Fig. 5) have
a long sinuous spur (tibial epiphysis) attached to the tibia
near the base and extending a little beyond the end. The
whole side of this epiphysis next to the tibia is covered with
fine bristles, forming a brush-like organ. The tibiae of the
middle legs have a pair of unequal spurs at the end, and the
hind tibiae have a similar pair at the end and a pair about one-
fourth of the length of the tibia above. All these spurs have
the outer part obliquely flattened, with a row of short, blunt

Explanation of Plate 51.

[All figures greatly enlarged.]

Drawn by C. P. Lounsbury.

1. Lateral view of the anterior part of body

of female.

2. Ventral view of female genitalia.

3. Antenna of the female.

4. Section of antenna, showing sensory pits.

5. Fore leg.

6. Middle leg.

7. Hind leg.

8. Part of hind leg, with abnormal appendage.

9. Foot, seen from below.

10. Foot, seen from the side.

PLATE 51.

10

EXTERNAL ANATOMY.

341

teeth around the edge of the flattened surface (Plate 51,
Figs. 6 and 7). On one of the hind legs of the male, at the
end of the tibia, was found an additional appendage on the
side opposite to the spurs (Plate 51, Fig. 8). This is the
only monstrosity we have thus far seen in the gypsy moth.

The wings differ somewhat in form in the two sexes, the
fore wings of the female being longer and more pointed
than those of the male. The venation is shown in Plate 52,
Figs. 1 and 2 (male), 3 and 4 (female). The frenulum at
the base of the hind wing of the male consists of a single
pointed bristle, while in the female it is composed of a clus¬
ter of much finer pointed bristles (Fig. 4). The surface of
the wings is sparsely covered with scales and hairs (Fig. 7),
and around the outer border of both the fore and hind wings,
at quite equal distances apart, is a row of blunt spines, two
of which are shown in Fig. 8, and one still more enlarged
is represented in Fig. 9. These spines appear to be hol¬
low, with a fine aperture at the outer end. Near the hinder
margin, towards the base of the fore wing, is an oval area
(Plate 52, Fig. 5), the surface of which is covered with
minute stout spines (Fig. 6). The lateral surface of the
metascutum (Plate 51, Fig. 1 g') is covered with a similar
series of spines.

In the “Berliner Entomologische Zeitschrift,” Yol.
XXXI, 1887, Dr. W. Donitz describes a singing Lepi-
dopteron. After referring to the list of Lepidoptera which
produce sounds, given by Swinton in his work on “Insect
Variety,” he describes an apparatus which he discovered in
Dionychopus niveus Men., a Bombycid moth found in Japan,
and also in Siberia. He states that when a fresh male is held
in such a manner that the wings can be moved back and forth
on each other, one can hear a slight chirping sound, which
continues as long as the wings are moved. He figured and
described an apparatus, on the basal part of the fore wings,
similar to that described above ; and a corresponding area on
the hind wings, where that of the fore wings overlies this
organ on the hind wings. In the gypsy moth no such organ
exists on the hind wing, but its counterpart is found on the
side ot the metathorax, as stated above, where the organ in

342

THE GYPSY MOTH.

the fore wings, when closed, rests on the side of the thorax.
A similar organ occurs in Ocneria mbea of Europe, of the
same structure and in the same place as in the gypsy moth.

The scales on the wings vary in form, as shown in Plate
52, Figs. 10-20. The striations are not shown in all these
figures. Fig. 15 represents one of the short and broad
scales with the longitudinal strife. Figs. 21 and 22 repre¬
sent cross-sections of a scale, the first from near the base,
the second from the broader part of the scale. After suitable
preparation and embedding in paraffine, a portion of the wing
was sectioned and these figures drawn from the mounted
sections. The surface of the scale next the membrane of
the wing is smooth, while the outer surface is covered with
lono-itudinal ridges.

The abdomen of the female (Plate 51, Fig. 1) is very
large, and densely clothed with yellowish hairs, especially
on the under side towards the posterior part. One of these
hairs is represented in Plate 52, Fig. 19, and a section of
it, near the basal fourth of the hair, greatly enlarged at
Fig. 10. The surface is covered with minute spines, which
incline towards the apex, and it also appears to be marked
with irregular cross-wrinkles. The ovipositor of the female
is shown in Plate 51, Fig. 2.

Mating.

After emerging the female crawls a short distance from
the pupa-case, and, by the time the wings have expanded,
and sometimes before, she begins to attract or “assemble ”
the imagoes of the opposite sex. In colonies where the
males are abundant, they often attempt to mate with females
almost as soon as the latter emerge. Seeking the female, the
male flies in a zigzag course until she is found, when he
hovers around her for a few minutes, rapidly vibrating his
wings.

The time spent in mating has been found to vary from
twenty-five minutes to three hours and eighteen minutes ;
the average time of twenty-four pairs being one hour and
nine minutes. After mating, the male is quite stupid, but
in about half an hour regains his normal activity.

Explanation of Plate 52.

[All figures enlarged.]

Drawn by R. A. Cooley.

2.

I.

Venation of fore wing of male.
“ “ hind “ “ “

3-

“ fore wing of female.

4-

“.hind “ “

5. Base of fore wing, showing outline of the spiny area.

6. Portion of the spiny area, showing the spines, greatly en¬

larged.

7. Area from near the middle of the upper side of the fore

wing of female, showing scales and hairs.

8. External outer border of wing, showing spines and a fringe

scale.

9. Single blunt spine from outer border.

10. Section of figure 19 greatly enlarged, showing spiny sur¬
face.

nf 12, 13, 14, 16. Various types of scales from the wings.

15. Scale from the upper side of the fore wing of the female,
showing the striae.

17, 18. Scales from the fringe of the fore wing.

19. Hair from the end of the abdomen of the female.

20. “ “ “ “ “ “ male.

21. Section of a scale near the base.

22. “ “ “ “ “ middle.

PLATE 52.

POLYGAMY.

343

Fertilization Experiment.

To determine the length of time necessary for fertilization,
twenty-five virgin females were exposed in infested localities.
After mating had commenced, the males were removed at
the end of given periods of time, varying from one minute
to one hour ; the females were placed in boxes, and allowed
to deposit their eggs.

In all cases where the male was removed before six
minutes, the eggs proved infertile ; but where they were
allowed to remain beyond that time, the eggs were fertile.

Polygamy .

As a rule, the males of this species mate with but one
female, or with two at the most, but instances have been
recorded where single males mated with six females, and
five other males mated with three females each. Polygamy
is exceptional among the females. In August, 1894, a
female moth, at the insectary, mated with three males ; but
nearly all females reared in confinement, as well as those
whose mating has been observed in the field, paired with
but a single male.

The fact that a male imago may fertilize several females
has a practical bearing on the work of destroying the gypsy
moth. It would seem to indicate that the destruction of the
males, either through natural or artificial agencies, is of but
little importance.

Length of Life of Imago.

The maximum number of days of the life of thirty-four
females which had not mated was found to be 10, the mini¬
mum 1, and the average 6.15 days. The maximum number
of days of the life of forty-two females which mated was
found to be 12, the minimum 1, and the average 7.69 days.
The actual length of life of the male moth is hard to deter¬
mine, as they probably live much longer when free than when
kept in confinement. Five males which had not mated lived
respectively 6, 7, 8, 11 and 8 days.

344

THE GYPSY MOTH.

Habits of Flight.

The gypsy moth is not nocturnal, and, unless disturbed,
but few of the males fly before 9 a.m. The time of greatest
activity is between 10 a.m. and 3 or 4 p.m., after which time
they seldom fly voluntarily. As already stated, they fly
most vigorously on warm days, and in a zigzag course.

The female moth has never been seen to fly in this coun¬
try, except on one occasion, and that was after the laying
of the eggs. Mr. F. H. Mosher, one of our most reliable
observers, while making observations in a colony of the
gypsy moth in the forest at Woburn, Mass., July 18, 1895,
saw a female gypsy moth that had finished or nearly finished
laying her eggs, upon being disturbed by males, drop to the
ground and fly ab(*ut twenty feet, striking the ground and
rising again at di^feices of about two feet. In Europe, C.
Wingelmuller, in the “ Wiener Illustrirte Garten-Zeitung,”
Jan. 15, 1890, page 269, says that “the female gypsy moth
does not shake off her sluggishness even during- the night,
the especial time of her activity ; and a short, lazy flight
from one tree to another close by is the most that she accom¬
plishes.” This helplessness is only on account of her body
being stored with eggs, which prevents her from taking a
longer flight. I have tried, again and again, at various
times during the day, to oblige the females to fly, by throw¬
ing them into the air and also by knocking them off from the
trees ; and in every case they only fluttered to the ground
without any attempt to move forward by using their wings.
On July 14, 1889, I was in the zoological gardens in Berlin,
and saw the gypsy moths in great abundance. They were
then in the imago stage, and occasionally females fluttered
down from the trees in precisely the same manner that they
do in this country when disturbed by the males. As our
employees have observed the habits of this insect at all hours
of the day and night, and have seen no real flight except in
the case above mentioned, and as the statement of Wingel¬
muller seems a little indefinite, I am inclined to think that
the female gypsy moth never voluntarily flies, nor indeed
can she do so before laying her eggs, because of the enor¬
mous weight she would have to sustain. It may further be

ASSEMBLING.

345

said that, although the wings of the female are of fair size,
they are not nearly as firm as those of the male, and it
would seem that by disuse they have become weakened ;
and, if the present conditions are continued sufficiently long,
the wings of the female gypsy moth may suffer the same fate
as those of the female of the white-marked Tussock moth
(Plate 39, Fig. 18).

The peculiar zigzag flight of the male may be the result
of natural selection. As the female does not fly, the male is
guided to her by the odor which she gives off, and which is
disseminated by currents of air ; and it is evident that males
flying in a straight line would not meet with the scent-laden
currents in as many cases as those which fly in a zigzag
course. It is therefore probable that more of those having
a tendency to an irregular course in flight would find and
mate with the females, and thus transmit to their male
offspring a like tendency to this particular flight, which, in
the course of generations, has become a fixed characteristic
of this species.

The Assembling of the Gypsy Moth.

It is a well-known fact that unfertilized females of the
gypsy moth are able to attract the males to them from a
greater or less distance. This is called assembling, and this
power to assemble is possessed by quite a large number of
moths more or less nearly related to the gypsy moth.

As has been previously stated, the caterpillars of this
insect have the habit of spinning down, or suspending them¬
selves from the trees on which they feed, especially when
disturbed ; and they frequently fall upon passing teams or
animals, and are carried by them to places more or less
remote. If, in any such case, caterpillars should be carried
into an uninfested region, and, making their way to suitable
food plants, should, in transforming, give rise to female
moths, there would be little or no danger of their establish¬
ing a new colony, unless they should attract male moths
from the infested region, and, having mated with them,
should therefore lay fertile eggs.

The following experiments were made by Mr. A. H. Kirk¬
land, assisted by Mr. J. P. Hylan, for the purpose of deter-

346

THE GYPSY MOTH.

mining, as fully as possible, how far the males might be
assembled by the females. The question to be solved was,
from how great a distance can a male moth recognize and
follow up the scent of the female ? There are many condi¬
tions affecting the distance over which assembling may be
possible. The following are a few of the more important : —

1. The place in which the female emerges. If this occurs
in a stone wall or rubbish heap, or in a hollow tree, the odor
could not possibly escape and be diffused as fully as if the
moth were exposed to the air on the outside of the tree, and
at some height from the ground.

2. The condition of either the male or female after emerg¬
ing. If the female is strong and in perfect condition, she
will assemble more males than a female partly denuded. If
the male is strong and active, he will, of course, be superior
in flight and action to one partially crippled or enfeebled.

3. The direction and velocity of the wind. The wind
must blow from the place where the female emerges toward
some place where male moths occur. A wind of high velocity
will carry the odors farther than a light breeze, but, at the
same time, offer greater resistance to the flight of the male
while following up the scent.

4. Weather and temperature. The flight of the males
is more vigorous on bright, warm days than when the air is
cold and damp.

5. The contour of the land and whether it is wooded or
not, thus forming wind-breaks. If there are forests or hills
between the female in question and the males to be attracted,
they will interfere with the direct passage of currents of air
carrying the odor, so that males may fail to be attracted
from much shorter distances than if in a region without these
obstructions.

Details of the Experiments.

A level area on the salt marsh between Edgeworth and
Somerville, entirely free from obstructions, was selected for
the scene of operations, and stations were established from
day to day, according to the direction of the wind.

Stations. — The first station chosen in each experiment
was the one where one or more females were to be located,

ASSEMBLING.

347

and this was always on the windward side of the marsh.
The females were enclosed in a moth trap (Plate 54),
which was painted on the outside with a mixture of castor
oil and resin, and placed a few feet above the ground. The
second station was established directly to leeward of the
first, and at a measured distance from it. In many cases a
third and even a fourth station was established at a known
distance from the first and other intervening stations. It
was often found necessary to establish three or even more
stations, a short distance apart, on the arc of a circle, the
radius of which was a known distance from the trap, to
compensate for the veering of the wind, which sometimes
carried the scent of the female out of a direct line to the
stations first established.

Marking the Males. — In order to carry on this work and
obtain results at all satisfactory, it was necessary to adopt
some system of marking the males which were to be liber¬
ated, in such a way as to enable one not only to recognize
them afterwards, but also to determine from what station
they came. At first they were marked by cutting a small
notch in a certain part of the margin of the wing, with fine
scissors. This method, while not apparently injuring them
in any wav, was objectionable, because of its being a muti¬
lation which might affect the results more or less, and
therefore it was abandoned in the later experiments, and
water-colors were used. It was found impossible to make
the colors adhere to the wings, when mixed in water ; but
fifty per cent, alcohol was found to mix well with dry car¬
mine colors, and, when applied to the wing, made a tolerably
permanent mark. There was no difference in the results
obtained from moths marked in the two ways. In marking,
the color was applied, by means of a soft brush, to a par¬
ticular spot on the wings, a different mark being used for
each station, and a different set of marks each day. The
male moths were marked and boxed each mornino;, the
marks recorded, and the moths taken into the field. The
females were enclosed in the cage of the trap at station No.
1, and the males were liberated at the other stations accord¬
ing to their marks. In this way it was possible, when a
male was taken at station No. 1, to determine from which

348

THE GYPSY MOTH.

of the other stations it came, and the direct distance from
that station. The negative results in so many of the experi¬
ments were not due to lack of care or attention to details,
but in some cases to a change of wind immediately after the
liberation of the males, and in others to a dying out of the
wind before the males had reached the females. Many of
the male moths, as is common with them when handled,
would drop to the ground and remain in the grass for a long
time ; and it was found necessary to liberate a number of
them at each station, in order to increase the chance of meet¬
ing with the scent from the female. The following experi¬
ments were made in July, 1895 : —

Experiment No. 1.

Weather, fair and clear. Wind, north-west ; average
movement, 12 miles. Two traps, containing seven female
moths each, were set up at 9.15 a.m., at station No. 1. At
station 2, one-fourth of a mile to leeward of the first station,
eight marked male moths were liberated at 9.25 a.m. At
station 3, one-half a mile to leeward of No. 1, seven marked
male moths were liberated at 9.35 a.m. Nothing resulted
from this experiment.

Experiment No. 2.

Weather, fair. Wind, at 6.10 a.m., west; from 10 a.m.
to 3 p.m., east; average movement, 10 miles. Two traps,
containing six female moths each, were set up at 10 a.m.,
ten feet from the ground. At station 2, one hundred and
fifty yards to leeward, nine marked male moths were liber¬
ated at 10.15 a.m. At station 3, half a mile to the leeward
of station 1, nine marked male moths were liberated. Four
males were seen flying about station 1, but only one was
captured, and this one was from station No. 3, half a mile
distant.

Experiment No. 3.

Cloudy. Wind, south-west to west ; average movement,
10 miles. Two traps, containing six female moths each,
were set up at station 1. Seven marked male moths were
let loose at 8.10 a.m. from station 2, two hundred yards to
leeward of the first station, and at 8.20 a.m. seven marked

ASSEMBLING.

349

males were liberated from station 3, half a mile to leeward
from station 1. No males reached the first station, but the
rain which fell from 11 a.m. till night may have prevented
the males from flying.

Experiment No. 4.

Weather, fair. Wind, north to east; average movement,
10 miles. Two traps, containing six females each, were set
up at 10.30 a.m. Forty marked males were liberated at
10.45 a.m. from station 2, one-fourth of a mile from the first
station, and thirty-eight marked males were liberated at
10.55 a.m. from station 3, one-half a mile from the first sta¬
tion. At 3.30 p.m. one male moth appeared in the vicinity
of the first station. An attempt to capture it was unsuccess¬
ful. In all probability it came from either station 2 or 3,
since there were no infested areas in the direction toward
which the wind was blowing.

Experiment No. 5.

Cloudy. Wind, east ; average movement, 9 miles. Two
traps, containing six female moths each, were set up at 8
a.m. Nine marked males were liberated at 8.30 a.m., one-
fourth of a mile to leeward of the first station, and nine
marked males were liberated at 9 a.m., half a mile to lee¬
ward of station 1. None of these males reached station 1.

Experiment No. 6.

Damp and cloudy, with light rains at intervals until 2 p.m.
Wind, north-east ; average movement, 6 miles. One trap,
containing a single female moth, was set up at 1.45 p.m.
Six marked males were liberated at 2.10 p.m., 427 yards
to leeward of the first station, and fifty marked males
were liberated at 2.30 p.m., at station 3. This station was
located 713 yards to leeward of the first station. At 3.30
p.m. one male from station 2 reached the trap, and at 4.15
p.m. one from station 3.

Experiment No. 7.

Fair. Wind, north-west; average movement, 12 miles.
Two traps, containing twelve female moths each, were set up

350

THE GYPSY MOTH.

at 8 a.m. At station 2, one-fourth of a mile to leeward of
station 1, six marked males were liberated at 8.30 a.m., and
at 2 r.M. seven more males were liberated at this station.
At station 3, one-half mile to leeward of station 1, six
marked males were liberated at 8.45 a.m., and at 2.15 p.m.
eight others similarly marked were also allowed to escape
at this station. There were no results from this experiment.

Experiment JVb. 8.

Fair. Wind, from nearly all directions ; average move¬
ment, 5 miles. Two traps, containing six female moths
each, were set up at 8.30 a.m. At station No. 2, one-fourth
of a mile to leeward of station 1, eight marked males were
liberated at 9.50 a.m. At station 3, one-half mile to lee¬
ward of station 1, six marked males were liberated at 9.08
a.m., and six other males similarly marked were liberated at
a distance of sixteen yards to the right of station 1. One
male moth from station 2 returned at 10.30 a.m. The wind
shifted to east and south-west, and at 1.30 a heavy rain pre¬
vented all further work.

The data concerning the direction and wind movement,
given in these experiments, were kindly furnished by Mr. J.
W. Smith, the Boston local forecast official, and, as the place
where the experiments were performed was within four miles
of the Boston observatory, the figures in all probability are
approximately accurate for the locality.

j Remarks on the Above Experiments.

These experiments show that, under favorable conditions,
female gypsy moths will assemble males from various dis¬
tances up to half a mile, and it is possible that they might
have been attracted from somewhat greater distances had
males been liberated in larger numbers from stations more
remote from the female. It must be borne in mind that
these experiments were conducted under what would seem
to be the most favorable conditions, namely, upon a level
area, where a sweep of the wind could be obtained ; yet it
may be possible that what was gained by the favorable con¬
ditions was in a measure offset by a slight weakening of the
males caused by the handling necessary while marking them.

ASSEMBLING.

351

As shown by these records, males were assembled 427 yards
(see experiment No. 6), 440 yards (see experiment No. 8),
713 yards (see experiment No. G) and 880 yards (see experi¬
ment No. 2).

A series of experiments, to determine the manner in which
the male gypsy moth recognizes the presence of the female,
was made at the insectary and in the field, with the follow¬
ing results : —

Experiment No. 9.

July 25. To determine the effect of alcohol upon the
antennae, as the shellac to be used later was dissolved in
alcohol, the antennae of a male moth were thoroughly bathed
in ninety-three per cent, alcohol at 10.50 a.m. The first
effect of this application might well be called a complete
intoxication. The moth lay for two or three minutes flat
on the table without stirring. At 10.53 he began to move,
but had only partial control of his limbs, and travelled with
unsteady gait a short distance on the bench. By degrees he
completely recovered his normal condition, and at 1.15 p.m.
he mated with a female in a normal manner.

Experiment No. 10.

July 30. At 9.30 a.m., the wings of four unfertilized
females were completely covered with shellac, after which
the moths were placed in the experimental room, and two
males in normal condition were liberated. At 10 a.m.,
a female attracted and mated with one of the males. At
10.50 a.m., the other male was attracted to a second female,
but did not mate. At 11.30 a.m., the same male was
attracted to a third female, with the same results as in the
preceding case. At 3 p.m., one of these females attracted a
male, which mated with her at once.

Experiment No. 11.

July 30. At 9.30 a m., the dorsal surface of four females
(with the exception of the wings) was coated with shellac
varnish, the moths then being introduced into the experi¬
mental room with a number of normal males. At 10.30
a.m., one female mated with a male. At 11.40 a female

352

THE GYPSY MOTH.

attracted a male, but did not succeed in mating. At 12 m.,
a female attracted a male, with the same result as in the pre¬
ceding case.

Experiment No. 12.

July 30. At 9.30 a.m., the head and thorax of four
females were completely coated with shellac varnish, after
which operation the moths became quite stupid and one of
them seemed apparently dead. At 4.30 p.m., one of the
females mated with a male, but none of the others mated.

Experiment No. 13.

July 30. At 10.15 a.m., four unfertilized females were
coated with varnish alonir the sides of the thorax and abdo-
men. They were then placed in a wire-gauze can, which
was attached to a tree, in the Woburn colony, at a height of
about six feet from the ground. This trap was visited by
thirty-eight males from 10.15 a.m. to 3 p.m.

Experiment No. 14.

July 30. Another can, containing four unfertilized females
in normal condition, and used as a check, was visited by
thirty-eight males from 10.15 a.m. to 3 p.m.

Experiment No. 15.

July 30. Another can, containing four unfertilized females,
whose wings were covered on both surfaces with shellac, was
exposed under similar conditions. This trap was visited by
seventy-six males from 10.15 a.m. to 3 p.m.

Experiment JVo. 16.

July 30. A can containing four unfertilized females, with
the whole of the body, except the wings, covered with shel¬
lac, was exposed under the same conditions. This trap was
visited by only one male. A check can containing four un¬
fertilized females, in normal condition, exposed in the same
manner and at the same place as those in the preceding
experiments, to determine what would lie the normal rate of
assembling, was visited by seventy-seven males from 10.15
a.m. to 4 P.M.

ASSEMBLING.

353

Experiment No. 17.

August 1. A can containing four unfertilized females,
with the last three segments of the abdomen coated entirely
with shellac, was exposed as in the previous experiments,
and was visited by twelve males from 10.15 a.m. to 4 p.m.

Experiment No. 18.

August 1. Another can, containing four unfertilized
females, which were coated with shellac over the whole
body, with the exception of the three posterior segments,
was exposed under the same conditions as in the preced¬
ing experiments, and was visited by twenty-six males from
10.15 a.m. to 4 P.M.

Experiment No. 1 9.

August 1. A can containing four unfertilized females,
with the tips of their abdomens covered with shellac, so as
to close the external openings of the body, was exposed
under the same conditions as in the preceding experiments,
and was visited by eleven males from 10.15 a.m. to 4 p.m.

Experiment No. 20.

August 2. A single unfertilized female, in normal con-
dition, wTas placed in a small cardboard box, having a cheese¬
cloth top, and exposed on the branch of a tree, at a distance
of five feet from the ground. This box was visited by
twenty-eight males from 10.30 a.m. to 3 p.m.

Experiment No. 21.

August 2. A wire-gauze can, containing an unfertilized
female that had been denuded of hair, but whose wings were
in a normal condition, was exposed under the same con¬
ditions as in the preceding experiments, and was visited by
thirteen males from 10.30 a.m. to 1 p.m.

Experiment No. 22.

August 2. This experiment was conducted under the same
conditions and at the same time as preceding experiments,

354

THE GYPSY MOTH.

except that the can contained a female whose wings were
removed close to the body. This trap was visited by tour-
teen males from 10.30 a.m. to 3 p.m.

Experiment JVo. 23.

August 6. A female, with all appendages and down re¬
moved, was suspended in a mosquito-net bag in the centre of
a colony in Hawke’s woods, Saugus. She received no visits
from males up to 5 p.m.

Experiment JVo. 24.

August 6. Same place as above. At 10.45 a.m., a de¬
nuded female was suspended in a mosquito-bar box from a
tree, at a height of five feet from the ground. At 5 p.m. she
had received no visits from males.

Experiment JVo. 25.

July 25. At 1.45 p.m. , the antennae of two male moths
were covered with shellac varnish. This produced no ap¬
parent effect upon the moths. The males were kept in close
proximity to females during the remainder of the afternoon,
but none of them attempted to mate. July 25. At 1.45
p.m. , the antennse of two males were covered with a coating
of shellac, and the moths were then placed in a small card¬
board box with four unfertilized females. July 26, at 7
a.m. , the moths had not mated.

Experiment JVo. 26.

July 25. At 1.45 p.m., the antennte of a male moth,
which had just begun to mate with a female, were covered
with shellac varnish. This apparently produced no effect,
as the male did not leave the female until 2.20 p.m.

Experiment JSTo. 27.

July 25. At 3.48 p.m., a fresh, vigorous male was
deprived of both fore legs and then placed on the experi¬
mental bench near a female. The odor of the female was
driven towards him by the use of a fan, and he at once recog¬
nized her presence, and at 3.51 p.m. the moths mated.

ASSEMBLING.

355

Experiment No. 28.

July 26. At 8.50 a.m., one male moth, with three legs
removed, was placed on the experimental bench three feet
from four unfertilized females. At 9 a.m., he flew to the
partially drawn curtain and remained there until 10.45, when
he flew down from the window and mated with a female.
At 11 a.m. his antennae were cut off, but this did not pro¬
duce any appreciable effect. They remained together until
11.30. After leaving the female, he remained inactive dur¬
ing the rest of the day.

Experiment No. 29.

July 26. At 8.50 a.m., a male moth, with its wings
removed, was placed on the experimental bench at a distance
of three feet from four unfertilized females. At 10.20 a.m.,
he approached rapidly within two inches of the females, but
eventually crawled away to a distance of three feet from
them. At 1.40 p.m., he was placed near a female on the
bench, but after a few minutes went away from her. At
2.05, he was placed within one foot of a female, and after
crawling slowly toward her, mated with her.

Experiment No. 30.

July 26. At 8.50 a.m., a male moth with both antennae
removed was placed three feet from four unfertilized females.
At 9, he had crawled a distance of one foot toward the
females. He remained quiet until 11 a.m., when he was
placed close to a female moth. He, however, paid no atten¬
tion to her, and, up to 5 p.m., made no attempt to mate.

Experiment No. 31.

July 26. At 9.28 a.m., the antennae of a small male were
coated with shellac and he was placed on the experimental
bench, at a distance of two feet from a number of females.
At 11.30, he had made no effort to mate with any of them.
He was then placed on a box containing a large number
of unfertilized females, but showed no animation. Other
males, with their antennae not coated, were continually hov-

356

THE GYPSY MOTH.

ering about the box. The male in question remained quiet
until 5 p.m.

Experiment No. 32.

July 26. At 3 p.m. , the eyes of three male moths were
covered with shellac, and they were then placed within two
feet of two mature, unfertilized females. At 3.05, one male
flew to the females and attempted to mate, but was unsuc¬
cessful. At 3.25, another male approached the females, in
the same manner, but with no better success, but at 3.35
two of the males were successful in mating with two
females.

Experiment No. 33.

J11I3' 27. At 9.30 a.m., two males with eyes and a part
of the head covered entirely with shellac were placed on the
experimental bench, three feet from four unfertilized females.
At 12 m., one of these males began to fly about, and at 1
p.m. he was found mating with a female five feet from the
place where he was at noon. At 1.45 he left the female, and
at this same time the other male, whose eyes had been cov¬
ered with shellac, mated with a female and remained with
her up to the time the experiment closed, at 5 p.m.

From the preceding experiments the following conclusions
may be drawn : —

1. Coating the abdomen of the female with varnish or
denuding it of hair deprives her, in a great measure, of the
power to assemble males. The amount of assembling which
takes place under these conditions varies inversely with the
amount of body surface coated or denuded.

2. The presence or absence of wings in either sex does
not greatly influence the assembling process.

3. The sense of sight is not necessary to the operations
of assembling.

4. The antennas are absolutely necessary to the male in
locating the female, and without them assembling is impos¬
sible. It is a well-known fact that the males of this species
coming from any distance always approach from the lee¬
ward side of the female, thus apparently indicating that the
assembling is the result of an odor given ofi* by the female,
and carried by the wind.

Plate OP

J.RLnirrton, del.

Hellotype Printing v..i

Explanation of Plate 53.

1.

2.

3*

4-

5-
6.

7-

7 a-
8.

8 a.

9-

9 a.

10.
io a.
io b.

10 c.

11.

1 1 a.
1 1 b.
nc.

1 1 d.
ne.

12.

12 a.
13-
14.
I5-

Drawn by J. H. Emerton.

Calosoma frigidum Kirby, natural size.

Menecles itisertus (Say), “ “

Podisus cynicus (Say), “ “

Podisus serieventris Uhl., “

Polisies pallipes St. Farg., “ “

Theronia melanocephala (Brulle), “ “

Pimpla pedalis Cress., female, “ “

“ “ “ male, “ “

Pimpla tenuicortiis Cress. X 4.

“ “ “ natural size.

For?nica subsericea Say, worker X 4.

“ “ “ “ natural size.

Diglochis onuiivorus (Walk.), female X 8.

“ “ “ “ natural size.

“ “ “ male X 8.

“ “ “ “ natural size.

Achcetoneura fernaldi Williston, female X 4.

“ “ “ “ natural size.

“ “ “ foot of female.

“ “ “ “ male.

“ “ “ face of female.

“ “ “ “ male.

Elachipiera dispar Williston X 8.

“ “ “ natural size.

Phlceothrips sp. ? X 32.

Nothrus sp. ? X 32.

Trombidium bulbipes Pack. X 32.

ASSEMBLING.

357

Concerning the assembling process in the Bombycicke, the
late Prof. C. V. Riley wrote as follows: “The power of
assembling among certain moths, for instance, especially
those of the family Bombycicke, is well known to entomolo¬
gists, and many remarkable instances are recorded. . . .
Now, in the moths of this family the male antennae are elab¬
orately pectinate, the pectinations broad and each branch
minutely hairy. These feelers vibrate incessantly, wdiile in
the female, in which the feelers are less complex, there is a
similar movement connected with an intense vibration of the
whole body and of the wings. There is, therefore, every
reason to believe that the sense is in some way a vibratory
sense, as, indeed, at base is true of all senses ; and no one
can study the wonderfully diversified structure of the an¬
tennas in insects, especially in males, as very well exemplified
in some of the commoner gnats, without feeling that they
have been developed in obedience to, and as a result of,
some such subtle and intuitive power, as this of telepathy.
Every minute ramification of the wonderfully delicate feelers
of the male mosquito, in all probability, pulsates in response
to the piping sounds which the female is known to produce,
and doubtless through considerable distance ” ( “ Insect Life,”
Yol. VII, page 39).

In view of the fact that the males of the gypsy moth will
assemble nearly as readily to empty boxes, bags, etc., in
which females of the species have been previously confined,
as to the females themselves, we are led to believe that with
this insect, at least, the process is one depending upon the
sense of smell alone.*

On Trapping Males.

The following experiments were made under my direction
by Mr. H. N. Reid in 1893, for the purpose of determining
whether it is possible to trap the males of the gypsy moth,
in any infested region, to such an extent that there would not
be enough left to mate with any considerable number of
females, so that a large proportion of the females would be
compelled to lay infertile eggs, and therefore greatly reduce

* In one case males were found to visit an empty pasteboard box which had con¬
tained female moths three days before.

358

THE GYPSY MOTH.

the number of gypsy moths in that locality the following
season.

For this purpose wooden boxes, 12 by 8 by 3 inches,
were made, without top or bottom, these being covered with
brass wire gauze. A hole was bored in one end for the in¬
troduction of the female moths, and this was closed by a
cork. Several different substances were used on these traps,
to capture the males when they flew against them, as mo¬
lasses, raupenleim, sticky fly-paper, etc. Molasses proved
of no value, as it ran too easily, and was not sticky enough.
The raupenleim wTas not sticky enough, and soon dried on
the outside, so that it would not hold the males when they
flew against it. Sheets of sticky fly-paper, with holes 9 by
4 inches cut from the centre, were tacked over the gauze ;
these proved very efficient in securing and holding the
males, but it was necessary to replace them with fresh ones
frequently, and, to avoid this, they were painted over with a
preparation of castor oil and resin, which proved to be bet¬
ter for the purpose required than the original fly-paper.
When a trap was first put up a sheet of fly-paper was
tacked on it, and each time the trap was visited the cap¬
tured males were removed and the paper recoated so far as
necessary. This gum was found to keep in good condition
for several days, unless a large number of males were caught
in it, or the trap wTas in a very dusty place. Even when the
males were not caught the first time they touched the paper,
they wTere so persistent that they would immediately fly
against it again, and be caught in a few minutes.

The fly-paper was removed from one trap (No. 14) after a
few days, and a pan of water with a little kerosene on the
top of it was suspended directly beneath the trap. On ac¬
count of the rapidity with which the males flv, and the light¬
ness with which they struck the trap, it was not expected
that they would be caught in the kerosene ; but, being very
persistent, in trying to go under the trap from one side to
the other they came in contact with the kerosene and were
destroyed. This plan was not very satisfactory, not only
on account of the expense, but also because the kerosene and
water were so frequently spilled by the wind.

To obtain “ bait” for these traps, it was found better to

TRAPPING MALES.

359

collect the female pupse and allow them to emerge in con¬
finement, because in this way the matter could be controlled
more successfully than in any other. It was also found that
the traps attracted best when placed but a few feet above the
ground.

Fifteen traps wTere used during these experiments. No. 7
was removed after six days, to be placed elsewhere, as noth¬
ing was captured on it up to that time. No. 14 had sticky
fly-paper on it the first five days, during which time it
caught two hundred males. The fly-paper was then removed,
and a pan containing the water and kerosene was suspended
an inch or two below the trap. During the next twelve days
sixty-five males were captured in the pan. The traps were
put out from July 31 to August 10, and were taken in from
August 19 to August 30. The records of the traps are
given below : —

No. 1 was put out July 31, and taken in August 19, having
captured 82 males.

No. 2 was put out July 31, and taken in August 19, having
captured 34 males.

No. 3 was put out August 1, and taken in August 28, having
captured 175 males.

No. 4 was put out August 1, and taken in August 28, having
captured 87 males.

No. 5 was put out August 2, and taken in August 30, having
captured 36 males.

No. 6 was put out August 2, and taken in August 25, having
captured 88 males.

No. 7 was put out August 2, and taken in August 8, having
captured nothing.

No. 8 was put out August 8, and taken in August 30, having
captured 167 males.

No. 9 was put out August 8, and taken in August 26, having
captured 37 males.

No. 10 was put out August 8, and taken in August 30, having
captured 85 males.

No. 11 was put out August 8, and taken in August 26, having
captured 213 males.

No. 12 was put out August 8, and taken in August 28, having
captured 131 males.

360

THE GYPSY MOTH.

No. 13 was put out August 9, and taken in August 30, having
captured 163 males.

No. 14 was put out August 10, and taken in August 30, having
captured 265 males.

No. 15 was put out August 10, and taken in August 28, having
captured 208 males.

Summary .

Omitting No. 7, which remained out but a few days, the
whole number of males taken by all the traps was 1,771.
The smallest number taken by any one of them was 34, the
largest number was 265 and the average 126.5.

o o

During the months of July and August, 1894, these ex¬
periments were repeated by Mr. F. C. Schrader and four
other assistants. One hundred and ninety-one traps were
put up in the worst infested districts of Malden, Medford
and Everett, and kept in working order during the time
that the males were flying. The traps were visited every
day, fresh gum applied when necessary, new females put
into the traps as often as needed, and careful records were
kept of the results. The trapping season began July 19,
and closed August 13. Two different styles of traps were
used. The first kind was made of two-quart tin varnish
cans, from each of which was suspended, about two inches
below it, a tin base 9 by 12 inches, dished, so as to slope
from the edges toward the centre, and attached by two strips
of tin to a loop on each of the narrow sides of the can. A
strip of tin was removed from each side of the can, and this
was replaced by brass wire gauze. The unfertilized females
were placed in the can, through the hole at the top, which
was kept closed by a cork stopper. The traps were sus¬
pended from branches of trees by hooks eight inches long,
attached to the handle of the cans.

The other kind was a four-leaved wooden trap, commonly
called the “Shaw” trap (Plate 54), devised by Mr. H. J.
Shaw. It consisted of' a horizontal base board of half-inch
lumber, one foot square, with narrow grooves at right angles
across the middle of the upper side. Two thin boards, twelve
inches wide and seven inches high, notched together in the
middle at right angles, were secured in the grooves in the
base board, thus forming four vertical wings. An opening

PLATE 54. “Shaw” moth trap used in the assembling- experiments. The “bait” or female
moths are enclosed in the wire-gauze can.

TRAPPING MALES.

361

was cat in the lower edge of the vertical boards at the
centre, and in this opening was secured a cylindrical wire-
gauze cage, three inches in diameter and height, and with a
convex tin top and bottom. The unfertilized females were
placed in this cage through a round hole in the top, which
was kept closed by a cork. The trap was suspended by
means of a hook fitting into a wire loop at the centre of the
top of the vertical wings. Several other kinds of traps of
various patterns were tried, but none proved so satisfactory
as the two described above ; and of these the four-leaved
wooden trap proved to be the best, as it allowed the females
to be exposed to the air on all sides, and also because it pre¬
sented a greater area of the sticky surface. The majority of
the males were caught on the base boards of the traps, the
greater number invariably being taken on the leeward side.
The “bait” used in all of these traps was unfertilized
female moths bred from pupse in confinement, though the
pupae themselves, and dead and fertilized females, were also
tried for the purpose of ascertaining whether they would
attract the males. It was found advantageous, when keep¬
ing pupae in confinement, to moisten them with a fine spray
of water from time to time, to keep them from drying up so
much as to prevent them from emerging. The “bait” in
the traps was renewed as often as necessary. The best
means of carrying the newly emerged females was found to
be a cloth-lined box, as they would cling to the lining, and
could be transported in this way with little or no injury.
The traps were painted over with a sticky gum composed of
sixty per cent, of crude resin and forty per cent, of crude
castor oil. The resin and oil were melted together, and
applied, while warm, to the traps by means of a flat varnish
brush, care being taken not to put the gum on the gauze.
Most of the traps required repainting about every second
day, though some required it oftener. A small pointed
trowel was used in removing the captured males from the
glue, and a pole with a small hook at the end was used in
removing and replacing the traps in the trees. The trapping
operations were closed August 13, for lack of “ bait,” and
also because so few males were then captured that it did not
seem wise to continue the work.

3o2

THE GYPSY MOTH.

It was repeatedly demonstrated, in different towns and
with different traps, that they can be handled much more
easily and will capture more males when hung low. or placed
near the ground, than when they are placed high in the trees.
The £um. when made in the proportion given above, runs and
drips in hot weather and in the warm sunshine, more on the
tin than on the wooden traps, so that great care was required
in placing them in certain localities near residences, lest the
dropping gum should do harm. The adhesive power of this
gnm is remarkable. Two young birds were caught on the
foot board of the tin traps in Malden. They were both dead
when found, and showed evidence of desperate efforts to
extricate themselves. In the struggle they had pulled out a
larire quantity of feathers, and. in the case of a half-grown
English sparrow, which lay upon its side with the head
directed from the trap, the feathers adhered so firmly that
the bird could not be pulled ofi* without tearing the body
apart. Careful observations showed that at least ninety per
cent, of the male moths were captured on the foot board. It
was also found that where the moths are abundant the traps
can be used advantageously within ten rods of each other, or
in adjacent lots.

The essential point for the successful working of a moth
trap is to have the female well exposed on all sides, so that
the wind may pass freely over her body, and carry the odors
awav without obstruction in any direction that the air may
be moving : and, at the same time, she should be sufficiently
protected to insure her existence as long as possible. The
average length of life of unfertilized female moths, in the
wooden, four-leaved traps, was seven days. One female
moth, put into the trap July 31, was alive August 9, but
was dead at the time of the next visit. August 11. Another
female wa? put into a trap August 1, and died August 11.
In some cases the moths put into the traps were caught in
the gum, which worked in at the bottom of the cans, and
died in a day or two. In the tin traps the female moths did
not live more than two or three days, and those in the old
wooden box traps used the year previous did not live any
longer, seldom exceeding two days.

In some instances, when there were no unfertilized females

PLATE 55. Female moths depositing their egg-clusters on the trunk
of an oak tree, Saugus, 1895.

OVIPOSITION.

363

for “ bait,” fertilized moths, dead moths or female pupae
were used. The fertilized females attracted the males in
about half the cases where they were used. Of eight traps
“ baited ” with fertilized females, three caught nothing, two
caught one each, two caught two each and one caught four¬
teen, being an average of two and one-half each. The aver¬
age catch of the same traps, “baited” with unfertilized
females, was twenty and eight-tenths each. In nineteen of
the traps dead females were used at times, but they proved to
be of little value, for only five out of the nineteen attracted
any males. The total number of females used was twenty-
three, and only twenty-four males were captured by such
“ bait.” In some cases, female pupae were used in the traps,
and gave rather surprising results, which seem to indicate
that the pupae possess in some degree the power to assemble
male moths, as twenty-one female pup* attracted seventy-
two males.

The following is a summary of the results obtained :
191 traps; total catch, 9,767 males; average, 51.2 each;
maximum catch, 431 males ; minimum catch, 0 ; maximum
catch by a single female, 420 ; minimum catch by a single
female, 0.

After the trapping season was over, the localities in Med¬
ford, where the greatest number of males was captured,
were carefully explored and the egg-clusters collected. In
the latter part of December these eggs were carefully ex¬
amined and their fertility determined, with the following
results : of 659 egg-clusters examined, 16, or 2.4 per cent.,
proved to be infertile. As a check on the work, an equal
number of egg-clusters taken from places not trapped for
males were collected and examined, and all proved fertile.

Oviposition.

The abdomen of the female is so heavy before depositing
her eggs that she simply clings head upward to the trunk
of a tree or other object on which she happens to be rest¬
ing (Plate 55) ; and when preparing to lay, and even during
the process of depositing the egg-cluster, she drops or scat¬
ters more or less eggs accidentally. A small hairy area is
first formed by rubbing the abdomen over the surface, thus

364

THE GYPSY MOTH.

depositing a small quantity of hair, which is caused to ad¬
here, probably by a slight discharge of fluids. One egg
is fastened to the surface, another is placed beside it and
others on each side of these. As soon as the foundation is
started, other eggs are laid upon it and the mass is built
along ; that part of the cluster next to the surface on which
the moth rests is always kept a little in advance of the
eggs laid on top of it, and is the widest part of the
structure. The eggs when laid are covered with an ad¬
hesive fluid, which not only causes them to adhere where
they have been placed by the ovipositor, but also causes
the abdominal hair of the female, which she rubs off by the
continual movement of the abdominal segments, to adhere
to them. As laying progresses, the abdomen shortens,
and the hair from the under side of the anterior segments
furnishes the covering for the last-laid eggs.

The term layer may properly be applied to the eggs that
are deposited on the surface upon which the moth is rest¬
ing, for they conform to that surface, however smooth or
uneven it may be, but those outside of this layer are packed
in very irregularly. In nearly every case where the eggs
are laid upon a vertical or nearly vertical surface, the lay¬
ing is done from below upwards, the lower eggs being the
first deposited, while the upper ones are the last. In gen¬
eral, from two to three days are required for oviposition,
but the time is subject to considerable variation. The
greater part of the egg-cluster is usually deposited during
the first twenty-four hours. In one case a large female
moth which began laying at 6 p.m., Aug. 6, 1895, did not
complete her egg-cluster until 11.30 a.m., August 16. The
female does not usually deposit all the eggs contained in the
body. In the case of the female mentioned above, there
were 201 eggs remaining in the abdomen of the moth, while
the egg-mass which she had deposited contained 794 eggs.

Eggs removed by Dissection of Female Moths.

The female moths are often attacked while laying, and
mutilated or entirely consumed by a few insectivorous birds
and predaceous insects. Of the latter, the large wood ants,
Camjponotus pennsylvanicus (De G. ) , sometimes kill the fe-

PLATE 56. Egg-clusters and pupae of the gypsy moth. From a photograph taken in Malden, Mass-

photograph taken in Malden, Mass.

PARTHENOGENESIS.

365

male moths, gnaw open the abdomen, and, after removing
the egg-mass, drag it to their nests. With the discovery
of these facts the question naturally arose, whether the
eo;<2;s thus removed from fertilized females would hatch and
thus start new colonies in the places to which they had been
carried. To settle this point, during the summer of 1895,
studies were made on fifty female moths. Some of these
moths were taken when the egg-cluster was about one-third
completed, some when the egg-cluster was one-half com¬
pleted, some when two-thirds, and others which had very
nearly completed laying. These moths were dissected, and
all of the eggs still remaining in the abdomen removed and
preserved in boxes. Examinations of these eggs, made
subsequently, showed that none of them were fertile.

A part of the egg-cluster deposited by twenty-five of
these moths was preserved, all of which proved more or
less fertile. This seems to demonstrate that, notwithstand¬
ing the mating of the moth, the eggs are not fertilized till
during the process of laying.

Parthenogenesis .

Parthenogenesis, or reproduction by means of the eggs of
unfertilized females, was thought to offer an explanation for
the existence of certain peculiarly situated colonies in the
infested territory. As has been previously stated, cater¬
pillars are sometimes dropped uninjured by the birds when
they are carrying them away to feed their young ; or they
may spin down from the trees upon passing teams or ani¬
mals, and be carried to greater or less distances and then
escape to suitable food plants, where they can feed and
pass their transformations. If a single caterpillar should be
carried, in any such way, to a distance from any colony
greater than males could be attracted, and from it should
emerge a female moth, she would doubtless lay her eggs,
and, if parthenogenesis occurs in this moth, these eirgs
might hatch, even though no male had been present to mate
with her.

To ascertain whether eggs laid by unfertilized females
will hatch, in July and August, 1893, 990 female pupae were
put in small pasteboard boxes and kept under a variety of

366

THE GYPSY MOTH.

circumstances, but all at the normal out-door temperature.
Some were kept covered with cheese cloth, others with the
regular box covers, and still others were kept covered a
part of the time with the covers and the rest of the time
with cheese cloth. One hundred and sixty of these pupte
were from larvse raised in confinement, while the rest were
collected in the field. Two hundred and thirty-three moths
emerged and laid their eggs, but without that regularity
that characterizes the egg-clusters of fertilized females.
Most of the females laid a considerable number of eggs,
though four laid no eggs but deposited some of their hair ;
one laid only a single egg, while two other females laid four
and five eggs respectively. The boxes containing these eggs
were kept under the same conditions as other boxes which
contained fertile eggs, which hatched at the usual time in
the spring ; but no trace of embryonic development could
be discovered within them during the fall, and they were
again critically examined the last of January, 1894, when
they were found to be more or less shrunken, and showed
no sign of an embryo within, as is the case with fertile eggs.
Early in the spring a piece of glass was glued over the top
of each box, so that the young caterpillars could not escape,
should any of the eggs hatch. They were daily inspected
till after the time when they should have hatched, and then
once a week till July, and less frequently till October, 1894,
but not an egg hatched. While this experiment does not
prove that parthenogenesis does not sometimes occur in the
gypsy moth, it would seem to indicate that it is probably
of rare occurrence. A few cases have been reported in
Europe. Carlier states that he has seen three generations
without mating having taken place, but the last genera¬
tion gave only males. Siebold, who refers to this case
in “ Entomologisclie Zeitung, Stettin,” Yol. XXII, page
443, expresses some doubt, since no exact account of events
was given. Weijnbergh, however, has given a very com¬
plete account of breeding this species from unfertilized
eggs for three generations, until, at last, the eggs dried
and brought his observations to a close. Dohrn, who
reports this case in “Entomologisclie Zeitung, Stettin,”
Yol. XXXII, page 30, expresses the opinion that the dry-

EGG-CLUSTERS OF UNFERTILIZED FEMALES. 367

ing up of the eggs of the last brood was not due to their
parthenogenetic characteristics, but to outside influences,
and further states that it would be premature to limit the
vitality of the products of parthenogenesis to two genera¬
tions. It is a matter of regret that Weijnbergh did not
examine the eggs each fall, and see whether the embryo
had formed ; for, had this been found, there would have
been greater reason to have supposed that the eggs had
dried up because of outside influences, as Dohrn conjectured.
Mr. W. J. Pearce of Bath, England, reports in “ The Ento¬
mologist,” Vol. XII, page 229, that he had a female of this
moth, which had not mated, lay eggs which hatched the
following year.

Egg-g’lusters of Unfertilized Females.

The egg-clusters deposited by unfertilized females, in the
experiments on parthenogenesis, in 1893, were, as a rule,
irregular, scattering and poorly covered with hair. As
these were all laid in boxes, it was thought that it might be
due, in part at least, to the smoothness of the box, which
did not allow the moth as good a foothold for oviposition
as is afforded by the surfaces usually selected for the pur¬
pose, such as the rough bark of trees, etc. The observa¬
tions of the field inspectors led them to various conclusions,
some contending that unfertilized females never lay the
regular egg-clusters characteristic of the fertilized female,
while others were of the opposite opinion. Investigations
were made during the summer of 1895, to learn whether it
is possible to determine, from the form and completeness of
an egg-cluster, whether the eggs contained in it are fertile.
August 2, twenty-five recently emerged, unfertilized female
moths were placed in a cage, made by tacking cheese cloth
over a hoop, which projected from the trunk of a white oak
( Quercus alba) . This species of tree was selected because
the bark is of such a nature as to give the moths the most
favorable opportunity for egg-laying. At the end of two
weeks, all the moths being dead, the cage was opened and
six very imperfectly formed egg-clusters were found. They
were, in fact, simply small patches of eggs, with but little
of the usual covering of hair. October 10, the eggs were

368

THE GYPSY MOTH.

shrivelled, and the clusters partly washed away by the rains.
From these as well as other observations made this season
it seems more than probable that a female gypsy moth that
has not mated does not make a perfect egg-mass, and that
an experienced observer may distinguish in most cases an
egg-cluster that is infertile from one that is fertile.

In-and-in Breeding.

A cluster of eggs laid by one female gypsy moth was
placed in a breeding cage in the spring of 1893, to deter¬
mine whether the two sexes would emerge at the same time,
mate and lay fertile eggs. This was for the purpose of
ascertaining whether it would be possible for a fertile
female, if transported to a new region, to lay eggs capable
of establishing a new colony ; or, if a single cluster of eggs
should be carried outside of the infested region, whether a
new colony would result. The eggs used in this experi¬
ment commenced hatching May 5, 1893, and the caterpillars
were fed on apple leaves till they reached maturity, when
they pupated. The moths emerged as indicated in the fol¬
lowing table : —

Date.

June

20.

July

1.

July

2.

July

3.

July

4.

July

5.

July

6.

July

7.

July

8.

July

9.

July

10.

July

12.

Total.

Male, .

3

5

8

32

13

60

76

26

2

20

19

3

267

Female,

-

-

2

16

15

62

69

20

4

16

-

7

211

In all there were 478 moths, 267 males and 211 females,
which mated as readily as those from different egg-clusters ;
and, as their eggs proved fertile, there is every reason to
believe that, under favorable circumstances, this cluster of
eggs could have established a colony of moths. See “ The
Entomologist,” Vol. XIX, page 281 (1886).

Internal Anatomy.

The following description of the internal anatomy of the
different stages of the gypsy moth was prepared by Mr. A.
H. Kirkland.

PLATE 58.

EXPLANATION OF PLATE 58.

Drawn by A. H. Kirkland.

1. Internal anatomy of larva of gypsy moth X 2 : nc., nerve

cord; sg., silk gland; oe., oesophagus; b., brain; as.,
anterior stomach; dv., dorsal vessel; ps , posterior
stomach; ro., reproductive organ; mv., malpighian
vessels; i., intestine; r., rectum.

2. Internal anatomy of larva about to pupate X 2 : as., ante¬

rior stomach; ps., posterior stomach; dv., dorsal ves¬
sel ; ro., reproductive organ.

3. Section through anal segment of larva about to pupate,

showing development of cremaster in anal shield X 4 :
as., anal shield; c., cremaster; r., rectum.

4. Section through head of larva about to pupate, showing the

development of the antenna cases beneath the larval
head covering X 4: dv., dorsal vessel; ce., oesophagus;
b., brain; a., antenna case.

5. Internal anatomy of female pupa X 2: dv., dorsal vessel;

ro., rudimentary accessory organs of reproductive sys¬
tem ; r., rectum.

6. Internal anatomy of female moth X 2 : od., oviduct; cp.,

copulatory pouch; nc., nerve cord and ganglia; s.,
atrophied stomach; b., brain; dv., dorsal vessel; r.,
rectum ; ag., accessory glands of reproductive system.

7. Right silk gland of full-grown larva, enlarged.

8. Posterior tip of silk gland, greatly enlarged.

9. Part of malpighian vessel, greatly enlarged.

10. Part of dorsal vessel of imago, showing aortic arch.

Drawn by R. A. Cooley.

11. Micropyle of egg with surrounding rosette, greatly enlarged.

12. A part of the same, still more enlarged

INTERNAL ANATOMY.

369

The figures of the internal anatomy were made from dis¬
sections of alcoholic specimens of the different stages, the
work being performed at the entomological laboratory of
the Massachusetts Agricultural College. In preparing the
material for dissection the insects were first placed for
twenty-four hours in fifty per cent, alcohol, then, for the
same period of time, in seventy-five per cent, alcohol, and
then kept in commercial alcohol until needed for use. The
dissections were made under water, by using a small wax-
bottomed, dissecting pan. The dissections of the pupee were
not wholly satisfactory, since the rapid breaking down of
the larval organs and the correspondingly rapid development
of the organs of the imago obscured the relations of the
different parts, and made the correct interpretation of them
a difficult task. The longitudinal section of the pupa, as
shown in Plate 58, Fig. 5, is a composite figure, made
up from the dissections of several pupae from five to seven
days old.

The Alimentary Canal and its Appendages.

From the medium large mouth' cavity the oesophagus
(Plate 58, Fig. 1, oe) leads back through the oesophageal
collar formed by a division of the double commissure which
connects the brain (b) with the sub-oesophageal ganglion in
the first thoracic segment. Here it expands into a peculiar
thin-walled organ, which, from its position and size, may be
called the anterior stomach (as). This anterior stomach,
which is practically an enlarged continuation of the oesoph¬
agus, is distinctly separated from the posterior stomach,
stomach proper, by a well-defined constriction formed by a
strong sphincter muscle, possibly valvular in function.
The anterior stomach fills the thoracic and a part of the first
abdominal segments. A marked distinction from the pos¬
terior stomach is the fact that it is not supplied with the
prominent annular muscle bands which are characteristic of
the latter organ, although it possesses both annular and
longitudinal muscle fibres. In the larger caterpillars it is
usually distended by a dark, viscid, semi-fluid mass, con¬
taining the recently devoured food, and, as shown by micro¬
scopic examination, numberless bacteria. The posterior

370

THE GYPSY MOTH.

stomach (ps) extends backward from the anterior stomach
to the eleventh segment and nearly fills the body cavity.
The contents of this organ are of a more solid nature than
those of the anterior stomach. In the eleventh segment
this organ tapers abruptly to form the short intestine (i),
which has two enlargements, separated from each other by
a sharp constriction. Between the stomach and the intes¬
tine, and also where the intestine enters the rectum, there
is a well-marked constriction. In the last body segment
the intestine expands into the large distended rectum (r),
which completely fills the cavity and discharges at the anus
beneath the anal shield. Six narrow longitudinal muscles
extend the entire length of the alimentary canal. These
muscles form six definite depressions on the intestine and
rectum, and give to the excrement of the larva its peculiar
incised appearance.

The malpighian vessels (Fig. 1, mv) consist of six double
convoluted tubes which are attached to the walls of the pos¬
terior stomach and discharge into the intestine. These ves¬
sels are simply convoluted tubes (Fig. 9), and do not pos¬
sess the bulbose lateral enlargements found in many other
Lepidoptera. They are composed of a thin outer membrane
and an inner layer of thick-walled nucleated cells, arranged
around a central lumen, some parts of which, in the alco¬
holic specimens, are often filled with a yellow-brown crys¬
talline mass (urates). Fresh malpighian vessels macerated
in water give quantities of minute crystals. I have been
able to demonstrate the presence of uric acid in these ves¬
sels by the use of the “ murexid ” test.

Small white granules are occasionally found deposited
throughout all the different tissues of the larva, but, owing
to their extremely small size, I have been unable to collect
a sufficient quantity for analysis. In similar granules re¬
moved from the tobacco worm ( Protoparce celeus ) I have
found uric acid, as shown by the “murexid” test, and
phosphoric acid, as demonstrated by the reaction with am¬
monium molybdate.

The silk glands, two in number, lie along the lateral walls
of the body cavity of the larva. Each gland consists of a
small thread-like tube, which leads forward from the poste-

INTERNAL ANATOMY.

371

rior part of the body, gradually enlarging in the seventh
segment, thence extending forward to the fourth segment,
where it bends on itself and leads backward and upward to
near the middle of the eighth segment. Here it reaches its
maximum diameter. It bends downward and gradually
tapers again to a thread-like duct, which extends forward,
and, after a more or less irregular course, discharges at the
spinneret on the under side of the labium.

In the full-grown larva (Fig. 1, sg) these glands are dis¬
tended with the silk-forming fluid ; in those which have spun
their cocoon (Fig. 2) they have contracted to less than
one-half of their original size. One of these glands is
shown in Fig. 7, and its extreme posterior tip in Fig. 8.

When the caterpillar is ready to pupate (Fig. 2), the
alimentary canal is emptied of its contents, the anterior
stomach (as) shrinks to less than one -half of the diameter
of the posterior stomach (ps), the latter having also
shrunken to about one-half of its original diameter. The
intestine and rectum undergo a corresponding diminution.
In the pupal stage (Fig. 5) the anterior stomach grows still
narrower, the posterior stomach and rectum shorten, while
the intestine, although less than one-fourth of the diameter
of the larva, elongates to nearly twice its original length.
In the imago (Fig. 6) the digestive system is atrophied, the
anterior part being represented by a slender thread-like
remnant of the oesophagus and anterior stomach, while the
posterior stomach has been transformed into the small
shrunken stomach (Fig. 6), at the hinder end of which may
be found the remains of the malpighian vessels. A slender
intestinal tube connects the stomach with the rectum (r),
which lies in the upper posterior part of the abdominal
cavity, and is usually filled with a thick cream or salmon
colored fluid.

It is interesting to note that the digestive system of the
male imago does not appear to have undergone so marked
a degeneration as that of the female. The stomach is much
better developed, and the relation of the different parts can
be more clearly demonstrated.

372

THE GYPSY MOTH.

Dorsal Vessel or Heart.

This organ, in a caterpillar, is a simple longitudinal tube
(Fig. 1, dv), lying immediately beneath the dorsal line and
extending the whole length of the body. It is closed at the
posterior end, while the anterior end opens at the base of the
brain. Bands of muscle fibres, placed more or less oblique¬
ly, appear in the walls of the organ, while it is supported at
the sides by fan-shaped muscles (alee) which are attached
to the upper body walls.

In the pupal stage (Fig. 5, dv) a marked bend is found
near the anterior end of the dorsal vessel, while faint muscle
fibres can be traced, extending from the bend to the dorsal
wall of the thorax.

In the imago (Fig. 6) the dorsal vessel (dv) follows
the contour of the upper surface of the abdomen, bends
abruptly downward at the junction of the abdomen and
thorax, enters the thoracic cavity, bends obliquely upward
to the dorsal wall, where it is firmly attached by muscle
fibres, then extends downward and slightly backward,
thence forward to the head, where it terminates at the base
of the brain. I have been unable to discover any aortal
chamber, such as was found by Burgess in Anosia plexippus,
although the aortal arch (Fig. 10) is well defined.

Respiratory System.

This system is not figured in the plates, but possesses the
general features common to Lepidoptera. The spiracles
open internally by short tubes which communicate with two
Ions: lateral tracheae. These extend the whole length of the
body, and give off ramifications to all the organs. Opposite
the spiracles are clusters of tracheae of medium size, which
are distributed over the surface of the alimentary canal.
The tracheae are composed of an outer semi-transparent
sheath, made up of large, thin cells, the nuclei of which are
readily revealed by staining with haematoxylin. Within
this sheath is a chitinous tube, bearing on its inner surface
a fine spiral ridge, which gives the tracheae their distinguish¬
ing characteristic.

INTERNAL ANATOMY.

373

Nervous System.

This consists of a double supra-cesophageal ganglion or
brain (Fig. 1, b) in the head, an oesophageal collar, a sub-
oesophageal ganglion and a row of ganglia extending along
the median ventral part of the body cavity. The ventral
ganglia are connected by a double commissure (nc). The
brain gives off nerves to the ocelli, the sub-oesophageal gan¬
glion supplies the mouth parts, while from the ventral gan¬
glia nerves are distributed to the feet, prolegs and internal
organs.

In the caterpillar there are eleven ventral ganglia, includ¬
ing the sub-oesophageal. The posterior one is by far the
largest, being formed by a fusion of two ganglia. During
the pupal stage (Fig. 5) the number of ganglia is reduced
by fusion. In the imago we find two thoracic and four
abdominal ganglia, which are connected with the brain by
a double commissure.

The Fat Body.

In its fullest development this body forms an internal
cylinder of fat, which surrounds the alimentary canal and
lines the body cavity of the caterpillar. It is represented
by the dark dotted area in Plate 58, Fig. 2. It is liber¬
ally supplied with trachea? and is most prominent in well-
fed, full-grown caterpillars. In the pupal stage (Fig. 5) the
fat body diminishes as the reproductive system develops, the
development of the latter taking place at the expense of
the former. One fact, which seems worthy of record in
this connection, is that almost no fat can be found in the
female imago, while there is an appreciable quantity pres¬
ent in the male. Since the male is the sex that flies, this
fat may be necessary to furnish the energy expended in
flight.

Reproductive System.

This system is represented in the caterpillar by a pair of
small reddish-brown organs (Fig. 1, ro), which lie one on
each side of the dorsal vessel in the ninth segment. From
these organs a pair of thread-like appendages (ducts ?) lead

374

THE GYPSY MOTH.

backward for a short distance. A careful sectioning of a
single reproductive body shows it to be composed of fila¬
ments, which are coiled upon each other, forming a com¬
pact mass, which is enclosed in the external envelope. In
the mature caterpillar, and even in those of the fourth molt,
there is a marked difference in the structure of the repro¬
ductive organs, seemingly indicative of sexual differentia¬
tion. One form, apparently that of the female, is made up
of medium long, thick tubes, composed of an outer wall, a
thicker inner layer and a central lumen, which is enlarged
at intervals, and contains in these enlargements large cell-
like bodies surrounded by many smaller cells (nutritive
cells ?) .

That which is apparently the male form is made up of
much smaller and somewhat longer tubes of a more nearly
even diameter. These tubes are closely coiled on each
other within the sac formed by the outer envelope. These
organs increase in size as the insect approaches the pupal
stage. Although our studies on the reproductive system
in the pupa are not yet completed, one point is well estab¬
lished : the development of the reproductive system of the
future imago is accompanied by a corresponding diminu¬
tion of the fat body with which the newly formed pupae
are filled. In this stage the accessory organs and glands of
the reproductive system are first recognizable (Fig. 5, ro).
The reproductive organs of the male imago (Plate 59,
Fig. 1) consist of a single button-shaped testis (t), formed
by the fusion of the two reproductive bodies of the cater¬
pillar ; the paired seminal vessels (vs) and duct with the
accessory glands. Four enlargements occur on each of the
seminal vessels, two near the testis and two near the junc¬
tion of the two vessels. The last enlargement has a blunt,
lateral projection, which receives the duct from the acces¬
sory gland. The common duct formed by the union of the
two seminal vessels tapers for a considerable part of its
course, then enlarges to form the seminal reservoir proper
(sr) at the base of the penis (p), into which it discharges.
Around the base of the penis, and attached to the lateral
body walls, are bands of muscle fibre (m), which evidently
serve to exsert the organ. The Avhole system is so compli-

EXPLANATION OF PLATE 59.

Drawn by A. H. Kirkland.

1. Reproductive system of male imago, greatly enlarged: t.,

testis; ag., accessory gland; vs., vesicula seminalis ;
sr., seminal reservoir; m., muscle at base of penis;

p. , penis; co., Clasping organs.

2. Reproductive system of female imago, enlarged: rs., recep¬

tacle of semen or copulatory pouch; od., oviduct;

ag. , accessory glands; oo., ovaries.

/

PLATE 59.

NATURAL ENEMIES.

375

cated that no attempt has been made in the plate to repre¬
sent the various windings of the vessels and glands as they
occur in the insect.

The female reproductive system (Fig. 2, also Plate 58,
Fig. 6) consists of the two ovaries (oo), each composed of
four egg-bearing tubes, the oviduct (od) formed by the
union of the ovarian tubes, the accessory glands (ag), and
the copulatory pouch or receptacle of semen (rs). The
ovarian tubes are closely coiled upon each other, and form
an egg-mass which completely tills the body cavity. On
the dorsal surface of the oviduct is the point of union with
the large paired and small single accessory glands. These
glands probably secrete the viscid coating of the eggs, which
enables the latter to adhere in masses to the surface on
which they may be deposited. Beneath the oviduct, and
connected with a separate external opening, is the copula¬
tory pouch (Plate 58, Fig. 6, cp). This is a medium-
sized pear-shaped organ, and connects with the oviduct by
means of a slender tube.

Natural Enemies of the Gypsy Moth.

The birds which play so very important a part in destroy¬
ing the gypsy moth have been fully treated of in Part I of
this work by my colleague, Mr. Forbush, and we pass to
the consideration of the other natural enemies of the insect.
Under these we will consider the animal and vegetable para¬
sites, the predaceous insects and other insectivorous animals,
except the birds.

Hymenoptera .

In all our field operations we have endeavored, from the
first, to learn as much as possible about our native parasites,
and particularly to what extent they attack the gypsy moth.
For this purpose we have paid especial attention to collect¬
ing the different species found to be parasitic upon this
insect, and to studying their habits. The Hymenopterous
parasites of the gypsy moth thus far found are as follows :
Theronia melanocephala (Br.), Phnpla pedalis Cress., Pim-
pla tenuicornis Cress. (Plate 53, Figs. 8, 8a), Anisocyrta
sp., Diglochis omnivorus (Walk.) (Plate 53, Figs. 10,
10a).

376

THE GYPSY MOTH.

The first two and perhaps the last are the most useful in
destroying the gypsy moth, and probably are far more
successful than the Dipterous parasites, since the latter lay
their eggs on the outside of the caterpillars, and many of
them are thrown off on the molted skin before they hatch ;
while the eggs of the Hymenopterous parasites are deposited
in the tissues beneath the skin.

During the summer of 1895, Theronia melanocephala
(Plate 53, Fig. 6) was the most abundant of the Hymen¬
opterous parasites, and in the larger colonies could be
seen on warm days flying about from tree to tree, almost
invariably alighting on the burlap bands, and even crawling
under them in its search for pupae. In Lexington, on one
occasion, one of these insects was seen to go from tree to
tree until it had examined seven burlaps. After searching
the burlaps, the trunk of the tree above and below was
inspected, the antenna? all the time being kept in constant
motion. It has been reported that this parasite attacks
the caterpillar when about to pupate ; but in nearly all the
cases where its oviposition was observed this year, some
eiaht or ten, the insects attacked were in the pupal stage.
The point of attack was on the ventral surface, at the
lower margin of the wing-cases, next the abdominal seg¬
ments. Here the chitinous integument is very thin, and
oilers the least resistance to the insertion of the ovipositor.
Alien a suitable pupa is found, the parasite, after selecting
the point for attack, curves the end of the abdomen beneath
the body between the legs, and inserts the ovipositor into the
pupa by a succession of movements, the whole operation
requiring about a minute and a half. Alien disturbed by
the writhing of the pupa or otherwise, the parasite with¬
draws her ovipositor and later stings again. Only one
parasite has been reared from each parasitized gypsy moth,
and therefore we may infer that but a single egg is deposited
in a pupa. Mr. C. E. Bailey captured a specimen of Tlier-
onia melanocephala in the act of stinging a gypsy moth
pupa which already contained a Dipterous maggot. Un¬
fortunately, the pupa was so crushed that it was impossible
to ascertain what the result would have been.

On one occasion a wood pewee was seen to snap up one

NATURAL ENEMIES.

877

of these parasites, while apparently in search of pupae.
There is no doubt that our birds which take small insects
on the wing also destroy many Hymenopterous and Dipter¬
ous parasites.

Pimpla jpedalis (Plate 53, Figs. 7, 7a) was obtained
from the pupae of the gypsy moth the past season, as well
as in previous seasons, and was also bred in great numbers
from the cocoons of the tent caterpillar ( Clisiocamjpa ameri-
ccina). From about two quarts of the cocoons of the latter
insect only twenty-five moths were obtained, the rest pro¬
ducing parasites, most of which were Pimpla pedalis, though
a few specimens of Theronia melanocephala were also ob¬
tained. Pimpla pedalis was seen ovipositing in the cocoons
of the tent caterpillar ; but as I have bred this parasite from
larvae of Tortrix fumiferana received by mail, and reared
under such conditions that it was impossible for parasites to
approach them, I am led to believe that Pimpla pedalis , as
well as Theronia melanocephala , oviposits not only in pupae
but also in caterpillars. The fact that these parasites breed
in the tent caterpillar and other insects, as well as in the
gypsy moth, is of special interest; for the tent caterpillars
pupate about four weeks earlier than the gypsy moth, and the
parasites emerge from them just in time to attack that insect,
so that this succession of hosts favors the multiplication of
the parasites. How these parasites pass the winter I do not
know, but think it very probable that they hibernate as
imagoes. Ichneumon grandis was taken in January, 1895,
hibernating in the imago stage, in a stone wall at Swamp-
scott, along with pupa shells of the gypsy moth and cocoons
of Pyrrharctia Isabella.

The following is a list of the European Hymenopterous
parasites of the gypsy moth, some of which, however, are
known to be hyperparasites : —

Pteromalus halidayanus Rtz.
(hyper).

Pteromalus pini Hartig. (hyper).
Pteromalus boucheanus Rtz.
(hyper).

Eupelmus bifasciatus Giraud.
Eurytoma abrotani Panz.

Microgaster calceatus Hal.
Microgaster (?) tenebrosus Wesm.
Microgaster tibialis Nees.
Microgaster ( ?) liparidis Rtz.
Microgaster pubescens Rtz. — calcea¬
tus Hal.

Microgaster fulvipes.

378

THE GYPSY MOTH.

Apanteles glomeratus L.
Apanteles fulvipes Hal.
Apanteles melanoscelus Rtz.
Apanteles solitarius Rtz.
Pimpla flavicans Rtz.

Pimpla instigator Gr.
Mesochorus pectoralis Rtz.
Mesochorus gracilis Brischke.

Mesochorus splendidulus Gr.
Mesochorus confusus.

Campoplex conicus Rtz.

Campoplex difformis Gr. = Limneria.
Pesomachus hortensis Gr. (hyper).
Hemiteles fulvipes Gr.

Trogus flavatorius Pnz.

Ichneumon disparis Poda.

It is interesting to note that all the genera included in
the above list are represented by species in this country ;
yet, aside from the genus Pimpla, no members of the dif¬
ferent genera have been found to attack the gypsy moth.

Predaceous Wasps and Hornets.

The following species of wasps and hornets have been
observed feeding upon the different stages of the gypsy
moth: Vespa maculata Linn., Vespa consobrina Sauss.,
Vespa germanica Fab., Polistes pallipes St. Farg.

At a new colony of gypsy moths, in North Saugus, in the
early part of August, a large number of Vespa maculata
were observed flying close to the ground, around the base
of the trees or carefully searching the trunks up and down,
sometimes even going up into the tops of the trees. They
were closely watched, and a maculata was seen to fly after a
male moth, follow its zigzag flight as it attempted to escape,
and finally capture and carry it to a small branch. The
hornet soon dismembered the moth and began feeding upon
the abdomen.

Two other hornets of the same species were seen flying
after male moths. The first one chased a moth up above
the tree tops and then off to one side and out of sight.
The other followed a moth for about eight rods through the
woods, and then caught him, but flew off before it could be
taken with a net.

At another time a number of large brown wasps ( Polistes
pallipes ) (Plate 53, Fig. 5) were noticed flying about the
trees. When they discovered a branch on which caterpillars
had clustered they alighted, and, running along the under
side of the branch and leaves, each wasp located its prey,
left the branch, and, flying about the caterpillar, finally

NATURAL ENEMIES.

379

alighted upon its back, at the same time stinging it upon
or near the head, usually from behind. The result of this
was to completely paralyze the caterpillar, for a time at
least, wThen the wasp sucked the fluids from the body by
cutting holes through the body wall, beginning near the
head and working toward the posterior end. In some cases
the wasp nearly cut the head and first or second segment
from the body, and not unfrequently they were seen to cut
off a part of the caterpillar and fly away with it.

The work of the wasps was not confined to a few isolated
cases, but they were busy every day between the hours of
9 a.m. and 3 p.m., killing and carrying away the caterpillars.

One of the most remarkable observations of the season of
1895 was made by Mr. C. E. Bailey, a most careful and reli¬
able field observer. While watching the birds at Wayte’s
Mount, Malden, for the purpose of discovering to what ex¬
tent the different species of birds destroy the gypsy moth,
he saw a large insect seizing gypsy moth caterpillars and
flying away with them. Being provided with a net, he suc¬
ceeded in capturing this insect while it was flying away with
a third-molt gypsy moth caterpillar. The insect proved
to be the American saw-fly ( Cimbex americana). I am not
aware that this species has ever before been discovered to
be predaceous in its habits, but its mandibles and other
mouth parts are so developed that one can well believe it
capable of predaceous propensities.

Mr. W. L. Tower reported that on July 17, 1894, he saw
a specimen of Tremex , or of a closely allied genus, take a
full-grown gypsy moth caterpillar and fly away with it. As
the insect was not captured, and under the circumstances
could not be closely identified, we should not have con¬
sidered it worth while to mention it here but for the reason
that it may also have been the American saw-fly, and, if so,
a verification of the predaceous habits of that insect. An
examination of the mouth parts of Tremex columbci will con¬
vince one that this insect is not predaceous, and therefore
the probabilities are increased that the insect seen by Mr.
Tower was the American saw-fly.

380

THE GYPSY MOTH.

Ants attacking Female Imagoes.

The following field observations show that the female
imagoes, while laying, are often attacked and killed by
black ants.

Aug. 11, 1894, a female, trying to deposit an egg-cluster
on the trunk of an oak tree, was attacked at 10.20 a.m.
by a large black ant, which seized her antennas with its
mandibles. The ant was captured, and the moth resumed
laying; but at 1.40 p.m. was found in a hole in the ground,
with a number of ants working upon her. One leg was
gone and two more nearly severed from the body. At 2.40
all of the legs and both antennae were missing, and the
wings nearly destroyed. At 4.40, the thorax having been
severed from the body and the abdomen opened from the
anterior end, the ants commenced to carry off the egg-
masses.

Another female moth, while crawling in the grass, was
attacked by the ants at 11.40 a.m., which seized her by the
ovipositor and dragged her some distance. At 2.40 p.m.
the ants, still at work, had torn the head from the body and
carried it up into the tree, and soon after they opened the
abdomen and greedily devoured the ovarian tubes. A third
female, just beginning to lay, was seized by a large black
ant, which dragged her to the ground, where nine more ants
began to dissect her. The antemue and legs were removed,
the abdomen opened, and the ants soon began feeding upon
the egg-masses.

To determine whether the ants will eat the eggs, the fol¬
lowing investigations were made : Four female moths were
divested of their heads and wings, the abdomens opened so
as to expose the egg-masses, and then placed at the base of
four tfees. In about half an hour two of the moths were
visited by several black ants, and a short time later nine
ants were working upon one moth. These ants feasted for
an hour or more upon the egg-masses, with their mandibles
closed and their heads thrust down among the eggs, as if
sucking up the body fluids. Then they began to sever the
thorax from the abdomen and to tear off s pi all clusters of
eggs, from three to seven each, and carry them with the

PREDACEOUS COLEOPTERA.

381

other parts of the body into their nests, in an oak tree, two
and a half feet from the ground. When the last piece had
been removed, the large ants left the held and were suc¬
ceeded by a smaller species, that gathered up the scattered
eggs and minute pieces of tissue and carried them off.
Soon the large black ants returned to another moth, and
began carrying away masses of eggs. The smaller species
worked upon the same insect, but were not able to make
so much progress. In no case were the ants seen to eat a
single egg; they only devoured the body tissues and fluids,
particularly the ovarian tubes enclosing the eggs. Two
harvest spiders also appeared and fed upon the egg-masses.

Specimens of these ants were sent to Mr. Theo. Per-
gande, who identified them as Camponotus pennsylvanicus
De G. (Plate 53, Fig. 9, 9a), and the large and small
workers of Formica subsericea Say.

In connection with the attack of ants upon the gypsy
moth, the following note is of interest : In the early part
of the work of trapping the male moths, in 1894, attention
was called to the fact that in the midst of the most densely
infested part of a grove there was a single hickory tree on
which no egg-clusters, caterpillars or any trace of the gypsy
moth had been found, in spite of the fact that the trees and
shrubs almost touching it on every side were all found to
be badly infested. The tree in question was inhabited by
small black ants, in fact, was full of them, and to these
probably owed its escape from the ravages of the gypsy
moth, while other trees of the same species, not inhabited
by ants, were infested. The larger species of black ants
have also been seen feeding on dead caterpillars and pupae
of the gypsy moth.

Predaceous Coleoptera.

Several species of beetles have for some time been known
to destroy the gypsy moth. On the 20th of May, 1892,
Mr. C. H. Rowe found the fiery hunter ( Calosoma calidum )
devouring the young gypsy moth caterpillars at the base of
an oak tree in Malden. The beetle was captured, and sub¬
sequently liberated in a breeding cage containing thirty-six
full-grown caterpillars, and others were added as they were

382

THE GYPSY MOTH.

needed. In five days ninety-three caterpillars were de¬
stroyed, only portions of the larval skins remaining. The
beetle was fed for two weeks with various species of cater¬
pillars and the larvae of leaf-eating beetles. There seemed
to be no choice made of the different species of caterpillars
supplied, but all were in due time attacked and more or less
eaten. From the number of caterpillars eaten in the five
days, Mr. Rowe estimates that the average daily consump¬
tion of this beetle is about equal to six full-grown gypsy
moth caterpillars. Mr. Rowe also reports the larvae of two
species of Harjpalus feeding on young gypsy moth cater¬
pillars.

For the purpose of ascertaining more fully the habits of
the predaceous beetles, the following species were observed
in confinement, in the insectary at Malden, during the sum¬
mer of 1895, and later they were confined and fed in cages
out of doors. One specimen of Calosoma scrutator was
brought in June 28, and put into a cage with ten gypsy
moth caterpillars, which were at once attacked by the beetle.
The favorite place of attack seemed to be the middle of the
body. As the viscera of the caterpillar came out the beetle
chewed away steadily, apparently seeking the fatty parts.
In two days fourteen caterpillars were eaten. At the end
of this time the beetle was placed in a cage with another
individual of the same species. July 1, the two beetles
killed seven gypsy moth caterpillars, and eleven more were
put in the cage. The next day ten were dead, and ten more
of the fourth and fifth molt were put in. One caterpillar
pupated, and the pupa was destroyed by the beetles. July
3, six: caterpillars were killed, and eight more of the fourth
and fifth molt were put in. July 4, one of the beetles died.
The remaining beetle killed four caterpillars July 5, but
died on the next day, after killing two more caterpillars.
These two beetles killed, in all, thirty-six gypsy moth
caterpillars.

Another individual of this species was placed in a cage
July 2, and kept supplied with gypsy moth caterpillars.
July 18, another beetle of the same species was placed in the
cage and supplied with food. The first beetle, during the

PREDACEOUS COLEOPTERA.

383

fifteen days before the second was put in, destroyed thirty-
one caterpillars and three pupae ; and, after the other beetle
was put in with it, the two destroyed fifty gypsy moth
caterpillars and one Sphinx drupiferarum caterpillar before
July 24, when the first beetle died. The remaining beetle
destroyed four gypsy moth caterpillars, one sphinx cater¬
pillar and one male gypsy moth between July 24 and July
30. Another Ccdosoma scrutator was then put into the cage,
and August 5, when they were placed out of doors, they had
killed eight caterpillars, three pupae and two female moths.

Two specimens of Ccdosoma frigidum (Plate 53, Fig.
1) , male and female, were put into a cage together at the in¬
sectary, June 28, and supplied with gypsy moth caterpillars.
This species is much smaller and lliore active than C. scru¬
tator. They are not so clumsy, but are able to seize the
caterpillars and destroy them while on a vertical surface, as
on the trunk of a tree. July 27, one of these beetles died,
and the other was removed to be used by the artist. Dur¬
ing this time they killed ninety-two gypsy moth caterpillars,
three pup* and one female moth.

Three other individuals of this species were put into a
cage in the insectary, July 21, and supplied with gypsy
moth caterpillars. One of the beetles died the second day,
and on August 5 the other two were placed in an outside
cage. During the fifteen days that these beetles were fed
in the insectary they killed thirty-nine gypsy moth cater¬
pillars, two pup*, two sphinx caterpillars and one cut¬
worm.

Calosoma calidum. — Three specimens of this beetle were
placed in a cage July 12, and supplied with gypsy moth
caterpillars. July 19, twenty-three caterpillars had been
killed, and another beetle was put into the cage. July 27,
one of the beetles died, the four having killed thirty-four cat¬
erpillars and one pupa since July 19. Fifteen gypsy moth
caterpillars, four pup*, eight cut-worms and two Sphinx
drupiferarum caterpillars were killed between July 27 and
August 5.

One specimen of Carabus serratus was supplied with
gypsy moth caterpillars, and killed five before it died.

384

THE GYPSY MOTH.

Platynus limbatus was also found feeding on pupee in the
field, but it would not feed upon them in confinement.

For the purpose of keeping and feeding some of our pre¬
daceous beetles, under as natural conditions as possible,
Mr. Kirkland very ingeniously arranged a number of cages
(Plate 60), and attached them to the trunks of trees in the
woodland near the insectary. These cages were of wire
netting, bent into a nearly cylindrical form. The edges
were fastened to the two sides of the tree trunk, the lower
end extending down into the ground and the upper end
covered by a piece of cloth, one side of which was secured
to the tree, the other covering the top of the wire screen
cage, and held in place by a rubber strap, the ends of which
were fastened to the trunk of the tree. This rubber band
could easily be removed from the top of the cage and the
cloth lifted sufficiently to give free access to the interior.
A few small stones and some moss were so arranged on the
ground, at the bottom of the cage, as to furnish hiding-
places for the beetles. Each cage had a tag attached to it,
on which was the number and other necessary data.

Two specimens of Ccdosoma scrutator were placed in cage
No. 1, August 9, and supplied with gypsy moth caterpillars.
August 20, fourteen caterpillars had been killed.

Five specimens of Calosoma frigidum and one of Calo-
somci calidum were put into cage No. 2, August 9, and
supplied with caterpillars. One specimen of C. frigidum
died August 13, and August 20, twenty-five caterpillars had
been killed by these beetles.

Ten specimens of Harpalus caliginosus were put into cage
No. 3, August 9, and supplied with caterpillars, and August
20, twenty-two of these caterpillars had been destroyed by
the beetles.

Ten specimens of Harpalus jpennsylvanicus were placed
in cage No. 4, August 9, and furnished with caterpillars;
August 20, twenty-three caterpillars had been killed by the
beetles.

During the summer of 1891, Mr. E. P. Felt obtained a
specimen of Dermestes lardarius from a mass of gypsy moth
pupae.

PLATE 60. Cages used in rearing predaceous beetles.

PARASITIC DIPTERA.

385

Several Coleopterous larvae have been found feeding upon
the egg-clusters of the gypsy moth, but we have been unable
to obtain the imagoes from them. During the past year
Air. C. H. Rowe succeeded in rearing a specimen of Ptinus
brunneus from a gypsy moth egg-cluster.

The following species of predaceous beetles are said to
attack the gypsy moth in Europe : —

Calosoma sycophanta (L.) (larva).

Tiresias serra (Fab.) (eggs).

Dermestes ater (Panz.) (eggs and pupae).

Dermestes lardarius (L.) (eggs and pupae).

Dipt era.

In June, 1891, while on a visit to the territory infested
by the gypsy moth, my attention was first called to the fact
that flies were depositing their eggs on the caterpillars ; and
since that time the field workers have reported these para¬
sitic flies in no less than ten towns, showing that they
probably occur throughout the entire infested region. The
number of these eggs on a single caterpillar was reported
by twelve different inspectors who observed them, as vary¬
ing from one to twenty, though some state that they have
seen the caterpillars “ nearly covered,” and others “ eggs in
great numbers on them.” Directions were then given to
collect and rear the parasitized caterpillars till these para¬
sites should emerge. It was found that many of the cater¬
pillars molted their skins before the eggs of the parasites
hatched, and therefore comparatively few of them were able
to make their way into their insect hosts and destroy them.
If the caterpillars had not molted before the eggs of the
parasites hatched, their destruction would have been vastly
greater. During the summer of 1893, Mr. Reid collected a
number of caterpillars on which the eggs of the parasites
had been laid. Two hundred and thirty-five of these cater¬
pillars, having from one to thirty-three eggs on them, were
fed in cages until they changed to pupae ; and from these
two hundred and twenty-six moths emerged, but only four
Dipterous parasites were secured from this entire number.
The caterpillar which had thirty-three parasite eggs on it

386

THE GYPSY MOTH.

when brought in molted before these eggs hatched, passed
all its transformations, and the moth emerged from it in
good condition.

In July, 1895, a careful examination was made to deter¬
mine the proportion of caterpillars in the held that had the
eggs of the Dipterous parasites attached to them. July 3,
hve trees were examined in Dorchester, and 2,200 cater¬
pillars were found, 500 of which had the eggs of parasites
on them. July 8, six trees were examined in Medford, and
1,847 caterpillars found, 397 of which bore parasite eggs.
The total number of caterpillars examined was 5,547, of
which 1,597, or nearly 29 per cent., had the eggs of Dip¬
terous parasites attached to some part of the body.

Several Dipterous parasites were bred, during the summer
of 1895, from infested pupa?, the majority of which pro¬
duced only one parasitic hy, while a few produced two.
Many parasitized pupa; contain maggots which have not yet
pupated. The vitality of these Dipterous parasitic larvae is
very remarkable. One of them was placed in a twenty per
cent, solution of formol at night, August 15, and twenty-
four hours later it was found swimming around, apparently
uninjured. The larva was at once removed from its formol
“bath,” and was still living October 1, but had not pupated.
In several cases where two larvae were found in a small pupa
of the gypsy moth, and there seemed an insufficient amount
of food for them, a large female pupa was cut open and a
parasite larva placed on the cut end of each half. They at
once burrowed into the tissues and fed there several days.
One larva ate the substance of six female pupae in this way
before reaching its full growth.

Fifty gypsy moth caterpillars, having eggs of a Dipterous
parasite on them, were collected in Dorchester, June 21,
1895, and carefully bred in separate boxes. The eggs were
deposited without regularity on nearly every part of the
body. Forty-three of these caterpillars passed their trans¬
formations, producing perfect moths, six males and thirty-
seven females ; while seven died, but not because of the
parasites, for .the caterpillars had all molted before the eggs
of the parasite had hatched. Two hundred and fifty-two

PARASITIC DIPTERA.

387

other caterpillars taken in the field, and bearing Dipterous
ecu's, were fed and carried through their transformations
with the same result as in the case cited above.

All the Dipterous parasites bred from the gypsy moth,
and also those collected in 1891, were sent to Dr. S. AV.
AVilliston for determination. They were determined by
him as follows : —

Exorista , two species ; Phorocerci, four species. These
are true parasites.

Gaurax anchora Loew, whose larvae had been observed
by Osten Sacken in multitudes upon the pupae enclosed in
the cocoons of the Geer op ia moth ; Pliorci scalaris Loew ;
Phora incisuralis Loew, var. The last three species are
regarded by Dr. AVilliston as accidental parasites entering
the pupae of the gypsy moths while the flies are in the larval
state, and then feeding in and destroying the moths.

Sarcophaga , two species. Schiner expresses very grave
doubts whether the species of Sarcophaga ever feed on any¬
thing but dead animal matter, while Brauer states that their
larvae are sometimes parasitic.

Cyrtoneura stabulans Fall. According to Hartig and
Bremi, the larva of this species is sometimes found in the
caterpillars of certain Bombycid moths.

In 1894, I sent another lot of Diptera bred from the gypsy
moth to Dr. AVilliston for determination, and in reply he
wrote as follows : “I send you herewith the manuscript on
the Diptera sent me, except a portion of that formerly sent
to you, the specimens of which have got mislaid or rather
lost in the general collections, and have not yet been found.
There wTere several specimens, how many I do not know,
but not including the Tachinids which I had separated out.”
Should the above-mentioned species be found, there may
prove to be something of interest to add to our list. Dr.
AVilliston kindly sent the following descriptions for publi¬
cation in this report : —

Achoctoneurct fernaldi n. sp. (Plate 53, Fig. 11, a— e.)
21ale. — Frontal stripe deep brown, a little narrower than
the sides of the front; sides light golden yellow, reaching
a little way on the sides of the face. At each angle of the

388

THE GYPSY MOTH.

eye there is a stout bristle curved backward ; on either side
of the frontal stripe a single row of bristles, of which the
two uppermost are stronger than those before them, and are
curved backward. The frontal row extends down on the sides
of the face for a short distance beyond the base of the an¬
tennae and to nearly opposite the uppermost bristle of the
facial row ; the proclinate ocellar bristles moderately strong.
Antennae wholly black, the third joint but little more than
three times the length of the second joint. Face satiny
white ; vibrissal bristles situated a little distance above the
oral margin ; above them is a row of not very strong bristles
extending about midway to the root of the antennae. Sides
of the face wholly bare, except for the previously mentioned
bristles. Cheeks covered with short, black, bristly hairs,
their length equal to about half that of the eyes. Eyes
wholly bare. Palpi yellowish. Mesonotum shining blue
black, with inconspicuous stripes. Scutellum broadly red¬
dish on the apex, the apical pair of bristles small and decus¬
sate. Abdomen shining blue black, with a broad, variable,
white pollinose, basal band on the segments ; first and
second segments each with a pair of marginal Jbristles ;
third segment with a posterior row ; the general covering
of the abdomen is composed of rather stout bristly hairs,
which are more abundant, longer and intermixed with finer
hairs distally. Legs wholly black, the front femora whitish
pollinose behind ; pulvilli much elongated ; the claws elon¬
gate and slender. Wings grayish hyaline ; third vein with
a few short bristles at the very beginning ; angle of the
fourth vein without a stump, though with a fold appearing
somewhat like one.

Female. — Differs from the male in the front being wider,
in the presence of two proclinate orbital bristles on each
side, in the abdomen being less hirsute and in the short
claws and pulvilli. Length of male, 10 mm. ; of female,
12 mm.

Twenty-five specimens from Professor Fernald, labelled
as follows: “From larvae which died in parasitic cage
Aug. 27 (male), 28 (male and female), 29 (male), 1893,
laboratory Gypsy Moth Department, Malden.” “ Emerged

PARASITIC DIPTERA.

389

from pupa of P. dispar Aug. 22, 1893 ” (female) ; and
“Emerged from gypsy moth pupae Aug. 24 (male), 27
(female), 29 (female), 1891; Sept. 2 (female), 1891.”

I have compared these specimens with a female type of
A. (Masicera) frenchi Williston, with which the species is
closely allied, and find the following differences : The facial
bristles ascend higher in A. frenchi, reaching two-tliirds or
more of the distance to the root of the antennae, while in
A.fernaldi they do not go more than half way, and some¬
times even less than that. The bristles of the front do not
descend so far as in A. frenchi. But the chief difference,
and one by which the species will be readily recognized, is
the relatively much shorter third joint of the antennae in the
present species. In A. frenchi it is fully live times the
length of the second. The marginal bristles of the abdo¬
men seem to be stronger in A. frenchi. In the type female
compared there are none on the first segment, but I suspect
that the species has them normally.

From Achcetoneura ( Masicera ) spiling ivor a Towns., Trans.
Am. Ent. Soc., Yol. XIX, page 286, the length of the
antennae and the red sides of the abdomen are sufficient
to distinguish. From A. ( Masicera ) euftchice Towns, the
differences are also evident.

Scircophaga, sp. Female. — Sides of the front and face
wholly silvery white ; median frontal stripe black. Antennae
black, third joint between three and four times the length
of the second joint. Abdomen black, silvery white, mar-
morate ; fourth segment wholly black. Legs black, the
hind tibiae not ciliate. Palpi black. Length, 12 mm.

One specimen, labelled “ From parasitic material, Aug.
1, 1893, Gypsy Moth Department, Malden.” The single
specimen is not in the best state of preservation, and it is
difficult, if not impossible, to either identify it with any
previously described species or to give a description which
will enable the species to be again determined with cer¬
tainty. The diagnosis given above wil serve to exclude all
but nearly related species.

Cyrtoneura stabulans. — Musca stcibulans Fallen. Mei-
gen, Schiner (Cyrtoneura) , etc. Europe, Xew Zealand,
North America.

390

THE GYPSY MOTH.

Female. — Front a little less than one-third of the width
of the head, gray pollinose on the sides, the median stripe
deep reddish brown or black, broader than the sides, nar¬
rowed below ; a pair of proclinate ocellar bristles pres¬
ent ; the lateral row of bristles has an outward curvature.
Second joint of the antennae reddish ; in front somewhat
blackish, and with erect bristles ; third joint black, about
three times the length of the second; arista thickened at
the base, plumose. Sides of the face narrow, bare. Cheeks
in width about equal to the length of the third joint of the
antennae, with a row of bristles on the inferior margin
reaching to the moderately stout vibrissae a little above the
oral margin ; bare on the upper part, and with short bristly
hairs below. Sides of the face and the upper part of the
cheeks reddish in ground color, covered with silvery pubes¬
cence. Mesonotum gray pollinose, variable, with four nar¬
row, shining black stripes, the lateral ones interrupted.
Scutellum broadly reddish at the apex ; apical bristles long,
decussate. Abdomen uniformly covered with gray pol¬
len, moderately variable in different reflections, the ground
color everywhere shining black. Legs yellow; the front
femora in large part and the base of the middle femora
black ; all the tarsi blackish. Wings grayish hyaline ; first
posterior cell only a little narrowed at the tip ; penultimate
section of the fourth vein shorter than the antepenultimate
section. Length, 6—7 mm.

Three specimens, labelled “Emerged from gypsy moth
pupae, Aug. 20--21 and 25, 1891.” This species is the one
which I have commonly identified as C. stabulans Fall., but
I have never compared it directly with European specimens.
According to Scliiner, it has been bred from Bombyx pyri
and Lophyrus, and also from various species of Boletus.

Elachiptera dispar n. sp. (Plate 53, Figs. 12 and 12a.)
Female. — Head yellow, a minute spot at the ocelli and the
arista black. Thorax light yellow ; a narrow median stripe
extending from the front margin of the mesonotum to the
tip of the scutellum; a small oblique spot on each side,
contiguous with the front end of the stripe, and the disk of
the mesonotum, black. Abdomen yellow ; second segment,

PARASITIC DIPTERA.

391

except a broad triangle whose apex reaches the hind mar¬
gin, and all of the following segments, black. Legs light
yellow ; the front tibiae and tarsi brown, the other tarsi
brownish. Wings cinereous hyaline. Length, 2 mm.

Two specimens, labelled “Emerged from gypsy moth
pupae, Aug. 21, 1891.” The arista has been broken away
in both specimens, save the basal part; this part, however,
is so thickened and pubescent that I believe that I am not
in error in referring the species to Elachiptera ( C r assise ta) ,
where it finds its nearest ally in E. eunota Loew.

Pliora setcicea Aldrich, Can. Ent., Vol. 24, page 144,
Brookings, South Dakota (reared from Cimbex americana).

Notwithstanding the difference of locality and habits, I
believe that the specimens bred from the gypsy moth par¬
asitic material and sent to me by Professor Fernald are of
the same species as those described by Professor Aldrich.
I have only males, and it is possible that the females may
show some discrepancies. The specimens differ from the
description only in the male genitalia, which do not have
the projecting abdominal segment as described, and in the
first weak vein of the wings, which is distinctly curved and
not “ almost straight.” The species will be best recognized
by the arrangement of the lowermost frontal bristles, for
the position of which the reader is referred to the figure and
description given by Aldrich. Otherwise the species may
be briefly described as follows : —

Male. — Head black, antennre fuscous ; palpi yellow, with
black bristles ; proboscis yellow. Thorax black. Abdomen
black ; halteres light yellow. Front and middle legs yellow,
the hind ones more brownish. One spur at the tip of the
tibiae, save of the front pair, where there are none. Wings
hyaline ; second heavy vein (third longitudinal) furcate ;
bristles on costal border long. Length, 1.5 mm.

It is probably true that the species of Pliora are not truly
parasitic, but live in any dead or decayed material that
comes in their way ; still, it is not certain but that they may
attack the living insect.

The following list of the European Dipterous parasites
of the gypsy moth has been compiled from various sources.

392

THE GYPSY MOTH.

Many of the names are taken from a list furnished me by
Dr. S. AY. Williston : —

Exorista lucorum Meig.

Exorista (Myxexorista) libatrix
Panz.

Exorista erythrostoma Hrtg.
Parexorista sussuraus Rond.
Meigenia bisiguata Schin.

Tachina bella Meig,

Tachina piuivora Ratz.

Tachina larvincola Ratz.

Tachina monacha Ratz.

Tachina noctuarum R. D.

Tachina quinquevitala Hrtg.
Tachina rustica Fall.

Tachina larvicola Hrtg. (?)

Tachina moreti R. D.

Tachina (Echinomyia) conjugata
Rond.

Tachina (Echinomyia) fera L.
Tachina bimaculata Hrtg.

Eutachina larvarum L.

Phoi'ocera concinnata Meig. = M.

serrieventris Rond. (?)
Sarcophaga affinis Fall.
Thelymorpha vertiginosa Fall.
Argyrophylax gilva Hrtg.
Parasitigeua segregata Rond.
Macharsea serriventris Rond.
Chajtomyia crassiseta Rond.

It will he observed that the single species of Tach iniclce
thus far known to infest Porthetria dispar, in North
America, belongs to a different genus, or sub-genus, from
any in the above list, all of which are Tachinids except one.
It will be of interest to determine the earlier or normal host
of Achoetoneura fernaldi.

Predaceous Piptera.

Of the predaceous Diptera the following species have
been taken feeding upon the imagoes of the gypsy moth :
j Oasyllis sacrator Walk., attacking the females while laying ;
Asilus sericeus Say, capturing the male imagoes on the
wing.

Predaceous Hemiptera Heteroptera.

The following account of the predaceous Hemiptera Heter¬
optera, known to feed on the gypsy moth, has been prepared
for this report by A. II. Kirkland, B.Sc., assistant entomol¬
ogist.

An important factor in the destruction of the gypsy moth
caterpillars is the aid rendered by several species of pre¬
daceous bugs, which, in badly infested localities, attack the
caterpillars in considerable numbers, and in some places
apparently feed upon them in preference to any other kinds
of Lepidopterous larvae. The predaceous bugs thus far found
feeding upon the gypsy moth are Podisus cynicus (Say),

PREDACEOUS HEMIPTERA.

393

P. serieventris Uhl. and Menecles insertus (Say). Perillus
circumcinctus Stal. has also, this year, been doubtfully re¬
corded, in a single instance, as attacking gypsy moth cater¬
pillars. The following pages present the facts we have
ascertained concerning the habits of each species, together
with the life history of P. serieventris.

General Habits. — All these species appear to be arboreal
in habits, although they are occasionally taken on the ground.
Their chosen food in this region seems to be the caterpillars,
of the different Lepidoptera, and in the search for them the
bugs often climb trees to a great height. The bugs seek
out caterpillars in their hiding-places in the rough bark, or
even follow them to their feeding-places on the foliage, and
attack them both during the day and at night. These pre¬
daceous insects possess a considerable degree of activity,
most noticeable on warm days, and have also the ability to
exist for some time without food, especially in the earlier
stages. During the present summer, at the insectary, speci¬
mens of P. serieventris were found to be alive and fairly
active at the end of live days from hatching, without once
having taken food. This marked degree of vitality of the
young bugs is perhaps not surprising, since from the time
of hatching to the time of first feeding, the element of chance
enters most strongly into their career, for they may often,
of necessity, travel over a large part of a tree before
finding food for the first time. These species are found on
all parts of the trees, and, while they are more or less gre¬
garious in the first and second stages, in the later stages
they usually feed independently of each other. I have re¬
peatedly seen the imagoes of P. serieventris fly short dis¬
tances, which would indicate that this is its ordinary mode
of transit from one tree to another. This latter species
shows a considerable attraction to light.

Of the three species mentioned, M. insertus seems to be
the most local in its distribution in the infested district.
In the restricted areas in which it occurs it is fairly abun¬
dant, but its limited distribution in the territory infested bv
the gypsy moth renders it of less importance than P. cynicus
or P. serieventris. The two latter species are very gener-

394

THE GYPSY MOTH.

ally distributed throughout the iufested regiou, and the
good they do in destroying the caterpillars of this insect is
of no little importance. The larger of the two species,
P. cynicus , occurs in smaller numbers than P. serieventris ,
and, although it will destroy more caterpillars during its
feeding season, yet from the moderate numbers in which
it occurs it is not so valuable an ally as P. serieventris.
Whether these insects are devoured by birds to any great
extent I am unable to state. The odoriferous glands with
which they are provided would seem to be a means of pro¬
tection against their natural enemies. A pair of crows,
confined at the insectary, devoured all specimens offered
them of the three species of these bugs, and Mr. Forbush
informs me that in nature these insects may possibly be
destroyed to some extent by crows, since these birds are
known to include the Heteroptera in their bill of fare.

Method of rearing Predaceous Bugs. — The problem of
breeding any Heteropterous insect presents at the outset
many difficulties, and but little assistance is given by the
literature on this sub-order of insects. Concerning this sub¬
ject, Douglas and Scott, in their work on “ British Hemip-
tera,” Yol. I, page 5, 1865, wrote: “It is probable, in
consequence of the fact that the Hemiptera-Heteroptera are
in all stages of their existence active and suctorial, and the
consequent difficulty of supplying them, in confinement, with
fresh, appropriate food, that but few observations upon their
natural history have been recorded. . . . But, whether
each species casts its skin the same number of times ; how
long the individuals of each species remain as larva, pupa
or imago ; what species have more than one brood in a
year, and what constitutes the food of each species, — are
matters that, in the great majority of instances, remain to
be determined. There is, therefore, a wide field for re¬
search in the natural history of this sub-order of insects.”

While considerable has been done toward gaining a
knowledge of the life histories of many of our plant-feeding
Heteroptera, in the thirty years which have elapsed since
the above was written, as yet we know but little of the life
history of those members of the family which are predaceous

PLATE 61.

FIG. 5.

FIG. 1. (xi2)

FIG. 2. (xl2)

FIG. 3. (x 8)

FIG. 6. (x 6)

0

FIG. 7.

Co.

FiG. 10.

Suffolk Eng.

FIG. 9. (X5)

Explanation of Plate 61.

Drawn by A. H. Kirkland.

Podisus serieventris Uhl.

i- Egg.

2. Newly hatched nymph.

3. Nymph after first molt.

4. Spiny armor on surface of egg, greatly enlarged.

5. Curved spine from upper part of egg, greatly

enlarged.

6. Nymph after second molt.

7. Antenna of nymph.

8. Tarsus of nymph.

9. Nymph after third molt.

10. Out-door cage used in rearing this species.

PREDACEOUS HEMIPTERA.

395

upon other insects. The first stumbling block met with, in
attempting to raise these insects, was the provision of a
suitable breeding-cage, and many attempts made, both dur¬
ing 1894 and 1895, to breed them in confinement in boxes,
jars, etc., gave only negative results. With the establish¬
ment of an insectary at Malden and increased facilities for
out-door experimentation, in June, 1895, other attempts
were made to construct a cage in which one might rear
these insects under the nearest possible approach to natural
conditions. After several experiments a breeding-cage was
devised which gave the desired result (Plate 61, Fig. 10).
This consists of a fine wire gauze, semi-ellipse, fastened
tightly at the sides to a small tree trunk, and closed at the
bottom by a tight-fitting wooden base, the cage, on the
whole, being quite similar to those used in rearing the pre¬
daceous beetles. The top is covered by a piece of cloth,
held firmly in place by a rubber band, while a small wooden
hoop is placed around the inside of the top of the cage, in
order to prevent the band from pulling the cage out of
shape. The cages used are twelve inches in height by
four inches in width, the maximum distance of the outer
part from the tree being five inches. In cages like the one
described the bugs were fed on Lepidopterous larvae and
reared through their different stages. For many careful
notes on the feeding habits of these insects I am indebted
to Mr. II. L. Frost, who assisted me in the work. In
these cages we were able to successfully carry specimens of
P. serieventris through all their transformations.

Life History of P. serieventris Uhl.

The Egg. — The eggs have been found deposited in small
clusters on the bark of trees, on leaves and on the burlap
bands. When first laid they are of a glistening, whitish-
gray color, but this soon changes to a bronze, which grows
darker as the embryo develops, up to within about a day
previous to hatching. At that time the eggs grow lighter
in color, possibly due to the entrance of air into the shell.
Each egg-cluster contains from ten to thirty eggs, two or
three clusters being laid by each female. The eggs (Plate

396

THE GYPSY MOTH.

61, Fig. 1) are ovoid, .9 mm. in length and .8 mm. in
width. The smaller end of the egg is attached to the sur¬
face on which the cluster is deposited. At the top of the
egg is a well-defined circular cap. The greater part of the
surface of the egg is covered by irregular rows of minute
short spines (Plate 61, Fig. 4), nearly absent at the base
of the egg, while around the circumference of the cap is a
row of long, slightly curved capitate spines (Plate 61, Fig.
5), arranged in a circle. The eggs hatch in about eight
days. Four lots of eggs kept at the insectary hatched in
seven, eight, eight and nine days respectively. In hatching,
the circular disk at the top of the egg is pushed back, but
usually remains attached at one point.

First Stage. — The newly hatched bug (Plate 61, Fig. 2)
is 1.5 mm. in length. Form, ovate, head, thorax and abdo¬
men distinctly separated. Head smooth, broadly elliptical,
wider than long, of a deep copper color, and sparsely clothed
with short, pale-brown hairs ; eyes large, projecting later¬
ally. Antennae 1 mm. long, four-jointed, of the same color
as the head, but lighter at the joints, and clothed with a few
hairs. The basal joint is stout, slightly curved outward;
the second and third joints are of the same length as the
basal, and each is enlarged at its outer end, which is quite
sharply truncate. The fourth joint is from one-fourth to
one-third longer and wider than the other joints, being quite
broadly dilated. The thorax is of the same color as the
head, and widened posteriorly. A faint sulcus, indicated
by a narrow line, extends from the centre of the head down
the dorsal line of the thorax to the abdominal segments.
Abdomen yellowish red, varying to vermilion. On the dor¬
sum of the abdomen are three large, dark, bronze-colored
spots, extending transversely, and separated by a narrow
line of the body color. A short, narrow line of the same
color as the spots sometimes occurs in front of the anterior
spot, and also immediately behind the posterior one.
Around the lateral margin of the abdomen on each side is
a row of semi-elliptical bronze-colored spots. Just ante¬
rior to the first of these spots is a narrow, wedge-shaped
marking of the same color, while at the extreme posterior

PREDACEOUS HEMIPTERA.

397

end of the abdomen is a larger horizontal spot, which covers
the anal segments and often connects the two posterior
lateral spots. The under surface of the body is yellowish
red, darkest on the abdominal segments. The lateral row
of semi-elliptical spots, similar to those upon the upper sur¬
face, extends around the entire margin of the abdomen.
Beak stout, four-jointed. Both beak and legs are of a dark
copper color. Tarsi two-jointed ; claws simple, two in num¬
ber, light brown, each with a darker pulvillus ; legs sparsely
clothed with pale-brown hairs.

The first molt takes place in about four days from the
time of hatching, and is accompanied by a marked increase
in size.

Second Stage. — The second stage of this insect is repre¬
sented on Plate 61, Fig. 3. Length, 3.5 mm. ; body a little
longer in proportion to the width than in the first stage ;
head quadrangular, with two faint sulci, extending backward
from the anterior margin for about one-third of the length
of the head. Eyes prominent. Basal joint of antennae short
and stout ; second joint cylindrical, truncate at the end, twice
as long as the basal joint ; third joint slightly longer than
basal joint, and somewhat rounded at the outer end ; fourth
joint appressed at each end, and of nearly the same length
as the second joint. The thorax is slightly serrate around
the outer margin, and its outer angles project by the base
of the head for a short distance. The color of the head and
thorax is dark seal brown, varying to a pitchy black. Ab¬
domen of the same color as in the preceding stage, but
with four horizontal spots instead of three, the second and
third spots being much larger than the first and fourth.
Lateral spots as in the first stage. The under surface of
the head and thorax is marked with dark brown, that of the
abdomen being the same color as in the preceding stage.
Beak and legs dark brown, lighter on the tarsi.

The second molt, with an accompanying increase in size,
takes place from eight to ten days after the first molt.

Third Stage. — The third stage is represented by Plate
61, Fig. 6. Length of body, 6 mm. ; form somewhat ovate,
narrowest in front. The head is narrowed from that of the

398

THE GYPSY MOTH.

preceding stage, and the eyes are very prominent. Antennae
as in the second stage. The outer anterior angles of the
head are rounded, as well as that part of the anterior margin
included between the two sulci ; the latter extend backward
about one-third the length of the head. The outer margin
of the thorax is serrated, as in the preceding stage. The
color of the body in this stage is subject to great variation,
but brown or black predominates upon the head and thorax
and some shade of red upon the abdomen. Usually the head
and thorax are margined with a narrow, pale-yellowish-white
line, while four small spots of pale-yellowish brown occur
on opposite sides of the dorsal line of the pro-thorax, and
two spots of the same color on each side of the dorsal line
of the meso-thorax. The abdomen bears the same markings
as in the preceding stages, but the ground color varies to a
considerable degree. From each side of each dark marginal
spot a creamy- white line extends in towards the large dorsal
spots. In some cases these lines are very wide, and give to
the abdomen a very light and somewhat striped appearance ;
in other cases they are nearly obscured by the red ground
color. The beak, legs and under surface of the body are
marked the same as in the second stage. As the nymph of
the third stage approaches the molting period, the outlines
of the scutellum and wing pads become somewhat apparent.

The third molt occurs from live to six days after the pre¬
ceding one.

Fourth Stage. — This stage is shown on Plate 61, Fig. 9.
Length of body, 8.5 mm. General form of body, aside from
head, nearly elliptical, slightly widened posteriorly. Head
with two deep sulci, and closely appressed to the anterior
margin of the thorax. Antennae as in the preceding stage,
the second joint much the longest. The yellow marginal
band of the head and thorax is wider than in the third stage,
otherwise the colors of the upper surface of the body are the
same as those of the third stage. The under surface of the
body sometimes varies to a brownish tint, but in general it
is like that of the preceding stage. The color of the legs
and beak is not changed from that of the third stage. The
wing pads and scutellum appear in this stage. Nymphs in

PREDACEOUS HEMIPTERA.

399

the fourth stage show great rapacity, and a corresponding
growth is made.

The fourth and last molt takes place in from twelve to
seventeen days from the third molt, and the insect attains
the imago form.

Fifth Stage, or Imago. — The following is Professor
Uhler’s original description of this species, taken from
“Proceedings of the Boston Society of Natural History,”
page 94, Vol. XIV., 1870: —

“ P. serieventris, n. sp. Similiar to P. modesties Dallas,
but of a more blackish-gray color. Pronotum, sides less
deeply sinuated, the humeral angles not so prominent, ob¬
tusely triangular, blackish ; the surface less regularly punct¬
ured, those each side anteriorly and in the corners finer,
confluent, presenting the appearance of four blackish spots,
the middle surface somewhat bald, yellow. Scapus and basal
joint of the antennae blackish outwardly. Scutellum punct¬
ured with black, the punctures at the base aggregated in a
large patch, the basal angles with a large, smooth, whitish
spot, the tip smooth, white. Pectus remotely punctured
with fuscous, the impressed portion of the propleura, the
middle of the mesopleura and exterior part of the metapleura
with a large patch of black, confluent punctures, the exterior
margin smooth ; exterior end of the osteolar duct black, the
sulcus broad, not reaching to the tip. Legs pale orange
yellow, the femora pointed with black, the dots more or less
aggregated beyond the middle. Corium less coarsely punct¬
ured, the punctures fuscous or rufous ; those of the costal
area coarser, the finer ones aggregated in small patches ;
the surface adjoining the inner surface and tip of the medium
suture smooth, with a more or less embrowned spot before
the tip ; embolium yellow, with a fuscous spot at base ; the
membrane tinged with brown ; the basal margin, nervures
basally, and a broad, longitudinal streak running to the tip,
blackish. Tergum with large clouded spots each side and
behind ; connexivum bright yellow above, with a quadran¬
gular black spot at the base and apex of each segment, on
the under side having a corresponding series of spots which
are sometimes reduced to mere dots. Venter punctured

400

THE GYPSY MOTH.

with rufous and black, the latter arranged each side in a
longitudinal series of patches ; interior to these is a row of
black spots, and upon the middle line four round spots, with
the largest one at the posterior end.

“ Length to tip of abdomen, 9 millims. Humeral width,
5 millims.

“No. 40, Harris Collection $ . ‘ Cambridge, Mass., April

20, 1827.’

“The specimens vary very much in depth of color and in
the size and distinctness of the markings.

“In my own collection are specimens from Maine and
Minnesota. A female from Massachusetts is twelve millims.
in length.”

In the imago state the antennas and tarsi (Plate 62, Figs.
4 and 5) are increased by an additional joint, and become
respectively five and three jointed. The imago varies in
color from a blackish gray to a light brownish gray, though
none of the specimens so far taken or reared are of as light
color as P. modestus Dali. The males (Plate 62, Fig. 1),
as a rule, are slightly smaller than the females (Plate 62,
Fig. 2), and their humeral angles are somewhat sharper,
more nearly approaching those of P. spinosus Dali.

For the identification of the specimens reared at the in¬
sectary I am indebted to the courtesy of Prof. P. R. Uhler.

The following extract from notes upon an individual of
the third brood, reared from eggs laid Aug. 14, 1895, will
serve to illustrate the life history of a single generation :
Predaceous bug, No. 142, Podisus serieventris Uhl.

Hatched August 22 ; the first molt occurred August 26.
Up to this date the bug had been fed upon the remains of
four climbing cut-worms ( JVoctua c-nigrum'). The second
molt took place September 3. Between the first and second
molt it killed four larvae of JVoctua c-nigrum and two larvae
of Phynchagrotis alternata. The bug molted for the third
time September 8, having killed in the mean time two full-
grown caterpillars of Vanessa anti op a and two of Anisota
senatoria. The fourth molt occurred September 21.
Between the third and fourth molt it had killed eight full-
grown caterpillars of Vanessa antiopa , two larvae of Ani-

Explanation of Plate 62.

Drawn by A. H. Kirkland.

Podisus

serieventtis

Uhl.

I.

Male imago.

4-

Antenna of imago.

2.

Female imago.

5-

Tarsus of imago.

3-

Rostrum of imago.

6.

Wings of imago.

PLATE 62.

PREDACEOUS IIEMIPTERA.

401

sotci senatoria and one partly grown larva of Teleci jpolyphe-
mus. In the imago stage the insect (female) killed five
larvae of Anisota senatoria. It was placed with a male Sep¬
tember 25, and mated September 30. On October 12, it
was found partly hidden under some loose bark and leaves
which had been placed in the bottom of the breeding-cage,
and at the present writing (Jan. 1, 1896) it is still alive, and
hibernating without having deposited its eggs.

Feeding Habits. — In attacking a full-grown larva the
bug apparently first makes a preliminary investigation, and,
with antennae elevated, carefully inspects the caterpillar on
all sides. After sidling around for some time, the point of
attack is selected, usually the softer integument at the an-
nulations of the body, the beak (Plate 62, Fig. 3) is swung
down and out, projected horizontally forward and inserted
in the side of the larva. Its entrance is at first unnoticed
by the caterpillar, but after a few minutes a vigorous struggle
ensues, which sometimes, but rarely, results in the bug being
obliged to release its hold. In a short time the caterpillar
grows weaker, apparently becomes stupefied, and the bug,
after inserting its beak in new places, till the greater part
of the body fluids have been extracted, finally leaves the
dead, empty and flaccid larva hanging to the 'tree. The
time consumed in feeding on a full-grown gypsy moth
caterpillar varies from ten minutes to two or three hours,
the bug as a rule feeding longest upon the thoracic seg¬
ments.

The newly hatched bug seems to be unable to cope with
large caterpillars, and I am led to believe that under natural
conditions their early food is small larvae. On June 10,
1895, at Winthrop, Mass., I found twelve nymphs of P.
serieventris , of the first and second stage, feeding upon
small, dark beetle larvae, which were abundant upon leaves
of Plantago major. In the breeding cage the young nymphs
were first fed upon the remains of soft-skinned larvae, such
as Phynchagrotis alternata and JVoctua c-nigrum , the cater¬
pillars being cut up into small bits before feeding them to the
bugs. It was necessary to place the young bugs in close
proximity to the food thus provided, and for this purpose a

402

THE GYPSY MOTH.

small camel's-hair brush was found to be of great assistance.
After passing the first molt the nymphs were able to care
for themselves, and would boldly attack full-grown cut¬
worms, of the species mentioned, when the latter were
placed in the cages. AYith increasing age and size they fed
readily upon hairy larvae ( P. dispar , Tolype velleda , et «?.).
The period of greatest rapacity and of greatest growth is
between the third and fourth molt, during which time the
nymph feeds almost continuously.

This insect has been taken in the field attacking all stages
of the gypsy moth. Individuals in the first stage were this
year found feeding upon the eggs of the gypsy moth, but
when confined to this food died at the end of a few days.
It is not an uncommon thing for them to attack a pupa, and
on one occasion I found four nymphs in the second and third
stages feeding upon a single female pupa. Female gypsy
moths while depositing their egg-clusters, and males while
mating, are also occasionally attacked by this insect.

This species has been found feeding upon the larvae of
Vanessa antiopa , Hyphantria cunea , Orgyia leucostigma ,
Attacus promethea , Clisiocampa americana and disstria and
Paleacrita vernata. It has also been known to devour the
dead imagoes of Limenitis Ursula and Pyropliila pyrami-
doides. In confinement it readily attacks the larvae of
Datana ministra , Attacus cecropia , Telea polyphemus ,
Anisota senatorial Dryocampa rubicunda, Tolype velleda,
Pili yncha grot is alternata, SVoctua c-nigrum and Cimbex
americana .

AYhen pressed by hunger these insects develop cannibal
tendencies and feed upon other individuals of the same
species, and also occasionally attack Podisus cynicus and
Jlenecles insertus , while the two latter species have in turn
been found feeding upon P. serieventris . I have seen P.
serieventris feeding in confinement upon leaves of Quercus
rubra , but I think it very doubtful if it is phyllophagous to
any marked degree.

Mating — Polygamy — Oviposit ion. — Mating takes place
in from three to six days from the time the insect reaches

PREDACEOUS HEMIPTERA.

403

the imago state. The time required for the process of
mating varies from twelve to forty-eight hours.

That the males of this species are polygamous is evident
from the fact that one male confined in a breeding cage at
the insectary successfully fertilized three females. AVith the
exception of the females of the last brood, oviposition takes
place in from eight hours to two or three days from the
time of mating. The female deposits a cluster of from ten
to thirty eggs, then rests and feeds for a few hours, but later
resumes the work of egg-laying. In this way some three
or four clusters of eggs are deposited, the whole process of
egg-laying usually taking from one to four days.

Hibernation. — That the insect hibernates in the imago
state seems to be an assured fact, since specimens of the
last brood reared at the insectary, and left in the breeding-
cages out of doors, are alive at the time of this writing
(Jan. 1, 1896). The imagoes of the last brood mate soon
after reaching the mature form, and the fertilized females
feed at intervals for a week or two ; but with the advent of
cooler weather seek hibernating quarters, such as the crev¬
ices in the rough bark of trees, under burlap bands, etc., or
even under the dead leaves upon the ground, sometimes
burying themselves one or two inches beneath the surface.
All of the males reared during the past year died without
attempting to hibernate.

Humber of Annual Broods. During the summer of 1895,
imagoes of this species were more or less abundant about the
last of June and the middle of August, and in fewer numbers
from the middle to the last of September, although individ¬
uals were taken throughout the summer. Xymphs were
found in considerable numbers at such intervals, subsequent
to the appearance of the imagoes, as would lead one to believe
that they were distinct broods. I have reared two broods
of this species between the last of June and the latter part
of September ; and this, in connection with the facts that
young nymphs have been found in early June, and that the
fertilized female imagoes of the last brood hibernate, would
seem to be nearly conclusive evidence that the species is
three-brooded in this region.

404

THE GYPSY MOTH.

Spiders.

At occasional intervals during the past four years, spiders
have been seen to attack and destroy the eggs, and also the
caterpillars and imagoes, of P. dispar. In the summer of
1895, a predaceous spider, found in Chelsea, was brought
into the insectary and supplied with gypsy moth cater¬
pillars, which it readily destroyed. This spider was kindly
determined by Mr. J. II. Emerton as Phidippus tripunctatus.

Our common harvest spider ( Phalangium dor saturn) was
found by Mr. Mosher feeding on a male gypsy moth.

Mites have been found so frequently destroying the eggs
that we must acknowledge that in some localities they are
very important factors in reducing the numbers of the gypsy
moth. Mr. E. P. Felt observed the work of these mites on
the gypsy moth eggs in confinement, and found that they
destroyed the eggs very rapidly. They are most abundant
in the fall, but do not feed to any marked degree during
the winter. These mites were referred to Prof. Herbert
Osborn, who determined them as two different species. The
first was JVothrus , near ovivorus Pack. (Plate 53, Fig. 14),
and the other was Trombidium bulbipes Pack. (Plate 53,
Fig. 15). A species of Phloeothrips (Plate 63, Fig. 13) was
also found destroying the eggs.

Insectivorous Vertebrates.

Of the vertebrate enemies of the gypsy moth, the common
skunk, Mephitis mephitica (Shaw), has been found feeding
upon the female moths which were laying their eggs at the
base of trees, or upon rocks, rubbish, etc. It is probable
that these animals also feed upon the pupae to some extent
in badly infested regions.

The wood frog ( Rcina silvatica LeC.) has been reported
in one instance as attacking the female moths. In August,
1895, Mr. F. H. Mosher took a specimen of the tree frog
( Hyla pickeringii Holbr.), feeding upon the caterpillars
of the second brood of the gypsy moth, at Woburn.

The common garden toad ( Bufo lentiginosus americanus
LeC.) was this year found by Mr. Kirkland to be devouring

VEGETABLE PARASITES.

405

great numbers of the caterpillars in infested brushlands.
Stomach examinations of three toads, taken in such a place,
June G, 1895, showed them to contain respectively seven,
fifteen and sixty-five gypsy moth caterpillars, or remains of
the same.

Mr. Samuel Henshaw published a report upon the gypsy
moth in Massachusetts, in Bulletin No. 2G, United States
Department of Agriculture, Division of Entomology, page
75, in which he gives the following list of invertebrates that
destroy the larvae of the gypsy moth : Cicindela 6-guttata ,
Camponotus herculaneus , Sinea diadema , and undetermined
Syrphus , and Chrysopa , Lithobius forficatus ; also the fol¬
lowing spiders : Epeira strix, Steatoda borealis, Lycosa sp.,
Drassus sp., Ayalena ncevia, Phidippus galathea (mysta-
ceus'), Epiblemum scenieum, Marptusa familiaris and
Thomixus sp.

Mr. Henshaw’s letter of submittal is dated “Cambridge,
Mass., Dec. 7, 1891,” and therefore his observations were
probably made during the summer of 1891.

Vegetable Parasites.

A very careful watch has been kept for any indication of
vegetable parasites, either fungi or microbes, and nothing
has thus far been discovered. YYe consulted with Drs.
Farlow and Thaxter of Harvard University, both eminent
authorities on the subject, and, after describing to them the
habits of the insect, neither of these gentlemen gave us en¬
couragement that vegetable parasites would prove to lie a
very important factor in the destruction of the gypsy moth ;
yet, in wet seasons, where the caterpillars were very abun¬
dant, the parasitic fungi, if any could be found to attack this
species, might prove more or less serviceable.

The caterpillars of the nun moth ( Lymantria monacha),
in Europe, when very abundant, are often attacked by an
epidemic or contagious disease known as the top or head
sickness ( Wipfelkrankheit) , a very good account of which
has been given by Wachtl and Kornauth in their “ Beitrage
zur Kenntniss der Morphologie, etc., der Nonne,” page 17.
Drs. Tangl, Scheuerlen, Hofmann, Tubeuf and Jager have

406

THE GYPSY MOTH.

made careful investigations of this disease, but have had
very little success in inoculating healthy caterpillars with
cultures made from those which were diseased.

Importing Parasites.

No attempt has been made to import parasites thus far,
for the reason that the law requires the work to be con¬
ducted with direct reference to the extermination of the
gypsy moth, and, therefore, the general destruction of the
insect would also destroy the parasites. There is no reason
why our native Hymenopterous parasites may not prove
quite as effective as those of any other country, since there
is no parasite known which coniines itself exclusively to the
gypsy moth, and, as has been shown, we have several species
which attack it as readily as any in its native country.

Insect ary.

In the early part of the work on the gypsy moth, the
more difficult and important experiments and observations
were conducted in the insectary at Amherst ; but it seemed
desirable, and even necessary, to repeat many of the ex¬
periments on a far more extensive scale than was possible
at that place, and it was therefore decided to fit up and equip
a room for this purpose, in the store-house on Commercial
Street, Malden. This building stands on piles, about six
feet from the ground, which is swampy and wet. The front
of the building is on a level with the street, which is built
up to the grade indicated.

In the room thus fitted up many experiments were con¬
ducted, a large number of which gave very .satisfactory
results. But in the experiments on insecticides, where a
check series was conducted, with no poisons used on the
food, the mortality was often so great that we felt very un¬
certain about the results in the cages where the caterpillars
were fed on leaves sprayed with insecticides, whether they
died from the effects of the poison, or because of the un¬
healthful surroundings.

In the early part of the summer of 1895, a small lot of
land, in the edge of the woodland in the suburbs of Malden,

PLATE 63. Experiment station and insectary, Malden, Mass.

INSECTICIDES.

407

was leased, and an insectary was erected for experimental
purposes. This building (Plate 63) is sixteen by twenty
feet on the ground, with a greenhouse on the south side, six
by eight feet, and a covered shed on the north side, seven
by eight feet. It contains, on the first floor, besides the
main laboratory with tables, closets, etc., a private labora¬
tory and a chemical room. The second floor contains a
lodging-room for the employees.

The experimental work carried on in this building, during
the summer of 1895, has proved far more satisfactory than
that in the building on Commercial Street, because of the
greater conveniences and more healthful conditions.

Insecticides.

Experiments with Substances for destroying Eggs .

The value of egg-destruction, as an exterminative meas¬
ure, was recognized at an early stage in the work of com¬
bating the gypsy moth, and led to an extensive study of
substances which might be advantageously used for this
purpose. The requisites necessary in such a substance are :
that it shall be effective wherever applied ; that it shall
leave a permanent stain or color, enabling one to distinguish
treated from untreated egg-masses ; and that its price shall
be within practical limits. The substances found to be
of the greatest value, together with an explanation of the
method of applying them, have already been described in
Part 1.

During the year 1892, Mr. F. C. Moulton experimented
with the following substances on the eggs of the gypsy
moths, to discover something that could lie readily applied
to the egg-clusters and effectually destroy them. To some
of the preparations were added substances which contain no
destructive power, but were used simply to change the color
of the egg-clusters on trees, so that those which had been
treated might be readily distinguished from the others.

Ammonia. — January 21 . Five egg-clusters were treated
for five minutes with ammonia gas, made by heating strong
aqua-ammonia. Apparently the eggs were not affected, for,
by March 24, nearly all had hatched.

408

THE GYPSY MOTH.

Benzine. — January 22. A small amount of benzine was
poured upon an egg-cluster and then allowed to evaporate.
Apparently the eggs were not affected, for by March 24,
about three-tenths of them had hatched. Yearly live-tenths
of the caterpillars died while hatching.

Bromine. — January 19. Five egg-clusters were placed
in a box and a small amount of liquid bromine turned on
them. At the end of fifteen minutes they were entirely
destroyed.

Bromine Vapor. — January 19. Five egg-clusters were
submitted to the action of bromine vapor in a closed box
for ten minutes. At the end of this time the eggs were
destroyed. Another experiment on the same date, in which
the eggs were exposed for fifteen minutes, gave similar re¬
sults. From egg-clusters treated, on the same date, with
bromine vapors for a period of ten minutes, the vapor not
being closely confined, a few caterpillars hatched. Four
caterpillars hatched from other egg-masses treated in the
same manner.

Chlorine. — January 15. One egg-cluster was submitted
for five minutes to the action of chlorine gas, made by add¬
ing ten parts (by weight) of hydrochloric acid to eight
parts of black oxide of manganese, and then applying a
strong heat to the mixture. The egg-cluster was bleached
and the eggs destroyed. Four other experiments, in which
egg-clusters were exposed to the action of chlorine for
seven, ten, fifteen and thirty minutes respectively, gave
similar results. March 12. Some chloride of lime was put
into a flask and sulphuric acid added to it. The chlorine
was then conducted into a bottle containing gypsy moth
egg-clusters. It entirely destroyed the eggs, with but one
exception. January 19. Five egg-clusters were treated
with chlorine under a hood made of oil-cloth stretched over
a frame, but, as the oil-cloth was not large enough to en¬
tirely cover it, a part of the gas escaped. One egg-cluster
was bleached, while the others were apparently not affected ;
about one-third of the eggs hatched the following spring.

Carbon Bisulphide. — January 19. Five egg-clusters
were submitted to the action of hot vapors of carbon bi-sul-

INSECTICIDES.

409

phide for five minutes. The carbon bi-sulphide was put
into a flask and slightly heated, the vapors passing over a
bottle containing the egg-clusters, condensing and wetting
them, which caused the eggs to become white and soft, after
which they all dried up. Two lots of eggs exposed to the
vapors of carbon bi-sulphide, in a similar manner, for ten
and fifteen minutes respectively, were completely destroyed.
January 19. Five egg-clusters, placed in a tin box covered
with paper, were treated for fifteen minutes with carbon bi¬
sulphide, which caused them to grow white and soft, thus
destroying them. January 21. Five egg-clusters were
treated with cold vapors of carbon bi-sulphide for fifteen
minutes, care being taken that the vapors should not wet
the egg-clusters. The eggs apparently were not affected,
and, by the 24th of March, about one-half of them had
hatched. January 25. Five egg-clusters were treated for
fifteen minutes to the action of cold vapors of carbon bi-sul¬
phide. The eggs were placed in a glass, which was put in
a large tin box containing carbon bi-sulphide. The eggs
were not affected by this treatment, and, by the 24th of
March, all had hatched. February 9. A number of egg-
clusters were treated in the same manner as in the preced¬
ing experiment, and, although the eggs did not appear to
be affected, none hatched.

Calcic Chloride. — January 21. One egg-cluster was
soaked for half a day in a solution of calcic chloride, made
by dissolving one-eighth ounce of calcic chloride in two
cubic centimeters of water. The solution did not penetrate
the egg-cluster, and nearly all the eggs hatched.

Corrosive Sublimate. — February 1. A few crystals of
corrosive sublimate were dissolved in alcohol, and the solu¬
tion poured over five egg-clusters. March 22, some of the
eggs had partly N hatched, but the caterpillars soon died.
February 1. Five egg-clusters were treated in the same
manner as in the preceding experiment. Two or three
caterpillars hatched and others came partly out of the shell,
but, March 22, all were dead. Three other lots of eggs were
treated in the same manner, March 3. None of these eggs
hatched.

410

THE GYPSY MOTH.

Creosote Oil. — March 14. A small amount of creosote
oil was dropped upon live egg-clusters, and, although it did
not appear to injure the eggs, none of them hatched. March
31. A mixture of creosote oil and pine tar, fifty per cent,
of each, was dropped upon some egg-clusters. It pene¬
trated them at once, and, later, shrivelled the eggs so that
none hatched. March 31. Another lot of egg-clusters was
treated in the same manner, and the eggs destroyed. Two
experiments with a mixture of creosote oil, fifty per cent.,
and turpentine, fifty per cent. , gave results like those of the
preceding experiments. April 7. About eight thousand
eggs were saturated with a solution of pine creosote oil,
forty-five per cent., turpentine, forty-five per cent., and
coal tar, ten per cent. It penetrated the egg-clusters read¬
ily, and attacked the eggs so that none hatched.

Coal Tar. — March 5. A mixture of coal tar, thirty per
cent. , phenol, forty per cent. , and turpentine, thirty per cent. ,
was dropped upon ten egg-clusters. It quickly penetrated
the eggs, turning them black and softening the shell so that
none hatched. Several other experiments with similar tar
mixtures gave equally as satisfactory results.

Magle Mills Powder. — March 11. A mixture of Eagle
Mills Powder, fifty per cent., and turpentine, fifty per cent.,
was dropped upon ten egg-clusters, but the mixture was too
thick to penetrate. March 11. A solution of Eagle Mills
Powder, ten per cent., water, sixty per cent., and alcohol,
thirty per cent., was dropped on some egg-clusters, and
quickly penetrated to the bottom. This did not injure the
eggs, for, by April 12, nearly all had hatched.

Hydrocyanic Acid Gas. — January 11. One egg-cluster
was submitted to the action of pure concentrated hydro¬
cyanic gas, in the following apparatus : A Florence flask,
containing one-half an ounce of potassium cyanide and about
twenty cubic centimeters of water, was connected with a
wide-mouthed bottle by a tube bent twice at right angles.
The bottle also contained an escape tube. An unbroken
egg-cluster was placed in the bottle, then sulphuric acid was
added to the potassium cyanide in the flask. The hydro¬
cyanic acid gas passed over into the bottle, driving the air

INSECTICIDES.

411

out through the delivery tube. After the air was all out,
the delivery tube was stopped by a cork ; and, as the action
was still going on, the gas in the apparatus was under pres¬
sure and remained so for thirty minutes, when the egg-
cluster was removed. No change could be detected, either
with the naked eye or by use of the microscope, and, by
March 24, about one-half of the eggs had hatched. On the
same date, nine other egg-clusters were treated in the same
manner, using the same apparatus under the same condi¬
tions. An examination of the eggs failed to show any
change. These eggs hatched February 6. January 12.
Five egg-clusters were treated with hydrocyanic acid gas,
for thirty minutes, under a hood made by spreading oil¬
cloth over three bottles. The edge of the cloth came down
to the table, but not close enough to exclude the air, as there
were numerous crevices under the cloth. The density of
hydrocyanic acid gas, being .706, causes it to rise. The
egg-clusters were placed on a small card-board stand which
reached nearly to the top of the hood, which was punctured
several times, so that the gas might readily pass through.
Forty cubic centimeters of sulphuric acid were then added
to one-half ounce of potassic cyanide, the gas being passed
under the hood. No change was visible in the eggs after
this treatment, and nearly all of them hatched. January 12.
Five egg-clusters were treated with hydrocyanic acid gas,
under a hood made of wet unbleached cotton, the cloth being
drawn closely to the table and weighted down, so that no air
could pass under the hood ; with this exception, the process
and conditions were the same as in the preceding experi¬
ment. Nearly all of the eggs hatched after being subjected
to this treatment. January 12. Ten egg-clusters were
treated with pure, concentrated hydrocyanic acid gas for
one hour. The apparatus consisted of three four-ounce
Florence flasks, marked A, B and C. Flask A contained
about one-half an ounce of potassic cyanide, B contained
concentrated sulphuric acid, and C the ten egg-clusters. A
was connected with B by means of a tube which dipped
below the surface of the sulphuric acid in B. The escape
tube from B passed through the stopper of C. There was

412

THE GYPSY MOTH.

also a small escape tube for the air to pass out. Sulphuric
acid was added to the potassic cyanide in flask A, and the
hydrocyanic acid gas passed through the sulphuric acid in
B, which thoroughly dried it ; it then passed out into C.
After the air had all passed out of C, the escape tube was
stopped. The gas was generated for an hour, after which
time an examination of the eggs showed no change, and
nearly all of them subsequently hatched. A duplicate ex¬
periment gave similar results. January 13. Five egg-
clusters were treated with pure, concentrated hydrocyanic
acid gas for one hour and a half. None of the eggs hatched.
January 13. Five egg-clusters were treated for two hours
with hydrocyanic acid gas under a hood. An examination
of the eggs, made January 14, showed them to be slightly
dried, but, by March 24, about eight-tenths of the eggs had
hatched. January 15. Five egg-clusters were treated with
hydrocyanic acid gas for fifteen minutes. The eggs did not
appear to be affected, although none of them hatched.

Hydrogen Arsenide. — April 7. Five egg-clusters were
treated for fifteen minutes with hydrogen arsenide, made by
pouring a solution of arsenic into a mixture of granulated
zinc and hydrochloric acid. None of these eggs hatched.
November 5. A number of egg-clusters were treated for
one hour with hydrogen arsenide. None of the eggs
hatched. February 6. About twenty-five broken egg-clus¬
ters were treated with hydrogen arsenide for forty-five
minutes. The gas was made as follows : A solution of
arsenic was poured into a mixture of hydrochloric acid and
zinc. The gas which was given off' was dried by passing
through a U tube containing calcium chloride, then into the
bottle containing the eggs. None hatched. Several other
experiments with this gas gave similar results.

Hydrogen Sulphide. — April 7. Some egg-clusters were
submitted to the action of hydrogen sulphide for ten
minutes. At the end of this time the eggs were shrivelled
and none hatched. January 30. Several egg-clusters were
treated for one hour with hydrogen sulphide gas, which wras
made by adding dilute sulphuric acid to iron sulphide. It
was passed through a U tube and then into a bottle con-

PLATE 64. Pine and. other trees attacked by the gypsy moth
caterpillars at Lexington.

INSECTICIDES.

413

taming the egg-clusters. None hatched. February 3. Ten
egg-clusters were treated with hydrogen sulphide for one
hour. None hatched. April 12. Some broken egg-clus¬
ters were treated, in an open bottle, for two hours, with
hydrogen sulphide. None of them hatched.

Hydrochloric Acid Gas. — March 31. Some egg-clusters
were submitted for fifteen minutes to the action of hydro¬
chloric acid gas, formed by adding sulphuric acid to salt.
This destroyed the eggs by drying them up. Several egg-
clusters were submitted to the action of hydrochloric acid
gas for thirty minutes. None hatched.

“ Infernal” Mixture. — February 17. A number of new
egg-clusters were treated with a gas made by adding fifty
per cent, of sulphuric acid to fifty per cent of turpentine.
They were left exposed to the action of the gas over night,
which destroyed them so that none hatched. February 19.
Five egg-clusters were treated for two hours with this gas.
The eggs were bleached a little, and none hatched. Febru¬
ary 22. Five egg-clusters were subjected for five hours to
the action of the above-mentioned gas. The eggs were
stained red, and shrivelled so that none hatched. February
22. Five egg-clusters were submitted for ten hours to the
action of this gas, which entirely destroyed the eggs. Eggs
exposed to the action of this gas on February 19, for a
period of thirty minutes, wTere uninjured, and hatched on
March 24.

Nitrogen Dioxide. — March 31. Several egg-clusters
were submitted to nitrogen dioxide for fifteen minutes. The
gas was formed by adding sulphuric acid to salt and nitre.
The eggs were entirely destroyed. April 1. A number of
egg-clusters were submitted for five minutes to the action
of nitrogen dioxide. The eggs were entirely destroyed.
August 24. Eggs were treated with nitrous dioxide in a
hollow tree. The gas was generated as in the preceding
experiments. After this treatment the eggs were taken into
a warm room, where they began to hatch on February 31.

Potassic Cyanide. — March 15. A solution of potassic
cyanide in water, fifty per cent., and of alcohol, fifty per
cent., was dropped upon five egg-clusters, which it pcne-

414

THE GYPSY MOTH.

trated readily, but did not affect the vitality of the eggs.
March 15. Several egg-clusters were treated in the same
manner as in the preceding experiment, and about one-tenth
of the eggs hatched.

Pine Tar Mixtures. — February 1. A mixture, com¬
posed of fifty per cent, of pine tar and fifty per cent, of
phenol, was poured upon five egg-clusters. It soaked into
the clusters readily, and blackened them, apparently de¬
stroying the eggs. February 3. A mixture of pine tar,
fifty per cent., and turpentine, fifty per cent., was dropped
upon five egg-clusters. It penetrated readily, turning the
eggs black and apparently destroying them. February 3.
A mixture containing equal parts of pine tar, phenol and
turpentine was dropped upon five egg-clusters, completely
destroying the eggs. A mixture composed of forty per
cent, of pine tar, forty per cent, of phenol, twenty per cent.
of alcohol, with corrosive sublimate, was dropped upon ten
egg-clusters, and, although the eggs did not appear to be
destroyed, none hatched. March 6. A mixture of pine
tar, fifty per cent., alcohol, forty-five per cent., tannic acid,
two and one-half per cent., and ferrous sulphate, two and
one-half per cent., was dropped upon a number of egg-
clusters, which it readily penetrated, rendering the eggs soft.
The object of the last two substances was to give the solu¬
tion a black color. March 6. A mixture of pine tar, fifty
per cent., alcohol, forty-five per cent., and Stafford’s ink,
five per cent., was dropped upon some egg-clusters. It
readily penetrated to the bottom layer, destroying the
eggs.

Phenol. — January 21. A small amount of liquid phenol
was poured upon an egg-cluster. This burned the eggs to
a crisp. January 21. Five egg-clusters were treated for
ten minutes with vapors of phenol, one hundred per cent.,
care being taken that the egg-clusters should be dampened
by the vapors. The eggs were badly burned. January 21.
Five egg-clusters were treated for fifteen minutes in the
same manner as in the preceding experiment, except that
the vapors were not allowed to wet the egg-clusters. Ap¬
parently the eggs were not injured, for, by March 24, nearly

INSECTICIDES.

415

all had hatched. January 25. A mixture of phenol, ten
per cent., and alcohol, ninety per cent., was poured upon
live egg-clusters, which were blackened and burned. Jan¬
uary 25. Five egg-clusters were treated with a mixture of
phenol, twenty per cent., and water, eighty per cent. This
mixture was stirred until it became milky white, then a little
was poured upon the egg-clusters, and seriously burned
them. January 30. A mixture of phenol, four per cent.,
and water, ninety-six per cent., was poured upon live egg-
clusters. The mixture penetrated only a part of the egg-
cluster, and nearly one-half of the eggs hatched. January
30. A mixture of phenol, three per cent., and water,
ninety-seven per cent., was poured upon live egg-clusters.
About nine-tenths of the eggs hatched. February 1. A
mixture composed of phenol, fifty per cent., and sulphuric
acid, fifty per cent., was dropped upon five egg-clusters.
This mixture slowly penetrated the egg-clusters and de¬
stroyed the eggs. February 2. A mixture containing fifty
per cent, alcohol, twenty-five per cent, phenol and twenty-
five per cent, of sulphuric acid, was dropped upon five egg-
clusters, destroying the eggs. February 26. A mixture
of fifty per cent, alcohol, twenty-five per cent, phenol,
twenty-five per cent, sulphuric acid, with a little potassic
ferricyanide and ferrous chloride, was dropped upon some
egg-clusters. The mixture readily penetrated the clusters,
turning them dark blue and completely destroying the eggs.
February 2. A mixture of alcohol, fifty per cent., phenol,
twenty-five per cent., and sulphuric acid, twenty-five per
cent., was dropped upon five egg-clusters. It readily pene¬
trated the clusters, turning them black and completely de¬
stroying the eggs. February 25. A mixture of alcohol,
sixty per cent., phenol, twenty per cent., and sulphuric
acid, twenty per cent., Avas dropped upon some egg-clusters,
turning them black and completely destroying the eggs.
March 1. A mixture of phenol, fifty per cent., turpentine
and nitric acid, fifty per cent., Avas dropped upon some
egg-clusters, entirely destroying the eggs. March 14. A
mixture composed of phenol, fifty per cent., turpentine with
a small amount of concentrated nitric acid, fifty per cent.,

416

THE GYPSY MOTH.

was dropped upon some egg-clusters, entirely destroying
the eggs.

Pyroligenous Acid. — February 10. Eight egg-clusters
were moistened with pyroligenous acid, but it would not
penetrate the clusters.

Spruce Gum. — Twenty per cent, of spruce gum, thirty-
live per cent, of rosin, thirty-five per cent, of cotton-seed
oil, five per cent, of turpentine and five per cent, of pine
tar were melted and mixed together, and some egg-clusters
saturated with the solution. None of the eggs hatched.

Sulphur Di-oxide. — January 25. Five egg-clusters
were placed in a tight box and submitted for ten minutes to
the fumes of burning sulphur. March 24, about three-fifths
of the eggs had hatched. January 25. Five egg-clusters,
placed in a tight wooden box, were submitted for twenty
minutes to the fumes of burning sulphur. March 24, nearly
all of the eggs had hatched.

Turpentine. — A quantity of turpentine was poured on
five egg-clusters. It readily penetrated, but apparently did
not affect the eggs, as nearly all of them hatched.

During the month of October, 1893, Mr. C. W. Minott
experimented in the field with a number of mixtures having
creosote oil as a basis. All of these mixtures were effective
in destroying the eggs of the gypsy moth. The lowest per
cent, of creosote oil used was in a mixture composed of
eighty per cent, of turpentine and twenty per cent, of creo¬
sote oil. Even when diluted to this degree, it was found to
be effective.

The following experiments on the eggs of the gypsy moth
were conducted by Mr. Kirkland, in 1895 : —

Kerosene. — January 5. Twelve egg-clusters were treated
with kerosene oil ; these hatched April 20. April 25. Five
egg-clusters treated with kerosene oil ; hatched May 1.

Turpentine. — January 5. Ten egg-clusters treated with
turpentine ; hatched April 18.

Kerosene and Turpentine. — May 2. Egg-clusters which
had commenced hatching were soaked in a mixture com¬
posed of equal parts of kerosene and turpentine. May 6.

INSECTICIDES.

417

Six eggs-clusters re-commenced hatching, and a few cater¬
pillars emerged.

Crude Castor Oil and Turpentine. — January 5. Five
egg-clusters, treated with the above mixture, hatched April
30.

Paraffine Gas or Residuum Oil. — Thinking this oil might
be of some value for treating egg-clusters, a number of
experiments were made which gave very satisfactory re¬
sults. January 5. Twelve egg-clusters were treated with
paraffine gas oil, none of which hatched. During the winter
and spring of 1895, from one hundred to two hundred egg-
clusters were treated with paraffine gas oil, with the result
that none of them hatched.

Paupenleim. — April 27. Five egg-clusters were care¬
fully covered with Raupenleim, the layer being about one-
eighth of an inch thick. None of the eggs hatched.

The experiments in treating egg-clusters with various
gases were made with a view to finding some practical way
of dealing with stone walls, hollow trees and other more or
less inaccessible places, in which eggs had been laid in
large quantities. The substances which were found to give
the most satisfactory results, i. e. , chlorine and bromine
vapors, were tested on a large scale in the field, but here
their use was found to be, at best, only partially effective.

Insecticides for Destroying the Caterpillars.

Spraying with the common arsenical poisons, such as
Paris green, London purple, etc., was one of the first
methods employed for the destruction of the caterpillars
of the gypsy moth, and the failure of these poisons to do
effective work in the field has already been stated. When
it became evident that the caterpillars were not being de¬
stroyed in any great numbers by these poisons, an effort
was made to discover a more effective poison, and much
time and labor were spent in this undertaking. The most
careful attention was given to this problem; for, with
modern spraying machinery, the thorough application of
a poison to trees is easily accomplished, and thus a cheap,

418

THE GYPSY MOTH.

practical and effective method of destroying the caterpillars
of the gypsy moth would be provided if a poison could be
found which would meet the exigencies of the case. It will
be seen by the records which follow that we have experi¬
mented with insecticides in general use, which are adapted
to our work, and also with many new insecticides which
were prepared for this purpose by our former chemist,
Mr. F. C. Moulton.

All of the insecticide experiments here recorded were
performed under my immediate supervision, by Messrs.
Reid and Schrader in 1893, Messrs. Minott, Mosher and
Kirkland in 1894, and by Mr. Kirkland and his assistants
in 1895.

Details of the Experiments.

The caterpillars used in the field or out-door experiments
were taken from infested trees near the place of experi¬
mentation. Those used in the in-door experiments were,
as a rule, from eggs hatched early in the season by means
of artificial heat.

In the in-door experiments on young caterpillars lettuce
was the food plant generally used, leaves of elm, apple or
willow being substituted as soon as such foliage could be
obtained. In the field experiments the caterpillars were
confined upon branches of trees on which they were known
to feed readily.

All poisons used in the experiments of 1893, and the
greater part of those used in 1894, were carefully weighed
out in the insectary at Amherst. During the latter part
of 1894, and throughout the season of 1895, they were
weighed on a very accurate set of balances at the Malden
office.

The poison was applied to the foliage used in the in-door
experiments both by dipping the leaves in the poison mixt¬
ures and by spraying with small hand bellows. In the
field experiments the poison was always applied by use of
the spraying bellows. After heavy rains the branches on
which the caterpillars were confined were resprayed in the
same manner as would be adopted in spraying operations
in the field. In nearly all cases a small amount of glucose

INSECTICIDES.

419

was added to the poison mixtures, in order to increase the
adhesive qualities. In the experiments conducted at the
insectary the caterpillars were confined in glass jars or in
lantern globes. In the field experiments the caterpillars
were sacked in (enclosed by means of a thin cloth bag of
proper dimensions) upon the branches of trees. In the case
of the in-door experiments the poisoned food was renewed
and the jars cleaned daily. For the field experiments
branches of sufficient size to allow the caterpillars to feed
till reaching maturity were chosen, and thus, as a rule, no
change was necessary.

Each jar or sack used in the experiments was given a
number, which was recorded in a book, in which the records
of the ten caterpillars used in each experiment were carefully
noted. In many of the experiments a “check” was em¬
ployed, to determine the normal death rate of caterpillars
feeding on unpoisoned food. This check consisted of the
same number of caterpillars confined in a jar or bag in the
same manner as those in the experiment, with the exception
that they were kept supplied with fresh, unpoisoned food.

Daily observations were made both upon caterpillars feed¬
ing on the poisoned and unpoisoned food, and the results
recorded. Many of the experiments on young caterpillars
were discontinued at the end of about a fortnight, or after
they had entered the succeeding molt.

The following pages contain the records of the experi¬
ments which have been conducted with the different insecti¬
cides : —

Experiments with Paris Green,
h lb. Paris Green to 150 gal. Water.

No. 1. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of £ lb. to 150 gal. of
water. Two died on the third, three the fourth, one the
fifth, three the sixth and one the seventh day.

Check experiment : none dead.

No. 2. — April 26, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of £ lb. to 150 gal. of water.

420

THE GYPSY MOTH.

Three died the second, three the third, one the fourth and
one the fifth day, and two escaped.

Check experiment : none dead.

No. 3. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 4 lb. to 150 gal. of
water. Two died the third, one the fourth, three the sixth,
two the seventh and two the eighth day.

Check experiment : one died the third day.

No. 4. — June 10, 1894. Ten caterpillars of the second
molt were placed on elm leaves which had been sprayed
with Paris green, in the proportion of i lb. to 150 gal. of
water. One died on the seventh, two the eighth, five- the
ninth and two the tenth day.

Check experiment : none dead.

No. 5. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of i lb. to 150 gal. of
water. One died the fourth, two the fifth, two the sixth,
two the seventh, one the eighth, one the ninth and one the
eleventh day. ,

Check experiment : none dead.

No. G. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 4 lb. to 150 gal. of
water. Three died the third, two the fourth, one the fifth,
one the sixth and three the seventh day.

Check experiment : one died the fifth and one the sixth
day.

No. 7 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of 4 lb. to 150 gal. of water, and ten fourth-molt
caterpillars placed upon it. July 5, the foliage was so badly
burned that the caterpillars were removed to an unsprayed
branch. July 30, the food supply having given out, they
were again removed to another unsprayed branch. Five
of these caterpillars died before pupating, and, of the five
that began to pupate, three emerged. Foliage very badly
burned.

INSECTICIDES.

421

No. 8 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of £ lb. to 150 gal. of water, and six fourth-molt
caterpillars placed upon it. July 5, the foliage was so badly
burned that the caterpillars were transferred to a freshly
sprayed oak branch. July 19, the branch was resprayed
on account of heavy rains. Of the six caterpillars, only
two, and possibly one of these was injured, died before
pupating. Of the four that pupated, two emerged. The
foliage of the hop-hornbeam was very badly burned, while
that of the oak was in good condition.

No. 9. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of £ lb. to 150 gal. of
water. One died the third day; one pupated the fourth,
three the seventh and three the eighth day ; two died the
eleventh day.

Check experiment : three pupated the fourth day ; one
died the seventh and one the eighth day.

No. 10 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 1 Hi. to 150 gal. of water. One died the eighth and one
the eleventh day ; one pupated the thirteenth day ; one died
and two pupated the fourteenth day ; one pupated the twen¬
tieth, one the twenty-third, one the twenty-eighth and one
the twenty-ninth day.

No. 11 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of i lb. to 150 gal. of water, and ten caterpillars, of
the fifth molt, placed upon it. July 5, the foliage was so
badly burned that the caterpillars were transferred to a
freshly sprayed branch of oak. On the 15th of July, for
lack of food, they were again removed to another branch of
oak which had also been sprayed. Only one caterpillar
died before pupating, and that one lived twenty-four days
after the first spraying. Of the nine that pupated, five
emerged. The foliage of the hop-hornbeam was very badly
burned, while that of the oak was only slightly so, if at all.

THE GYPSY MOTH.

m

No. 12 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of £ lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 5, the foliage was so badly
burned that the caterpillars were removed to another branch
of hop-hornbeam which was not sprayed. July 11, the
foliage having been entirely stripped from the branch, they
were again removed to another unsprayed branch. Of these
caterpillars, none died before pupating, and four of them
completed the process of pupation and emerged. Foliage
very badly burned.

| lb. Paris Green to 150 gal. Water.

No. 13. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of | lb. to 150 gal. of
water. Four died the second, five the third and one the
fourth day.

Check experiment : none dead.

No. 14. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of | lb. to 150 gal. of water.
Three died the second, four the third, two the fifth and one
the sixth day.

Check experiment : none dead.

No. 15. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of | lb. to 150 gal. of
water. One died the fourth, one the fifth, one the sixth,
one the seventh, three the eighth and three the ninth day.

Check experiment : none dead.

No. 16. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of | lb. to 150 gal. of
water. One died the fifth, one the seventh, three the eighth,
two the ninth and three the eleventh day.

Check experiment : none dead.

No. 17. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed

INSECTICIDES.

423

■with Paris green, in the proportion of ^ lb. to 150 gal. of
water. One died the second, three the third, three the fifth,
three the sixth and one the seventh day.

Check experiment: one accidentally killed the seventh
day.

No. 18. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of | lb. to 150 gal. of
water. Two died the second, three the third, three the fifth
and two the sixth day.

Check experiment : one pupated the third and one died
the fourth day.

No. 19 (field experiment). — June 27, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of | lb. to 150 gal. of water, and six fourth-molt
caterpillars placed upon it. July 8, the foliage was so
badly burned that the leaves fell off, and the caterpillars
were removed to another branch which had not been sprayed.
By August 12, all of the caterpillars were dead, with the
exception of one which pupated and emerged.

No. 20 (field experiment) . — June 27, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of ! lb. to 150 gal. of water, and ten fourth-molt
caterpillars were placed upon it. July 8, one caterpillar
had died and the foliage had become badly burned. The
remaining caterpillars were transferred to a freshly sprayed
oak branch. July 19, all the caterpillars were dead. Foli¬
age slightly burned.

No. 21. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of | 11). to 150 gal. of
water. One died the second and one the third day ; two
died and one pupated the fourth day ; two died and one
pupated the sixth day ; one died the eleventh and one the
twelfth day.

Check experiment : one pupated the third day ; one died
the fourth day ; one pupated the sixth, two the eighth, one
the ninth and one the eleventh day.

No. 22 (field experiment). — July 7, 1894. Ten cater-

424

THE GYPSY MOTH.

pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of | lb. to 150 gal. of water. Two died and one pupated
the seventh day ; two pupated the fourteenth, two the six¬
teenth, one the nineteenth, one the twenty-first and one the
twenty-third day.

No. 23 (field experiment). — June 27, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of |- lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 8, one died, and the food
having given out, those remaining were transferred to an¬
other branch. Of these, six pupated and emerged, while
the other three pupated, but died without emerging. The
foliage which was sprayed was so badly burned that the
leaves curled and fell off.

No. 24 (field experiment). — June 27, 1894. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of l lb. to 150 gal. of water, and nine fifth-molt
caterpillars placed upon it. July 8, two having died, the
remaining caterpillars were transferred to a freshly sprayed
oak branch, as the foliage of the liop-hornbeam was burned
to a crisp. By the 4th of August all the caterpillars were
dead. While the foliage of the hop-hornbeam was badly
burned, that of the oak remained in good condition.

1 lb. Paris Green to 150 gal. Water.

No. 26. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaVes which had been treated
with Paris green, in the proportion of 1 lb. to 150 gal. of
water. Two died the first, five the third and one the fourth
day ; two escaped.

Check experiment : none dead.

No. 27. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 1 lb. to 150 gal. of water.
One died the first, two the second, five the third, one the
fourth and one the fifth day.

Check experiment : none dead.

No. 28. — May 28, 1894. Ten caterpillars, of the first

INSECTICIDES.

425

molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 1 lb. to 150 gal. of
water. Three died the third, one the fourth, one the fifth,
four the sixth and one the seventh day.

Check experiment : one dead.

No. 29. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 1 11). to 150 gal. of
water. One died the second, one the third, two the fourth,
one the fifth, four the seventh and one the eighth day.

Check experiment : none dead.

No. 30. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 1 lb. to 150 gal. of
water. Two died the second, three the third, two the
fourth, one the sixth and two the seventh day.

Check experiment : none dead.

No. 31. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 1 lb. to 150 gal. of
water. Four died the third, one the fourth, one the fifth,
two the sixth, one the seventh and one the eighth day.

Check experiment : one died the fifth day ; one pupated
and one died the sixth day.

No. 32 (field experiment). — June 26, 1893. A branch
of apple tree was sprayed with Paris green, in the propor¬
tion of 1 lb. to 150 gal. of water, and ten fourth-molt cater¬
pillars placed upon it. Of these, four died without pupating,
and, of the six which began to pupate, none emerged.
Foliage slightly burned.

No. 33 (field experiment) . — June 26, 1893. An apple-
tree branch was sprayed with Paris green, in the proportion
of 1 lb. to 150 gal. of water, and nine fourth-molt cater¬
pillars placed upon it. July 16, the branch having been
broken off by the wind, the caterpillars were transferred to
another tree, and the branch sprayed. Five died before
pupating, and, of the four which pupated, two emerged.
Foliage badly burned.

No. 34. — July 10, 1894. Ten caterpillars, of the fifth

426

THE GYPSY MOTH.

molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 1 lb. to 150 gal. of
water. One died the fourth day ; three died and one pu¬
pated the sixth day ; two died the ninth, one the tenth, one
the eleventh and one the twelfth day.

Check experiment : one died the second day ; two pupated
the sixth, one the seventh, one the ninth and one the tenth
day.

No. 35 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 1 lb. to 150 gal. of water. Two pupated the fourteenth,
two the sixteenth and three the eighteenth day ; one died
the nineteenth and two pupated the twentieth day.

No. 36 (field experiment). — June 26, 1893. A branch
of apple tree was sprayed with Paris green, in the propor¬
tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater¬
pillars were placed upon it. Of these, six died before pu¬
pating ; four pupated, three of which emerged. For some
reason the foliage appeared to be quite badly burned,
although the Paris green was in the proportion commonly
used for spraying.

No. 37 (field experiment). — June 26, 1893. A branch
of apple tree was sprayed with Paris green, in the propor¬
tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater¬
pillars placed upon it. In this experiment the poison took
effect more quickly than in the corresponding experiments,
all of the caterpillars having died within three weeks.

No. 38 (field experiment). — July 12, 1893. A branch
of hop-hornbeam was sprayed with Paris green, in the pro¬
portion of 1 lb. to 150 gal. of water, and ten caterpillars of
the fifth molt placed upon the branch. July 21, the foliage
was so badly burned that the caterpillars were transferred
to a freshly sprayed branch of oak, which was resprayed
July 27, on account of the rain. Four caterpillars pupated,
two of which emerged. Foliage of the hop-hornbeam very
badly burned ; that of the oak burned somewhat less.

No. 39 (field experiment). — July 12, 1893. Paris green,
in the proportion of 1 lb. to 150 gal. of water, was allowed

INSECTICIDES.

427

to stand for nearly three hours, to determine the difference
in action between this and the experiments where the poison
had not been allowed to stand. An oak branch was sprayed
with this mixture, and ten large tifth-molt caterpillars
placed upon it. July 21, the branch was resprayed on
account of heavy rain, and on July 25 the foliage became so
badly burned that the caterpillars were transferred to a
freshly sprayed oak branch. Seven of the ten began to
pupate, but of these only two emerged, and one of those
was imperfect. Foliage of the first branch was very badly
burned, while that of the second was in good condition.

lh. lbs. Paris Green to 150 gal. Water.

No. 40. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 1£ lbs. to 150 gal.
of water. One died on the first, one the second and six the
third day ; two escaped.

Check experiment : none dead.

No. 41. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 1£ lbs. to 150 gal. of
water. Five died the second, three the third and two the
fourth day.

Check experiment : none dead.

No. 42. — May 28, 1895. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of li lbs. to 150 gal. of
water. Four died the third, three the fourth and three the
fifth day.

Check experiment : one died the fourth day.

No. 43. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of H lbs. to 150 gal. of
water. Two died the second, one the third, one the fourth,
one the fifth, two the sixth, two the seventh and one the
eighth day.

Check experiment : none dead.

No. 44. — June 21, 1894. Ten caterpillars, of the third

428

THE GYPSY MOTH.

molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of If lbs. to 150 gal.
of water. Two died the third, two the fourth, three the
fifth, one the sixth and two the seventh day.

Check experiment : none dead.

No. 45. — June 29, 1895. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of If lbs. to 150 gal.
of water. Two died the second, four the third, three the
fourth and one the fifth day.

Check experiment : one died the fourth day.

No. 46 (field experiment). — June 26, 1893. An apple-
tree branch was sprayed with Paris green, in the proportion
of If lbs. to 150 gal. of water, and eight fourth-molt cater¬
pillars placed upon it. Six caterpillars in this experiment
died gradually, one lived over ten weeks on the foliage and
pupated. Another lived on the foliage a month, then pu¬
pated and finally emerged. Foliage somewhat burned.

No. 47 (field experiment) . — June 26, 1893. An apple-
tree branch was sprayed with Paris green, in the proportion
of 1 f lbs. to 150 gal. of water, and ten fourth-molt cater¬
pillars placed upon it. Of these, all but one died before
beginning to pupate, and that one was not able toi complete
the process. It took more than a week for the poison to
begin to act, and the last caterpillar lived over six weeks.
The foliage was badly burned.

No. 48. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 1± lbs. to 150 gal. of
water. Two died and one pupated the third day; one died
the fourth, two the sixth, three the eighth and one the
twelfth day.

Check experiment : one died the second day ; one pupated
the fourth, one the fifth, one the sixth and one the seventh
day.

No. 49 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on a willow branch
which had been sprayed with Paris green, in the proportion
of If lbs. to 150 gal. of water. One died and one pupated

PLATE 65. White pine and other trees stripped by the cater¬
pillars of the gypsy moth.

INSECTICIDES.

429

the seventh day; one died the thirteenth day; one died and
two pupated the fourteenth day ; two pupated the eighteenth,
one the twenty-seventh and one the thirty-first day.

No. 50 (field experiment). — June 26, 1893. An apple-
tree branch was sprayed with Paris green, in the proportion
of l.J lbs. to 150 gal. of water, and ten fifth-molt cater¬
pillars placed upon it. By the 5th of August all had died,
none having completed the process of pupation, although
two or three had begun. The foliage was badly burned.

No. 51 (field experiment) . — June 26, 1893. An apple-
tree branch was sprayed with Paris green, in the proportion
of 1£ lbs. to 150 gal. of water, and ten fifth-molt cater¬
pillars placed upon it. Of these caterpillars, six died with¬
out pupating ; three began to pupate, but died later ; and
one pupated and emerged. The foliage was badly burned.

No. 52 (field experiment). — July 14, 1893. An oak
branch was sprayed with Paris green, in the proportion of
li lbs. to 150 gal. of water, and ten fifth-molt caterpillars
placed upon it. On July 20, the branch was resprayed on
account of rain. Seven of the caterpillars pupated, four
of which emerged. Three of these seven began pupating
before they had time to eat any of the poisoned food.
Foliage badly burned.

2 lbs. Paris Green to 150 gal. Water.

No. 53. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 2 lbs. to 150 gal. of
water. Two died the first, one the second, six the third
and one the fourth day.

Check experiment : none dead.

No. 54. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 2 lbs. to 150 gal. of water.
One died the second, four the third, one the fifth and four
the sixth day.

Check experiment : none dead.

No. 55. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated

430

THE GYPSY MOTH.

with Paris green, in the proportion of 2 lbs. to 150 gal. of
water. Five died the third, two the fourth, one the sixth,
one the seventh and one the ninth day.

Check experiment : one died the fourth day.

No. 56. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 2 lbs. to 150 gal. of
water. One died the second, two the third, one the fourth,
four the seventh and two the eighth day.

Check experiment : none dead.

No. 57. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 2 lbs. to 150 gal. of
water. One died the second, one the third, four the fifth,
two the sixth and two the seventh day.

Check experiment : one died the seventh day.

No. 58. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 2 lbs. to 150 gal. of
water. Two died the second, five the third, one the fourth,
fifth and sixth days.

Check experiment : one died the fourth and one the sixth
day.

No. 59. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 2 lbs. to 150 gal.
of water. One pupated the fifth day ; two died and four
pupated the sixth day ; one pupated the seventh day ; one
died the tenth and one the fourteenth day.

Check experiment : four pupated and one died the fourth
day ; one pupated the fifth day, one the sixth, one the ninth
and one the eleventh day.

No. 60 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 2 lbs. to 150 gal. of water. One pupated the fourth and
one died the thirteenth day ; three pupated the fourteenth
and one died the seventeenth day; two pupated the nine¬
teenth and two the twenty-sixth day. Foliage badly burned.

INSECTICIDES.

431

3 lbs. Paris Green to 150 gal. Water.

No. 61. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 3 lbs. to 150 gal. of
water. Five died the second, four the third and one the
fifth day.

Check experiment : none dead.

No. 62. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 3 lbs. to 150 gal. of water.
Two died the second, one the third, three the fourth, one
the fifth and three the sixth day.

Check experiment : none dead.

No. 63. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 3 lbs. to 150 gal. of
water. Eight died the third day, one the seventh and one
the eighth day.

Check experiment : none dead.

No. 64. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 3 lbs. to 150 gal. of
water. One died the second day, one the third, four the
fifth, three the seventh and one the ninth day.

Check experiment : none dead.

No. 65. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 3 lbs. to 150 gal.
of water. One died the second, two the third, two the
fourth, four the fifth and one the sixth day.

Check experiment : none dead.

No. 66. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 3 lbs. to 150 gal. of
water. Two died the first, one the second, three the third,
two the fourth and two the sixth day.

Check experiment : none dead.

No. 67. — July 10, 1894. Ten caterpillars, of the fifth

432

THE GYPSY MOTH.

molt, were placed on elm leaves which had been sprayed
with Paris green in the proportion of 3 lbs. to 150 gal. of
water. One died and one pupated the third day ; one
pupated the fourth and one the fifth day ; one pupated and
one died the sixth day ; one died the seventh, two the ninth
and one the fourteenth day.

Check experiment : three pupated the fourth day, one
pupated and one died the sixth day ; one pupated and one
died the ninth day ; three died the fourteenth day.

No. 68 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 3 lbs. to 150 gal. of water. One died the third, one
the fourth and one the fifth day ; one pupated the sixth, one
the fifteenth, one the eighteenth, one the twenty-first, one the
twenty-fourth, one the twenty-eighth and one the thirty-
first day. Foliage badly burned.

4 lbs. Paris Green to 150 gal. Water.

No. 69. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 4 lbs. to 150 gal. of
water. Five died the second and four the third day ; and
one escaped.

Check experiment : none dead.

No. 70. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 4 lbs. to 150 gal. of water.
Two died the second, five the third, one the fourth and one
the fifth day ; and one escaped.

Check experiment : two died the fourth day.

No. 7i. — May 28, 1895. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 4 lbs. to 150 gal. of
water. One died the fourth, two the fifth and seven the
sixth day.

Check experiment : one died the fifth day.

No. 72. — June 10, 1894. Ten caterpillars, of the
second molt, were placed on elm leaves which had been

INSECTICIDES.

433

sprayed with Paris green, in the proportion of 4 lbs. to 150
gal. of water. Two died the second, three the fourth, two
the fifth, two the sixth and one the eighth day.

Check experiment : none dead.

No. 73. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 4 lbs. to 150 gal. of
water. Four died the second, four the third, one the fifth
and one the sixth day.

Check experiment : none dead.

No. 74. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 4 lbs. to 150 gal. of
water. Four died the third day; two pupated the fourth
day ; three died the fifth and one the sixth day.

Check experiment : one died the third day.

No. 75. — Jnly 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 4 lbs. to 150 gal. of
water. One died the second day, two pupated and two died
the third day ; two pupated and one died the sixth day ; one
died the seventh and one the eighth day.

Check experiment : one pupated the fourth day ; one died
the sixth day.

No. 76 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 4 lbs. to 150 gal. of water. One died and two pupated
the fifth day ; one died the sixth and two the seventh day ;
'one pupated the fourteenth, one the fifteenth, one the nine¬
teenth and one the twenty-second day. Foliage badly
burned.

5 lbs. Paris Green to 150 gal. Water.

No. 77. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Two died the first and seven the third day ; and one
escaped.

Check experiment : none dead ; one escaped.

434

THE GYPSY MOTH.

No. 78. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 5 lbs. to 150 gal. of water.
One died the first, three the second, two the third, three the
fourth and one the fifth day.

Check experiment : one died the second day.

No. 79. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Five died the third, three the fourth and two the
sixth day.

Check experiment : one died the third day.

No. 80. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Two died the second, three the third, one the fourth,
one the fifth, one the sixth, one the seventh and one the
eighth day.

Check experiment : none dead.

No. 81. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Six died the second and four the third day.

Check experiment : none dead.

No. 82. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Two died the second, two the third and two the
fourth day ; one died and one pupated the fifth day ; two
died the eighth day.

Check experiment : one died the third day ; one pupated
the fourth day ; two died the fifth day.

No. 83. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 5 lbs. to 150 gal. of
water. Two died the third day ; two pupated the sixth and
one the seventh day ; one pupated and one died the eighth
day ; two died the ninth day ; one pupated the eleventh
day.

INSECTICIDES.

435

Check experiment : five pupated the fourth and one the
fifth day ; one died the eleventh day.

No. 84 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 5 lbs. to 150 gal. of water. One pupated the fourth,
three the seventh, one the thirteenth, three the fourteenth,
one the seventeenth and one the twenty-first day. Foliage
badly burned.

6 lbs. Paris Green to 150 gal. Water.

No. 85. — April 20, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. One died the first, six the second and three the third
day.

Check experiment : none dead ; one escaped.

No. 86. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green, in the proportion of 6 lbs. to 150 gal. of water.
Five died the second, one the third and four the fourth day.

Check experiment : none dead.

No. 87. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. Four died the third, three the fourth, one the fifth,
one the seventh and one the eighth day.

Check experiment : one died the fourth day.

No. 88. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. Four died the first, one the second, two the fourth,
one the fifth and one the sixth day ; one was lost.

Check experiment : none dead.

No. 89. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. Five died the second, two the third, two the fifth
and one the sixth day.

Check experiment : none dead.

436

THE GYPSY MOTH.

No. 90. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. Four died the first, two the second, one the third,
fourth, fifth and sixth days.

Check experiment : one died the third day.

No. 91. — July 10, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green, in the proportion of 6 lbs. to 150 gal. of
water. Two died the third day ; one died and one pupated
the fourth day ; two died and one pupated the sixth day ;
two died the eighth and one the twelfth day.

Check experiment : one pupated the fifth day ; one died
the seventh day ; two died and two pupated the eighth day ;
one pupated the ninth and one the tenth day.

No. 92 (field experiment) . — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green, in the proportion
of 6 lbs. to 150 gal. of water. Two died the fourth, one
the sixth and one the seventh day ; one pupated the eighth
and one the thirteenth day ; one died the fourteenth day;
one pupated the fifteenth, one the nineteenth and one the
twentieth day. Foliage badly burned.

Experiments with Paris Green and Lime.
i lb. Each of Paris Green and Lime to 150 gal. Water.

No. 1. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of £ lb. each
to 150 gal. of water. One died the second and nine the
third day.

Check experiment : none dead.

No. 2. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of £ lb. each to 150
gal. of water. One died the second, one the third, seven
the fifth and one the sixth day.

Check experiment : none dead.

No. 3. — May 28, 1894. Ten caterpillars, of the first

INSECTICIDES.

437

molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of £ lb. each
to 150 gal. of water. Three died the third, two the fourth,
two the sixth, one the seventh and two the eighth day.

Check experiment : none dead.

No. 4. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been treated with
Paris green and lime, in the proportion of 4 lb. each to 150
gal. of water. One died the fourth, one the sixth, four the
ninth, two the tenth and two the eleventh day.

Check experiment : none dead.

No. 5. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 4 lb. each
to 150 gal. of water. One died the fourth, four the sixth
and five the seventh day.

Check experiment : none dead.

No. G. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of £ lb. each
to 150 gal. of water. Two died the first, one the second,
fourth, fifth, sixth and seventh and three the eighth day.

Check experiment : one pupated the sixth day.

No. 7. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 4 lb. each
to 150 gal. of water. One died the first day; one died and
one pupated the second day ; two pupated the third day ;
one died the fifth, one the eighth, one the ninth and two the
tenth day.

Check experiment : two pupated the fifth day ; one died
and one pupated the eighth day ; one pupated the ninth day.

No. 8 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 4 lb. each to 150 gal. of water. One died the
fourth, one the fifth and one the seventh day ; one pupated
the tenth, one the fourteenth, one the sixteenth and four the
eighteenth day.

438

THE GYPSY MOTH.

| lb. Each Paris Green and Lime to 150 gal. Water.

No. 9. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of | lb. each
to 150 gal. of water. Two died the second, six the third
and two the fourth day.

Check experiment : none dead.

No. 10. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of | lb. each to 150
gal. of water. Two died the second, five the third and three
the fourth day.

Check experiment : none dead.

No. 11. — May 2, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of f lb. each
to 150 gal. of water. One died the third, one the fifth, four
the seventh, two the eighth and two the ninth day.

Check experiment : none dead.

No. 12. — June 10, 1895. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of | lb. each
to 150 gal. of water. Two died the sixth, six the seventh
and two the eighth day.

Check experiment : none dead.

No. 13. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of | lb. each to
150 gal. of water. Four died the fifth, one the sixth, four
the seventh and one the eighth day.

Check experiment : none dead.

No. 14. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of | lb. each
to 150 gal. of water. One died the third, five the fourth,
one the fifth, two the sixth and one the seventh day.

Check experiment : one died the fourth day.

No. 15. — July 11, 1894. Ten caterpillars, of the fifth

INSECTICIDES.

439

molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of | lb. each
to 150 gal. of water. Two died the first day; two pupated
the fifth day ; three died the ninth, two the tenth and one
the fourteenth day.

Check experiment : one lost and one pupated the third
day; one pupated the fourth, one the fifth and one the
sixth day; one died the eighth, three the twelfth and one
the thirteenth day.

No. 16 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of f lb. each to 150 gal. of water. Two died the
third day ; two pupated the sixth and one the thirteenth
day ; one died and one pupated the fourteenth day ; one
died and two pupated the eighteenth day.

1 lb. Each Paris Green and Lime to 150 gal. Water.

No. 17. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 1 lb. each
to 150 gal. of water. Eight died the second, one the fourth
and one the fifth day.

Check experiment : none dead ; five escaped.

No. 18. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 1 lb. each to 150
gal. of water. One died the second, six the third, one the
fourth, one the fifth and one the sixth day.

Check experiment : one died the second day.

No. 19. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 1 lb. each to
150 gal. of water. One died the fourth, two the fifth, three
the sixth, two the eighth, one the ninth and one the tenth day.

Check experiment : one died the sixth day.

No. 20. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 1 11>. each

440

THE GYPSY MOTH.

to 150 gal. water. One died the second, four the sixth, four
the seventh and one the tenth day.

Check experiment : none dead.

No. 21. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed

with Paris green and lime, in the proportion of 1 lb. each

to 150 gal. of water. One died the third, two the fifth, two
the sixth and five the seventh day.

Check experiment : one died and one lost the seventh day.

No. 22. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed

with Paris green and lime, in the proportion of 1 lb. each

to 150 gal. of water. Three died the second, two the third
and one the fourth, fifth, sixth, seventh and eighth days.

Check experiment : one died the third day.

No. 23. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 1 lb. each to
150 gal. of water. One died and one pupated the second
day ; two pupated the fourth, two the fifth and one the
eighth day ; two died the tenth and one the fourteenth day.

Check experiment : one died and one pupated the third
day ; one died the seventh, one the eighth and one the tenth
day.

No. 24 (field experiment). — Ten caterpillars, of the fifth
molt, were placed on willow branches which had been sprayed
with Paris green and lime, in the proportion of 1 11 >. each to
150 gal. of water. One died the sixth and three the seventh
day ; one pupated the eleventh, one the twelfth, two the thir¬
teenth, one the fifteenth and One the seventeenth day.

lh. lbs. Each Paris Green and Lime to 150 gal. Water.

No. 25. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 1^ lbs. each
to 150 gal. of water. Five died the second, two the third
and one the fourth day, and two escaped.

Check experiment : one died the fifth day, and five es¬
caped.

INSECTICIDES.

441

No. 26. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 1£ lbs. each to
150 gal. of water. Four died the second, live the third and
one the fourth day.

Check experiment : one died the second day.

No. 27. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of LI lbs. each
to 150 gal. of water. Four died the third, one the fourth,
two the fifth and three the sixth day.

Check experiment : one died the fifth day.

No. 28. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 1£ lbs. each
to 150 gal. of water. One died the second, one the fourth,
four the sixth, three the seventh and one the eighth day.

Check experiment : none dead.

No. 29. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 1J lbs. each
to 150 gal. of water. Three died the third, one the fourth,
four the fifth and two the sixth day.

Check experiment : none dead.

No. 30. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 14 lbs. each
to 150 gal. of water. Four died the third, two the fourth,
two the fifth and two the sixth day.

Check experiment : one pupated the fourth day.

No. 31. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, jn the proportion of 1£ lbs. each
to 150 gal. of water. Two pupated the third and one the
fifth day ; two died and one pupated the seventh day ; one
died the eighth, two the ninth and one the eleventh day.

Check experiment : one died the third day ; one pupated
the fourth, two the fifth, one the eighth and one the tenth
day.

442

THE GYPSY MOTH.

No. 32 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of li lbs. each to 150 gal. of water. One died
the fourth day ; one died and one pupated the seventh day ;
one pupated the ninth, one the thirteenth, one the sixteenth,
two the eighteenth, one the twenty-sixth and one the twenty-
eighth day.

2 lbs. Each Paris Green and Lime to 150 gal. Water.

No. 33. — April 2G, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 2 lbs. each
to 150 gal. of water. Three died the second, four the third
and three the fourth day.

Check experiment : none dead.

No. 34. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 2 lbs. each to
150 gal. of water. One died the second, five the third, two
the fourth and two the fifth day.

Check experiment : none dead.

No. 35. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 2 lbs. each
to 150 gal. of water. One died the third, one the fourth,
one the fifth, two the sixth, four the seventh and one the
eighth day.

Check experiment : none dead.

No. 36. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 2 lbs. each
to 150 gal. of water. One died the second, one the fourth,
two the fifth, three the sixth and three the seventh day.

Check experiment : none dead.

No. 37. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 2 lbs. each
to 150 gal. of water. Two died the second, two the third,
one the fifth, three the sixth and two the seventh day.

INSECTICIDES.

443

Check experiment : two lost the seventh day.

No. 38. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 2 lbs. each
to 150 gal. of water. Two died the second, two the third,
two the fourth, two the fifth, one the sixth and one the
eighth day.

Check experiment : one died the fourth, one the fifth and
one the sixth day.

No. 39. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 2 lbs. each to
150 gal. of water. Two pupated the second day; one died
the third day ; one died and one pupated the fifth day ; one
pupated the sixth day ; one died the seventh, one the ninth
and two the tenth day.

Check experiment : one died the third day ; two died and
two pupated the ninth day.

No. 40 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 2 lbs. each to 150 gal. of water. One pupated
the sixth day ; two died the seventh day ; one pupated the
eighth day ; one died and one pupated the thirteenth day ;
one pupated the fourteenth, one the sixteenth, one the
twentieth and one the twenty-second day.

3 lbs. Each Paris Green a\icl Lime to 150 gal. Water.

No. 41. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. Four died the second, two the third,
one the fourth and three the fifth day.

Check experiment : none dead.

No. 42. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 3 lbs. each to 150
gal. of water. Two died the second, three the third, one
the fourth and four the fifth day.

444

THE GYPSY MOTH.

Check experiment : none dead.

No. 43. — May 28, 1894. Ten caterpillars, of the first
molt, were placed -on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. One died the third, three the fifth,
four the sixth and two the seventh day.

Check experiment : none dead.

No. 44. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. One died the second, two the third,
one the fourth, two the fifth, three the sixth and one the
seventh day.

Check experiment : none dead.

No. 45. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed'
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. Five died the third, two the sixth and
three the seventh day.

Check experiment : two died the seventh day.

No. 46. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. Two died the first, one the second,
two the third, one the fourth, one the fifth, two the sixth
and one the seventh day.

Check experiment : none dead.

No. 47. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 3 lbs. each
to 150 gal. of water. Two pupated the second and one the
third day ; two died the seventh and four the ninth day ;
one pupated the eleventh day.

Check experiment : one died the third day ; two pupated
the fifth day ; one died the eighth and one the tenth day.

No. 48 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 3 lbs. each to 150 gal. of water. One died
the fourth and two the fifth day ; two died and one pupated

INSECTICIDES.

445

the seventh day; one pupated the tenth, one the fourteenth,
one the fifteenth and one the twenty-first day.

4 lbs. Each Paris Green and Lime to 150 gal Water.

No. 49. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 4 lbs. each
to 150 gal. of water. Six died the second and four the third
day.

Check experiment : none dead.

No. 50. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 4 lbs. each to 150
gal. of water. Five died the second, four the third and one
the fifth day.

Check experiment : none dead.

No. 51. — May 28, 1894. Ten caterpillars, of the fifth
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 4 lbs. each
to 150 gal. of water. Three died the fourth, three the fifth,
three the sixth and one the seventh day.

Check experiment : none dead.

No. 52. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 4 lbs. each
to 150 gal. of water. One died the third, two the fourth,
three the fifth and four the seventh day.

Check experiment : none dead.

No. 53. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 4 lbs. each
to 150 gal. of water. Three died the second, four the third,
one the fifth and two the sixth day.

Check experiment : none dead.

No. 54. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which were sprayed with
Paris green and lime, in the proportion of 4 lbs. each to 150
gal. of water. One died the first, one the second, two the
third, four the fourth and two the fifth day.

Check experiment : none dead.

446

THE GYPSY MOTH.

No. 55. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 4 lbs. each
to 150 gal. of water. Three pupated the second day; one
died the third, one the fourth, one the fifth, two the sixth,
one the seventh and one the eighth day.

Check experiment : two pupated the third, one the fourth
and one the sixth day.

No. 56 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 4 lbs. each to 150 gal. of water. One died
the fourth, one the fifth, one the sixth and one the seventh
day ; one pupated the ninth day ; one died and one pupated
the tenth day ; one pupated the thirteenth, one the seven¬
teenth and one the eighteenth day.

5 lbs. Each Paris Green and Lime to 150 gal. Water.

No. 57. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 5 lbs. each
to 150 gal. of water. One died the first, two the second and
five the third day ; and two escaped.

Check experiment : none dead.

No. 58. — May 9, 1895. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 5 lbs. each to 150
gal. of water. One died the second, one the third, five the
fourth and three the fifth day.

Check experiment : none dead.

No. 59. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 5 lbs. each
to 150 gal. of water. Two died the third, one the fourth,
two the fifth, three the sixth and two the eighth day.

Check experiment : none dead.

No. 60. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 5 lbs. each

INSECTICIDES.

447

to 150 gal. of water. Four died the second, one the third,
two the fourth, two the fifth and one the sixth day.

Check experiment : none dead.

No. 61. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 5 lbs. each
to 150 gal. of water. Two died the second, one the third,
two the fourth, two the sixth, two the seventh and one the
eighth day.

Check experiment : one died the seventh day.

No. 62. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 5 lbs. each
to 150 gal. of water. Two died the second, four the third,
three the fourth and one the sixth day.

Check experiment : none dead.

No. 63. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 5 lbs. each
to 150 gal. of water. Two pupated and two died the second
day ; one died and one pupated the third day ; one died the
seventh and three the eighth day.

Check experiment : two pupated the third day ; one died
and three pupated the fifth day ; one pupated the eighth
day.

No. 64 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 5 lbs. each to 150 gal. of water. One died the
fourth, one the fifth, one the sixth and one the seventh day ;
two died and one pupated the eighth day ; one pupated and
one was lost the fourteenth day ; one pupated the thirty-
third day.

6 lbs. Each Paris Green and Lime to 150 gal. Water.

No. 65. — April 26, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 6 lbs. each
to 150 gal. of water. Six died the second, three the third
and one the fourth day.

448

THE GYPSY MOTH.

Check experiment : none dead.

No. 66. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
Paris green and lime, in the proportion of 6 lbs. each to 150
gal. of water. One died the second, three the third, three
the fourth and three the fifth day.

Check experiment : one died the third day.

No. 67. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with Paris green and lime, in the proportion of 6 lbs. each
to 150 gal. of water. Six died the third, two the fourth,
one the fifth and one the sixth day.

Check experiment : none dead.

No. 68. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been treated with
Paris green and lime, in the proportion of 6 lbs. each to 150
gal. of water. Three died the second, three the third, two
the fifth, one the sixth and one the seventh day.

Check experiment : none dead.

No. 69. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed with
Paris green and lime, in the proportion of 6 lbs. each to 150
gal. of water. Two died the second, one the third, two the
fourth, one the sixth and four the seventh day.

Check experiment : one accidentally killed the seventh day.

No. 10. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 6 lbs. each to
150 gal. of water. Six died the second, two the third and
two the fourth day.

Check experiment • one died the third day.

No. 71. — July 11, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with Paris green and lime, in the proportion of 6 lbs. each to
150 gal. of water. One died the first day; one died and
two pupated the second day ; one died the third day ; one
pupated the filth day ; three died the seventh and one the
eleventh day.

Check experiment : one pupated the third day ; one died
and four pupated the fifth day ; one died the tenth day.

INSECTICIDES.

449

No. 72 (field experiment). — July 7, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with Paris green and lime, in the
proportion of 6 lbs. each to 150 gal. of water. One died
the fourth, one the sixth, two the seventh and one the eighth
day ; one pupated the fourteenth, one the fifteenth, one the
sixteenth and two the eighteenth day.

Experiments with Arsenate of Lead.

| lb. Arsenate of Lead to 150 gal. Water.

No. 1. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of lb. to 150 gal.
of water. One died the fifth, one the sixth and one the
seventh day ; those remaining lived and molted.

No. 2. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves, which had been treated with
arsenate of lead, in the proportion of ^ lb. to 150 gal. of
water. One died the fifth day ; those remaining lived and
molted.

Check experiment : none dead.

No. 3. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of ^ lb. to 150 gal.
of water. All lived through the experiment.

Check experiment : none dead.

No. 4. — Jane 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of ^ lb. to 150 gal.
of water. All lived through the experiment.

Check experiment : none dead.

No. 5. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of ^ lb. to 150 gal.
of water. One died the seventh, three the eighth and one
the ninth day ; one pupated the tenth day ; one died the
eleventh day. The remainder lived through the experiment.

Check experiment : one was lost the seventh day ; one
pupated the eighth day ; two died the tenth day.

450

THE GYPSY MOTH.

^ lb. Arsenate of Lead to 150 gal. Water.

No. 6. — March 7, 1894. Ten caterpillars, three days
old, were placed upon lettuce leaves which had been treated
with arsenate of lead, in the proportion of ^ lb to 150 gal.
of water. On the ninth day six were dead and four lost.

No. 7. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of \ lb. to 150 gal. of
water. All lived through the experiment (seventeen days).

Check experiment : none dead.

No. 8. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of \ lb. to 150 gal.
of water. One died the third, one the fourth, one the
seventh and one the ninth day ; the remainder lived through
the experiment.

Check experiment : none dead.

No. 9. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of i- lb. to 150 gal.
of water. One died the fifth and two the eleventh day ; the
remainder lived through the experiment.

Check experiment : none dead.

No. 10. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of ^ lb. to 150 gal.
of water. One died the fourth, one the fifth and one the
sixth, two died and one pupated the seventh, two died the
eighth, one the tenth and one the eleventh day.

Check experiment : one died the seventh and one the
ninth day ; one was lost the tenth day.

No. 11 (field experiment). — June 29, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of ^ lb. to 150 gal. of water, and nine fourth-molt caterpil¬
lars placed upon it. July 31, for lack of food, they were
transferred to a fresh branch, which was left unsprayed. All
these caterpillars pupated and six emerged. Foliage unin¬
jured.

No. 12 (field experiment). — June 29, 1893. A branch

INSECTICIDES.

451

of oak was sprayed with arsenate of lead, in the proportion
of | lb. to 150 gal. of water, and ten caterpillars, of the
fourth molt, were placed upon it. Three of these died before
pupating, the last one dying thirty-seven days after the first
spraying. Of the seven that pupated, all emerged. Foliage
uninjured.

No. 13 (field experiment). — June 29, 1893. A branch
of a small oak was sprayed with arsenate of lead, in the
proportion of l lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 20, the branch was re¬
sprayed on account of the rain on the 18th. Only one cater¬
pillar died before pupating, and seven were able to complete
the process of pupation and emerge. Another one fed on
the leaves for nine days after the spraying and pupated, but
was injured in removing, and therefore not couuted in the
above summary. Foliage uninjured.

No. 14 (field experiment). — June 29, 1893. A branch
of a small oak tree was sprayed with arsenate of lead, in the
proportion of ^ lb. to 150 gal. of water, and nine fifth-molt
caterpillars were placed upon it. July 20, the branch was
resprayed on account of rain. Only one caterpillar died
before pupating, and that on the forty-first day after the first
spraying. Of the eight that pupated, two died without
emerging. Foliage uninjured.

\ lb. Arsenate of Lead to 150 gal. Water.

No. 15. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 4 lb. to 150 gal.
of water. On the eighth day all were dead.

No. 16. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 4 lb. to 150 gal. of
water. One died the fifth day ; the remainder lived through
the experiment and molted.

Check experiment : none dead.

No. 17. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 4 lb. to 150 gal.
of water. One died the third, one the fourth, two the fifth,

452

THE GYPSY MOTH.

one the tenth and one the eleventh day ; the remainder lived
through the experiment.

Check experiment : none dead.

No. 18. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of £ lb. to 150 gal.
of water. Two died the fifth, one the seventh, three the
eighth, two the ninth, one the tenth and one the twelfth day.

Check experiment : none dead.

No. 19. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed with
arsenate of lead, in the proportion of £ lb. to 150 gal. of
water. Two died the third, three the seventh, two the
eighth, one the tenth and two the twelfth day.

Check experiment : two died the seventh and one the
eighth day ; two were lost.

No. 20 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of £ lb. to 150 gal. of water, and ten fourth-molt
caterpillars placed upon it. On the 19th of July, the food
having given out and two of the caterpillars having died,
those remaining were transferred to a freshly sprayed branch.
Of the ten, two died before pupating, and of the eight that
pupated, five emerged. Foliage uninjured.

No. 21 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of £ lb. to 150 gal. of water, and nine fourth-
molt caterpillars placed upon it. July 19, as the food supply
was nearly gone, the caterpillars were removed to a freshly
sprayed branch. One died before beginning to pupate, and
of the eight which pupated, six emerged. Foliage unin¬
jured.

No. 22 (field experiment). — June 29, 1893. A branch
of a small oak tree was sprayed with arsenate of lead, in the
proportion of y lb. to 150 gal. of water, and nine fourth-
molt caterpillars were placed upon it. July 20, they were
transferred to a freshly sprayed branch, both on account of
the food supply and rain. It was noticeable that on the old
branch the caterpillars had eaten all of the old, tough leaves,
and left the young and fresh ones. Two died before pupat-

INSECTICIDES.

453

ing, and, of the seven that pupated, four emerged. Foliage
uninjured.

No. 23 (field experiment). — June 29, 1893. An oak
branch was sprayed with arsenate of lead, in the proportion
of ~ lb. to 150 gal. of water, and ten fourth-molt caterpillars
were placed upon it. July 20, the branch was resprayed on
account of rain. One died before pupating, and eight of
the nine that pupated emerged. Foliage uninjured.

No. 24 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of £ lb. to 150 gal. of water, and nine fifth-molt
caterpillars placed upon it. On the 19th of July, they were
removed to a freshly sprayed branch. Of the eight that
pupated, six emerged. Foliage uninjured.

No. 25 (field experiment). — June 28, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of y lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 15, as the food supply was
getting low, the caterpillars were removed to another branch
which was not sprayed. Three died before pupating, and, of
the seven which pupated, six emerged. Foliage uninjured.

No. 26. — June 29, 1893. An oak branch was sprayed
with arsenate of lead, in the proportion of ^ lb. to 150 gal.
of water, and nine fifth-molt caterpillars placed upon it.
July 5, they were transferred to a freshly sprayed branch.
Only one of these caterpillars died before beginning to
pupate, and, of those that pupated, seven emerged. Foliage
uninjured.

No. 27 (field experiment). — June 29, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of h lb. to 150 gal. of water, and ten fifth-molt caterpillars
placed upon it. July 15, for lack of food, they were trans¬
ferred to a freshly sprayed branch. None of these cater¬
pillars died before pupating, and five emerged. Foliage
uninjured.

| lb. Arsenate of Lead to 150 gal. Water.

No. 28. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of | lb. to 150 gal.
of water. On the fourth day one died, on the fifth three, on

454

THE GYPSY MOTH.

the sixth two and on the seventh three ; the remaining one
was lost.

No. 29. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of | lb. to 150 gal. of
water. All lived through the experiment.

Check experiment : none dead.

No. 30. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of | lb. to 150 gal.
of water. One died the eighth and three the tenth day ;
those remaining lived through the experiment.

Check experiment : none dead.

No. 31. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of | lb. to 150 gal.
of water. Two died the fifth, one the ninth, one the
eleventh, two the thirteenth and four the eighteenth day.

Check experiment : none dead.

No. 32. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of | lb. to 150 gal.
of water. One died the third, one the seventh and one the
ninth day ; one pupated the tenth day ; one died and one
pupated the eleventh day ; and four died the twelfth day.

Check experiment : one pupated the tenth day and two
died the eleventh day.

No. 33 (field experiment). — June 27, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of | lb. to 150 gal. of water, and nine fourth-
rnolt caterpillars placed upon it. Of these, three died before
pupating, and, of the six which pupated, three emerged.
Foliage uninjured.

No. 34 (field experiment). — June 27, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of | lb. to 150 gal. of water, and nine fourth-
molt caterpillars placed upon it. Of these, seven pupated
and emerged, one began pupating but died later, and one
died in the larval stage. Foliage uninjured.

No. 35 (field experiment). — June 27, 1893. A branch

INSECTICIDES.

455

of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of | lb. to 150 gal. of water, and ten caterpillars,
of the fourth molt, placed upon it. July 8, the foliage was
so badly burned that the nine remaining caterpillars were
transferred to a freshly sprayed branch of oak. By the 19th
of July all were dead. The foliage of the oak was slightly
burned.

No. 36 (field experiment). — June 27, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of | lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. All died without pupating.

Xo. 37 (field experiment) . — June 27, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of lb. to 150 gal. of water, and nine tifth-molt
caterpillars placed upon it. Of these, only one completed
the process of pupation and emerged, three haying died
before beginning to pupate-. Foliage uninjured.

1 lb. Arsenate of Lead to 150 gal. Water.

Xo. 38. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leayes which had been treated
with arsenate of lead, in the proportion of 1 lb. to 150 gal.
of water. One died the fifth, three the sixth and one the
seyenth day ; and five were lost.

Xo. 39. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 1 lb. to 150 gal. of
water. All lived through the experiment and molted.

Check experiment : none dead.

Xo. 40. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 1 lb. to 150 gal.
of water. Four died the fourth, one the seventh, one the
eighth and one the ninth day; the remainder lived through
the experiment.

Check experiment : one died the third and one the seventh
day.

Xo. 41. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 1 lb. to 150 gal.

THE GYPSY MOTH.

456

of water. One died the second, one the seventh, three the
ninth, four the tenth and one the eleventh day.

Check experiment : none dead.

No. 42. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 1 lb. to 150 gal.
of water. One died the fifth, two the sixth, three the seventh
and four the eighth day.

Check experiment : one died the seventh and one the
eighth day.

No. 43. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 1 lb. to 150 gal.
of water. One died the second, one the third, two the
fourth and one the fifth, sixth, seventh, eighth, ninth and
tenth days.

Check experiment : one lost and one dead the seventh day.

No. 44 ( field experiment ) . — June 26, 1893. An apple-
tree branch was sprayed with arsenate of lead, in the pro¬
portion of 1 lb. to 150 gal. of water, and eight fourth-molt
caterpillars placed upon it. Of these, only one died before
pupating, and, of the seven which pupated, three emerged.
Foliage uninjured.

No. 45 (field experiment). — June 26, 1893. A branch
of an apple tree was sprayed with arsenate of lead, in the
proportion of 1 lb. to 150 gal. of water, and eight fourth-
molt caterpillars placed upon it. Of these, six died before
pupating, and, of the two which pupated, one emerged.
Foliage uninjured.

No. 46. — Jnly 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 1 lb. to 150 gal.
of water. One died and one pupated the second day ; one
died the third, one the fourth, two the fifth, one the seventh,
tenth, eleventh and sixteenth days.

Check experiment : one pupated the third day ; one died
the seventh, eighth, ninth and eleventh days ; two pupated
the twelfth day ; one died the thirteenth and one the four¬
teenth day ; and one was living at the close of the experi¬
ment.

INSECTICIDES.

457

No. 47 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the pro¬
portion of 1 lb. to 150 gal. of water. One pupated the fifth
and one the sixth day ; one died and one pupated the seventh
day ; one pupated the twelfth day ; one died the thirteenth,
one the fifteenth and one the sixteenth day ; one pupated the
twenty-fourth and one the twenty-eighth day.

No. 48 (field experiment). — June 26, 1893. An apple-
tree branch was sprayed with arsenate of lead, in the pro¬
portion of 1 lb. to 150 gal. of water, and eight fifth-molt
caterpillars placed upon it. Of these, only one died before
pupating, and, of those that pupated, one died without
emerging. Foliage uninjured.

No. 49 (field experiment) . — -June 26, 1893. An apple-
tree branch was sprayed with arsenate of lead, in the pro¬
portion of 1 lb. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. One of these died before pupat¬
ing, and, of the remaining nine, eight completed the process
of pupation and emerged. The foliage was uninjured.

No. 50 (field experiment). — July 1, 1893. A small oak
branch was sprayed with arsenate of lead, in the proportion
of 1 lb. to 150 gal. of water, and ten large fifth-molt cater¬
pillars placed upon it. All died within twelve days after
spraying. Foliage uninjured.

1\ lb. Arsenate of Lead to 150 gal. Water.

No. 51. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 1£ lbs. to 150
gal. of water. One died the fourth, three the fifth, one the
sixth and one the twelfth day ; those remaining lived
through the experiment.

No. 52. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. of
water. Three died the fifth day ; the remainder lived through
the experiment and molted.

Check experiment : none dead.

No. 53. — May 28, 1894. Ten caterpillars, of the first

458

THE GYPSY MOTH.

molt, were placed on lettuce leaves which had been treated
with arsenate' of lead, in the proportion of 14 lbs. to 150
gal. of water. One died the third, one the fourth, two the
fifth, three the sixth and two the ninth day ; the remainder
lived through the experiment.

Check experiment : none dead.

No. 54. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 14 lbs. to 150
gal. of water. One died the fifth, two the sixth, one the
seventh, two the eighth, three the ninth and one the eleventh
day.

Check experiment : none dead.

No. 55. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed with
arsenate of lead, in the proportion of 14 lbs. to 150 gal. of
water. Two died the third, two the fifth and one the sixth
day ; one died and one pupated the seventh day ; two died
the eighth and one the ninth day.

Check experiment : one died the ninth day.

No. 56. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed with
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. of
water. One died the first, one the second, two the third,
two the fourth, two the fifth and two the seventh day.

Check experiment : one pupated the second day ; one died
the fourth and one the sixth day.

No. 57 (field experiment). — June 24, 1893. An apple-
tree branch was sprayed with arsenate of lead, in the pro¬
portion of 1^ lbs. to 150 gal. of water, and nine fourth-molt
caterpillars placed upon it. Two died before pupating, and,
of the seven that pupated, one died Avithout emerging.
Foliage uninjured.

No. 58. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed with
arsenate of lead, in the proportion of 14 lbs. to 150 gal.
of water. One died and one pupated the fourth day ; one
died and one pupated the fifth day ; two died the sixth and
one the seventh day ; one pupated the ninth day ; two died
the eleventh day.

INSECTICIDES.

459

Check experiment : three pupated the fourth and two the
fifth day ; one died and one pupated the seventh day ; one
died the eighth day ; and two were living at the close of the
experiment.

No. 59 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the pro¬
portion of 1^ lbs. to 150 gal. of water. One died the fifth
day ; one pupated the eleventh and one the twelfth day, one
died the fourteenth day ; one pupated the fifteenth day, one
died the sixteenth day ; one pupated the eighteenth, one the
twentieth, one the twenty-first and one the twenty-fourth day.

No. GO (field experiment). — June 24, 1893. A branch
of apple tree was sprayed with arsenate of lead, in the pro¬
portion of 1.4 lbs. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 10, one caterpillar having
pupated and been removed, those remaining were transferred
to a freshly sprayed apple branch. Only four of the ten
which pupated emerged. Foliage uninjured.

2 lbs. Arsenate of Lead to 150 gal. Water.

No. 61. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 2 lbs. to 150 gal.
of water. One died the first, four the fourth, two the fifth
and two the sixth day ; and one was lost.

No. 62. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 2 lbs. to 150 gal. of
water. On the fifth day five were dead ; two died the sixth
and three the seventh day.

Check experiment : none dead.

No. 63. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 2 lbs. to 150 gal.
of water. On the fourth day two died; on the fifth, three;
on the sixth, two ; on the seventh, one ; on the eighth, one ;
and on the eleventh, one.

Check experiment : one died the sixth day.

No. 64. — June 10, 1894. Ten caterpillars, of the second

460

THE GYPSY MOTH.

molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 2 lbs to 150 gal.
of water. One died the second, three the fourth, three the
fifth, one the sixth, one the seventh and one the tenth day.

Check experiment : none dead.

No. 65. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 2 lbs. to 150 gal.
of water. Four died the third, three the fourth, two the
sixth and one the seventh day.

Check experiment : one lost the seventh and one the
eighth day.

No. 66. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 2 lbs. to 450 gal.
of water. Two died the fourth, four the fifth, two the sixth
and two the seventh day.

Check experiment : one died and two pupated the second
day ; two died the third day, two the fourth and three the
fifth day.

No. 67 (field experiment). — June 21, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of 2 lbs. to 150 gal. of water, and ten fourth-
molt caterpillars placed upon it. Four of these caterpillars
began to pupate, and, as the food gave out, those remaining
were transferred to a branch which had not been sprayed,
two more pupating after their removal. The other four cater¬
pillars died from the effects of the poison. Foliage uninjured.

No. 68 (field experiment). — June 24, 1893. A branch
of apple tree was sprayed with arsenate of lead, in the pro¬
portion of 2 lbs. to 150 gal. of water, and eight fourth-molt
caterpillars placed upon it. On account of the rain, the
branch was resprayed twice. One caterpillar pupated, and
from the pupa a male moth emerged. The rest were all
dead by the 9th of August. Foliage uninjured.

No. 69 (field experiment). — June 24, 1893. A branch
of apple tree was sprayed with arsenate of lead, in the pro¬
portion of 2 lbs. to 150 gal. of water, and nine fourth-molt
caterpillars placed upon it. Five of the caterpillars died
before pupating, and, of the four that pupated, three emerged.,

INSECTICIDES.

461

The poison acted very slowly, as none of the caterpillars
died for nearly three weeks, and one lived eight weeks.

No. 70. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 2 lbs. to 150 gal.
of water. One died the second day ; three died and one
pupated the fifth day ; one died and one pupated the sixth
and seventh days ; and one pupated the tenth day.

Check experiment : two pupated the fourth, three the fifth,
one the sixth, seventh and eighth days ; and two were living
at the close of the experiment.

No. 71 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the propor¬
tion of 2 lbs. to 150 gal. of water. One died the first day ;
one pupated the third day ; one died the fourth and one the
fifth day ; one pupated the eighth and one the twelfth day ;
one died and one pupated the thirteenth day ; one pupated
the fifteenth and one the eighteenth day.

No. 72 (field experiment). — June 21, 1893. A branch
of a small hop-hornbeam was sprayed with arsenate of lead,
in the proportion of 2 lbs. to 150 gal. of water, and ten fifth-
molt caterpillars were placed upon it. July 14, all were
dead. In this experiment the caterpillars died gradually,
the first one dying two days after the poison had been
applied, the last one living twenty-two days. The foliage
of the tree was uninjured.

No. 73 (field experiment). — June 24, 1893. A branch
of apple tree was sprayed with arsenate of lead, in the pro¬
portion of 2 lbs. to 150 gal. of water, and nine fifth-molt
caterpillars placed upon it. In this experiment the poison
was nearly all washed oil’ by heavy rains soon after it was
applied. Four of the caterpillars molted and two pupated,
but all were dead August 2. Foliage uninjured.

No. 74 (field experiment). — June 24, 1893. A branch
of apple tree was sprayed with arsenate of lead, in the pro¬
portion of 2 lbs. to 150 gal. of water, and nine fifth-molt
caterpillars placed upon it. Six of the nine caterpillars died
before pupating, and, of the three which pupated, only one
emerged. Foliage uninjured.

462

THE GYPSY MOTH.

No. 75 (field experiment). — July 7, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 2 lbs. to 150 gal. of water, and ten caterpillars, of the fifth
molt, placed upon it. On July 22, and also on the 27th, the
branch was resprayed on account of rain. In this experi¬
ment only one caterpillar began pupating, and that one was
not able to complete the process.

No. 76 (field experiment). — July 7, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 2 lbs. to 150 gal. of water, and ten fifth-molt caterpillars
placed upon it. Three of these began pupating, and one
emerged ; but, as this one began to pupate very soon after
the poison was applied, it probably did not get any ill effect
from it. Foliage uninjured.

3 lbs. Arsenate of Lead to 150 gal. Water.

No. 77. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 3 lbs. to 150 gal.
of water. Six died the third, one the fourth and three the
sixth day.

No. 78. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 3 lbs. to 150 gal. of
water. One died the third, three the fourth, two the fifth,
one the sixth and one the seventh day ; the remainder sur¬
vived.

Check experiment: none dead.

79. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 3 lbs. to 150 gal.
of water. Two died the fourth, one the fifth, two the sixth,
one the seventh, three the eighth and one the ninth day.

Check experiment : one died the sixth day.

No. 80. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 3 lbs. to 150 gal.
of water. One died the fourth, eight the fifth and one the
sixth day.

Check experiment : none dead.

INSECTICIDES.

463

No. 81. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 3 lbs. to 150 gal.
of water. Three died the fourth, five the sixth and two the
seventh day.

Check experiment : one died the seventh day.

No. 82. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 3 lbs. to 150 gal.
of water. Two died and one pupated the second day; two
died the third, two the fourth and three the fifth day.

Check experiment : two pupated the second and one the
fifth day.

No. 83 (field experiment). — June 30, 1893. A branch
of a small oak tree was sprayed with arsenate of lead, in the
proportion of 3 lbs. to 150 gal. of water, and seven fourth-
molt caterpillars placed upon it. The branch was resprayed
July 20, on account of rain. All of these caterpillars died
within twenty-five days after the first spraying, and five days
after the second. Foliage uninjured.

No. 84 (field experiment). — June 30, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 3 lbs. to 150 gal. of water, and eight fourth-molt cater¬
pillars placed upon it. August 27, all were dead. Foliage
uninjured.

No. 85. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on leaves which had been sprayed with
arsenate of lead, ill the proportion of 3 lbs. to 150 gal. of
water. One died and one pupated the third day ; one
pupated the sixth day ; three died the seventh day ; one died
and two pupated the ninth day ; and one pupated the thir¬
teenth day.

Check experiment: one pupated the fourth, fifth and sixth
days ; one died the seventh day ; one pupated the eighth and
two the ninth day ; and one died the eleventh day.

No. 86 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the propor¬
tion of 3 lbs. to 150 gal. of water. One died the first and
one the second day ; one pupated the fifth, two the sixth and

464

THE GYPSY MOTH.

two the eighth day ; one died the fourteenth day ; one
pupated the twenty-fifth and one the twenty-eighth day.

No. 87 (field experiment). — June 30, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 3 lbs. to 150 gal. of water, and ten caterpillars of the fifth
molt placed upon it. All died within three weeks, and six
of the ten in less than one week after the branch was sprayed.
Foliage uninjured.

No. 88 (field experiment). — June 30, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 3 lbs. to 150 gal. of water, and ten caterpillars of the fifth
molt placed upon it. July 20, the branch was resprayed on
account of rain. Only two of these caterpillars pupated and
but one emerged. Foliage uninjured.

4 lbs. Arsenate of Lead to 150 gal. Water.

No. 89. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. Three died the third, two the fourth and five the
fifth day.

No. 90. — May 9, 1895. Ten caterpillars, six days old,
■were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 4 lbs. to 150 gal. of
water. One died the third, two the fourth, five the fifth and
two the sixth day.

Check experiment : none dead.

No. 91. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. Two died the third, three the fourth, two the
fifth and three the seventh day.

Check experiment : none dead.

No. 92. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. One died the second, one the third, one the
fourth, two the fifth, one the sixth, two the seventh and two
the eighth day.

Check experiment ; none dead.

INSECTICIDES.

465

No. 93. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. One died the third, one the fourth, two the fifth,
three the sixth and three the seventh day.

Check experiment : one died the seventh day.

No. 94. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. One died the second, five the third, two the
fourth, one the fifth and one the sixth day.

Check experiment : one pupated and one died the second
day ; one pupated the third day ; and one died the fifth day.

No. 95 (field experiment). — June 21, 1893. A branch
of hop-hornbeam was sprayed with arsenate of lead, in the
proportion of 4 lbs. to 150 gal. of water, and ten fourth-molt
caterpillars placed upon it. In this experiment eight of the
ten caterpillars died within nine days ; the other two lived
twelve and thirteen days longer. Foliage uninjured.

No. 96. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 4 lbs. to 150 gal.
of water. One pupated and two died the fourth day, two
pupated and three died the fifth day ; one died the sixth and
one the seventh day.

Check experiment : one died the fourth day.

No. 97 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the propor¬
tion of 4 lbs. to 150 gal. of water. One died and one
pupated the third day ; one died the fifth and one the sixth
day ; one pupated the seventh and one the ninth day ; one
died the eleventh day ; one pupated the twelfth day ; one
died the fifteenth day ; one pupated the twenty-ninth day.

No. 98 (field experiment). — June 21, 1893. A branch
of hop-liornbeam was sprayed with arsenate of lead, in the
proportion of 4 lbs. to 150 gal. of water, and ten fifth-molt
caterpillars placed upon it. July 12, all were dead. Al¬
though these were fifth-molt caterpillars, they succumbed to
the poison much quicker than those of the fourth molt, six

TIIE GYPSY MOTH.

466

dying within a week, and the last one dying in a little over
two weeks. Foliage uninjured.

5 lbs. Arsenate of Lead to 150 gal. Water.

No. 99. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 5 lbs. to 150
gal. of water. One died the lirst, two the third, one the
fourth, four the fifth, and one died and one was lost the sixth
day.

No. 100. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 5 lbs. to 150 gal. of
water. Four died the third, three the fourth and three the
fifth day.

Check experiment : none dead.

No. 101. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 5 lbs. to 150 gal.
of water. Three died the fourth, one the fifth, four the sixth
and two the seventh day.

Check experiment : none dead.

No. 102. — June 10, 1894. Ten caterpillars, of the
second molt, were placed on lettuce leaves which had been
treated with arsenate of lead, in the proportion of 5 lbs. to
150 gal. of water. Two died the second, three the fifth, one
the sixth, three the seventh and one the ninth day.

Check experiment : none dead.

No. 103. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been treated
with arsenate of lead, in the proportion of 5 lbs. to 150 gal.
of water. Two died the third, two the fourth, one the fifth
and five the sixth day.

Check experiment : none dead.

No. 104. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been treated with
arsenate of lead, in the proportion of 5 lbs. to 150 gal. of
water. Three died the second, two the third, two the
fourth, one the fifth and two the sixth day.

Check experiment : one died and two pupated the second

INSECTICIDES.

4G7

day ; one pupated the third day ; two died the fourth and
one the fifth day.

No. 105 (field experiment). — June 21, 1893. A branch
of oak was sprayed with arsenate of lead, in the proportion
of 5 lbs. to 150 gal. of water, and ten fourth-molt caterpillars
placed upon it. July 5, the last one was dead. In this
experiment five or six days wTere required for the poison to
take effect ; after that time, however, the caterpillars died
rapidly.

No. 106. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 5 lbs. to 150 gal.
of water. One pupated the third day ; one died the fourth
and one the fifth day ; one pupated and one died the sixth
day ; two died the seventh and one the eighth, twelfth and
thirteenth days.

Check experiment : one died the third day ; one pupated
the fifth day ; two died the sixth and one the seventh day ;
one died and one pupated the eleventh day ; one pupated
the twelfth day.

No. 107 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been treated with arsenate of lead, in the propor¬
tion of 5 lbs. to 150 gal. of water. One died and one
pupated the fourth day ; two died the eleventh and two the
twelfth day ; one pupated the seventeenth, one the nineteenth
and two the twentieth day.

6 lbs. Arsenate of Lead to 150 gal. Water.

No. 108. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water. One died the first, one the second, three the third,
four the fourth and one the fifth day.

No. 109. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 6 lbs. to 150 gal. of
water. Two died the first, five the third and three the fifth
day.

Check experiment : none dead.

468

THE GYPSY MOTH.

No. 110. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water. Two died the third, one the fourth, two the fifth,
two the sixth and three the eighth day.

Check experiment : one died the sixth day.

No. 111. — June 10, 1894. Ten caterpillars, of the second
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water. One died the third, two the fourth, three the fifth,
three the sixth and one the eighth day.

Check experiment : none dead.

No. 112. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water. One died the second, three the third, two the
fourth, one the fifth, two the sixth and one the seventh day.

Check experiment : none dead.

No. 113. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water. Three died the second, two the third, three the
fourth and two the sixth day.

Check experiment : one died and one pupated the second
day ; one died the third and one the fifth day.

No. 114 (field experiment). — July 1, 1893. A branch
of a small oak tree was sprayed with arsenate of lead, in the
proportion of 6 lbs. to 150 gal. of water, and ten large fifth-
molt caterpillars placed upon it. All died within three
weeks from the time of spraying. Foliage uninjured.

No. 115. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of w ater. Two died and three pupated the fourth day ;
three died the seventh, one the ninth and one the tenth day.

Check experiment : one died and two pupated the fourth
day ; one died the fifth day ; two pupated the sixth and one
the seventh and eighth days.

No. 116 (field experiment). — July 9, 1894. Ten cater-

INSECTICIDES.

469

pillars, of the fifth molt, were placed on willow branches
which had been treated with arsenate of lead, in the propor¬
tion of 6 lbs. to 150 gal. of water. One died the second
day ; one pupated the third day ; two died the fifth, two the
sixth and one the eleventh day ; one pupated the thirteenth,
one the sixteenth and one the nineteenth day.

7 lbs. Arsenate of Lead to 150 gal. Water.

No. 117. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 7 lbs. to 150 gal.
of water. Three died the first, three the second and four
the fifth day.

No. 118. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 7 lbs. to 150 gal. of
water. One died the second, five the third, two the fourth,
one the fifth and one the seventh day.

Check experiment : none dead.

No. 119. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 7 lbs. to 150 gal.
of water. Five died the third, one the fourth, two the sixth
and two the seventh day.

Check experiment : one died the fourth day.

No. 120. — June 10, 1894. Ten caterpillars, of the
second molt, were placed on elm leaves which had been
sprayed with arsenate of lead, in the proportion of 7 lbs. to
150 gal. of water. One died the fourth, one the fifth, seven
the sixth and one the ninth day.

Check experiment : none dead.

No. 121. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 7 lbs. to 150 gal.
of water. One died the second, four the third, four the
sixth and one the seventh day.

Check experiment : none dead.

No. 122. — June 28, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed

470

THE GYPSY MOTH.

with arsenate of lead, in the proportion of 7 lbs. to 150 gal.
of water. One died the first, one the second, five the fourth
and three the fifth day.

Check experiment : two pupated the second and three the
third day ; two died the fifth day.

No. 123. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 7 lbs. to 150 gal.
of water. One pupated the third day ; three died and one
pupated the fifth day ; one died the seventh, one the eighth,
two the ninth and one the twelfth day.

Check experiment : two pupated the fifth day ; one died
the seventh, ninth and tenth days.

No. 124. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on willow branches which had been
sprayed wTith arsenate of lead, in the proportion of 7 lbs. to
150 gal. of water. One pupated the second day; one died
the third, one the fifth, one the sixth, one the eighth and
one the tenth day ; one died and one pupated the eleventh
day ; one pupated the sixteenth and one the thirty-first day.

8 lbs. Arsenate of Lead to 150 gal. Water.

No. 125. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 8 lbs. to 150 gal.
of water. Three died the second, four the third and three
the fifth day.

No. 126. — May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 8 lbs. to 150 gal. of
water. Two died the third, three the fourth, four the fifth
and one the sixth day.

Check experiment : none dead.

No. 127. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 8 lbs. to 150 gal.
of water. Two died the third, two the fourth, two the fifth,
three the sixth and one the seventh day.

Check experiment : none dead.

No. 128. — June 10, 1894. Ten caterpillars, of the

INSECTICIDES.

471

second molt, were placed on lettuce leaves which had been
sprayed with arsenate of lead, in the proportion of 8 lbs. to
150 gal. of water. Four died the second, two the fourth,
one the fifth, one the sixth and two the seventh day.

Check experiment : none dead.

No. 129. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 8 lbs. to 150 gal.
of water. One died the second, three the third, one the
fourth, three the fifth and two the sixth day.

Check experiment : none dead.

No. 130. — June 29, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves, which had been sprayed
with arsenate of lead, in the proportion of 8 lbs. to 150 gal.
of water. One died the second, three the third, four the
fourth and two the fifth day.

Check experiment : four pupated the second, one the third
and one the fifth day.

No. 131. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 8 lbs. to 150 gal.
of water. One pupated the fourth day ; three pupated and
two died the fifth day ; two pupated the seventh day ; one
died the ninth and one the twelfth day.

Check experiment : one pupated the fourth, fifth, seventh
and ninth days.

No. 132 (field experiment). — July 9, 1894. Ten cater¬
pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the propor¬
tion of 8 lbs. to 150 gal. of water. One died the third and
one the fourth day ; one pupated the eighth day ; one died
the thirteenth day; three pupated the sixteenth, two the
twentieth and one the twenty-second day.

10 lbs. Arsenate of Lead to 150 gal. Water.

No. 133. — March 7, 1894. Ten caterpillars, three days
old, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 10 lbs. to 150 gal.
of water. Five died the second, four the third and one the
fourth day.

472

THE GYPSY MOTH.

No. 134.— May 9, 1894. Ten caterpillars, six days old,
were placed on lettuce leaves which had been treated with
arsenate of lead, in the proportion of 10 lbs. to 150 gal. of
water. Three died the second, two the third, two the fourth
and three the fifth day.

Check experiment : none dead.

No. 135. — May 28, 1894. Ten caterpillars, of the first
molt, were placed on lettuce leaves which had been treated
with arsenate of lead, in the proportion of 10 lbs. to 150 gal.
of water. One died the third, three the fourth, three the
fifth, one the sixth and two the seventh day.

Check experiment : none dead.

No. 136. — June 10, 1894. Ten caterpillars, of the
second molt, were placed on lettuce leaves which had been
sprayed with arsenate of lead, in the proportion of 10 lbs. to
150 gal. of water. Three died the second, one the third,
one the fourth, two the fifth, two the sixth and one the
seventh day.

Check experiment : none dead.

No. 137. — June 21, 1894. Ten caterpillars, of the third
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 10 lbs. to 150 gal.
of water. Three died the fourth, four the sixth and three
the seventh day.

Check experiment : none dead.

No. 138. — June 29, 1894. Ten caterpillars, of the fourth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 10 lbs. to 150 gal.
of water. One died the second, three the third, five the
fourth and one the fifth day.

Check experiment : one pupated the second and one the
third day ; one pupated and one died the fifth day.

No. 139. — July 9, 1894. Ten caterpillars, of the fifth
molt, were placed on elm leaves which had been sprayed
with arsenate of lead, in the proportion of 10 lbs. to 150 gal.
of water. Two died and one was lost the fifth day ; four
died the sixth and three the seventh day.

Check experiment : one pupated the fourth, two the fifth,
one the sixth and one the seventh day.

No. 140 (field experiment). — July 9, 1894. Ten cater-

INSECTICIDES.

473

pillars, of the fifth molt, were placed on willow branches
which had been sprayed with arsenate of lead, in the propor¬
tion of 10 lbs. to 150 gal. of water. Two died the second
day ; three pupated the fourth day ; two died the fifth and
one the sixth day ; one pupated the thirteenth and one the
fifteenth day.

No. 141 (field experiment) . — June 21, 1893. A branch
of a small oak tree was sprayed with arsenate of lead, in the
proportion of 10 lbs. to 150 gal. of water, and eight fifth-
rnolt caterpillars placed upon it. August 19, all were dead.

25 lbs. Arsenate, of Lead to 150 gal. Water.

No. 142. — July 1, 1893. A small branch of oak was
sprayed with arsenate of lead, in the proportion of 25 lbs.
to 150 gal. of water, and ten large fifth-molt caterpillars
placed upon it. All died within one week. Foliage unin¬
jured.

Even larger proportions of this poison than the above
were occasionally used in spraying operations in the field,
with fairly satisfactory results.

Comparative Effects of Paris Green, Paris Green and Lime
and Arsenate of Lead.

A careful study of the comparative effect of equal weights
of the three substances used in the preceding experiments
shows that there is practically no choice between Paris green
and Paris green and lime, so far as the destruction of the cater¬
pillars is concerned. The largest amount of these poisons
which can be used without injuring the foliage is about 1 lb.
to 150 gal. of water, and at this, or even a much larger rate,
the percentage of caterpillars destroyed is not satisfactory.
Since arsenate of lead in almost any strength is not injurious
to foliage, a much larger amount can be used than of any of
the more soluble arsenical compounds ; thus the superiority
of this poison as an insecticide is at once evident. While
arsenate of lead may be considered the best insecticide for
destroying the gypsy moth in the caterpillar stage, even this
poison is of small value in exterminating this insect, since
many of the caterpillars survive after feeding upon leaves
sprayed with large proportions of this poison.

474

THE GYPSY MOTH.

The experiments previously recorded show that a consid¬
erable amount of time is required for the poison used to
affect the caterpillars. Those in the earlier molts were
killed in a short time, but in the later molts a much smaller
per cent, was destroyed, many of the caterpillars transform¬
ing and producing imagoes.

In considering these experiments, it should be remem¬
bered that the insects were in confinement, and obliged to
eat the poisoned leaves, while in field work they may some¬
times find leaves that have not been sprayed, or that have
received but little of the poison, and, therefore, the results
in some cases might be somewhat different from those
obtained in these experiments.

The remarkable ability of the gypsy moth to resist the
action of arsenical poisons is shown in the case of other
poisons. Mr. Moulton covered a piece of lettuce leaf with
strychnine, and fed it to a caterpillar. In about an hour the
caterpillar appeared to be dead, but soon revived and fed
again for a short time upon the poisoned leaf, when it rolled
over on its back and for several hours remained apparently
dead, but afterwards revived again and appeared as well as
ever.

Analyses of Poisoned Larvae.

The remarkable resistance to the action of arsenical
poisons shown by the gypsy moth led us, in the summer
of 1894, to institute a series of investigations on the dis¬
position of arsenic by caterpillars when feeding on poisoned
food. For this purpose, gypsy moth caterpillars which
had fed for some time upon poisoned leaves without ap¬
parent injury, and also those which had died as a result
of arsenical poisoning, were carefully dissected, the differ¬
ent organs and tissues being subsequently analyzed at the
chemical laboratory of Harvard University. The work was
performed, under my direction, by Messrs. Kirkland and
Moulton, the former preparing the material and making
the dissections, the latter conducting the analyses. All the
operations involved were carried on with extreme care, in
order to prevent the accidental introduction of any arsenical
substance. After each dissection the instruments used were

PLATE 66. Full-grown gypsy moth caterpillars about to pupate on
the trunk of a walnut tree. From a photograph
taken in Arlington, July 9, 1891.

ANALYSES OF POISONED LARVAL

475

carefully washed in dilute acid and in distilled water, while
the purity of all chemical reagents employed in the analyti¬
cal work was demonstrated by a number of preliminary
tests. The method used in testing for the presence of
arsenic was the so-called Berzelius-Marsh process (Ameri¬
can Chemical Journal, October, 1891), by means of which
a minute quantity of this poison can be readily recognized.
The results obtained from analyses of the organs and tissues
of a large number of caterpillars, which were feeding un¬
harmed on food treated with a liberal amount of Paris green
or arsenate of lead (the only poisons used) , did not differ
materially from those of analyses of the same parts of cater¬
pillars which had died from arsenical poisoning, while in
many caterpillars no arsenic was found.

In both cases arsenic was found chiefly in the stomach,
intestinal and rectal contents, and throughout the walls of
the alimentary canal. It was also found in the excrements,
in the malpighian vessels, the dorsal vessel and blood and
in the muscular tissue, thus showing that the arsenic prob¬
ably passes from the alimentary canal, where it is quite
equally distributed, into the blood, and is carried by the
circulation throughout the body, and thus eventually per¬
meates all organs and tissues. Owing to the small size of
the parts subjected to analysis, some of them being of almost
microscopic dimensions, it was an extremely difficult process
to determine quantitatively the amount of arsenic present ;
yet this was accomplished by a comparison of the results
of the analyses with a series of finely graduated arsenic
“mirrors,” for the use of which we are indebted to the
courtesy of Professor Hill of Harvard University.

In some caterpillars, which had fed for a long time upon
food treated with the arsenical compounds previously men¬
tioned, a considerable amount of arsenic was found ; while
those which had fed for a shorter time, as a rule, contained
smaller quantities of the poison. Many of those which had
thus fed for two or three weeks, when killed, were found to
contain more arsenic than caterpillars which had succumbed
to arsenical poisoning. One caterpillar, which had fed in
an out-door cage, upon willow leaves sprayed with arsenate

476

THE GYPSY MOTH.

of lead in the proportion of 2 lbs, to 150 gal. of water, from
July 9 to July 28, 1894, and which at the time of dissection
was full grown, normally active and healthy, yielded .025
milligrams of arsenic. If, for the purpose of illustration,
the weight of arsenic thus found be compared with the
weight of this caterpillar, and this ratio applied to the aver¬
age weight of the adult human being, we obtain the rather
surprising result that such a caterpillar would withstand
uninjured an amount of arsenic, in proportion to its weight,
equivalent to twelve and one-half times the fatal dose for an
adult human being, in proportion to the weight of the latter.
This illustrates the ability of this insect to resist arsenical
poisoning.

Since the quantities of arsenic found were small in com¬
parison with the amount the insect consumed, it is evident
that a considerable part of the poison must have been
eliminated from the body. The presence of arsenic in the
excrements of poisoned caterpillars indicates one source of
elimination. These investigations upon poisoned cater¬
pillars show that an apparently large quantity of arsenic
may enter and even permeate all parts of the body of the
caterpillar without interfering with the vital processes, and
that a considerable part of the poison consumed with the
food is eliminated, chiefly in the excreta.

One interesting result obtained from the analyses of the
different stages of the gypsy moth, made in 1893 and 1894,
is that pupa? and imagoes from caterpillars which have been
reared on leaves sprayed with Paris green or arsenate of
lead may contain arsenic in recognizable quantities. Several
pupae and a few female imagoes, obtained under these con¬
ditions, when subjected to chemical analysis gave ample
evidence of the presence of arsenic in their bodies. This
shows that the presence of arsenic in the pupa may not
materially interfere with the processes involved in the de¬
velopment of the imago.

Since, as has been repeatedly demonstrated, moths reared
from poisoned larvae are capable of reproduction, it is also
evident that the arsenic contained in their systems does not
injure the reproductive function.

INSECTICIDES.

477

Experiments with London Purple and Acetate of

Lead.

No. 1. — July 7, 1893. London purple and acetate of
lead, in the proportion of | lb. each to 150 gal. of water,
were thoroughly mixed and allowed to stand and settle for
one hour and a half. It was then stirred and allowed to
stand one-half hour longer, at the end of which time it was
strained through two thicknesses of cheese cloth, a small
amount of glucose added, and an oak branch sprayed with
the mixture. Ten caterpillars, of the fifth molt, were then
placed upon the branch. July 22, for lack of food, they
were transferred to a freshly sprayed branch. None of these
caterpillars died for nearly two weeks after the branch was
first sprayed, but after they were transferred to the second
sprayed branch they died more rapidly. Three began pu¬
pating, but none emerged. The foliage of the first branch
was slightly burned, while that of the second was in good
condition.

No. 2. — July 6, 1893. A branch of a small oak tree
was sprayed with London purple and acetate of lead, in the
proportion of | lb. each to 150 gal. of water. The London
purple and acetate of lead were mixed in a little water, glu¬
cose added and thoroughly stirred ; the rest of the water was
then added and the mixture thoroughly stirred again. Ten
fifth-molt caterpillars, five very large and five small, were
then placed on the branch. July 25, the branch was re¬
sprayed, on account of rain. Two of these caterpillars
began to pupate, but none emerged. They died gradually,
the last one living nearly a month. Foliage considerably
burned.

No. 3. — July 6, 1893. A branch of oak was sprayed
with London purple and acetate of lead, in the proportion
of 1 lb. each to 150 gal. of water. The London purple and
acetate of lead were thoroughly mixed with water in a
beaker, a teaspoonful of glucose was added and the mixture
thoroughly stirred. Eleven fifth-molt caterpillars were
placed on the branch. July 20, the branch was res prayed,
on account of rain. Of the eleven caterpillars, only two

478

THE GYPSY MOTH.

were able to complete the process of pupation and emerge.
Foliage in good condition.

No. 4. — July 6, 1893. A branch was sprayed with the
same mixture and at the same time as in the preceding
experiment, and ten fourth-molt caterpillars placed upon it.
Only two of these began to pupate, and both died without
emerging. Foliage but slightly, if at all, burned.

No. 5. — July 6, 1893. A branch of a small oak tree
was sprayed with the same mixture as in the preceding
experiment, and at about the same time. Ten fifth-molt
caterpillars, some of which were very large, were placed on
the branch. July 20, the branch was resprayed, on account
of rain. Only two of the caterpillars began to pupate, one
of which emerged. The remainder died on the twenty-
fourth day after the first spraying. The foliage was slightly
burned.

No. 0. — July 7, 1893. A branch of oak was sprayed
with 1 lb. of London purple and 2 lbs. acetate of lead to
150 gal. of water, and ten fifth-molt caterpillars placed upon
it. Of these ten, only one began to pupate, and this one
died before completing the process. Foliage only slightly
burned.

No. 7. — July 7, 1893. A branch of oak was sprayed
with London purple and acetate of lead, in the proportion
of 2 lbs. each to 150 gal. of water. The London purple
and acetate of lead were thoroughly mixed in a beaker, the
proper amount of glucose added, and, after being stirred,
the mixture was poured into the sprayer, the rest of the
water added and the whole mixed together. Ten fifth-molt
caterpillars, five large and five small, were then placed on
the branch. July 20, the branch was resprayed, on account
of rain. All of the caterpillars except one died before
beginning to pupate, and this one was not able to complete
the process. Foliage in good condition.

No. 8. — July 8, 1893. An oak branch was sprayed
with London purple and acetate of lead, in the proportion
of 3 lbs. each to 150 gal. of water. A teaspoonful of glu¬
cose was added, and the mixture thoroughly stirred. Ten
large fifth-molt caterpillars were placed on the branch. All

INSECTICIDES.

479

but one of these died before pupating, and this one did not
emerge. Foliage slightly burned.

No. 9. — July 8, 1893. A branch of oak was sprayed
with the same mixture and at the same time as in the pre¬
ceding experiment, and ten fifth-molt caterpillars placed
upon it. Only one of the^e pupated, and that one did not
emerge. Foliage slightly burned.

No. 10. — July 8, 1893. A branch was sprayed at the
same time and in the same manner as in the preceding
experiment, and ten fifth-molt caterpillars placed upon it.
July 22, and again on the 25th, the branch was resprayed,
on account of rain. Six of the ten caterpillars pupated,
three of which emerged. The foliage was somewhat burned.

“ Antinonnix.”

No. 1. — July 22, 1893. A branch of oak was sprayed
with antinonnin, in the proportion of 3 lbs. to 150 gal. of
water, and fifteen caterpillars of the fifth molt placed upon
it. July 24, the branch was resprayed, on account of rain.
Six of the caterpillars pupated, four of which emerged. Foli¬
age in good condition. The antinonnin, when sprayed on
the leaves, presents a bright yellow, glistening appearance,
and badly stains everything with which it conies in contact.
It is also easily washed off by rain.

No. 2. — July 24, 1893. A branch of oak was sprayed
with antinonnin, in the proportion of 3 lbs. to 150 gal. of
water, and ten caterpillars of the fifth molt placed upon it.
Five of these pupated, three of which finally emerged. Foli¬
age slightly burned.

No. 3. — July 27, 1893. A branch of oak was sprayed
with antinonnin, in the proportion of 3 lbs. to 150 gal. of
water, and fifteen caterpillars of the fifth molt placed upon
it. Two of these died before beginning to pupate, and ten
pupated and emerged. Foliage in good condition.

No. 4. — July 24, 1893. A branch of hop-hornbeam was
sprayed with antinonnin, in the proportion of 3 lbs. to 150
gal. of water, and ten fifth-molt caterpillars placed upon it.
Six of these pupated and finally emerged. Foliage quite
badly burned.

480

THE GYPSY MOTH.

No. 5. — July 27, 1893. A branch of oak was sprayed
with antinonnin, in the proportion of 3 lbs. to 150 gal. of
water, and ten fifth-molt caterpillars placed upon it. This
experiment was started too late to be of any great value as a
test for the insecticide, as all the caterpillars pupated very
soon after the branch was sprayed, so that probably few if
any of them ate enough of the poisoned food to affect them.

Arsexate of Zinc.

Prepared in the same manner as arsenate of lead, by sub¬
stituting a soluble zinc salt for the acetate of lead.

No. 1. — July 11, 1893. A branch of oak wTas sprayed
with arsenate of zinc, in the proportion of 1^ lbs. to 150 gal.
of water, and ten tifth-molt caterpillars placed upon it.
July 22, and again on the 25th, the branch was resprayed,
on account of heavy rains. Three of the caterpillars began
pupating, but none emerged. Foliage badly burned.

No. 2. — July 11, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 11 lbs. to 150 gal.
of water, and live large and live small caterpillars placed
upon it. July 22, the branch was resprayed, on account of
rain. Six of the caterpillars pupated, four of which emerged ;
two of these, however, began to pupate before they had time
to eat much of the poisoned food. Foliage slightly burned.

No. 3. — July 10, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 2 lbs. to 150 gal.
of water, and ten large fifth-molt caterpillars placed upon it.
Six of these began pupating, but none emerged. Foliage
badly burned.

No. 4. — July 10, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 3 lbs. to 150 gal.
of wrater, and five large and five small caterpillars of the
fifth molt placed upon it. July 22, the branch was resprayed,
on account of rain. Five of the ten caterpillars began pu¬
pating, but none emerged. Foliage badly burned.

No. 5. — July 10, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 3 lbs. to 150 gal.
of water, and ten very large fifth-molt caterpillars placed
upon it. July 20, they were transferred to a freshly sprayed

INSECTICIDES.

481

branch, which, July 25, was resprayed on account of rain;
Five of the ten pupated, one of which emerged. Foliage
badly burned.

No. 6. — July 10, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 3 lbs. to 150
gal. of water, and ten tifth-molt caterpillars placed upon it.
Five of these began pupating, but none emerged. Foliage
badly burned.

No. 7. — July 6, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 6 lbs. to 150 gal.
of water, and ten fifth-molt caterpillars placed upon it. At
the end of two weeks all were dead. Foliage burned.

No. 8. — July 6, 1893. A branch of oak was sprayed
with arsenate of zinc, in the proportion of 6 lbs. to 150 gal.
of water, and ten fifth-molt caterpillars placed upon it. All
but one died within a week, and this one died eleven days
after the branch was sprayed. Foliage burned.

Arsenic.

No. 1. — July 12, 1893. A branch of oak was sprayed
with arsenic, in the proportion of 6 lbs. to 150 gal. of water,
and ten caterpillars of the fifth molt placed upon it. July
19, the branch was resprayed, on account of rain, and again
on the 25th. Of the ten caterpillars, six began pupating,
one of which pupated and emerged. Foliage badly burned.

No. 2. — July 12, 1893. A branch of hop-hornbeam was
sprayed with arsenic, in the proportion of G lbs. to 150 gal.
of water, and ten caterpillars of the fifth molt placed upon
it. July 19, the foliage was so badly burned that the cater¬
pillars were transferred to a freshly sprayed branch of oak.
Only one began pupating, and this one did not emerge.
Foliage of hop-hornbeam very badly burned, while that of
the oak was in good condition.

“ Chloro-naptiioleum.”

No. 1. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf which had been sprayed
with chloro-naptholeum. At the end of seven days, all the
caterpillars but one were alive and in good condition.

482

THE GYPSY MOTH.

. No. 2. — May 15, 1894. Ten caterpillars, before the first
molt, were placed on a leaf and sprayed with chloro-naptho-
leum. One died on the fifth and one on the eighth day ;
those remaining seemed in good condition.

No. 3. — May 15, 1894. Ten caterpillars were placed in
a dish and sprayed with chloro-naptholeum, and then placed
on a fresh leaf. Fresh leaves for food were given them at
four different times. One died on the fourth day and one on
the sixth day ; those remaining were in good condition.
The strength of the chloro-naptholeum used in this trial was
in the proportion of 1 11). to 100 gal. of water. As this
neither killed the caterpillars nor burned the leaves, it was
repeated with a stronger solution.

No. 4. — May 22, 1894. Ten caterpillars, before the first
molt, were placed on a leaf which had been sprayed with
chloro-naptholeum. One died on the fifth, two on the sixth,
two on the seventh, two on the eighth and one on the ninth
day ; the remaining two were alive and in good condition
at the end of thirteen days.

No. 5. — May 22, 1894. Ten caterpillars, before the first
molt, were placed on a leaf and both sprayed with chloro-
naptholeum. One died on the fourth, three on the sixth
and six on the eighth day.

No. G. — May 22, 1894. Ten caterpillars, before the first
molt, were placed in a dish and sprayed with chloro-nap¬
tholeum, and then placed on a fresh leaf. Three died on
the third, one on the fourth, three on the fifth and three on
the sixth day. The strength of the chloro-naptholeum used
in this trial was in the proportion of 1 lb. to 50 gal. of
water.

“Electric” Insecticide.

No. 1. — June 22, 1894. A leaf was sprayed with elec¬
tric insecticide, and ten caterpillars, of the second molt,
placed upon it. Six died on the second and four on the
third day. The leaf was badly burned.

No. 2. — July 22, 1894. Ten second-molt caterpillars
were placed on a leaf and sprayed with electric insecticide.
All died on the second day. Leaf badly burned.

No. 3. — June 2, 1894. Ten caterpillars, of the second

INSECTICIDES.

483

molt, were dipped in electric insecticide and then placed on
a fresh leaf. Nine died on the second and one on the third
day. The leaf was burned by contact with the caterpillars.

“ Elphona.”

No. 1. — May 15, 1894. Ten caterpillars, before the
first molt, were placed upon a leaf which had been sprayed
with Elphona. On the third day all were dead.

No. 2. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf and sprayed with Elphona.
Four died on the third, three on the fourth and three on the
fifth day.

No. 3. — May 15, 1894. Ten caterpillars, before the
first molt, were placed in a dish and sprayed with Elphona.
Nine died on the first and one on the second day. Foliage
badly burned.

These three insecticides, “ Chloro-naptlioleum,” “Elec¬
tric” and “Elphona,” were sent to the department by their
manufacturers with the claim that they would kill the gypsy
moth, but experiments with them proved that when used in
proportion sufficiently large to destroy the caterpillars they
burned the foliage very seriously.

“Hyannis Tobacco Mixture” (a Contact Insecticide
with Tobacco as a Basis).

No. 1. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf which had been sprayed
with Hyannis tobacco mixture. One died on the fourth
and one on the sixth day.

No. 2. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf and both sprayed with
Hyannis tobacco mixture. One died on the third, three on
the fifth, one on the sixth and two on the seventh day.

No. 3. — May 15, 1894. Ten caterpillars, before the
first molt, were placed in a dish and sprayed with Hyannis
tobacco mixture. One died on the third, three on the
fourth and two on the sixth day. The strength of the
Hyannis tobacco mixture used in this trial was in the pro¬
portion of 1 part to 100 parts of water.

484

THE GYPSY MOTH.

No. 4. — May 22, 1894. Ten caterpillars, before the
first molt, were placed on a leaf which had been sprayed
with Hyannis tobacco mixture. Three died on the fourth,
five on the fifth and two on the sixth day.

No. 5. — May 22, 1894. Ten caterpillars, before the
first molt, were placed on a leaf and both sprayed with
Hyannis tobacco mixture. Seven died on the third, two on
the fourth and one on the sixth day.

No. 6. — May 22, 1894. Ten caterpillars, before the
first molt, were placed in a dish and sprayed with Hyannis
tobacco mixture, and then put on a fresh leaf. Six died on
the fourth, two on the fifth and two on the seventh day.
The strength of the mixture used in this trial was in the
proportion of 1 part to 50 parts of water.

“ SuLPHO-NAPIITHOL.’’

No. 1. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf which had been sprayed
with sulpho-naphthol. Two died on the fourth, one on the
sixth and one on the seventh day.

No. 2. — May 15, 1894. Ten caterpillars, before the
first molt, were placed on a leaf and both sprayed with
sulpho-naphthol. Two died on the second, one on the
third, one on the fifth, one on the sixth and one on the
seventh day.

No. 3. — May 15, 1894. Ten caterpillars, before the
first molt, were placed in a dish and sprayed with sulpho-
naphthol, then placed on a fresh leaf. Three died on the
second and one on the fourth day. The strength of the
sulpho-naphthol used in this trial was in the proportion of
1 part to 100 parts of water.

No. 4. — May 22, 1894. Ten caterpillars, before the
first molt, were placed on a leaf which had been sprayed
with sulpho-naphthol. Three died on the fourth, two on
the fifth, one on the sixth, three on the seventh and one on
the ninth day.

No. 5. — May 22, 1894. Ten caterpillars, before the
first molt, were placed on a leaf and sprayed with sulpho-
naphthol. Eight died on the fourth, one on the fifth and
one on the sixth day.

INSECTICIDES.

485

No. 6. — May 22, 1894. Ten caterpillars, before the
first molt, were placed in a dish and sprayed with sulpho-
naphthol, and then put on a fresh leaf. Six died on the
fourth, one on the fifth, one on the sixth and two on the
seventh day. The strength of the sulpho-naphthol used in
this trial was in the proportion of 1 part to 50 parts of
water.

Cyanides.

Studies on the anatomy of the caterpillars, made in 1894,
by Mr. Kirkland, showed that the contents of the alimentary
canal were strongly alkaline. This suggested the idea that
some compound might be prepared which would be inert
under ordinary circumstances, but when taken into the diges¬
tive system of the insect would decompose in the alkaline
medium and form a deadly poison. Following out this idea,
Mr. Moulton prepared a number of the compounds of cyanic
acid, which were experimented with during the summer of
1895. The substances tried were the cyanides of lead,
copper, antimony, zinc and mercury. The last-mentioned
compound burned the foliage badly, hence but few experi¬
ments were made with it. Of the other compounds, cyanide
of copper was the only one which gave effective results, and
these were not as satisfactory as can be obtained from the
use of the same weight of Paris green. The other cyanides
are practically valueless, since caterpillars were fed through¬
out their entire life on foliage treated with large proportions
of these three compounds, without suffering injurious effects.

Contact Insecticides.

Whale-oil soap, several proprietary soap powders, soft
soap and kerosene emulsion were experimented with during
the summer of 1891, for the purpose of finding a cheap con¬
tact insecticide, for use where the caterpillars cluster in
masses on trees, fences, etc. All of these insecticides were
found to be fairly effective.

Food Selection.

The following experiments were conducted, both at the
storehouse and in the field, by Mr. Kirkland, during

486

THE GYPSY MOTH.

the summer of 1894, to determine, if possible, whether the
gypsy moth caterpillars are able in any way to select their
food, and thus choose the non-poisoned leaves in preference
to leaves treated with arsenical poisons. For this purpose,
a definite number of caterpillars were confined upon leaves
treated with poisons applied in various ways, and the results
carefully noted for several days, or as long as there was a suf¬
ficient amount of food for them to eat without being forced
to partake of either the poisoned or non-poisoned leaves.

Experiment No. 1. — Six elm leaves were selected, and
a series of bands and dots painted upon each, with Paris
green, in the proportion of 3 lbs. to 150 gal. of water.
When the poison was sufficiently dry, so that it did not run
upon the surface of the leaves, each one was placed in a box
with three fourth-molt caterpillars. Sixty-five per cent, of
the feeding was upon the unpainted parts of the leaves and
thirty-five per cent, upon the painted parts.

Experiment No. 2. — A series of bands and dots was
painted upon six willow leaves, with Paris green, in the
proportion of 3 lbs. to 150 gal. of water. After the poison
had been applied, each leaf was placed in a box with three
caterpillars of the fourth molt. These fed about equally
upon the painted and unpainted parts.

Experiment No. 3. — Six willow leaves were selected,
and a number of transverse bands painted upon each with
Paris green, in the proportion of 3 lbs. to 150 gal. of water.
The bands were one-fourth of an inch wide, and the un-
painted space between them one-half of an inch in width.
Each leaf was then placed in a box with three fourth-molt
caterpillars. Sixty per cent, of the feeding was upon the
non-poisoned part of the leaves and forty per cent, upon
the poisoned parts.

Experiment No. 4. — A medium-sized twig on an apple
tree was selected, and from it were removed all the damaged
and a part of the perfect leaves, so that there were only
twenty-five leaves left upon the twig. On each of these
were painted three broad, transverse bands, with Paris
green and lime in water, in the proportion of 3 lbs. of
Paris green and 5 lbs. of lime to 150 gal. of water. Ten

INSECTICIDES.

487

caterpillars of all sizes below the third molt were then
placed upon the twig, and sacked in by drawing a bag,
made of cheese cloth, over it, and tying the open part
closely around the base of the twig, to prevent the escape
of the caterpillars. Sixty per cent, of the feeding was upon
the unpoisoned and forty per cent, upon the poisoned por¬
tion of the leaves.

Experiment JVo. 5. — Three large willow leaves were
painted with Paris green, in the proportion of 3 lbs. to 150
gal. of water, as follows: on leaf No. 1, three transverse
bands; on leaf No. 2, three oblique bands; on leaf No. 3,
a band one-fourth of an inch in width around the entire
margin of the leaf. Each leaf was then placed in a box with
a full-grown caterpillar. Leaf No. 1 was eaten equally on
the poisoned and unpoisoned areas ; leaf No. 2 was eaten
wholly upon the unpoisoned parts ; leaf No. 3 had the mar¬
gin eaten in two places.

Experiment JVo. 6. — Three willow leaves were prepared
in the same manner as in the preceding experiment, except
that, besides the Paris green, 5 lbs. of lime were added to
the water. Leaf No. 1 had a long, narrow strip eaten from
the margin, passing through the ends of the three trans¬
verse bands of poison ; leaf No. 2 was eaten equally on the
poisoned and unpoisoned parts ; leaf No. 3 was eaten deeply
on the margin.

Experiment JVo. 7. — Three willow leaves were prepared
as before, using arsenate of lead, in the proportion of 6 lbs.
to 150 gal. of water, instead of Paris green and lime. Leaf
No. 1 was eaten equally from the painted and unpainted
portions ; No. 2 was eaten in the same manner ; and No. 3
had the margin eaten in two places.

Experiment JVo. 8. — A small twig of oak, bearing six
leaves, was sprayed with Paris green, in the proportion of
10 lbs. to 150 gal. of water, and another twig, bearing the
same number of leaves, was left unsprayed. Both were
enclosed in a sack with ten full-grown caterpillars. July
15. The greater part of the feeding was upon the unsprayed
leaves. July 16. More was eaten from the unpoisoned
than the poisoned leaves, yet six of the caterpillars had died.

488

THE GYPSY MOTH.

Experiment No. 9. — Two twigs of wild cherry were
trimmed so that only six leaves remained on each. One of
these twigs was sprayed with Paris green, in the proportion
of 3 lbs. to 150 gal. of water, and the other was left un¬
sprayed. Ten full-grown caterpillars were placed upon
the twigs, which were then enclosed in a sack. July 15.
None of the leaves were eaten. July 16. Arery little was
eaten from the unpoisoned leaves and a larger amount from
the poisoned leaves. July 17. The result was the same.
July 18. Ten times as much had been eaten from the
poisoned as from the unpoisoned leaves. July 19. Nearly
all of the leaves upon the poisoned twig had been eaten,
and but a small portion on the unpoisoned. Three of the
caterpillars died.

Experiment No. 10. — A twig of apple, bearing five
leaves, was thoroughly sprayed with Paris green and lime
in water, in the proportion of 3 lbs. of Paris green and 5
lbs. of lime to 150 gal. of water, and a similar twig was left
unsprayed. Ten full-grown caterpillars were sacked in
upon the two twigs. The first day the larger part of the
feeding was upon the poisoned leaves ; on the succeeding
day nearly all of the poisoned and about half of the un¬
poisoned leaves were eaten.

Experiment No. 11. — Alternate leaves of a twig of wild
cherry were painted with Paris green and lime, in the pro¬
portion of 3 lbs. of Paris green and 5 lbs. of lime to 150 gal.
of water, in such a manner as to cover the entire surface of
the leaves. Ten fourth-molt caterpillars were then sacked
in upon the twig. The feeding was nearly equal upon the
poisoned and unpoisoned leaves.

Experiment No. 12. — A twig of apple was prepared in
the same way, using arsenate of lead, in the proportion of 3
lbs. to 150 gal. of water, and ten fifth-molt caterpillars were
sacked in upon it. Nearly all of the feeding was upon the
poisoned leaves.

Experiment No. 13. — A twig of wild cherry was sprayed
with arsenate of lead, in the proportion of 6 lbs. to 150 gal.
of water, and a similar twig on the same branch left
unsprayed. Ten caterpillars of the fifth molt were sacked

INSECTICIDES.

489

in upon the twigs. The amount eaten upon each twig was
about equal, possibly a little more from the unpoisoned
than from the poisoned twig.

Experiment No. 14. — A twig of apple was sprayed with
arsenate of lead, in the proportion of 2 lbs. to 150 gal. of
water, and a similar twig left unsprayed. These twigs
were enclosed in a sack containing ten caterpillars of the
fifth molt. The feeding was about equal upon the poisoned
and unpoisoned leaves.

Experiment No. 15. — Alternate leaves on a small twig
of apple were painted with arsenate of lead, in the propor¬
tion of 6 lbs. to 150 gal. of water, and ten caterpillars of
the fifth molt were sacked in upon it. The poisoned and
unpoisoned leaves "were eaten equally.

Summary.

Of the four experiments where the caterpillars ate more
of the poisoned than of the unpoisoned leaves, Nos. 9 and
10 give most decided results against the choice of unpoi¬
soned food. Of the four cases where the caterpillars ate
more from the unpoisoned than from the poisoned food,
Nos. 1, 3 and 4 give but a small margin upon which to base
a conclusion. The fourth, No. 8, is of somewhat doubtful
value, because six of the caterpillars died upon the second
day of the experiment. Balancing experiments Nos. 1, 3,
4 and 8 against Nos. 6, 9, 10 and 12, there remain seven
experiments where there was no apparent choice of food.

A fair conclusion from these results is that there was
no discrimination against foliage treated with the poisons
employed.

Effect of Ixsecticides on Foliage.

No. 1. — June 26, 1893. A mixture of f lb. of Paris
green, £ lb. of lime and 2 quarts of glucose to 150 gal. of
water was applied to some quince bushes. About one-
fourth of the leaf surface was destroyed by burning.

No. 2. — July 12, 1893. A branch of apple tree was
sprayed with Paris green and lime, in the proportion of 1

490

THE GYPSY MOTH.

lb. of each to 150 gal. of water. The branch was sprayed
twice, on account of rain. The foliage was very badly
burned.

No. 3. — July 12, 1893. A branch of apple tree was
sprayed with the same mixture, and by July 30 the foliage
was very badly burned.

Xo. 4. — July 12, 1893. In order to get as near as
possible the exact effects of lime on the foliage, the two fol¬
lowing experiments were used as checks on those preceding.
They were sprayed within an hour of each other, and all
conditions were as nearly the same as it was possible to
have them. In this experiment a branch of hop-hornbeam
was used as a check to Xo. 1. The branch was resprayed,
on account of rain. July 30, the foliage was burned worse
than that of experiment Xo. 1, even though the branch in
the latter had been sprayed three times.

Xo. 5. — July 12, 1893. An apple-tree branch was used
as a check to experiment Xo. 2. The branch was resprayed,
on account of rain, and August 6 the foliage, though some¬
what burned, was not as much so as in experiment Xo. 2.

Xo. 6. — July 12, 1893. An apple-tree branch was
sprayed with Paris green, in the proportion of 1 lb. to 150
gal. of water, the mixture having been allowed to stand for
nearly three hours. August 6 the foliage was very badly
burned.

Xo. 7. — July 13, 1893. A branch of hop-hornbeam was
sprayed with Paris green and lime, in the proportion of 1
lb. each to 100 gal. of water. The branch was resprayed
twice, on account of rain. July 27, the foliage was very
badly burned.

Xo. 8. — July 12, 1893. A branch of apple tree was
sprayed with arsenic, in the proportion of 1 lb. to 25 gal.
of water. July 19, the branch was resprayed, on account
of rain, and again on the 25th. August 6, the foliage was
badly burned.

Xo. 9. — July 20, 1893. A branch of apple tree was
sprayed with arsenate of zinc, in the proportion of 1 lb. to
50 gal. of water. August 6, the foliage was badly burned.

Xo. 10. — July 1, 1893. A small hop-hornbeam branch

INSECTICIDES.

491

was immersed in a solution of 2 11 >s. of arsenate of lead
mixture, making 1 lb. of precipitate to 150 gal. of water.
Foliage uninjured.

Xo. 11. — July 1, 1893. This experiment was similar to
the one preceding, except that the branch was sprayed, in¬
stead of being immersed. A branch of a small oak tree was
sprayed with arsenate of lead mixture, in the proportion of
2 lbs. to 150 gal. of water. Foliage uninjured.

The “burning” effect of Paris green, when used in any
proportion greater than 1 lb. to 150 gal. of water, has been
ascribed to the presence of a small quantity of soluble
arsenic contained in the poison. Many chemists and ento¬
mologists have recommended the addition of lime to the
mixture of Paris green and water used in spraying, in order
to neutralize this soluble arsenic. ‘Our experiments, how¬
ever, have tended to prove that the addition of lime is of
questionable value.

In some cases we have used a considerable strength of
Paris green and lime without burning the foliage, while in
other cases a marked burning has resulted. The same vari¬
ation in burning effects is often noticed where Paris green
is used alone. We are led to believe that the burning
caused by the use of Paris green and lime is dependent in a
great measure upon the amount of lime added, and also
upon the length of time the mixture is allowed to stand,
as our experiments have shown that, where a consider¬
able quantity of lime is added to the Paris green mixture
and allowed to stand for some time, there is far greater
danger of burning the foliage than there would be from the
use of Paris green alone, thus apparently indicating that
the lime decomposes the Paris green in part, and forms a
more soluble compound of arsenic.

At my request, Dr. Charles Wellington, professor of
chemistry at the Massachusetts Agricultural College, has
made a series of analyses of Paris green mixed with water
and of Paris green and lime mixed with water, with a view
of determining whether the lime would decompose the
arsenite of copper contained in the Paris green, and in¬
crease the per cent, of soluble arsenic in the mixture. An

492

THE GYPSY MOTH.

extract from his report on the result of these investigations
is given below : - —

Paris green, a preparation of arsenite of copper, is insoluble in
water, but yields to it a small amount of arsenious oxide, with a
mere trace of copper.

The Paris green employed iu these examinations was a mixture
of several samples, all obtained from the Hampden Paint and
Chemical Company of Springfield, Mass.

Its composition was as follows : —

Water, .

Per Cent.

1.20

Copper oxide, ....

30.46

Arsenious oxide, ....

59.94

Insoluble, .

.12

Other material and difference,

8.28

Total, .....

. 100.00

After allowing mixtures of Paris green and water to stand with
occasional agitation, I have found the following amounts of arse¬
nious oxide in solution : —

Taken.

Time

of Standing
(Hours).

Found Arsenious

Oxide (Grains
per Gallon).

Paris Green

(Pounds).

Lime (Pounds).

Water

(Gallons).

a, . . 1

None.

150

3

0.33

b, . . 1

None.

100

3

0.46

c, . . 1

None.

125

1

4

0.11

The free arsenious acid would appear to be the cause of the
damage to the foliage.

Alkaline substances generally neutralize arsenious acid, forming
with it salts known as arsenites. Lime, soda and potash are
materials which thus act. Any one of these could be added to
the mixture in such proportion as to exactly neutralize all free
acid.

These substances, however, are sufficiently powerful as bases to
withdraw the arsenious acid from the copper. This is accom¬
plished either partially or wholly, according to the favoring cir-

ANALYSES OF PARIS GREEN.

493

cumstances of concenti’ation and heat. In moderately concentrated
solutions of soda or potash (i.e., sodium hydrate or potassium
hydrate) all the copper is removed from Paris green as insoluble
cuprous oxide. Soluble soda or potassa arsenite is then formed.

In such dilute solutions as are here considered, this could not
occur, and yet considerable portions of the arsenious acid may be
removed from the copper compound. To show this, I have made
the following determinations with the use of lime. In each case the
Paris green and lime were mixed, placed in the water, the mixture
agitated occasionally and at the end of the designated time fil¬
tered : —

Taken.

Time

of Standing
(Hours).

Found Arsenious

Oxide (Grains
Per Gallon).

Paris Green

(Pounds).

Lime (Pounds).

W ater

(Gallons).

d, . . 1

5

50

3

0.77

e, . . 1

5

100

3

0.92

A • • i

5

125

3

1.09

0

150

3

1.33

By substituting for this very large amount of lime smaller quan¬
tities, proportionally smaller quantities of arsenious oxide were
dissolved.

To illustrate the relative solvent effect in different periods of
time, the following determinations serve : —

Taken.

Time

of Standing
(Hours).

Found Arsenious

Oxide (Grains
Per Gallon).

Paris Green

(Pounds).

Lime (Pounds).

Water

(Gallons).

h ,

1

5

125

JL

0.69

i.

1

5

150

l

0.74

A

1

5

125

3

1.09

/c,

1

5

125

10

1.23

Trials with the use of soda gave the following results : —

Taken.

Time

Found Arsenious

Paris Green

of Standing

Oxide (Grains

(Pounds).

Soda (Pounds).

(Gallons).

(Hours).

rer Gallon).

1, . . 1

1

125

*

0.17

m, . l

2

125

T

0.31

494

THE GYPSY MOTH.

The lime is understood to he quicklime, the soda to be crystal¬
lized neutral soda carbonate.

It is thus seen that either with the use of lime or of soda a
certain quantity of arsenious oxide is removed from Paris green
beyond that which water alone would remove. The actual amount
removed depends upon the proportions of the substances mixed,
as well as the time allowed for solution. In every case this amount
is in the form either of lime or soda arsenite, and is in solution.

The ‘ ‘ burning ” of foliage which occurs as the result of
spraying w ith arsenical poisons is due to the presence of
soluble arsenic, which is found to some extent in Paris
green and to a greater degree in London purple. Other
poisons which contain arsenic in a practically insoluble
form, as, for instance, arsenate of zinc, when sprayed on
the foliage and fully exposed to atmospheric influences as
wrell as to the physiological action exerted by the leaves
themselves, sometimes decompose to a certain extent, and
give rise to soluble compounds of arsenic. The effect of
soluble arsenic on leaves is to kill the protoplasmic contents
of the cells which compose the living or assimilative part
of the leaf, as is shown by the illustrations given below : —

Fig. 1. Section through normal leaf of
pig-nut hickory {Cary a porcina) , show¬
ing structural elements. E, epidermis;
PC, palisade cells; SP, spongy paren¬
chyma; S, stoma or breathing pore.
{After Kirkland.)

Fig. 2. Section through leaf of same
tree, “ burned ” by excess of Paris
green. Cell contents ( protoplasm ) of
palisade cells and spongy parenchyma
dead and dried up ; cell walls shrivelled.
{After Kirkland.)

Leaf Area or Trees.

To gain a better knowledge of the surface wdiich needs to
be covered in spraying operations, during the summer of

LEAF AREA OF TREES.

495

1895 studies were made, under my direction, by Messrs.
Kirkland and Ilylan, upon the leaf area of three average-
sized trees, as follows : —

The dimensions of a medium-sized Baldwin apple tree
were carefully measured and the leaves upon one-fourth of
the tree counted. The average area of a single leaf was
computed by careful measurement of ten average leaves,
and the total leaf area ascertained by multiplying the whole
number of leaves by this last factor. The data concerning
the tree are given below : —

Height of tree, 23 feet.

Diameter of top, 23 feet, 9 inches.

Diameter of trunk, 1 foot, 5£ inches.

Number of leaves, 99,040.

Average area of single leaf, 30.188 square centimeters.

Leaf area of tree, 298.981952 square meters or 3,218.25 square
feet.

A second Baldwin apple tree afforded data as follows : —

Height, 18 feet, 5 inches.

Diameter of top, 26 feet, 7 inches.

Diameter of trunk, 1 foot, 5^ inches.

Number of leaves, 108,540.

Average area of single leaf, 29.294 square centimeters.

Leaf area of tree, 317.957076 square meters or 3,422.49 square
feet.

The leaf area of a red oak ( Quercus rubra') was computed
with the following result : —

Height of tree, 41 feet, 6 inches.

Diameter of top, 37 feet.

Diameter of trunk, 1 foot, 3 inches.

Number of leaves, 35,764.

Average area of single leaf, 83.5705 square centimeters.

Leaf area of tree, 298.88 square meters or 3,217.16 square feet.

In the actual spraying of trees the poison mixture should
be thoroughly applied to both surfaces of th<3 leaf ; so that,
to find the amount of surface necessary to be covered in
spraying these trees, the area should be doubled.

APPENDICES.

Append ix A

REPORT OF A CONFERENCE HELD AT THE ROOMS OF THE
STATE BOARD OF AGRICULTURE, BOSTON, MASS.

March 4, 1891.

Present : Profs. C. V. Riley and C. H. Fernald, Mr. Samuel
Scudder of Cambridge, Mayor Wiggin of Malden, Selectmen
L. S. Gould of Melrose, W. C. Craig of Medford, and W. A.
Pierce of Arlington, Messrs. Shaler, Appleton and Sessions of
the Gypsy Moth Commission, and others.

Professor S iialer. You know that about twenty years ago an
interesting Frenchman brought an interesting bug to this country.
His name was Trouvelot, and he brought the creature thinking to
introduce it as a valuable silk- worm. I begged him to destroy
his specimens, and at one time he said he had. It appears, how¬
ever, that they got away from him. Last year I went before the
Legislature and begged for some money, advising them to put a hun¬
dred thousand dollars at the disposition of a trustworthy commission.
They appropriated fifty thousand dollars and appointed a commission
which did a good deal of work and expended a good deal of money
and energy. I begged them to bend their energies to bringing in the
boundaries as far as possible, to pay the market price for eggs and
grubs, and to put their inspection work in progress ; but they went
into a miscellaneous sprinkling and burning over the whole terri¬
tory. The result now is that, as nearly as I can ascertain, it
would take a line thirty miles long to enclose the area these insects
occupy. They are found in a territory of not far from fifty square
miles, though not all over it. I should think that not more than
ten square miles were solidly occupied. On the rest of it there
are colonies here and there. The situation seems to me discour¬
aging in a certain way, but it is an encouraging fact that in about
twenty years they have not occupied more than about fifty square
miles, and it shows that they are not to be readily transported to a
great distance. Another encouraging fact is that, as far as I can
learn, save at two or three very limited points south of the Charles
River, the creature may be enclosed in this line on this side the

iv

THE GYPSY MOTH.

river [a map was shown] , which it does not seem to have passed
easily. It passed these few points probably in hauling manure.

Professor Fernald. Are you quite sure of the boundaries?
They are reported in Maine and Western Massachusetts.

Professor Shaler. I know they are, but putting the worst face
upon it, as I am at present doing, I think an area of something
like five by ten miles is the region that has got to be closely
studied. There is a reasonable suspicion of it over an area of say
fifty square miles, and the work has got to be done over that area.
One of the discouraging features is that there is a great traffic
through this territory. Railroads and wagon roads go through it,
and there is a large traffic in manure out of the district. We have
twenty-four thousand dollars to spend for certain, and I am sure
the Legislature will give us anything in reason we ask for.

Mr. Appleton. It seems to me the situation is this : Can we
eradicate this thing, and, if so, how? If we cannot eradicate it
entirely, what is the best we can do? Now, the first question to
consider, it seems to me, is, Can we eradicate it, or not?

Professor Shaler. We should like to have the opinion of ex¬
perts on that point. Professor Riley, will you give us your word ?

Professor Riley. I will be very glad to give you whatever
suggestions I can on the subject. I have taken the same interest
in this matter since it was so prominently announced that I do in
all matters of applied entomology, and I have felt that in the main
Professor Fernald’s original suggestions were very wise. The in¬
sect, as Professor Shaler has well said, has but limited powers of
spreading. While the female has wings, it is heavy bodied and
flies but little, and the history of the past twenty years shows that
its spread has been very gradual. Therefore we have a condition
of affairs totally different from that prevailing in the insect’s native
home, Europe, and we are justified in making a strong effort to
undo the harm that has been done. That brings up, first of all,
the question : Is it practicable to exterminate it, or not ? In view
of Professor Shaler’s statement, I have serious doubts, because, if
it may be said to occur in an area of say fifty square miles, if it is
found even in a number of central points of distribution in that
area, there is great danger, in my judgment. My own fears would
be that it has got into the woods and on to trees that are not so
easily treated. So long as it was confined to cultivated trees and
plants under cultivation I think there would have been no difficulty
at all, and the authorities would have been blameworthy in allow¬
ing it to go out from Massachusetts over the rest of the country.

Professor Shaler. I don’t think it has gotten into the woods.
I think it is still confined to the artificial grounds, as yet.

APPENDIX.

v

Mr. Appleton. Don’t you think it would be a good plan to
ask these gentlemen representing the different towns what their
experience is in that direction ?

Mr. Craig thought, in a general way, that they did not attack
forest trees ; were confined, as a rule, to orchard trees and trees
surrounding houses. Thought the reason the spread -was not
greater the last twenty years was because the people took the in¬
sect for some kind of canker-worm, and took pains to burn them
off the trees, which they did until they became too numerous to
control. He recommended the use of tarred paper tied round the
trees with a string. Undoubtedly the commissioners had destroyed
a great many of the insects.

Professor Riley. It is well known to feed upon a number of
different forest trees that grow with us, and in the event of its
getting beyond cultivated plants I should, as I said, have very
little hope of its ultimate extermination. I am not an alarmist,
and I do not believe that our people need be so very seriously
affected if it is not exterminated ; but, aside from that, the loss
would go on increasing annually, and it would become a very
grievous additional pest to those the farmer and fruit grower
already have to contend with. The thing you have to consider is
this : from what I could gather from the accounts in the news¬
papers, three measures were adopted : first, by attempting to
destroy the eggs ; secondly, by attempting to destroy the cater¬
pillars after they had hatched by means of arsenical spraying ;
thirdly, by endeavoring to stop the artificial spread of the pest on
vehicles, manure wagons, etc.

Individually I have always felt, and so expressed myself, and
still feel, that the proper way would be to use whatever funds the
State will give you during a limited time, and concentrate all effort
and all expenditure in the month of June on the destruction of
caterpillars, and not to bother about the destruction of the eggs or
the prevention of the spread of the insect. These latter methods,
necessarily intrusted to persons who may be efficient or who may
not, are apt to bring the whole subject into popular disrepute and
disfavor. You may reduce the numbers, but you will never exter¬
minate it by destroying the eggs. Therefore, as a single spraying
of a tree will kill five thousand caterpillars just as well as one,
there is nothing to be gained by the work of destroying the eggs.
Moreover, I do not believe there is much to be gained in the work
of preventing its spread by the examination of vehicles on the
main thoroughfares and on the railroads. On the contrary, I
believe that the only way to accomplish that end is by a very strict
law which the Legislature should pass, giving the power to some

VI

THE GYPSY MOTH.

committee to absolutely prohibit the sending of nursery stock or
any plant growth or material, probably including manure, out of
an infected district without inspection. My belief is that a rigid
quarantine law, making it a penal offence for a nurseryman to
send cuttings or trees from any given infected area, without first
having the sanction of this commission, would be effective in pre¬
venting the spread. That is to say, there should be a competent
person or persons appointed, to whom all such shipments should
be submitted, and only upon their approval should such shipments
be allowed to pass out from that area. That would be the only
simple and efficient way of preventing its spread. My impression
is that the danger is far greater from overlooking a batch of eggs
during the months of the year when such a thing is possible, and
of the insects being transmitted in that way, than there would be
in the mere carrying of the caterpillars. I would therefore con¬
centrate all effort on the destruction of the caterpillars.

I believe that even in an area as extended as Professor Shaler
indicates, if the Legislature would appropriate a hundred thousand
dollars the thing could be done. Let it be used under the intelli¬
gent guidance of some one who has had experience, who knows
practically how to spray, who can go to work intelligently and
instruct his men, and have a sufficient force to examine every tree
and cultivated plant upon which this insect is known to feed, and
make sure that wherever it is it will be destroyed before the change
into the chrysalis state takes place. In other words, I do not see
why, with one hundred thousand dollars, a single year ought not
to suffice to stamp it out from the area in which you know it to be
found. I believe it can be done, and that the State of Massachu¬
setts would be justified in making the attempt.

In Europe this injury is at times not great, at other times it is
quite extensive ; but it is chiefly notable in those places where
there are very large areas of cultivated forests. Bavaria, for
instance, has lately suffered greatly from it. Experience there
has shown that it is easily checked by the use of sticky bands,
very much the same methods as you have employed here for the
canker-worm. They use several kinds of glue (manufactured and
some of them patented by different firms), which is procured in
large quantities and smeared on the trees, being made in such a
way that it does not dry. I presume it comes nearest to our
printers’ roller glue. The caterpillars never pass above it from
below. Coming down the tree they jump over it. The devices
for putting it on are very simple. That is the method which ex¬
perience has shown to be the most satisfactory there, but it is a
preventive method, and chiefly to be considered when you have

APPENDIX.

Vll

given up the fight for extermination. The main thing for you to
do is to try to stamp it out during the active season and use all
your energies to that end. The arsenicals are not expensive, and
if an analysis is made of the Paris green, or whatever form of
arsenic is used, to insure its purity, I can see no reason why the
whole area should not be practically cleared off during a single
season. That should be carefully followed up by close observa¬
tion, with a view of repeating it in the case of some omitted centre
or point where they may be found in a subsequent year. In case
they have not gone into the woods, it seems to me feasible to ex¬
terminate them.

I would make one other suggestion, and that is, that as an
auxiliary method it would be well to spend five hundred or six
hundred dollars in sending one or two persons abroad next sum¬
mer with no other object than to go to some section of northern
Europe to collect and transmit to authorized persons here a certain
number of the primary parasites of this species, which are known
to check i£s ravages over there. The insect was undoubtedly
brought over by Trouvelot without any of its natural checks. In
my judgment it would be well worth trying to import its parasites
from abroad. The advantage would be this : if you failed to
exterminate it by spraying, its parasites, seeking for this partic¬
ular host, would be more apt to find the overlooked or escaped
specimens than man would.

Professor Ferxald. Do you think that any of our native par¬
asites will be liable to attack this insect?

Professor Riley. Experience justifies the belief that some of
them may, in time.

Professor Ferxald. Have we a case on record?

Professor Riley. Yes, though they are not numerous. Pieris
rapce, or the imported cabbage-worm, has some native parasites.
There are other cases, but I should have to consult my notes.

[Note by Professor Riley. Several native species attack Scoly-
tus rugulosus : the same is true of the hop aphid, Pliorodon humuli,
and of several important species of bark lice.]

Professor Ferxald. In reply to the question which was first
asked, as to whether it is possible to eradicate the insect at all,
let me suppose a case. Suppose we have a tree like the elm I see
yonder, and suppose we know it to be the only tree in America
that is infested. I think you will all agree with me that for a small
sum of money all moths on it could be destroyed. Suppose there
were two, — suppose all the trees on the Common were infested.
If they could be destroyed on all those trees, it is only a ques¬
tion of time and money to eradicate them from a much larger

vm

THE GYPSY MOTH.

territory. It is a question of time and intelligent labor. I say
intelligent advisedly. Right here I would suggest very earnestly
that the committee or commission employ a scientific man upon it.
This is the advice I gave, with all the force I could, to the former
commission, for there are a thousand and one things constantly
coming up in work of this kind, and it is necessary to have some
one who knows and is able to answer questions. As to the ques¬
tion of territory, I only raised that to know how it had been
determined. It is possible it is not so extensive as indicated, but
it may be.

Professor Shaler. I thought it best to put it at the highest
figure. My own opinion is that we shall not have to deal with an
actual area of more than nine or ten square miles.

Professor Riley. Is it not true that so far you have found this
pest chiefly on orchard trees?

Professor Shaler. On orchard trees and elms.

Professor Riley. That is unfortunate, because it increases the
difficulty of treatment.

Mr. Craig. They are more numerous ou and generally select
orchard trees, but even pine trees have been attacked by them
and in some cases the branches stripped. Maple trees are also
attacked.

Professor Shaler. I have seen them ou some maple trees and
heard of others, but it seems to be a case of starvation when they
come to that.

Mr. Craig. My observation is that the older the tree the more
they will attack it.

Professor Fernald. With regard to a scientific man on the
commission, if you can get an entomologist who is also a business
man you will be fortunate, but in my judgment it is important to
have a business man too.

To go back to the question of territory, I agree with Professor
Riley that it is rather stupendous ; but if you can destroy the
insects over a small area, why cannot you over a large one? The
whole thing is experimental ; it is unprecedented to destroy so
many insects scattered over so large a territory, but my impres¬
sion is that they can be destroyed. The question is, how to do it.
I was informed last summer that Paris green destroyed the larvae
of this insect up to a certain size ; beyond that size they were able
to eat it and grow fat. I urged the commission to try a branch
with caterpillars that had not eaten any Paris green, but I cannot
learn that they did it. If their statements are correct, I must lose
the little faith I had in regard to the efficacy of Paris green. My
experiments at Amherst on the use of Paris green do not seem to

APPENDIX.

IX

tally with the results they obtained. They used one pound of
Paris green to one hundred and fifty gallons of water, and when
Mr. Sessions and I went over there in the summer we saw that the
trees were burned very little. The same proportions used at
Amherst burned the trees very badly. Yet Professor Cook and
others have reported that a much larger proportion of Paris green
could be used. The Paris green I used I had analyzed and know
just what it was. I expect there is either some great difference
between the climate of Amherst and this region — or something
else.

Mr. Craig. So far as my own orchard is concerned, where the
Paris green was used a streak was burned here and there, in other
places not. I think it was not kept stirred up.

Professor Fernald. Suppose it is not possible to destroy these
insects : even then I believe it would pay to make annual appro¬
priations to hold them in check. We know what the farmers are
paying annually to destroy the potato beetle, and if this insect
spreads over the Commonwealth of Massachusetts I should sup¬
pose it was capable of doing more damage than the potato beetle.
It seems to me, if it is not possible to stamp it out, it is wise to
hold it in check where it is.

Mr. Sessions. I have heard the idea advanced by somebody
from Medford that possibly the reason the caterpillars apparently
eat Paris green and live is that after a certain stage of their
existence they stop eating altogether.

Professor Fernald. They do not stop eating long before they
spin their cocoons. The time is not more than twenty-four hours.

Professor Siialer. I should like to ask about the chances for
more satisfactory insecticides. I should like to ask if we may
reckon among the insecticides certain compound salts of calcium
which are very acrid, and whether a solution of them would be
efficacious?

Professor Fernald. I have had no experience with them.

Professor Siialer. The question is, whether it would serve in
this case. Do you know, Professor Riley?

Professor Riley. I should have most faith in the arsenicals.
The relative value of the different forms of arsenic spraying depends
partly upon the kind of tree treated, partly upon the condition
of the atmosphere, and very materially upon the purity of the ma¬
terial. Paris green has this advantage, that it may be used much
more strongly with less injury to the trees ; and it has this disad¬
vantage, as compared with London purple or pure arsenic, that it
is not soluble in water, and you have to keep stirring it. I have
no doubt that the experience Professor Fernald referred to was

X

THE GYPSY MOTH.

due to the inferior character of the Paris green in the one case
and its purity in the other. It should be applied with a spraying
nozzle that would simply touch it to the leaves, and it should be
mixed with a substance to make it adhere. In other words, all
this work should be superintended by a careful, practical man,
who knows what to do. A part of the advantage of using the
arsenicals in this part of the country would be that, aside from the
destruction of Ocneria , it would pay to use it as against the tent
caterpillar, the codling moth and various other insects that are so
prevalent in your orchards. It is one of the curious things which
strike a man travelling through Massachusetts that in a State
where applied entomology has had its origin iii America, an insect
as common as the tent caterpillar, and which may be so easily mis¬
taken for this very Ocneria , should be so abundant, and that so
little should be done to control it. You will have the same
trouble with the Ocneria. You can’t get the average Massachu¬
setts farmer to bestir himself about it.

Professor Shaler. Am I not right in supposing that our first
care should be to drive this pest in on the periphery at all costs,
but to make surest of its destruction on the periphery? The num¬
ber of inspectors we could have would be limited, therefore we
should take the extremest care with the periphery. With that in
view, how would it do, from now until the time the eggs hatch
(they are conspicuous things, — you can see them a great distance,
and boys could gather them in quantities), to pay the school-boys
what would be a tempting price per ounce for the eggs? We
would secure a very large destruction on that basis, I think, be¬
tween now and the time the eggs hatch. We could put a person
in each town who should gather the eggs once a day, pay for and
destroy them, — that is, in the regions that are thoroughly in¬
fected. In that way I think we should diminish the number that
are to be killed in the spi’ing, and that at small cost.

Professor Ferxald. In reply to that, Professor Riley has
already expressed his opinion. A year ago I had just the same
opinion that Professor Riley has, and expressed it to the commis¬
sioners, but they had already gone to work. I talked with some
entomologists about it, and they differed from me ; they thought
it was beneficial to use other means than Paris green. Theoreti¬
cally it seems to me that any other means would be a needless
expenditure of money, and Professor Riley’s suggestion to exter¬
minate them in one year would be a good one if it could be accom¬
plished ; but I question whether it would be wise for us to go
from this meeting to the Legislature with that proposition. If
you failed to do it in one year and came back for a second appro-

APPENDIX.

xi

priation, you might find it difficult to get it. This is merely a
policy suggestion. I can conceive that, even with the most thor¬
ough work that can be done with Paris green in spraying trees, a
few might escape and start a new colony. Then in another twenty
years this thing would come up again.

Professor Shaler. Do you gentlemen agree that we must look
forward to a careful and continuous work against this moth ?

Professor Riley. As I said before, we have nothing to do
with the experience or methods of Europe, where the insect pre¬
vails over vast areas, and where nobody expects to exterminate
it. Yet there have been instances of similar extermination, as,
for instance, what the Prussian government did with the potato
beetle ; and here you have an opportunity to show that you can
stamp this thing out. I expect a few will escape. That is why
I made the suggestion that it would be wise to introduce such par¬
asites as can be used against it, with a view of permitting them
to search out those which may have escaped. The matter, as I
said, may not be possible ; but, if it is, it is onty possible in that
way, and all other efforts would, I think, be rather puerile, and
serve to bring the whole thing into popular disfavor. Set the
school-boys to work on the eggs ; that is good as a prophylactic
measure, and would do a certain amount of good, but the good
would be very slight as compared with the effective work you
ought to do in the actual destruction of the caterpillars. As I
said before, the fact that the insect has been diminished in num¬
bers would be rather against the efficient extermination of the
larvae in summer, for the reason that it is harder to find an isolated
bunch of caterpillars in a county than when they are numerous.
I still hold to the belief that whatever funds the Legislature can
give you should be devoted to a prompt and effective attempt
at stamping out.

Professor Shaler. Suppose every tree sprayed, what reason
have we to believe that we should have disposed of the pest?

' Professor Riley. There would be need for some years after¬
ward of the greatest care. I would not attempt to kill the young
caterpillars ; wait until they are somewhat advanced, so that the
work could be concentrated within a narrow limit of time.

[At this point Mr. Scudder came in.]

Professor Shaler. The discussion has been, Mr. Scudder, on
the question as to whether it would be well to proceed at once to
the destruction of the eggs. There are places where the eggs are
abundant, and, as we know, they are conspicuous, and it seems
that between now and hatching time we might collect a consider¬
able per cent, of them, paying for them by weight or measure,

Xll

THE GYPSY MOTH.

and at once destroying them. Professor Riley thinks that would
diminish the conspicuousness of the colonies, so to speak, and
make it harder to find them, and thinks that an equal amount of
money would go further in poisoning with spray than it would in
collecting the eggs. I should like to hear from Mr. Scudder
what he thinks about the desirableness of doing anything with the
eggs.

Mr. Scudder. I feel that I have no right to speak in the
presence of others here who have given special study to economic
entomology, while I have not. All I can speak upon is the
natural history of the moth, and on that side of the question it
might be well to ask whether it is behaving the same in this
country as in the old country. There are a number of moths
single-brooded in the old country which are double-brooded here.

Professor Riley. I have assumed that it was single-brooded.

Professor Fernald. I have bred it twice, two years in succes¬
sion.

Mr. Scudder. If it is single-brooded, there is this point to be
brought out, that, as the caterpillar is a very liberal feeder, so, of
course, it is very much more difficult to reach by spraying, because
the spraying is not to be confined to a few kinds of trees, but to a
very large number, so that one would say you would have to spray
almost everything you came across. So with the eggs, which are
laid not always on trees, but on almost anything else. It there¬
fore becomes the most dangerous insect enemy we have had for a
long time, I think. If it is single-brooded, it seems to me that
nature has indicated the easiest means of attack. The eggs are
laid in batches, and are exposed for eight months of the year.
Therefore it seems to me that the egg is the place to attack. I
should suppose that the same amount of money expended in the
destruction of the eggs would effect a very much larger end than
the same amount of money spent in spraying.

Professor Riley. I have been trying to bring out what knowl¬
edge there is as to the actual range of the insect, and my remarks
on the possibility of stamping it out have all been based on that.
I want to say that if the insect has spread beyond the limits in¬
dicated by Professor Shaler, and got into the larger trees, I think
the question of stamping it out a very doubtful one. At the same
time there is an opportunity here for the State of Massachusetts to
make the experiment, and show what can be done by efficient
means and intelligence. I would rather offer a higher bounty to
every school-boy for pointing out where the caterpillars are to be
found during two weeks in June, than for gathering the eggs. I
believe that there is a chance of stamping it out, if it is not

APPENDIX.

xm

beyond the region where the trees are comparatively few in num¬
ber and not very large.

Professor Shaler. How would it do, as one of the early steps
in this work, to get all the information we can as to the periphery,
and publish maps showing it? Let us ask for information as to
the spread of the pest beyond those limits. I should hesitate
about offering a reward for the location of the caterpillars, because
there is the possibility of the school-boys planting them. A
reward for the eggs is much more easy, and we could probably
interest the school-boys in searching for them ; but it would hardly
do to offer a reward which might serve to spread the plague. All
these rewards for animals are very dangerous.

Professor Riley. On general principles it is bad policy, but
the same objection would apply to a reward for the eggs. If the
boys once learned that they could get a certain amount of money
for the eggs, they would not be so interested in exterminating them,
and thus cutting off future revenue.

Professor Shaler. I should state a definite reward, and not go
beyond a certain time.

Mr. Craig. We have two or three village-improvement associa¬
tions especially to take care of the trees. We extended an
invitation to the citizens to take part in the work, and they were
to notify certain committees wherever they found any eggs. This
was done to a large extent, and I think it aided the commissioners
very largely in finding out where the moths were.

Professor Shaler. You can tell us about the extent of the pest
in Medford. Over about how large a territory did it extend?

Mr. Craig. More or less from the Malden line over to Arling¬
ton.

Professor Shaler. About a mile and a half in the worst-
infested district.

Professor Riley. What was the result of the commission’s
work? Are the eggs found abundantly in that neighborhood?

Mr. Craig. I don’t believe there are one-tenth the eggs there
were when the commission commenced.

Professor Riley. What was the result of the commission’s work
last year? Was it appreciable on the number of eggs known to
have been there?

Mr. Craig. Yes, certainly. I differ from you two gentlemen
about destroying the eggs. I think it was the means of destroy¬
ing a great many of the pests. On many trees they were con¬
trolled by gathering the eggs.

Mr. Sessions. I have no scientific knowledge on the subject,
but it seems to me the first and most important thing we have to

XIV

THE GYPSY MOTH.

clo is to find the outside line, even if we don’t do any more than
that in one season. The old commissioners claim that they have
found it; our first business should be to verify that.

Professor Shaler. Did they make a map ?

Mr. Sessions. I think not.

Mr. Scudder. How do they know the moth wasn’t blown fifty
miles away by a storm ?

Professor Shaler. It may have been ; but it is a strong point
in our favor that after the creature has been twenty years on the
scene it still has a tolerably distinct periphery.

Professor Riley. That is what I have based my recommenda¬
tion to exterminate it on. I should not like to see the attempt
abandoned, but my remarks have all been made with a view of
economizing means and time in one effective effort to exterminate
it. All these other measures will come in if we have to deal with
the pest as a permanent thing among us. As a mere State meas¬
ure, with a view to not having the unenviable reputation of having
given a pest to the rest of the country or done nothing to prevent
its spread, Massachusetts has an excellent opportunity of showing
what may be done by intelligent, concentrated effort. All other
means are puerile as compared with destruction by the arsenicals.
All other means are now abandoned in fighting the canker-worm,
the codling moth and some other insects, and intelligent spraying
at the proper time has come to be looked upon as the most efficient
means of protection against these insects. My idea is that what
you ought to do is to employ a sufficient force of intelligent per¬
sons to scour that whole region in the month of June, and indicate
every plant that has a brood upon it.

Professor Shaler. Suppose you had a hundred persons search¬
ing at the same time, what general instructions could you give
them in determining what trees were infested ?

Professor Riley. The insect is gregarious, and therefore con¬
spicuous. There is no reason why intelligent search should not
detect it, even on the highest trees.

Professor Shaler. How much time could you reckon on hav¬
ing for your search after the creature came out ?

Professor Riley. I should say you could count on ten days
after it was hatched. Its gregarious nature makes that feasi¬
ble.

Professor Shaler. How much time is there before it begins to
spin?

Professor Riley. I believe it takes three or four weeks.

Professor Fernald. I think it highly desirable to make the
attempt to stamp it out. I don’t know that it can be done, but it

APPENDIX.

xv

is worth trying. If we cannot exterminate it, the other excellent
remedies can be used for holding it in check.

Professor Shaler. Had we not better wait until we can strike
a hard blow, and do the best we can this year with prevention ?

Professor Riley. I am strongly of opinion that you had better
not wait. Some contingencies may arise to give it a sudden
impetus. I would adopt the auxiliary methods of introducing
parasites, etc., and I would also have a special committee author¬
ized to inspect all nursery stock that goes out from the infested
region, and not allow it to go until passed upon by competent
men.

Professor Ferxald thought the Federal government might take
charge of the work. Professor Riley stated that he would be glad
to assist in any way possible, but that since the establishment of
State experiment stations the Federal government felt it had no
further function in the States, so far as local insects are concerned.
Professor Shaler thought the State of Massachusetts should make
the fight itself, and only ask for Federal aid in case it could not
exterminate the pest. Twenty-four thousand dollars were on hand,
and he thought that twenty-five thousand dollars or fifty thousand
dollars more could be counted on from the Legislature.

Mr. Scudder. I don’t understand the force of the arguments
used by my neighbors on either side [Professors Riley and Fernald]
of delaying the work by not taking the eggs at present. Why do
they want all the caterpillars out that they can get, in order to ex¬
terminate them?

Professor Shaler. It is a question of seeing them, I believe.

Mr. Scudder. I understand. But, if you destroy so many
eggs that say only one tree out of five is attacked, you have to
deal with only one-fifth as many trees in spraying.

Professor Riley. I want to tell Mr. Scudder just why I rather
urge the policy I have advised. First of all, it is from the politi¬
cal side. If you ask for an appropriation to stamp it out, you
must do your best to stamp it out. As Professor Fernald has
suggested, it is simply a question of means, and I would not think
of asking for less than one hundred thousand dollars, and I would
concentrate that where it would do the most good. Killing the
eggs is frittering the money away at a time when it is not of so
much value as if concentrated. Secondly, I have little faith in the
destruction of eggs in this case, where they are laid on so many
different objects. I remember distinctly a little cedar tree not
more than six feet high in my own grounds that was attacked by
the bagworm. I thought I would see whether I could not clear
them off. I worked for two consecutive months picking off from

XVI

THE GYPSY MOTH.

the tree the issue of not more than two females. Almost daily I
went to that tree, and found fresh specimens that I had overlooked
the day before. Yet in the Smithsonian grounds I have absolutely
stopped similar injury on larger trees in a few minutes by spraying.
It would have been no use, in my judgment, to have attempted to
eradicate them by hand picking. Suppose you have somebody
climb a tree and gather twelve batches of eggs, but he fails to get
the thirteenth. It will cost no more to spray a tree for the thirteen
batches than it will for the one.

Professor Shaler. When I came here I was strongly in favor
of offering a reward for the eggs, but I admit I am shaken now.

Mr. Scudder. I don’t think you can get sufficient force to spray
the trees thoroughly in the time allowed.

Professor Shaler. I think we shall have to ask the Agricultural
College to lend us say eighty or a hundred of their young men for
this work.

Mr. Sessions. There are many people living in the neighbor¬
hood of this spraying who claim that it was of no sort of value.
Do any of these gentlemen believe that?

Professor Riley. I think the reasons that have been given ex¬
plain why they had that experience. It was simply due to the
impurity of the Paris green and the imperfect manner of applying
it. You will always have more or less of failure until you put this
matter into the hands of men who can give their whole time to it
during that period. Only those men should be employed who
have ability and experience ; and one man, particularly, should be
engaged to superintend the whole work, and as many other com¬
petent persons as possible.

A tree fifty feet high is very easily sprayed. If the caterpillars
could not be killed by spraying, it would be better to cut the trees
down over the whole of the Middlesex Fells. It pays better to
make one grand effort than to fritter your energies away over a
number of years, and then fail. The Board in control of the
work should control everything. If Paris green is used, it should
all be issued by the Board, after being tested.

Professor Shaler. I should like to ask your opinion, gentle¬
men, whether any considerable risk to health is to be apprehended
from this large use of arsenic in the country. Is there any risk of
poisoning the water or of poisoning animals or men ?

Mr. Appleton. The committee on public health is having an
extended hearing on the use of arsenicals.

Professor Riley. If the spraying is copious and careless,
which is unnecessary, there is danger of stock feeding upon grass
which has been so impregnated, but there is no necessity for that.

APPENDIX.

XVII

The spraying should be of such a character that there would be
comparatively little falling from the tree or shrub sprayed.

Professor Siialer. Have you known of any cases of poisoning
in persons employed in spraying?

Professor Riley. No, I have seen none, but I have known of
cases where negroes would sit on the back of a mule with spray¬
ing pumps, going through cotton fields, and carelessly allow the
water to fall on them. I have known them to become sore in the
groin, but never knew of a fatal case.

Mr. Appleton. The spraying is washed off by the first rain,
of course?

Professor Riley. It should not be. The whole tree is en¬
shrouded in a vapor which is all-sufficient, and which is more
effective than a more copious spraying.

Professor Siialer. Is there any particular form of engine
which will give that form of spraying?

Professor Riley. There are various spraying devices in use,
depending largely on the height of the vegetation. If you want
to throw to any great height without the use of ladders, you need
a spraying device that will throw a strong jet. In almost all
cases you can use the cyclone nozzle in its Vermorel modification.

Mr. Scudder. I should like to say before going that it does
not seem to me likely that the thing will be exterminated, but
that it can be held in check for many years. The reason why I
don’t think it can be exterminated is because we have not enough
persons used to looking for the caterpillars to examine the trees
and say for certain that there are none there. I do think, how¬
ever, that it can be held in check.

Selectman W. A. Peirce of Arlington said they had very little
trouble with it in his neighborhood. The sentiment of the people
there was in favor of the continuation of the work.

Mayor Wiggin of Malden. We went through and marked
every tree that was infested, and then went through again and
sprayed them. The trees were not so infested as to be particu¬
larly noticeable.

Mr. Gould of Melrose. The selectmen did not believe there
were any gypsy moths in their town. As far as he knew, the
people were not disturbed by their presence. They would be
glad, however, to have the inspectors go through the town and
look for it, and would gladly second their efforts.

Professor Siialer. I think it would be a tax of probably more
than one hundred thousand dollars annually if not checked.

Professor Riley. There is no question of that, if it is allowed
to take its course. That is what makes it so vitally interesting to

XY111

THE GYPSY MOTH.

me, and why I am so impatient of any efforts to simply check it.
I have nothing to say about checking it ; I speak for stamping it
out. Mr. Scudder simply says he doesn’t think it will be exter¬
minated. As to how much of any given territory one individual
is capable of critically examining, a man who is capable of dis¬
tinguishing between this caterpillar and others, doing nothing
else, would, in my judgment, be able easily to go over a square
mile of ground a day, except in dense forest.

Professor Shaler. I don’t think so ; nothing like it. If the
work was done closely (and two together would do better work
than one), my impression is they would be doing good work to
get over a hundred acres a day.

Professor Riley. Well, say a hundred acres —

Professor Shaler. If we could get from the college say forty
young men as inspectors, we would have four thousand acres a day
inspected, and my impression is that the region covers about ten
thousand acres. That area can be thoroughly inspected by twenty
parties of selected men doing nothing else. They should mark
the infested trees and plat them on a map. As we are no longer
a paid commission, I would devote that money to experts. We
want the best expert we can select to superintend the actual appli¬
cation of the remedies. When a tree is marked as infested, let it
be numbered so and so; and when it is sprayed, let an account
be taken of that tree, so that by some system of checking we can
find whether every tree has been disposed of or not.

Professor Riley. The suggestion seems to me eminently wise.
But I suppose you could get the leading citizens in a community
interested also?

Mr. Sessions. I don’t believe you can get the college boys to
come.

Professor Riley. Not if you paid them? It would be an ex¬
cellent education for agricultural students ; and if you offered
them a hundred dollars each, you would have no difficulty in get¬
ting them, I think.

Professor Shaler. What month should the work be done in?

Professor Riley. As far as I can learn, the month of June. I
believe that about the second week in June will be the time to
strike, after having made all your plans, got your forces ready and
trained your men. It may be that the thing is not practicable,
but I can see nothing impracticable. It is simply a question of
mone}T and men. After this one thorough effort 3Tou need not ask
for another appropriation ; everybody will be interested, and then
you could afford to offer a big reward for any eggs that might es¬
cape. The attempt is well worth making.

APPENDIX.

xix

]\Ir. Sessions. A great obstacle is in procuring help you can
depend on.

Professor Riley. Let me make one other suggestion. While
the infested area is stated in the rough at fifty square miles, from
what Professor Shaler said there would probably be large portions
of it that would require nothing but inspection. Now, wherever
there are large trees difficult to climb, I would certainly take the
precaution to ring or band them, because that will prevent any
stray caterpillars from climbing up those trees. No caterpillars
will ascend such trees ; and if any escape, you will find them at
the foot of the trees. European experience shows this. •

Professor Shaler. Where can wre get on the track of the mixt¬
ure they use in Europe for that purpose ?

Professor Riley. You can use printers’ ink for that purpose.
In Newark I recommended the use of the fire department for
spraying certain very tall elm trees.

Professor Shaler. I presume we could make such an arrange¬
ment with the fire departments.

Mr. Craig. We have an engine that could be so used.

Professor Riley. I would modify my objection to egg collect¬
ing just so far that in the case of large trees it would be advisable
to do the work prior to aestivation. I think boys could go over
them, and in this direction winter work would be advisable. It
would also be advisable to have these large trees very carefully
inspected for the eggs ; but I do not believe you would be justified
in attempting to destroy the eggs over the whole area.

Professor Shaler. Is the energy of diffusion and the tendency
of the females to travel at all proportioned to their numerousness ?

Professor Riley. Yes ; it is a general principle with insects
that, in proportion as they become unduly multiplied, the migra¬
tory instinct is developed.

Professor Shaler. So that, in so far as we reduce the uumber
in a given field, we tend to reduce the expansive energy?

Professor Riley. Without doubt.

Professor Shaler. And, therefore, if we fail to exterminate it
this year, we shall at least diminish its expansive energy.

XX

THE GYPSY MOTH.

Appendix B.

REVISED RULES AND REGULATIONS ADOPTED BY THE STATE
BOARD OF AGRICULTURE,

Under Chapter 210, Acts of 1891.

Rules and Regulations for the Public.

1. All persons are forbidden by law to remove the eggs or
any other form of the gypsy moth from one city or town to
another, and are requested to exercise care against so transport¬
ing the gypsy moth on teams and carriages.

2. All persons are forbidden to remove from any locality in
the towns of Medford, Everett, Chelsea, Malden, Melrose, Cam¬
bridge, Winchester, Somerville and Arlington any hay, manure,
wood, bark, trees, rags, lumber or shrubbery of any kind, without
a written permit from the Board of Agriculture. Persons desiring
to remove such materials will notify the field director, 13 Stan-
wood Hall, Malden.

3. All persons are forbidden to in any way imitate or erase the
marks employed by this Board to designate trees, fences or build¬
ings which are infested or have been cleaned.

4. All vehicles leaving the above-named district may be
stopped by the officers of the Board and delayed until their con¬
tents have been sufficiently inspected to determine the fact that
they are not liable to transport the eggs or any other form of the
insect.

5. No person shall trim, scrape or cut down trees within the
district known to be infested by the gypsy moth, or remove them
without first notifying this Board, and having said trees thoroughly
inspected, and, if found infested, cleaned under its direction.

The eggs of the gypsy moth are frequently scattered abroad by
scraping the trees and by careless gathering ; therefore, all per¬
sons except the authorized agents of this Board are forbidden to
remove the eggs of the gypsy moth from the trees or other objects
upon which they may have been deposited, or to remove such
infested trees or objects from one place to another.

Land owners and tenants are requested to destroy all other
forms of the moth which they may find upon their premises.

APPENDIX.

xxi

6. All persons, upon notice, are required to confine their dogs
while the agents of this Board are at work upon their premises.

7. Owners or tenants are requested to gather and burn all
rubbish and useless material upon their premises that may provide
nesting-places for the gypsy moth, and to fill with cement or other
solid material all holes in trees upon their premises.

8. All persons are requested to keep the windows of their
houses protected by screens during the summer months, as the
moth often lays its eggs in houses, wherever it can gain admittance.

9. All persons having reasonable cause to believe that the
eggs, caterpillars or other forms of the gypsy moth exist on or
about their premises are earnestly requested to forthwith notify
E. H. Forbush, director, by letter addressed to his office in Mal¬
den, Mass. Information of the moth’s existence in isolated or
unsuspected localities will be gratefully received, and all persons
furnishing such information will receive the thanks of the Board.

10. Notice is hereby given that it will, in some cases, be nec¬
essary to remove boards from fences or buildings. In all cases
such boards will be eventually replaced, if possible, without
damage to the structure. Attention is called to the fact that any
damage done by the agents or servants of this Board, in the work
of exterminating the moth, may be recovered under provisions of
section 2, as above printed.*

Attention is also called to section 6, as above printed,* which
sets forth the penalties for obstructing any servant or agent of the
State Board of Agriculture under this act.

11. Courteous and considerate conduct is expected of all
agents and employees of the Board. Complaints in writing con¬
cerning any infraction of this rule should be sent to the director,
and will be heard by him or the committee.

E. W. Wood,

Augustus Pratt,

F. W. Sargent,

J. G. Avery,

S. S. Stetson,

Wii. R. Sessions,

Committee of the State Board of Agriculture.

Rules and ReguLxVtions for Agents and Employees.

It shall be the duty of employees to familiarize themselves with
the rules governing the gypsy-moth work. The violation of any
of the rules will be sufficient cause for discharge at any time with¬
out notice.

* See page 47.

XXII

THE GYPSY MOTH.

General Buies.

1. No person will be employed or retained who is known to
use intoxicating liquors as a beverage.

2. Smoking is strictly prohibited during hours of labor.

3. Courteous and considerate conduct is required of all agents
and employees of this Board.

4. All agents and employees (unless otherwise ordered by the
director) must wear at all times during working hours the uniform
caps and badges issued by the quartermaster.

5. Employees must provide themselves with the uniform pre¬
scribed by the State Board of Agriculture and said uniform must
be worn during working hours.

6. No employee shall sign the pay-roll for another unless he
has a written order from the person for whom he signs. Said
order must be made out on one of the blanks furnished by the
Board and must be sent with the pay-roll to the director’s office.

7. Superintendents and inspectors are empowered to recom¬
mend men for employment, promotion or discharge. Delinquents
should be sent with a sealed note of explanation to the office.

8. If an employee is unsatisfactory in any way, the inspector
or other officer immediately in authority over him should iuform
him at once of the fact and note it on the report of that day.

9. If men are delayed in getting to work by the lateness or
negligence of an inspector or a teamster, or if any inspector shall
order or allow his men to cease work before the regular hour, said
inspector or teamster will have the hours lost by himself and the
men deducted from his time, and superintendents shall report the
facts of the case.

10. Employees before signing receipts for tools should assure
themselves that the numbers on the tools and receipts agree.

11. If a transfer of tools from one employee to another is made
in the field, the tools will remain charged to the man who took
them from the storehouse, unless a record of such transfer is taken
in or mailed to the office within twenty-four hours of the time of
such transfer. Unless such notice is received, the employee to
whom the tools were originally charged will be held responsible
for them.

12. Inspectors may use time cards, when necessary, as a
medium for ordering tools.

13. Drivers and owners of wagons are responsible for tools
committed to their chaige.

14. An employee leaving the service of this Board must at
once return to the quartermaster all property of the Commonwealth

APPENDIX. xxiii

which has been in his charge. Otherwise, the full value of the
same will be deducted from his wages then due.

Rules for Inspecting Sections, Marking Trees and Destroying

Eggs.

15. Each inspector must keep in his note-book a complete
record of all work done in his section. This book is to be returned
to the director’s office when called for, and to be left there when
the inspector’s term of office expires.

16. Each inspector must carry his section map with him in the
field and locate upon the map (by means of such marks as may
be ordered by the director) each tree or locality that he finds
infested.

17. Each tree found infested must be at once marked with such
characters as may be designated by the director, the mark to be
on the trunk at three points equidistant from each other and five
feet from the ground.

18. When a tree is found infested which has been marked in a
previous season, the new mark is to be placed two inches above
each of the latest marks.

19. Each object on which egg-clusters of the gypsy moth are
found in “outside towns” must be marked with a spot of white
paint the size of a ten-cent piece, this spot to be within an inch of
each egg-cluster. Egg-clusters found in woodland must be sur¬
rounded with a ring of white paint.

20. No trees on highways, in orchards or upon grounds about
residences are to be cut, burned or trimmed unless it is found to
be actually necessary. In every case where a large bi’anch is cut
off the stump must be covered with coal-tar. Trees must not be
cut down unless written permission is obtained of the owner, or
unless it is so ordered by the director.

21. Each inspector will pay special attention to the trees and
shrubbery along the lines of railroad in his territory. The grounds
around railroad stations must be carefully inspected.

22. Inspectors are not to call at the office except to leave re¬
ports, or unless by special order of the director.

23. Each inspector or acting inspector having charge of two
or more men will foimi his men in line and call the roll at seven
a.m. at the place where he begins work. He will again form
them in line and call the roll at the close of the day’s work.

24. When the roll is called at night inspectors must state dis¬
tinctly to their men the point at which they will call the roll on
the following morning, and any employee who fails to answer this
roll-call will not be allowed full time.

XXIV

THE GYPSY MOTH.

25. Employees will exercise great care that they do not carry
living larvae from place to place either on their vehicles and cloth¬
ing or in any receptacle.

26. When employees under the direction of an inspector are
obliged to injure or destroy any property, or Avhen property is
accidentally destroyed, or accidents of any kind occur, the facts
must be reported at once to the inspector, and he must make a
note of the same in his report, giving an estimate of the amount
of damage done and names of all witnesses.

27. Inspectors must note (and ask their men to note) and
state in their reports the language and means used by persons ob¬
structing their work.

28. When troublesome dogs are encountered inspectors may
require the owners to confine them, under penalty of the law.

29 . Employees must not leave ladders standing or lying by the
curbstone in the street. They must be taken down when not in
use and removed to some safe place. Care must be used in
handling ladders and also in climbing trees, not to break or other¬
wise injure the branches.

30. Employees must exercise great care in blazing trees. The
inner bark should never be cut.

Fires.

31. No fires shall be kindled except by order of the division
superintendent.

32. Superintendents will demand that due caution is observed
in the kindling and management of fires. They will see that the
necessary appliances are at hand for the management and extin¬
guishing of all fires ordered kindled. Inspectors in charge will be
held responsible for the proper management of fires, or if fires are
left at the close of the day’s work without being extinguished.

33. No fires are to be built upon sidewalks, or near the curb¬
stones in the streets.

Spraying.

34. Inspectors must notify pedestrians not to walk under trees
which are being sprayed, and must avoid spraying on vehicles.

35. In spraying always station the tank to windward of the
sprayers, so that the spray may not blow over it.

36. Before beginning work on an estate inspectors must re¬
quest occupants to take clothing from lines, close windows and
remove anything that may by any possibility be injured by
spraying.

37. Employees must, use great care not to injure lawns, flower¬
beds, vegetable gardens or other property.

APPENDIX.

XXV

38. Inspectors are to handle and mix poisons.

39. The solution in the tank must be constantly stirred from
the time it is first mixed until the tank is empty.

40. Tanks must be fastened on the wagons in such a way that
they cannot be overturned.

41. If, during the spraying, a tree is found infested and un¬
marked, it must be marked. Each time a tree is sprayed it must
be marked with three round dots, the size of a ten-cent piece, the
first set being placed five feet from the ground, and each succeed¬
ing set an inch above.

42. Inspectors will carefully notice the effect of the spraying
and record the same in their daily reports.

43. The spray thrown on the trees must be as fine as possible.

44. Drivers of spraying wagons, when at work, will be under
the direction of the inspector in whose section they are employed.
Each inspector will keep the time of his driver and report the
same.

45. Inspectors must, when possible, draw water from the stand¬
pipes. When hydrants are used the inspector only shall open and
close them, exercising great caution to open and close them slowly,
but not closing them so tightly as to prevent opening.

46. At morning and at noon, before beginning spraying, each
nozzle must be turned into the bottom of the tank and a full
stream pumped for five minutes.

Reports.

47. The rating of superintendents and inspectors will be based,
not only on the quality of the work done by their men, but on the
fulness and excellence of their own reports. All reports must be
sent to the director’s office and are subject to his approval. Each
inspector must make out his report daily and give it to his super¬
intendent, or send it to the office (by mail or otherwise) on the
following day. Observations on the habits of the insect and other
items of interest, and any statements or complaints by citizens,
should be embodied in the reports.

48. Superintendents must notice whether the streets are re¬
ported in their proper sections.

49. Inspectors must give time of employees on each day’s
report.

50. In case of the absence of an employee the inspector must
give the reason (when known to him) for such absence on the
report of the day when such absence occurs.

51. Inspectors must observe the printed headings on reports
and fill spaces reserved under the same.

xxvi

THE GYPSY MOTH.

52. Inspectors must give the correct street and number of each
building and estate inspected and the full name of the property
owner or tenant.

53. If at work in two or more sections in a day, inspectors
must make a separate report for each section.

54. The name of the inspector, if at work, must appear in the
employees’ column.

55. When a man enters the employ of this Board the inspector
with whom he first serves shall make note of it at the time on his
daily report.

56. Each inspector will designate on each day’s report and
time card the exact point at which he will begin work on the next
working day and on wThat street and in what direction he will
move ; also the exact hour and place of roll-call and the place
designated for roll-call the following morning.

57. Whenever a marked tree is cut the inspector in charge
shall incorporate the fact (giving marks) in his daily report.

58. Inspectors will report as trees all young growth above
three inches in diameter.

59. When brush is cut and ground burned over inspectors will
report in square yards the area cleared daily.

60. If men are sent away on special duty by an inspector he
must state the reason on his report and mark time card “ see
report ” opposite such names.

61. Superintendents, special inspectors and all other assistants
in the field must state on their daily reports when and where they
meet their men; and inspectors must also note on their reports
the time of such visits.

Per order of the committee,

E. H. Forbush, Director.

MAP V. Fac-simile of a blue-print map (reduced) of Section 8. Medford. The crosses denote
principally infested shade and fruit trees in 1891.

APPENDIX.

XXV11

Appendix C.

AN EXTRACT FROM A DESCRIPTION OF SECTION 8, MEDFORD,
AS IT APPEARS IN THE SECTION BOOK, SHOWING THE
CONDITION OF THAT SECTION AND THE WORK DONE IN
IT IN 1891. [THIS SECTION INCLUDES THE GLENWOOD
DISTRICT.]

Medford, Section 8.

Boundaries.

Commencing at a point on the centre line of Main Street, in
front of the Boston & Maine station of the Medford branch rail¬
road ; thence easterly by the centre line of said railroad to the
centre line of the main line of the Boston & Maine Railroad ; thence
northerly on said main line of railroad to a creek flowing under
said railroad (the centre line of said creek being the boundary
line between Medford and Everett) ; thence northwesterly and
northerly by said boundary line to the centre line of Salem Street
to Valley Street; thence westerly by said Valley Street to Forest
Street ; thence southerly by the centre line of said Forest Street
and Main Street to the point in front of the railroad station, the
point of beginning.

Description.

Section 8, Medford, contains the cottage formerly occupied by
Mr. L. Trouvelot, the gentleman who imported the gypsy moth
and accidentally liberated it here. The southwestern angle of the
section near the Medford branch railroad station constitutes a
large part of the business portion of the town. It is quite com¬
pactly built up with dwelling-houses, shops, stores, etc. The
traffic with outside towns is considerable. The principal thorough¬
fare, Salem Street, is the high-road to Malden and the towns to
the east. Forest Street, which forms the western boundary, is
much used for carriage driving. On the Medford branch railroad
and within this section are the Park Street and Glenwood stations.
Near these stations and on the intervening land along the line are
the homes of small householders and people whose business is in
Boston. Here, as elsewhere through much of this section, each
house has its lot of land and generally a small garden or orchard.

XXV111

THE GYPSY MOTH.

The streets are usually well provided with shade and ornamental
trees, many of which are large and stately elms. In the spring of
1891, when work was first begun by the commission, the greater
portion of this plain, including the swamp, was covered with
a young coppice intermingled with bushes and undergrowth.
Near the southern border of this tract the Anderson Pressed
Brick Company erected extensive works in 1886 on the ground
used more than twenty years ago by Trouvelot for his silk-worm
pasture.

Gravelly creek runs through the western part of the section near
the Forest Street boundary. The northern boundary of the sec¬
tion lies close to the rocky ledge which marks the beginning of the
Middlesex Fells. Near the centre where the insect was first
colonized there is a large tract of woodland suitable for the shelter
and propagation of an insect pest. Upon the west several streets
much travelled, and with gardens and orchards on either hand, lead
toward the centre of the town. On the south is a railroad which
terminates at the heart of the infested district and is supported by
a traffic with Boston. The principal thoroughfare connecting
Medford with eastern towns runs through the heart of the section.
Another large thoroughfare marks its eastern border, and a stream
which flows north or south as the tides rise and fall rises in the
section and flows to the Mystic River. Here we have all the
requisites for the sustenance of the insect and all facilities for its
transportation in all directions.

The commission appointed by Governor Brackett to “ check the
spreading and secure the extermination ” of the gypsy moth un¬
doubtedly destroyed large numbers of moths in this section by
burning, by scraping off the eggs and by spraying ; yet when the
agents of the Board of Agriculture first entered the section, in
March, 1891, its condition was, to say the least, alarming. Some
parts of the brush and woodland were so infested with the eggs of
the species that it was utterly impossible with the men and means
at our command to destroy them by hand. There were acres of
ground where egg-clusters were numerous. Many eggs were laid
on the ground and were found in great numbers in excavations
where people had dug out clay or sand. A stone wall which was
torn down (the lower surfaces of the rocks being thereby exposed)
presented a remarkable spectacle. There being no large trees
near the wall, it formed a refuge and concealment for the moths
that fed on the neighboring bushes and saplings. On one rock
over one hundred large egg-clusters were counted. When the
number of eggs contained in a single egg-cluster is considered, it
is apparent that millions of caterpillars would have hatched in

APPENDIX.

XXIX

this wall had the eggs not been destroyed. The trunks of some
of the trees were actually yellow with egg-clusters. Though the
insects were not distributed equally over the entire section, there
were many places where eggs were found in sufficient numbers to
have let loose a destroying host upon the entire neighborhood. A
large per cent, of the yards within one-half mile of the Trouvelot
house were thus infested.

The yard of the Anderson Pressed Brick Company includes a
part of the wooded section hereinbefore described. At the present
time the eastern portion of the yard is covered with a scattered
growth of young oaks and bushes. Near the buildings and
attached to them on the east are several sheds in which are piled
many thousands of the finest quality of pressed brick. East of
these are several detached sheds also filled with brick. Near
them is a pile of broken bricks about thirty yards in length,
fifteen feet in width and ten feet in height. These sheds and the
brick-bat pile are among the oaks, the pile being heaped against
some of the trees. When the work in the brick yards was begun
by the commission on March 21, 1891, the entire premises were
infested by the gypsy moth. About three hundred thousand
bricks were stacked in the sheds and two hundred thousand out¬
doors under the trees. The crevices between these bricks gave
opportunity for the moths to deposit their eggs. The bricks
under the sheds near the buildings had not been much frequented
by the moth, but three-fifths of those under the trees were more or
less covered with eggs. The egg-clusters were found ou the
ground and under the floors, on the sides and under the roofs of
the sheds, under the stumps and about the roots of trees, on their
trunks and limbs and in almost every conceivable sheltered place.
As the infested bricks were likely to be transported in all direc¬
tions, the danger of the distribution of the moth by this means
appeared great. A capable man was at once stationed in the yard
to examine all bricks sent out. The finest quality of bricks sent
out previous to this time had been shipped to a distance. Most
of them were used for fireplaces and were cleaned by the brick
company before shipment, and in this way all eggs were probably
taken off. Many localities to which bricks had been shipped were
afterwards examined. The work in this yard was pushed with
the greatest energy. Two hundred and thirty-two thousand one
hundred and ninety-five bricks were examined, and all those
infested were cleaned and the eggs burned. The shed most badly
infested was burned. The floors, roofs, etc., of the others were
torn up wherever necessary, and the eggs taken from them.
Some of the trees near the shed were cut down and burned. The

XXX

THE GYPSY MOTH.

brick-bat pile was surrounded by a board fence eighteen inches
high. This was covered with tarred paper, and before the cater¬
pillars began to hatch in the pile the paper was covered with a
mixture of pine tar, printers’ ink and crude petroleum. This
fence the young caterpillars were unable to scale. The trees in
the brick yard were inspected and the eggs on them destroyed.
Fire was run through the underbrush, but this did not kill all the
eggs. One section of the yard wras burned experimentally by
spraying the ground with crude petroleum after the brush had
been set on fire. On this section no signs of the caterpillars
were seen during the year. In other sections, where some eggs
survived the burning and hatched, all vegetation was sprayed
with Paris' green several times during the season. At the end of
the season it was difficult to find any sign of the moth in the yard.
Trees and bushes were cut down over a tract of one hundred acres,
and fire was run over it. Any spot that escaped the fire was
thoroughly burned by the use of crude petroleum.

The inspection of the towns on the border line- of the infested
district occupied so much time in the spring of 1891 that it was
found necessary to neglect until egg-hatching time a large tract
near the centre of the district in Malden and Medford. Time was
found, however, to inspect the large trees along the highways and
railroads. The eggs found on them were destroyed and the trees
were banded with tarred paper, which was kept covered with the
mixture used in the brick yard. This prevented the larvae from
ascending these trees, and reduced the danger of their being
carried out of the district. Most of the trees in the section were
sprayed two or three times during the season with a mixture con¬
taining Paris green, in some places where badly infested they were
sprayed four times ; nearly all vegetation, in fact, was sprayed.
Holes in the tree trunks which offered hiding-places for the larvae
were filled with cement. Burlap bands were put about the trees
after the caterpillars began to cluster, and by these means the vast
increase was kept down.

As soon as the female moths had laid their eggs and died, a
small force of men began destroying the eggs. It was soon
noticeable that, while vast numbers of last season’s egg-clusters
which had hatched were found, very few newly laid clusters ap¬
peared. Every nook and crevice was searched with the greatest
care to discover and destroy all traces of the moth. While the
leaves remained on the trees, buildings, fences, woodpiles and all
hiding-places near the ground were searched. As the leaves fell
the trees were examined and cleaned of eggs. Where the trees
were thickly infested the leaves were raked up and burned ; thus

APPENDIX.

xxxi

every possible effort was made to exterminate the moth by gather¬
ing the eggs.

After going over the entire section carefully, an estimate of the
number of eggs found was made. Comparing this with the
estimated number found in the spring, it was seen that the number
found in the fall was about twenty per cent, of the number found
in the spring. The data for this estimate were very complete, and
were taken from the daily reports of the inspectors.

xxxii

THE GYPSY MOTH.

Appendix D.

REPORTS OF ENTOMOLOGISTS WHO VISITED THE INFESTED
REGION IN 1893.

Report of Dr. A. S. Packard of Brown University, late of
the United States Entomological Commission.

Providence, R. I., June 19, 1893.

Prof. C. H. Fernald.

My Dear Sir : — Having been asked to give my impressions
of the work now being done at Malden and vicinity in exterminat¬
ing the gypsy moth, I will say that it made a good impression on
me, and I have no adverse criticisms to make. Mr. Forbush seems
exactly adapted for the work intrusted to him. I was struck
with the ability shown in organizing and systematizing the whole
work, and the readiness and interest shown by the men under Mr.
Forbush. The office and its system, the storehouse and its appa¬
ratus, interested me very much, and the new and ingenious devices
for spraying and in other ways destroying the eggs and worms.
It seems to me the work is practical and thorough throughout,
and must bear good fruit this season.

In the short time I spent I saw nothing to find fault with, but
much to commend. I say this without wishing to merely say
something pleasant, but because I mean it.

Yours very truly,

A. S. Packard.

Report of Dr. J. A. Lintner, State Entomologist of New

York.

Office of State Entomologist, Room 27, Cafitol,
Albany, June 22, 1893.

Prof C. H. Fernald.

My Dear Sir : — The two days that I passed last week, in
compliance with the request of the gypsy moth committee of the
State Board of Agriculture and of yourself, in inspecting the oper¬
ations of the committee through its director, Mr. E. H. Forbush,
were highly gratifying and satisfactory to me. I wai not pre-

APPENDIX.

XXXlll

pared to see that such progress had been made toward the exter¬
mination of the notorious gypsy moth. It was a surprise to me
that in the brief space of three years the fearful ravages of the
insect as described to me and as pictured in photographs could
have been reduced to such a comparative harmlessness that to the
ordinary observer no indication of its presence was visible, and
that in a ride of an entire day through several of the “ infested
towns,” including a visit to localities which had been frightfully
scourged, not a single example of the caterpillar was found by
me, although diligent search for it was made.

How a work of such magnitude, extending over so large a terri¬
tory, could have been accomplished, was a wonder and an enigma
to me, until I became acquainted with the means by wrhich it had
been brought about. These are, in part : —

First. Your work at the insectary is largely supplementing
that being conducted at the Malden headquarters. I regard it so
exceedingly valuable and so absolutely essential to the best results
in field work, the one to check and therefore to aid the other.

Second. The committee, I am confident, have been both wise
and fortunate in their selection of Mr. Forbush as director of field
work. I think that I estimate correctly when I say that he is
eminently fitted for the important and responsible position. A
high degree of judgment and discretion has evidently been exer¬
cised in the selection of those employed by him and the retention
of those best qualified for the duties assigned them. The execu¬
tive ability displayed by him in the organization of his force, its
direction, guidance, supervision, equipment, accountability, etc.,
seems to me remarkable, and to go far toward the accounting for
the singular success that has attended his administration.

Third. The “ storehouse” greatly interested me. It may prop¬
erly be called an “ arsenal,” for it is furnished with all the
appliances needed for conducting in the most effective manner the
warfare in which you are engaged. In it are found not only all
of the more important instruments and materials that economic
entomology had tested in former years but many new ones, called
into use for the first time, as the need had become apparent and
the ability for their conception and production was at command.

With such means, as above indicated, your State, which has
been liberal in its appropriations, has a right to expect ample
returns. It will not be disappointed, for you have already accom¬
plished more than could have been reasonably expected.

I trust that your Legislature will see the wisdom of continuing
the work under suitable appropriations, until the extermination of
the insect has been attained, or at least until it shall have been

XXXIV

THE GYPSY MOTH.

reduced to entire harmlessness, and in position never again to
develop in injurious numbers or to invade other States.

I have been asked to offer such criticisms or suggestions as I
might deem it proper to make. I have found nothing to criticise,
but, on the contrary, have received instruction from what I saw.

Under the permission given, I will offer two suggestions : —

1. As what may be called the mechanical details of field work,
as burlapping, liming, spraying, egg collecting, etc., are steadily
diminishing, there will be the greater need (as well as the oppor¬
tunity) of scientific work, to round up, as it were, the labors of
the committee, to aid in its completion, to render it available for
future use wherever the necessity may arise in this or similar
insect invasions, and to make such a contribution to science as
Massachusetts has ever been ready to do when the occasion has
offered.

I would, therefore, suggest (and recommend, if I dare venture
to do so) that the committee, if possible, avail themselves of more
of your time and service. Your habits of thought, observation
and study seem specially fitted to the work that 3Tou are now con¬
ducting for the committee. Further, the experience that you have
gained is of so great value that it should not be lost to them. I
do not, however, see how this could be brought about under your
existing relations with the college and agricultural station. I am
sure that there is an ample field for your entire service. If the
committee could offer you a sufficient inducement, is it not pos¬
sible that, Avliile retaining your connection with the college and
station, you could be released from the discharge of the duties,
say for two or three years, and devote yourself wholly to the
gypsy moth ? So positive am I of the utility of such an arrange¬
ment, that I sincerely hope that it may be accomplished.

2. Just at this stage of the committee’s work I would sug¬
gest that the cultivation of the parasites of the gypsy moth be
entered upon and conducted with all the knowledge and skill that
can be brought to bear upon it. Far more is to be hoped from
this than from the costly and problematical search for and impor¬
tation of its European insect enemies. Nearly a score of native
parasites are already known to prey upon it, and we may expect
this number to be materially increased. Something like the fol¬
lowing method of cultivation might be pursued : —

Collect the pupae as soon as they are to be found, so as not to
give opportunity for the escape of the earlier maturing parasites.
None should be destroyed, but carry all carefully to headquarters
at Malden, suitable provisions having been previously made for
their reception and care.

APPENDIX.

XXXV

If 80,000, as reported, were collected last year, perhaps from
15,000 to 20,000 might be secured this year. Arranged in a
single layer, a case not exceeding twenty-five square feet of area
would be ample for them, and leave space at one end for feeding
larvae.

By means of cold storage, delay the development and emergence
of the parasites until larvae are in readiness in which they may
oviposit.

Egg-clusters collected this season shall be so regulated by
temperature that they will give out their larvae as soon as food is
obtainable for them.

With the feeding larvae in one part of the case with the pupae, they
will at once be found by the parasites and all of their eggs deposited
in them if the larval supply is proportioned to their need.

When the parasitism is finished, the larvae may be fed in con¬
finement to maturity, if practicable, provided that conditions
favorable to the prevention of disease or other fatality can be
given them ; or they may be transferred to isolated trees selected
for the purpose, where they may complete their growth and be pro¬
tected from destruction by birds by inclosing the trees in netting.
The following season the parasites, unless desired to extend their
multiplication by again rearing them in confinement, may be per¬
mitted to escape and seek their prey abroad.

The parasitized caterpillars might be conveyed to the localities
where the parasites are the most needed.

Gathering the parasites from the case after their death would
give every species which was parasitic on the larvae and pupae
(except such as may have emerged from the larvae), and their
proportionate number, from which the most efficient could be
ascertained. Examination would also show the proportionate
number of pupae that had been destroyed by parasites.

The above plan may not have been properly digested by me,
and there are no experiments of the kind to serve as a guide. So
far as I know it has not been attempted on a large scale (the
multiplication of icerya parasites in California was somewhat
similar) , but if done with the knowledge that you could bring to
bear upon it, I am sanguine of its success. Possibly by this
means only can the desired extermination of the gypsy moth be
attained.

If, under the existing law, the carrying of the living insect
from one town to another is prohibited, amendment for the above-
named purpose could no doubt be secured.

* Very truly yours,

J. A. Lintner.

xxx vi

THE GYPSY MOTH.

Report of Prof. John B. Smith. D.Se., of Rutgers College,
State Entomologist of New Jersey.

New Brunswick, N. J., June 20, 1S93.

Dear Dr. Ferxald : — Since my return to New Brunswick I have
been thinking over what I saw of the work of the gypsy moth
committee near Malden, Lynn and Swampscott, and with the
lapse of time my admiration for the work accomplished has in¬
creased rather than diminished. When I received your invitation
I was, I think I can truly say, free from actual prejudice, yet with
a disposition to believe that the work of the committee was
palliative merely, and that actual extermination was impossible, an
impression to which I had given public expression. I am pleased
to say that I have seen ample evidence to induce a change of
opinion, and my belief is now that if the committee is as well
supported as it deserves to be it will accomplish the end for which
it was created. "With this expression of my present belief, you
will understand that my suggestions are not in the nature of
adverse criticism.

First, concerning the experiments in progress at Amherst, at
the present time. These consist of a test of the action of certain
insecticides on larvre of all ages, and in contemplation are experi¬
ments concerning possible parthenogenesis, fixing the relative time
of issuing of the sexes from one batch of eggs and the effect upon
the fertility of the eggs of close breeding, — that is, between
males and females bred from the same egg-mass.

All these experiments are not only of the highest scientific
interest, but also of the utmost practical importance.

If parthenogenesis is possible, the danger of spreading the
insects by carrying off single specimens is vastly increased, and the
most stringent measures to prevent such distribution are justified.
While parthenogenesis in the Lepidoptera is extremely rare, yet
cases have been recorded in the same natural group to which this
insect belongs, and the inquiry is therefore by no means a merely
curious one.

Fixing the relative time of the emergence of the sexes of the
same brood is of very great importance, for, if males and females
issue at such intervals as to make it unlikely that they can pair,
the danger from the distribution of even several larvae from the
same batch of eggs is materially lessened.

The determination of the effect of in-breeding is equally im¬
portant, for much the same reason.

Finally, the experiments with insecticides are of peculiar interest,

APPENDIX.

xxxvii

from the fact that the caterpillars seem unusually resistant to the
action of arsenic in doses fatal to most of the insects known to us.

There is one criticism to be made on all the above experiments :
they are on too small a scale to render the results altogether convinc¬
ing and they are made in the wrong place at Amherst rather than at
Malden, Lynn or elsewhere in the infested region. The extreme
caution necessary to prevent the escape of specimens of the larvae
prevents the practice of certain lines of out-door work, the results of
which would supplement the in-door or laboratory experiments.

I would therefore suggest that the experiments now carried on
at Amherst be duplicated or transferred to some point within the
infested district where material is more abundant, and where there
is no danger of introducing the insect into new localities.

These experiments must of course be made by a trained ento¬
mologist, or by a competent man under detailed instructions. By
all odds the most satisfactory plan would be to have you carry on
the experiments yourself, for they would then command universal
acceptance and would be generally regarded as conclusive.

The result of the insecticide experiments thus far is so unusual
that I would recommend a further series of experiments to deter¬
mine exactly what becomes of the arsenic eaten by the insects ;
whether it is absorbed or whether it is excreted, and how much
arsenic an insect will contain when its intestinal canal is filled with
poisoned food and excreta therefrom. This could be done by
feeding larvae on leaves sprayed with a maximum amount borne
by the foliage for say three or four days, and then substituting
fresh food free from poison. A chemical test should be made
thereafter every day or every day or two, to ascertain the presence
or absence of arsenic in the larvae. Microscopic examinations of
the digestive tract of poisoned larvae should also be made, and
should be compared with that of healthy larvae, to ascertain
whether any lesion were caused that might result in a degenerated
adult. The excreta of larvae fed upon poisoned food should also
be analyzed to determine the amount disposed of in this way.

This is of course suggestive merely ; but in my opinion the
present occasion is an unusually good one to gather a mass of
facts whose importance to economic entomology it would be dif¬
ficult to estimate.

If I had reason to speak in approbation of the line of experi¬
ments laid out by yourself at Amherst, I found very much more
to admire in the infested district, in the actual field work under
the direction of Mr. Forbush. The mere organization of the force
and the plan of the work is excellent ; as to the results of the
methods adopted, the fact that in the entire infested district

XX XV 111

THE GYPSY MOTH.

visited by me — Malden, Lynn and Swampscott — only a single
half-grown larva was discovered speaks loudest.

I was extremely interested in the office organization, in which
the system of entering and classifying reports enables the director
and the members of the committee to determine at once the exact
condition of affairs in any district. The notes of observations
made by inspectors are many of them of the greatest interest,
and merit editing by an entomologist capable of recognizing facts
and separating them from inferences made by the observer.

The inspection of the tool-house was a revelation in the variety
of apparatus it afforded, all of it adapted to the special end in
view. The practical value of all the apparatus is obvious, and
while for an orchard the spraying outfits might be considered
clumsy and somewhat wasteful, yet when the character of the
work is considered the apparatus designed for the fruit grower is
manifestly insufficient. A most commendable feature in the work
has been seeking out means of taking advantage of the peculiarities
of the insect’s habits, which is, after all, the most philosophical
way of accomplishing the work in hand.

It would be altogether too long a task to go into details con¬
cerning the outfit of insecticide machinery, and I need only say
that I can find absolutely nothing to suggest in the way of improv¬
ing the methods of work.

The force under the direction of Mr. Forbush has accomplished
wonders, and I feel now that there is very good reason for the be¬
lief that the gypsy moth can be exterminated, provided the means
are furnished by the Legislature of Massachusetts in as liberal a
spirit at least as past appropriations have been made.

I have been asked to give an opinion on the feasibility of intro¬
ducing European parasites of this insect, to keep it in check. I
feel very decidedly that this would be money wasted. This and
its ally, the Nonne , are frequently destructive in Europe, and if
its parasites do not succeed in mastering it there, there is no reason
for believing that they can do better here.

Nature never works for the extermination of any of its creatures,
and if parasites ever exterminated their hosts the parasites them¬
selves would be exterminated for the want of food. A balance is all
that nature aims for. A parasite which would be able to exterminate
the gypsy moth in this country must be one that would prey on this
one insect only ; and even then it is very problematical whether
the result would be very satisfactory, for to enable the parasites
to do their work, artificial means of destroying the larvte would
have to be abandoned for fear of killing the parasites as well.

I am very strongly of the opinion, therefore, that nothing can
be gained by an attempted introduction of parasites.

APPENDIX.

XXXIX

The oft-citecl case of Vedalia destroying the cottony cushion
scale in California can have no application to this case, for the
circumstances there were so peculiar that they can rarely be dupli¬
cated, and are not similar here.

I am asked to express an opinion as to the work done and to be
done by the committee. I can only repeat what I have already
said, — the work done by the committee as at present organized
is admirable, and I am unable to point out a method in which it
could be improved.

Both the entomologist and the director thoroughly understand
the problem, and are working for success, — a success that I now
think they will attain.

As to the work yet to be done, I am not in a position to give an
opinion, because I had no time to cover the entire ground. From
what I could see at Malden, Lynn and Swampscott, I believe that
for at least two years more a full force of men should be em¬
ployed, using the methods that have proved so successful and
working from the outer limits toward the central district.

The most useful men should in all cases be retained from year to
year, for they will be worth at least double the sum any new man
could be valued at, and will know just exactly what is to be done
in all cases and just what to look for. After a few years the force
of men could be safely reduced to the inspectors and a few ordi¬
nary workmen, whose principal business would be a continuous
examination of the once-infested district, prepared to destroy any
isolated brood that may have escaped ; and finally this force could
be reduced to the director and a very few inspectors, who, with
the experience gained, could easily command the entire region
until lapse of time proved the insects exterminated.

Very truly yours,

John B. Smith.

Dr. C. H. Fernald, Entomologist , Gypsy Moth Commission, Amherst, Mass.

Report of Prof. Clarence M. Weed, D.Sc., of the New
Hampshire College of Agriculture and the Mechanic
Arts, Entomologist of the Agricultural Experiment
Station.

Hanover, N. H., June 16, 1893.

To the Gypsy Moth Committee.

Gentlemen : — In response to the invitation extended by you
through Professor Fernald, I recently visited the various depart¬
ments of gypsy-moth work, and beg leave to inform you of the
impressions thus received.

xi

THE GYPSY MOTH.

I first inspected the work in progress at the insectary at Am¬
herst, and found that a series of experiments with remedies was
being conducted under the most careful conditions ; in fact, I have
never seen a series of similar experiments carried on in so large a
scale in so thoroughly scientific a manner. They ought certainly
to furnish reliable results, which will be of great value outside of
the gypsy-moth work.

I next went to Malden, and in company with the other visitors,
Professor Fernald, Mr. Forbusli and Mr. Reid, looked over the
ground carefully. The general impression received was very
favorable as to the amount and methods of work. The results
already reached seem to be remarkable, and I was greatly surprised
at the scarcity of gypsy caterpillars. The methods of fighting the
pest have evidently been developed along with the knowledge con¬
cerning it, and are well adapted to the end in view.

The only suggestion I have to make concerns the lack of ade¬
quate facilities for studying the life history of the pest at head¬
quarters. It seems to me that if a room adapted to the purpose
could be set apart, and a man of entomological training be detailed
to make out the biological points yet in doubt, valuable results might
be reached. I should suppose that it would hardly be necessary to
call in an entomologist of note if Professor Fernald is willing to
supervise the work of the one detailed to carry on such observations
and experiments. In fact, the results would have an added value
if carried on both at Malden and Amherst under one direction.

I was especially interested to learn of the results that have been
reached with the arsenate of lead. Even if it does not kill gypsy
caterpillars as quickly as does Paris green, it seems probable that
it will make a valuable insecticide for many other purposes.

Thanking you for the opportunity you afforded, and assuring
you of whatever support I may be able to render, I am,

Yours respectfully,

Clarence M. Wbed.

Report of Dr. H. T. Fernald, of the Pennsylvania State

College.

State College, Centre County, Pa., June 19, 1893.

To the Gypsy Moth Commission.

Gentlemen : — In accordance with your request, extended to
me by Prof. C. H. Fernald, I have examined the work in progress
at Malden and Amherst, and am both interested and pleased with
what I have seen.

APPENDIX.

xli

Previous to my visit to Malden I felt some doubt as to whether
it was possible to exterminate the gypsy moth, as I had had
some previous knowledge of it and of its ravages in Massa¬
chusetts, being at Amherst when it was first reported to the ex¬
periment station there iu 1889, and having carefully looked over
the matter at that time. Since my visit a careful considera¬
tion of the methods used and of the results already obtained
has convinced me that extermination is not only probable, but
certain, if the work be prosecuted for a sufficient length of
time.

On one or two points I have gathered impressions which may
perhaps be worthy of mention here : —

1. I think that the position so far held by the committee with
reference to the effect of parasites is a wise one. I have never
heard of a case where an insect was exterminated by its parasites,
the relation of the two forms at any one time being, in numbers,
very close. A reduction in the numbers of the host is always
followed by a similar reduction in the numbers of the parasites,
leaving to those individuals of the host which have escaped an
opportunity for rapid and unchecked increase until overtaken by
a corresponding but later increase in numbers of the parasites.
For this reason parasites cannot be relied upon to do the work
needed in the case of the gypsy moth.

2. The method of burning over infested areas in connection
with burlapping the trees seems to me to be a most effective
method of procedure if the precaution of burning for a sufficiently
great distance beyond the limits of the infested area be carefully
observed. My impression is that the edge of the burned area
should always be at least two hundred feet outside these limits,
as far as these can be ascertained.

The work so far accomplished shows on its face that the
methods in use are the result of experience, and that they are
most efficacious.

It seems to me that two things are greatly to be feared : —

1. That the time is near when searches with negative results
may tend to produce carelessness on the part of the searchers.

2. That the apparent disappearance of the moths may lead
the Legislature into the error of abolishing the committee at the
time when its work will show the fewest results, but will in reality
be the most valuable, — in fact, would be absolutely necessary to
insure the prevention of some future invasion.

The work done by the committee in the way of testing insecti¬
cides in the field at Malden and in the laboratory at Amherst is
of great value, and the importance of learning with the greatest

xlii

THE GYPSY MOTH.

accuracy just how successful each method is, cannot be overesti¬
mated. The care with which the experiments at Amherst are
conducted guarantees the accomplishment of this most important
task, while the discovery of a new insecticide with the properties
which the arsenate of lead apparently possesses must certainly be
worth more to the State than all the money it has spent for the
extermination of the gypsy moth.

Yours respectfully,

H. T. Fernald.

APPENDIX.

xliii

Appendix E.

REPORTS OF ENTOMOLOGISTS WHO VISITED THE INFESTED
REGION IN 1894. — OPINION OF THE UNITED STATES EN¬
TOMOLOGIST.

Report of Dr. George H. Perkins of the University of Ver¬
mont, Entomologist of the Vermont State Agricultural
Experiment Station.

Burlington, Vt., July 10, 1894.

Prof. C. H. Fernald.

Dear Sir : — In accordance with your invitation to visit the
region infested by the gypsy moth, I went to Malden, as you are
aware, and through the very cordial assistance of both yourself
and Mr. Ware, assistant director, was enabled to see in a most
complete and satisfactory manner the appliances used and the
various methods of using them.

I wish to express my appreciation of the thorough and careful
manner in which the work was being done, and the evident desire
of those engaged in it to execute the trust committed to them as
faithfully and economically as possible. No work of the sort
which I have ever seen or heard of has impressed me as favorably
as did that of the officials engaged in the work of exterminating
the gypsy moth.

The whole nation should be grateful to the committee for what
it has already accomplished ; for it is my belief that, had not the
work been so well done in Massachusetts, the insect would ere this
have spread beyond the borders of that State and now threaten
the whole land. It is most gratifying to find, instead of this, that
the ravages of the moth have been very much reduced by the
efforts of the committee.

No one interested in economic entomology can investigate the
work in office and field without at once discovering that a vast
amount of very useful information has been gathered which should
not on any account be lost to science. On this account it is very
greatly to be desired that as full and complete a report as possible

xliv

THE GYPSY MOTH.

of the work of the committee be published, for much that such a
report would contain would necessarily be of general and permanent
value.

The question has been asked, Is it possible to exterminate an
insect which has become so abundant as the gypsy moth ? Before
I visited the infested region, and saw what had already been done,
I was quite doubtful as to the expediency or the possibility of
extermination ; but after investigation I thought differently. It
seems to me very clearly the wisest and most economical course,
for the present at any rate, to continue the work as it is now going
forward, and aim at extermination. The men and the methods
now employed are so successful that it would be unwise to discon¬
tinue them for several seasons to come.

It also seems to me that the functions of the committee might
be very advantageously extended, so that in their discretion they
could direct their destructive agencies against such other insects as
might be easily taken in hand.

When passing through some of the towns infested by the gypsy
moth we noticed many trees the foliage of which had been wholly
destroyed by the canker-worm ; and many of these trees could
have been spra}7ed by those engaged in spraying neighboring trees
for the moth at small cost of time or money.

It was very evident that private enterprise could not be
depended upon to deal with these pests. It is my own conviction
that the most efficient and the cheapest method of dealing with
any insect which has become numerous and destructive is that
adopted in the case of the gypsy moth, not leaving to private citi¬
zens the too great task, and thus ensuring failure, but bringing
the authority and the resources of the State to the work, and
carrying it forward to success.

Is it not probable that, had the gypsy moth not been stayed in
its destruction, the loss to property through the destruction of
shade and fruit trees would have been more than the cost of
extermination has thus far been?

It is to be hoped that the work so well done thus far will not
now be suffered to lag through lack of either funds or popular
suppqrt. There is every reason for continuing it, while to stop or
reduce it would be a great calamity.

I have not been asked to praise the work of the committee, but
rather to suggest improvements in their methods, and to criticise
whatever I might find deserving it. I have no criticism to offer,
nor am I able to make suggestions other than those given above.

I am, sir, very truly yours,

Geo. H. Perkins.

APPENDIX.

xlv

Refort of Prof. F. L. Harvet of the Maine State Col¬
lege, Botanist and Entomologist of the Maine Experi¬
ment Station, Orono, Me.

To the Members of the Gypsy Moth Committee of the Stale Board of
Agriculture of Massachusetts.

Gentlemen : — In compliance with your courteous invitation
(extended to me through Prof. C. II. Fernald) “to inspect the
work of the gypsy moth committee and give my impressions and
advice,” I visited Malden the latter part of July, and spent two
days examining the work of the committee in the office, labora¬
tories and field. Through the courtesies of Director E. H. For-
bush and others of the department every opportunity was afforded
me to gain a thorough knowledge of the scope and character of
the work of the committee.

I went to Malden with an entirely inadequate conception of the
territory affected, and the stupendous undertaking of the com¬
mittee to reduce or exterminate the gypsy moth. I first visited
the office, and was surprised by the ingenuity and thoroughness
displayed in keeping the field notes and indexing them for ready
reference. A mass of information regarding the habits, natural
history and anatomy of this insect has been accumulated by
Professor Fernald, Director Forbush and their assistants. This
seems so important that for the good of entomological science it is
hoped it may be sifted by a competent entomologist and published
as a monograph by the committee. The pains taken in examining
the men for field work and the almost military exactness required
of them in their labor and reports reflect great credit upon the
organizing ability of the director, and speak much for the
efficiency of the service.

The work being done in the laboratory and insectary upon the
life-history of the moth, its parasites and histology, and upon
remedies, was timely and thorough. I was especially interested
in the histological work, conducted by Mr. A. H. Kirkland, to
determine if possible what becomes of the arsenical poison the
full-grown larvm are known to eat with impunity, and also the
trap experiments under the direction of Mr. Kirkland.

The storehousj-Tor apparatus and supplies impresses one with
the magnitude of the work, and is instructive in the novel
apparatus invented to fight this pest.

The results obtained in the experiments on insecticides, by Mr.
F. C. Moulton, are most important, and bid fair to be of great
usefulness to economic entomology.

xlvi

THE GYPSY MOTH.

The field methods of searching for the eggs, larvae and pupae,
the burlapping of the trees and the careful burning of infested
areas was thorough and practical.

Upon the whole, the methods which have been born of experi¬
ence and adopted by the committee for coping with the pest
impressed me as ingenious and effective. I have no criticisms to
offer upon the work of the committee, and regard the results
obtained as marvellous.

Entomologists are generally agreed that it is impossible to
exterminate an insect by means of its parasites, so all that can be
hoped for in this direction is uncertain aid in holding it in check.
Whether it is possible to exterminate an insect by persistent and
thorough hand-picking, use of insecticides and fire is problematical,
because it has never been tried. It is a plausible problem, which
we hope, for the good of economic entomology, the gypsy moth
committee may have the opportunity to settle. By the efficient
work of the committee, in three years’ time, this insect, which was
legion and doing great damage over a wide area, has been reduced
beyond detection by common observation. We spent a whole day
in the field, and, though constantly on the alert for specimens,
saw only four male moths and no larvae, pupae or eggs. So thor¬
oughly has the work been done that intelligent people in the dis¬
trict wrongly regard the work of the committee accomplished. It
is the scattering colonies, the last one per cent., that will demand
more thorough work than the other ninety-nine per cent., and your
Legislature and citizens will need to be thoroughly impressed with
this fact.

Two policies present themselves : first, whether an attempt be
made to fight the moth to the finish ; second, whether an attempt
be made to merely keep it in check, and prevent an increase to
harmful numbers.

The gratifying work of the committee so far would suggest
continuance in the good work, with the idea of extermination.
This would absolutely require the employment of a force of men
large enough to keep the whole infested area under constant sur¬
veillance for some time. The present number of men employed
seems to me to be inadequate, as large areas in the infested dis¬
trict have to be neglected while inspection is going on in others.
Unless a large force can be kept constantly employed for some
years, the idea of extermination will have to be abandoned by the
committee.

If the second policy be adopted, then the work of the commit¬
tee for the present is practically done. Yet a permanent force
would be needed to keep the area under occasional surveillance*

APPENDIX.

xlvii

and its energies directed to checking local outbreaks. This would
be an interminable job, constantly menaced with the danger of
the pest spreading over large areas to adjoining States, until so
widely disseminated as to be beyond human power to control. It
would seem to me to be wiser to attempt the extermination of the
pest while in its greatly reduced numbers by the adoption of a
liberal financial policy, than to drop the work and in a decade or
sooner have it to do all over again.

We regret to learn (unofficially) that naturalists are breeding
this pest for purposes of study outside of the Commonwealth of
Massachusetts, in defiance of the strict laws regarding its dissem¬
ination.

I heard the committee criticised by citizens and others because
they would not destroy other injurious insects besides the gypsy
moth in the infested district. We understand this criticism to be
unjust , as the Legislature confined the duties of the committee
strictly to the suppression of this one insect, and to use the money
to destroy the others would be a perversion of funds.

That it would be a wise policy for every State to have an en¬
tomological commission, with duties as broad as the requirements
of economic entomology, we have no doubt. The fact that the
gypsy moth committee has paid strict attention to business is the
reason why they have in such a short time accomplished so much.

In closing, I desire to thank the committee for the opportunity
offered me to study the life-history of this insect, and to become
familiar with the ingenious and effective methods used in coping
with it. I hope the committee will receive the financial support
from the Legislative that will enable it to succeed in this stupen¬
dous undertaking, which does not alone interest Massachusetts
but also the adjoining States and the whole country.

Respectfully submitted,

F. L. Harvey.

Report of Prof. John II. Comstock of Cornell University,
late United States Entomologist.

Ithaca, N. Y., July 17, 1894.

Mr. William R. Sessions, Secretary of the Committee on the Exter¬
mination of the Cypsy Moth of the State Board of Agriculture.
Sir : — In compliance with the request of your committee, trans¬
mitted to me through Professor Fernald, I visited the region
infested by the gypsy moth, and spent several days studying what
is being done towards the extermination of this species. During

xlviii

THE GYPSY MOTH.

the greater part of this time I was accompanied by Professor
Fernald and Mr. E. H. Forbush, who explained to me very fully
the details of the work.

I was filled with admiration of the work that is being done by
these gentlemen, and, although I have given the matter very care¬
ful thought, I am unable to suggest any changes in their methods.
It seems to me that the methods they are following are the best
possible, so long as the object of the work is the extermination of
this insect.

But, after going over the infested region, I have come to
have grave doubts as to the advisability of attempting to exter¬
minate this pest. I am not prepared to say that I consider exter¬
mination impossible, but it seems to me that the attainment of this
desired end is highly improbable. It is true there are certain
peculiarities in the habits of this insect that give hopes of the
possibility of extermination. Thus the slowness with which the
species spreads naturally, owing to the fact that the female does
not fly, and the fact that the larva in its later stages descends from
the trees and hides during the day-time, rendering it possible to
trap it, greatly facilitate the work of destruction. On the other
hand, the wide range of food plants, the extent of the area in¬
fested, including as it does large forests, and the ease with which
the species may be artificially spread by means of vehicles, all
combine to make the task a very great one. Still, if you could be
provided with sufficient funds extending over a sufficiently long
period, I believe these difficulties could be overcome.

But I feel that this is too much to hope. If at this time, so
soon after the terrible ravages of the pest, the Legislature appro¬
priates less than two-thirds of the sum which your committee, after
careful investigation, deems necessary to carry on the work, it is
hardly probable that succeeding Legislatures would furnish the
means necessary to carry this work to a conclusion, involving as it
would a large outlay for many years after the insect had ceased to
be a pest. As I do not believe that the financial support would be
furnished you, I respectfully suggest that you consider the advisa¬
bility of adopting a different method of combating the pest. Much
of the work that is being done now would be unnecessary if the
object was merely to keep the insect from being unduly destruc¬
tive ; and, if there is no hope of your receiving the support nec¬
essary to exterminate the insect, the continuance of the present
methods would certainly involve a large unnecessary expenditure.

It is probable that if your warfare against this insect was re¬
stricted to those localities in which its injuries are of a serious
nature, its natural enemies would greatly increase and tend to

APPENDIX.

xlix

keep it in check. Already a considerable number of parasites is
known to infest it. There will be a tendency for them to increase,
so that in time serious outbreaks of this pest will probably be only
occasional and in limited areas. Such outbreaks could be easily
subdued.

While I believe that a change in the object of the work of your
committee seems imperative, I would not consider for a moment
the giving up of your warfare against the pest, but would advise its
continuance in the following manner : I would suggest no change
in the organization for carrying on the entomological work of the
State. A committee of the State Board of Agriculture, consti¬
tuted as is your committee, seems to me to be the most appropri¬
ate organization for this purpose. I would, however, recommend
the broadening of the scope of the work of this committee, so that
it should have authority to deal with any serious outbreak of insect
pests. I will not presume to indicate in detail the method of con¬
ducting this wrork, beyond suggesting that in their more general
features the horticultural laws of the State of California might
serve as a model.

Very respectfully, your obedient servant,

J. H. Comstock.

Extract from the President’s Address by L. O. Howard,
Entomologist of the United States Department of Agri¬
culture, DELIVERED BEFORE THE SlXTH ANNUAL MEETING OF
the Association of Economic Entomologists, Brooklyn,
Aug. 14, 1894.*

The work upon the gypsy moth, by the way, which has been
done by the State of Massachusetts since 1889, is one of the most
remarkable pieces of work, judging by results, which has yet been
done in economic entomology. The operations have been carried
on by a committee of the State Board of Agriculture, and the
means have been furnished by large annual appropriations by
the State Legislature. Three hundred and twenty-five thousand
dollars have already been appropriated.

A territory comprising something over one hundred square miles
was infested by the insect, which occurred in such extraordinary
numbers as to destroy many trees and almost to threaten the ulti¬
mate extinction of living vegetation, not only within the infested

• Insect Life, Vol. vii., No. 2, page 59.

THE GYPSY MOTH.

territory, but in all localities to which it might spread. It is
unnecessary to detail the steps by which relief was brought about.
Mistakes were undoubtedly made at first, and it is to the work of
the present committee that the main credit is due. The infested
territory has been reduced by one-half, and within the districts in
which the gypsy moth at present exists it is, practically speaking,
a comparatively rare species.

The future of the insect is, however, problematical. The con¬
tinuance of sufficiently large appropriations from the State Legis¬
lature to enable the work to be carried on on its present scale is
doubtful, and yet those in charge believe that still larger appro¬
priations are necessary to bring about extermination. They are
confident, however, that with sufficient means the insect can be
absolutely exterminated from the State of Massachusetts. With
the Legislature disinclined to continue the large appropriations,
the methods of the committee at present pursued will have to be
seriously altered. Given a small appropriation of say $25,000
annually, it will become necessary to adopt some law, like that
enforced in California, whereby much less frequent inspection
may be made, and the committee will have to rely in part upon
voluntary observers for information. Moreover, they will be
unable to conduct spraying operations upon a large scale, and the
expense of the destruction of insects will have to be assessed upon
the owners of the property upon which the insects are found, pro¬
vided such owners will not themselves undertake the destruction of
the insects. There will be many disadvantages from such a
course, and in the case of unproductive lands the expense will be
so great that the owner will prefer confiscation. Between some
such course as this and the continuance of the present methods,
however, there seems to be little choice, since if the appropriation
were taken away the insect will not only speedily reach its former
destructive height, but will spread far and wide over the country.

It may be urged that it will be only a few years before the insect
will take its place as a naturalized member of our fauna, and will
become subject to the same variations of increase and decrease as
our native species, and that it will, in fact, become little more to
be feared than species already existing with us, particularly if its
European natural enemies are introduced. Against this view,
however, it must be urged that the gypsy moth seems an ex¬
ceptionally hardy species, and that even in Europe it is a prime
pest. The caterpillar is tough and rugged, and seems little sub¬
ject to disease and to climatic drawbacks, and is wonderfully resist¬
ant to the action of ordinary insecticides. The gypsy-moth larva
will feed for days without apparent injury upon trees which have

APPENDIX.

li

been sprayed with Paris green or London purple in a solution so
strong as to somewhat burn the leaves. In fact, the committee, in
the spraying which they are carrying on at present, have found it
necessary to use arsenate of lead in as strong proportion as ten
pounds to one hundred and fifty gallons of water. The well-
known vitality of previously introduced European injurious in¬
sects is apparently increased to a striking degree by this species,
while the fact that it feeds on nearly all plants renders it a much
more serious pest than any of its forerunners. LTnder these cir¬
cumstances, therefore, any course other than energetic and well-
directed effort to keep the insect within its present boundaries will
be short-sighted in the extreme, although it is very doubtful to my
mind whether absolute extermination will or can ever be brought
about.

lii

THE GYPSY MOTH.

Appendix F.

THE DANGERS OF ARSENICAL POISONING RESULTING FROM
SPRAYING WITH INSECTICIDES.

Much has been written in regard to the supposed danger of fatal
poisoning to the consumers of fruit which has been gathered from
vines or trees which have been sprayed with arsenical mixtures.
The fallacy of these ideas has been repeatedly shown, and it is
now well understood that there is practically no danger of fatal
poisoning from eating sprayed fruit. There are, however, other
dangers, arising from the widespread and careless use of arsenical
insecticides, which have been almost entirely ignored. Entomolo¬
gists and pomologists officially connected with the experiment sta¬
tions of the country, the agricultural press and writers of works
on pomology and horticulture all join in recommending some of
the most deadly poisons as insecticides ; but they add scarcely a
word of caution in regard to their use. While the danger of acute
or fatal poisoning, which may arise from eating or drinking food
or liquids in which Paris green or some other form of the arsenites
has been accidentally mixed, is occasionally pointed out, the evils
arising from contact with the poison are seldom even noticed.
Arsenical preparations are applied broadcast to many cultivated
crops, and few if any precautions are taken against their effects
on the human system. Paris green is commonly sold without any
restrictions whatever, though fatal cases of accidental poisoning
from its use have been frequently chronicled.*

* “ Next to arsenious oxide, arsenite of copper gives rise to the largest number of
cases of acute arsenical poisoning. This compound forms the whole or a part of
the pigments known as Scheele’s green or Paris green, Schweinfurt or emerald green
(aceto-arsenite of copper). When pure, these pigments contain from fifty-five to
sixty per cent, of arsenious acid, to which their poisonous properties are mainly due.
During the past few years arsenite of copper has been sold extensively, under the
name of Paris green, for the purpose of killing potato bugs. Owing probably to
the ease with which it can be obtained, it has given rise to a considerable number of
cases of suicidal poisoning. Many cases of accidental poisoning have resulted from
the use of these compounds as pigments.” (Buck’s “ Reference Handbook of
Medical Science,” Yol. I, page 344.)

APPENDIX.

liii

The action of arsenic upon the human system is poisonous,
no matter how it may find entrance, whether through the skin,
wounds, the respiratory organs or the alimentary tract. Nor are
the symptoms essentially different, whatever its manner of en¬
trance. Thus, when applied outwardly to an abraded surface, it
exerts a specific action upon the mucous membrane of the stomach.
Hunter found that the stomach of a dog was considerably inflamed
in an experiment in which he applied arsenic to a wound, the
animal dying within twenty-four hours. In other cases, upon
applying a bandage to prevent the dog licking the arsenic from
the wound, Brodie found that the inflammation in the stomach was
more acute and more immediate than when the poison was taken
internally.

The curious fact that the mucous membrane of the stomach
inflames when arsenic is absorbed from a cutaneous surface or
from a wound is explained by the absorption of the arsenic into
the blood and its separation from the blood by the mucous mem¬
brane of the stomach, the arsenic in its passage exerting an irritant
action.

According to Blyth, a quack applied an arsenical caustic to a
chronic ulcer, with the result that the patient was seized with
symptoms of violent poisoning, and died six days after the appli¬
cation. Blyth says such fatalities are frequent.

The injurious effects produced by the absorption of poisons
through the pores of the skin are well known to toxicologists and
to the medical fraternity. Cases where sudden death has been
caused by the cutaneous absorption of deadly mineral or vegetable
poisons are on record. A case is mentioned by Blyth of a woman
aged fifty-one years, who died after a protracted illness, the result
of using a solution of arsenious acid to cure the itch.* Less
serious attacks of poisoning are not very uncommon among those
who use arsenic, while continued exposure to the influences of
mineral poisons often produces symptoms of chronic poisoning.

“The arsenical pigments more frequently give rise to external
local eruptions and chronic poisoning than to acute poisoning.” f

The first symptoms of chronic arsenical poisoning result from
the local action of the arsenic. Externally they consist of cutane¬
ous irritations, eruptions and even ulcers on the various exposed
portions of the body. The eruption of the face is sometimes
so serious as to render the victim unrecognizable. Inflammation

* “ Poisons, their Effect and Detection,” A. W. Blyth.
t “ Reference Handbook of Medical Science,” Vol. I, page 344.

liv

THE GYPSY MOTH.

of the scrotum, sometimes resembling hydrocele, is a frequent
symptom, and this inflammation extends to the adjacent parts.
There is frequently an irritation of the mucous membrane of the
eye, also oedema of the eyelids. This conjunctival inflammation is
manifested by redness and an intolerance of light. Other inflam¬
mations of the mucous membrane, resulting in irritation of the
nasal passages and throat, dry cough, loss of appetite, thirst,
nausea, a feeling of uneasiness or pain in the stomach and
intestines, and sometimes vomiting and diarrhoea ensue. Often
these symptoms are not very severe, but they are sometimes con¬
tinued for a long period, and in a few cases they have resulted
fatally. Other symptoms sometimes produced by the constitu¬
tional action of the poison are headaches, sleeplessness, muscular
debility, emaciation, depression of spirits, neuralgic pains in
various parts of the body, muscular trembling, occasional con¬
vulsions and paralysis of the extremities. It is said that fatty
degeneration of the liver, kidneys and other organs sometimes
takes place by a process analogous to that caused by the action
of phosphorus.*

The effects of the arsenical preparations when taken internally
are Well known, but the dangers arising from their absorption and
inhalation are not generally understood. Many people who have
been accustomed to using arsenic in some process of manufacture
or trade have occasionally suffered from acute attacks of arsenical
poisoning without being aware of the real cause of their sufferings.
Others, who have suffered for years from chronic arsenical poison¬
ing, being ignorant of the cause of their symptoms, have neglected
to remove it, and have attributed their condition to other agencies
or to disease. The inflammation of the mucous membrane of the
nasaHpassages and throat is often attributed to catarrh, while
the trouble with the stomach and intestines is usually attributed
to dyspepsia. Amateur and professional taxidermists, especially
those who use white arsenic in its dry form, sometimes suffer from
all the symptoms of both acute and chronic poisoning. Not in¬
frequently the death of taxidermists is caused or hastened by the
use of arsenic. In one case a taxidermist was rendered almost
totally blind for a considerable period by the use of arsenic.

Browne mentions a case of a man who formerly used dry
arsenic in preserving natural history specimens, and whose con¬
stitution was, he says, thoroughly broken up by it. An amateur
of long standing became paralyzed in one hand. This man was

* “ Poisons, their Effect and Detection,” Vol. II, page 495.

APPENDIX.

\v

not aware of the source of his trouble, and had never mentioned
the fact of his using arsenic to his numerous physicians, who had
therefore worked in the dark as to the real cause of his condition.*

Mr. C. J. Maynard, author of the “ Naturalists’ Guide,” “ Birds
of Eastern North America” and other works, was at one time so
seriously affected by the arsenic used in the preparation of skins
of birds and mammals that he was obliged to discard the pre¬
servative, suffering for several years from the symptoms of
chronic arsenical poisoning. Workmen in factories where arsen¬
ical preparations are made frequently suffer from arsenical poison¬
ing, either acute or chronic, and fatal cases are on record. Some
of the men employed in handling arsenate of soda, Paris green
and other insecticides in the storehouse connected with the gypsy
moth work have been somewhat affected by arsenical poisoning.
The effect of poisoning from arsenical wall paper is well known.

The cases of poisoning so far given are those of people who
have been exposed to the dust or fumes of arsenic in-doors. It
might be thought that persons working out of doors would not
be similarly affected. Out-door conditions, such as atmospheric
currents and sunlight, may lessen the danger of poison by inhala¬
tion. Yet arsenic, being chemically unchangeable and its poi¬
sonous properties not being affected by light, air or water, has
practically the same effect when brought in contact with the skin
or mucous membranes, whether the person using it is out-doors or
in-doors. Among the workmen employed in the manufacture of
an arsenical green which is obtained from arsenite of soda by
treating it with sulphate of copper and then with pyroligneous
acid, the symptoms of arsenical poisoning are very marked. The
process of manufacture usually takes place in the open air. The
evil consequences of working over the mixture appear in,boils,
pimples and an itching rash about the nostrils and in the flexures
of the arms. In severe cases headache, thirst and nausea occur.
Eruptions on the hands, face and other exposed parts, ulcers in
the groin and other symptoms of arsenical poisoning by absorp¬
tion are not uncommon among those who use Paris green in the
field, either in spraying trees or in dusting the poison over pota¬
toes or other field crops.

In these cases poisoning is probably caused by the absorption
through the pores of fine arsenical dust or spray, floating in the
atmosphere, or by the absorption of particles of arsenic which
reach the hands, face and other portions of the body in various

Montague Browne, “ Practical Taxidermy,” pages 6G, 67.

lvi

THE GYPSY MOTH.

ways. The absorption of the poison is likely to be greater when
the subject is perspiring freely, and the danger is greatest when
one is handling a form of arsenic which is more or less readily
soluble. Therefore the danger in handling arsenate of soda,
London purple or white arsenic is probably greater than that in
handling Paris green or arsenate of lead ; yet serious effects may
in time be produced by either of these latter poisons, and they
should be always used with the greatest care. The danger of
poisoning by respiration is probably greatest when the insecticide
is used in the form of a powder and thrown broadcast in air,
although, if the poison is mixed in water and a fine spray is
allowed to drift over the person, a small amount may be inhaled.
In either case the effects of the poison inhaled will be felt first in
the mouth, nasal passages and throat.

The danger of poisoning by spraying is increased in the case
of some individuals by their peculiar susceptibility to the effects
of the poison. The difference in susceptibility to these poisons
shown by different individuals under the same conditions is re¬
markable. It is possible that some persons may gradually become
accustomed to the use of arsenic, and eliminate from the system,
without experiencing ill effects, an amount of poison which would
prove very injurious to others more susceptible to its influence.
Some people who have once suffered from the symptoms of chronic
arsenical poisoning exhibit a marked susceptibility to the effects of
arsenic for years afterward.

During the spraying in 1891 two cases were known where
women, in whose faces a spray of Paris green was accidentally
blown by the wind, were immediately affected with a burning
sensation of the skin, followed soon after by eruptions. An
elderly woman who was also exposed to the spray suffered from
arsenical poisoning to such an extent that she required the services
of a physician for a considerable period. Her symptoms appeared
to arise from this exposure.

It is not generally known that serious effects sometimes follow
poisoning from arsenical spraying. Though there is ordinarily
little danger from the spraying of a few trees, even this may be
dangerous to one peculiarly susceptible to the action of the poison.
In such a case complete prostration, inflammation, serious ulceration
of the face and mouth and other parts of the body, suppuration,
copious salivation and delirium have followed within a few days.
A case of arsenical poisoning resulting fatally to an elderly
farmer has recently been reported. In this case death is said to

APPENDIX.

lvii

have been caused or hastened by his spraying orchard trees for
several years in succession with Paris green. If the poison comes
in contact with wounds or abrasions of the skin, ulcers are some¬
times formed which will not heal until spraying is given up.
Symptoms of a mild form of this poisoning resemble those pro¬
duced by the poison ivy ( Rhus toxicodendron ), and sprayers who
are poisoned usually attribute their symptoms to that cause.
While serious poisoning from spraying is rare, the mild symp¬
toms are quite frequently shown ; and in some cases, if spraying
is done continuously for a considerable period of time, chronic
poisoning will result. There is probably little danger of fatal
poisoning except in cases of invalids or elderly people.

In spraying with arsenites, serious effects may usually be avoided
by using the following precautions : cover any wound or abrasion of
the skin, so that the insecticide cannot come in contact with it ;
when spraying with an extension nozzle or pole, use an elongated
leather washer below the nozzle, so as to carry off the drip ; wear
rubber clothing and a rubber or oil hat of the shape of a “sou-
wester” or tarpaulin, and take care to stand as far as possible
to windward of the spray. The face and hands should be thor¬
oughly washed immediately after spraying, and the entire body
should be bathed daily.

The usual treatment for arsenical poisoning is well known to
medical men. An antidote for local external poisoning not gener¬
ally known is acetate of lead, commonly called sugar of lead. A
strong solution of this in water will allay serious inflammations
of the skin, caused by arsenical poisoning, but it should only be
applied externally, and even then with care, as it possesses poison-
ous properties.

lviii

THE GYPSY MOTH

Appendix G.

A LIST OF RESIDENTS OF THE INFESTED DISTRICT WHO
HAVE FURNISHED INFORMATION IN REGARD TO THE
GYPSY MOTH IN MASSACHUSETTS.

Statements in regard to the ravages, habits and spread of the
gypsy moth or the work of destroying it in Massachusetts have
been received from citizens whose names appear below. Lack of
space has made it impossible to print these statements, but
extracts from some of them will be found in Part I.

Arlington : —
Benjamin Campbell.

H. A. Fernald.

Chas. A. Greene, M.D.

Belmont : —

Mrs. Edwin F. Atkins.
Edward W. Brown.

W. L. Chenery.
Thomas L. Creeley.
Irving B. Frost.

C. F. and R. Hittinger.
Daniel F. Learned.
Gilman Osgood.

James K. P. Sargent.
Edward Skahan.

John W. Skahan.
Merton Simonds.

J. 0. Wellington.

Chas. W. Winn.

Boston : —

J. B. Alden.

John A. Bruen.

Mrs. T. J. Lane.

A. L. McCormack.
Wm. Tyner.

Cambridge : —
Wm. H. Eveleth.

Chelsea: — *

J. T. Bond.

Martin Curley.

J. Waldo Denny.

L. E. H. Jones.

Wm. Jones.

S. Kimball.

Everett : —

Timothy Murphy.

Lynn : —

J. G. Olin.

Malden : —

Mrs. Peter Campbell.
Michael Cleary.

Mrs. Margaret Connell.
Mrs. M. Cronin.
Richard Dexter.

Mrs. John Dowd.

James F. Eaton.

Mrs. J. W. Flinn.

Mrs. Daniel Kelly.

Wm. McLaughlin.

T. J. Neville.

Miss Abbie Sullivan.
Mrs. B. Wallace.

Medford : —

Miss R. M. Angelbeek.

Medford — Con.
Mrs. J. H. Archibald.
Geo. H. Bean.

James Bean.

Mrs. Wm. Belcher.

Mrs. John Benson.
Almon Black.

Miss A. B. Bockman.
Mrs. John Brown.

Oran Brown.

Miss Charlotte E. Camp.

E. Clark.

J. C. Clark.

L. M. Clifford.

J. S. Cotton.

W. C. Craig.

John Crowley.

A. W. Crockford.

D. W. Daly.

J. P. Dill.

C. R. Drew.

Mrs. G. H. Dudley.

Mrs. J. E. Fairbanks.
Mrs. M. F. Fenton.

Mrs. S. J. Follansbee.

F. E. Foster.

J. T. Foster.

Medford — Con.

J. N. French.

R. Gibson.

F. M. Goodwin.

J. O. Goodwin.

N. P. Hallowell.

Mrs. I. W. Hamlin.

J. W. Harlow.

Wm. B. Harmon.

Fred H. Haushalter.

E. G. Holmes.

John Hutchins.

A. R. Kervin.

Sylvester Lacy.

Mrs Chas. A. Lawrence.
Edward Loeffler.

Mrs. Thomas F. Mayo.
Miss R. A. McCarty.
Mrs. E. E. Merrill.

J. C. Miller, Jr.

A. P. Perry.

Mrs. F. P. Peirce.
Richard Pierce.

Mrs A. H. Plummer.
Mrs. M. M. Ransom.
Wm. S. Richards.

D. M. Richardson.
Jotham H. Rogers.

Mrs. E. M. Russell.

APPENDIX.

Medford — Con.

G. C. Russell.

Mrs. P. N. Ryder.
Miss Z. Sawyer.
Japhet Sherman.
Walter Sherman.

Mrs. W. H. Snowdon.
Mrs. F. T. Spinney.
Wm. R. Taylor.

Mrs. R. Tuttle.

Geo. H. Webster.

J E. Wellington.

S. F. Weston.

John G. Wheeler.

Miss H. T. Wild.

Melrose : —

Henry Lynde.

Mrs. E. A. Mansfield.
Mrs. A. C. Peyser.

Revere : —

J. W. Copeland.

S. S. Pratt.

Benj. Shurtleff.

Josiah B. Shurtleff.

Salem : —

Geo. W. Creesy.

Saugus : —

L. Mansfield.

W. H. Penny.

Somerville : —
J. H. Cahalan.

Asa Durgin.

Thos. H. Eames.
Sarah E. Fisk.
Albert Kenneson.

F. L. Newton, M.D.

I. L. Russell.

Swampscott : —
A. R. Bunting.

Jas. Pitman.

Wakefield : —

J. H. Carter.

Rufus Kendrick.

Watertown : —
M. W. Chadboume.
Nathan Drake.

J. W. Lovering.

J. E. Skinner.
Samuel Walker.
Solon F. Whitney.

Winchester : —
Louis Goddu.

H. W. Hight.

Chas. R. Mason.

W. D. Sanborn.

Winthrop : —

F. W. Belcher.

Chas. Burrill.

lix

INDEX

A.

PAGE

Abundance and destructiveness of the gypsy moth, .... 40

Acclimation of the gypsy moth, . 94

Achcetoneura fernaldi, . 387, 392

Acids used for destroying eggs, . 63, 123, 413, 416

Act to provide against depredations by the gypsy moth, . . .36, 47

Adviser, entomological, Prof. C. H. Fernald appointed, ... 57

iErostatic hairs, . 301

Africa, occurrence of gypsy moth in, . 267

Agalena ncevia, ........... 405

Age of egg-clusters, how determined, . 95

of new colonies, . 70, 80

Alarms, false, . 201

Albrecht on distribution of gypsy moth, . 268

Ale.Ua argillacea, . 325

Algiers, occurrence of gypsy moth in, . 267

Alisma plantago as a food plant, . 317

Altum, Dr. Bernard, advice concerning importation of parasites, . 288

on value of birds, . 211, 232

America, importation of gypsy moth into, . 3

importation of English sparrow into, . . . . . 233

occurrence of gypsy moth in, recorded by Professor Riley, . 3

American redstart attacking the gypsy moth, . 208

robin attacking the gypsy moth, . 208

Ammonia, eggs treated with, . 407

Amount of food consumed by caterpillars, . 315

Anabrus simplex, destruction of crops by, . 206

Analyses of Paris green, . 492

of Paris green and lime, . 493

of poisoned larvae, . 474

Anatomy of the gypsy moth, external, . 339

of the gypsy moth, internal, . 368

Anderson Brick Company, shipments from, . . . . .110

Anderson on ravages of gypsy moth in Shipov, .... 282

Angelbeek, Miss R. M., statement of, . 20, 27, 29

Animals, distribution of the gypsy moth by, . 103

injured by spraying . 161

Anisocyrta sp., . 375

lxii

THE GYPSY MOTH.

36, 39, 49,

Anisota senatoria, .

Anisopteryx pometaria destroyed by chickadee,
food plants of, ...

Annual inspection, the,

Antennae of gypsy moth,

function of, .

Anthrenus scrophularice, damage from,

Antinonnin, .

Ants attacking female moths,

Apanteles, species parasitic on gypsy moth in Europe
Apple trees attacked by gypsy moth in Europe,
trees injured by bad pruning,
trees, leaf area of, ....

Appleton, F. H., at conference on gypsy moth (Appendix
member of committee, .
resignation from committee,
visit to Washington, ....
Appropriation, balance of, on hand Jan. 1, 1894
efforts to secure an, from Congress,
expended by first commission,
expended by second commission, .

insufficient, .

loss by delay of, .

necessity of, in order to inspect woodland,
Appropriations, yearly, ....

Area, infested. See Infested region.

leaf, of trees, .

spiny, of wings of gypsy moth, .

Argyrophylax gilva, .

Arlington, area of woodland infested in, .
gypsy moths found in, ....
petition presented by selectmen of,

Army worm, cyclone burner recommended against,
gypsy moth mistaken for,

Arsenate of lead, .

of soda, experiments with,
of zinc, experiments with,

Arsenic as an insecticide,
effects of,

Arsenical poisoning (Appendix F).
poisons, comparative effects of,
effects on foliage, .
spraying with, '. y \

Arsenites, entomologists recommend spraying with,

Ash, exempt from ravages of gypsy moth in Kussia,

Asia, distribution of gypsy moth in,

Asilus sericeus,

Aspens attacked by gypsy moth,

Assembling of the gypsy moth,
power of pupae,

Atlanta Exposition, exhibit at,

69, 80, 87

A).

39, 61,
63, 68,

PAGE

400, 402
204
97
196
339
356
270
479
364, 380
378
277
174
495

49, 76
77
83

72
83

73
73

64, 69, 87, 88
78, 79, 84, 85
80

63, 68, 77, 84

142,

143,

494
341
392
87
58
36
121
33

145, 449, 473, 449
143

480

481
162

473
489
55, 417
45
282
267
392
277
345
363
201

342

INDEX.

Ixiii

PAGE

Attacris cecropia, . 387, 402

promethea, . 402

Aughey, Prof. Samuel, experiments on plover, ..... 204

on birds v. locusts, . 205

Australia, importation of rabbits into, ...... 233

importation of sparrow into, ....... 233

Avery, John G., elected member of gypsy moth committee, . . 84

B.

Bacteria, aid rendered by, .

. 288

occurring in larval stomach, ....

. 369

Bailey, C. E., observation on birds distributing the gypsy moth, . 236

observation on Cimbex americana,

. 379

observation on cuckoo, ......

212

observation on downy woodpecker,

. 221

observation on egg-feeding birds,

229

observation on Tlieronia melanocephala,

. . 376

observation on vireos, ......

222

observation on warbler, .

. 219

Baltimore oriole attacking the gypsy moth,

213, 225

Bands, burlap, .

167

pitch, .........

. 285

raupenleim, .

64, 129, 195

tar, .

285, 286

tree ink, .........

64, 128

wadding, .

127, 285

Barrett, C. G. , on disappearance of gypsy moth in England,

. 270

Bavaria invaded by nun moth, .....

. 208

Bay State Brick Company, shipments of wood to,

111

Bazin on ravages of gypsy moth in France,

. 277

Bean, James, statement of, .

. 20, 29

Bechstein on egg killing, ......

117

on ravages of gypsy moth, .

. 275

Bees, danger to, from spraying, .....

. 157

Beetles, cages for breeding, .....

. 384

predaceous, ........

. 381

Belcher, Mrs. William, statement of, ....

8, 11, 17, 26

Beling, Theodore, on methods of destroying the gypsy moth,

. 285

Belmont, colonies found in, .....

47

Benson, Mrs. John, statement of, ....

. 19, 27

Benzine, eggs treated with, .

. 408

Berlin, occurrence of gypsy moth at, .

274, 277

Bibliography of gypsy moth, .....

257-267

Birch attacked by gypsy moth in Europe, .

277, 282

Birds as destroyers of locusts .

. 205

attacking the gypsy moth, .

207

attracted to infested localities, ....

223

destroyed for milliners, ......

243

destruction of canker worms by, ....

96

destruction of parasites by, .

240, 376

lxiv THE GYPSY MOTH.

PAGE

Birds, distribution of gypsy moth by, . . .98, 214, 231, 235, 239

European, introduction of, . 232

feeding on the caterpillars, . 6, 96, 209, 228

feeding on female gypsy moth, . 228

feeding on male gypsy moth, . 228

feeding on the puprn of the gypsy moth, . 228

folly of destroying, ......... 205

most useful as moth destroyers, . 210

native, driven away by English sparrows, . 234

protection of, . 242

that may devour gypsy moth eggs, . 228

value of, . 203

value of, in Europe, . 284

v. useful insects, . 240

Black, Almon, statement of, . 20, 24, 28

Black-and-white warbler attacking the gypsy moth, . . .208, 225

Black-billed cuckoo attacking the gypsy moth, .... 207, 212

Blackbird attacking the gypsy moth, . 207

value of, . 204

Black-throated green warbler attacking the gypsy moth, . . .208

Bluebird attacking the gypsy moth, . 208, 218, 227

driven away by sparrows, ........ 234

Blue-jay attacking the gypsy moth . 6, 207, 225

distributing the gypsy moth, . 236

Board of Agriculture, State, advice of, concerning extermination, . 70

amount expended by, in 1891, 1892, 1893, ..... 74

appropriations recommended by, . 62, 68, 77, 84

bulletin issued by, . 56

conference at office of, ......... 45

extracts from reports of the, .... 65-67, 78, 81, 82

petition for an additional appropriation by the executive com¬
mittee of, . 78

reorganization of, suggested by fm. H. Bowker, ... 83

special meeting of, . 49

supersedes commission of 1891, . 47

Boards of health, information furnished by, . 107

Bockman, Miss A. B., statement of . 20

Bombycidse, assembling in the, . 357

Books, section, record of infested estates kept in, . . . 52

Boston & Maine Railroad, inspection of, . Ill

Boston, danger from traffic to, . 107

gypsy moth found in, ........ 70, 80

result of inspection of, in 1894, . 80

Bowker, Wm. H., elected a member of the committee, ... 76

reorganization of State Board of Agriculture suggested by, . 83

retirement of, from State Board of Agriculture, .... 83

Brackett, Gov. J. Q. A., commission appointed by, .... 38

extract from message, . 35

Bradley, J. Howard, appointed commissioner, . 38

Bi’anches, how broken, ......... 174

removal of, .......... 182, 184

INDEX.

Breeding cage for predaceous insects,
Bremer on distribution of gypsy moth,
Brick shipments, inspection of, .

Bromine used on eggs,

Brood, second, of gypsy moth, .

Brown, Thomas, on ravages of gypsy moth
Brown thrush attacking the gypsy moth,
Brush,' cutting and burning,

Brussels, ravages of gypsy moth in,

Buffalo carpet beetle, damage from,

Bufo lentiginosus.

Bugs, predaceous,

Buildings, comparison of yearly work on,
Bulletin of information, publication of,
Bullock, Representative AY. J. D., order pre
Bunting, towhee, attacking the gypsy moth,
Burlap, . . .57, 64, 69, 79, 114, 167, ]

Burner, cyclone, .
naphtha,

Burning, caterpillars killed by,
hollow trees, .
machines,

of eggs, ....
of foliage by arsenites,
pupae, ....
rubbish, ....

Burrelle, on use of burlap, .

c.

Cabbage butterfly, damage from,

Cadey, E. J., statement of, .

Cages for breeding predaceous insects
Calcic chloride, eggs treated with,

Calosoma calidum, . • .

frigidum,
inquisitor,
scrutator,
sycophanta, .

Camp, Miss C. E., statement of,

Camponotus pennsylvanicus, .

( herculaneus ,) .

Campoplex conicus,
difformis,

Canker worms destroyed by birds,
destroyed by spraying, .
importation of sparrows, against,
influence on destruction of gypsy moth cab
Cannon, Hon. George Q., on cricket ravages,
Carabus serratus, ......

Carbolic acid for destroying eggs,

Ixy

PAGE

384, 395

. 267

110

63, 125, 408

86, 295

France,

. 274

208, 225

85, 167, 193

. 279

. 270

. 404

241,392

93

34, 56, 199, 200

nted by,

72

225

5, 169, 170, 188, 213, 291, 335

. 121

122

. 57, 58,

59, 87, 126, 165

121

119-121

57, 118

159, 491

59

193

. 171

. 270

40

384, 395

. 409

381, 383

. 383

. 287

. . 382

287, 385

26

364, 381

. . 405

. 378

. 378

96, 204, 219

140

. 233

er pi liars, .

. . 222

. 206

. 123

lxvi

THE GYPSY MOTH.

Carbon bi-sulphide, eggs treated with,

Carlier on parthenogenesis, ....

Carpenter, F. B., cotton plants received from,

Carpocapsa pomonella taken under burlaps,

Castor oil on eggs,

Catbird attacking the gypsy moth,
destruction of silkworms by,
feeding habits,

Caterpillars of the gypsy moth attacked by Polistes pallipes
attacked by predaceous bugs,
attracted to light, .
become a serious nuisance, .
comparison of numbers of, destroyed annually
description of ,
destroyed by birds,
destruction of, by burning, .... 57, 5

destruction of, by spraying, .
detrimental to real estate,
disease among,
distance travelled by, .
distributed by birds,
distributed by spraying,
distribution of,
effect of cold on, .
effect of heat on, .

European methods for destroying
expense of destroying, .
feeding habits of, .
feeding on cotton plant,
first and last appearance of, .
food selection by, .
found on vehicles, .
indications of presence of, .
insecticides for destroying, .
killed by spraying,
length of life of the,
loss of weight in pupating, .
means of preventing spread of,
molting of,

not affected by insecticides, .
number from single egg-cluster,
number greatly reduced by exterminative methods,
obstruct railroad trains in Europe,
places of pupation,
poisoned, analyses of, .
prevented from ascending trees, .
scattering of. See Distribution,
spinning habits of,
sprayed with contact insecticides,
spread of, injury caused by, .

54

PAGE

408
366
324
171
417

6, 208, 213
6

237
378
392
310
14
93
300

7, 96, 209, 228
59, 87, 126, 165

58
21

. 280
58, 310
214, 236
. 113

58, 97, 112
96, 328
96, 327
117, 284
79

. 311

. 324

304
. 485

39
86

137, 417, 477
. 57, 64
96, 306
. 333

63

304, 308
157, 474
94, 297
60
280
335
474

64

102, 330
57, 163, 485

59

INDEX

lxvii

, 214

224,

received,

Caterpillars of the gypsy moth taken under burlaps,

traps for, .

value of burlap against, ....

vitality of, .......

Caucasus, The, occurrence of the gypsy moth in,

Cement, use of, on trees, .....

Ceylon, occurrence of gypsy moth in,

Chaetomyia crassiseta, .

Chelsea, outbreak of the gypsy moth in,

Chemicals for killing eggs, .

Chestnut-sided warbler attacking the gypsy moth,

Chewink attacking the gypsy moth,

Chianti, ravages of the gypsy moth in,

Chickadee, destruction of gypsy moth by, . 208, 210

feeding habits of, .....

China, North, occurrence of the gypsy moth in,

Chipping sparrow attacking the gypsy moth,

Chlorine used on eggs,

Chloro naptholeum, experiments with,

Chrysomela scalaris attacking elm trees,

Chrysopa sp., .

Cicindela 6-guttata, ....

Cimbex americana, ....

Circumstances favoring extermination,

Cities and towns from which false alarms have been
beyond infested area, inspected, .

Citizens, assistance of, in destroying the gypsy moth
of Medford on escape of the gypsy moth, .

Clark, J. C. , statement of, .....

Cleaning knives, .

Clercy, J. O., on birds v. insects,

Clifford, L. M., statement of, ....

Climate, increase of the gypsy moth retarded by,
of England, influence on foliage, .

Clisiocampa americana, .

destroyed by Baltimore oriole,

parasites of, . . .

Clisiocampa disstria, . .

Coal tar, eggs treated with, ....

use of, in pruning,

Coccyzus americanus.

erythrophthalmus,

Cocoon, formation of, .

Codling moth taken under burlaps, .

Cogswell, Hon. Wm., resolution introduced into Congress by, .
Colaptes auratus. See Flicker.

Cold, effect of, on caterpillars .

effect of, on eggs, .

Coleoptera, predaceous, ........

Collinson, Mr., importation of the gypsy moth into England by,

PAGE

. 114

170, 311

169
98, 325
. 263

40, 172, 187, 188
267
. 392

58

122, 407
. 208
207, 219
. 279

227,231,236
230, 237
. 268
207, 215, 226, 227
63, 125, 408
481
235
405
405
79, 402
244
201
198
77, 84
4

19,

34, 68

j- See Cuckoo.

24, 31
126
205
24
5
271
402
213
377
402
410
177, 186

. 332

171
83

96, 328
294, 295

. 381

. 269

Ixviii

THE GYPSY MOTH

Colonies of the gypsy moth, age of new,
exterminated,
found in woodland,

found outside of region infested in 1891,
isolated, ....
isolated, normal rate of increase in,
isolated, spread of,
means taken to find new,
resulting from traffic,

Colony, definition of, .

Colors of gypsy moth, explanation of,

Colt, W. C., observations on the flicker,
Commission appointed by Governor Brackett,
appointment of second,
first, amount expended by, .

Metropolitan Park, hold meeting with the

sion, .

removal of first, ....
report area of infested territory, .
second, amount expended by the, .
Commissions, consultation of first and second,
Commissioners, second, receive no remuneration,
Committee, agricultural, hearing held by, .
agricultural, Medford visited by, .
on gypsy moth, appointment of, .
entomological adviser appointed to,
information concerning the gypsy moth in
members of, elected, ....

name of, changed, .

organization of, .....
plans of, presented to legislature,
report of, on the inspection of towns borderin
report of Professor Fernald and the directo
work of, ....

Common names of the gypsy moth,

Comparative effects of different arsenical poisons,
Comstock, Prof. J. H., infested region visited by,
report of (Appendix E).

Condition of infested region in 1891, .

Conference at office of State Board of Agriculture
Congress, efforts to secure an appropriation from,
resolve asking for aid sent to,

Connell, Mrs. Margaret, statement of,
Consumption of food by gypsy moth caterpillars,

Contact insecticides, .

Contopus virens. See W ood pewee.

Cook, Prof. A. J., experiments with Paris green,

Corea, gypsy moth from, .

Cork oaks attacked by the gypsy moth,

Corrosive sublimate, eggs treated with,

Corvus americanus. See Crow.

gypsy m

r to

th

Europe o

70

nfested regioi

Appendix

PAGE

. 70, 80
65, 70, 248
85, 86, 107
70
54
95
97
105
109
196
272
221
38
45
73

78
45
39
73
45
45
84
36
49
57
67
76
76
49
66
65
69
49

256

473

79

ained by

A),

53
45
83
68
23
315

57, 58, 163, 485

162

338

274

409

INDEX.

lxix

PAGE

Cotton as a food plant, # . 324

trees banded with, . 127, 128

Cotton, John, statement of, . 27, 44

Coxe, Wm., on tree pruning, . . 178‘

Craig, W. C., at conference on gypsy moth (Appendix A), . . 45

statement of, . 19, 27

Creepers attacking the gypsy moth in Europe, . 209

attracted by meat, . 229

Cremaster, use of, . 333

Creosote and paint tube, . 124

eggs treated with, . 63, 123, 410

for destroying caterpillars, . 126

Cricket, destruction of crops by, . 206

Crimea, The, ravages of the gypsy moth in, . 279

Crockford, A. W., statement of, . 27, 30, 42

Cronin, Mrs. Margaret, statement of, . 23

Crow blackbird attacking the gypsy moth, . 207

Crowley, John, statement of, . 7, 18, 29

Crows attacking the gypsy moth, . 207, 217, 224

attacking the gypsy moth in Europe, . 209

attracted by meat, . 229

destroying predaceous insects, . 241,394

distributing the gypsy moth, . 237

experiments on gypsy moth eggs with, . 239

time required in digestion by, . 204

value of, . 204

Cuckoo as an insect destroyer . 205

attacking the gypsy moth, .... 6,207,211,212,225,227

attacking the gypsy moth in Europe, . 208, 211

Currant sawfly, damage from, . 270

Curtis on occurrence of the gypsy moth in England, . . . 269

Cutting and burning infested growth, . . . .39, 85, 164, 193

Cyanide of potash on eggs, . 413

Cyanides as insecticides . 485

Cyanocitta cristata. See Blue jay.

Cyclone burner for destroying the gypsy moth, .... 121, 127

nozzle, . 150

nozzle used for burning, . 120

Cyrtoneura stabulans, . 387, 389

D.

Daly, D. W., statement of, . 9

Damage by gypsy moth in Old World, . 273

Danger from bad pruning, . 173

from freight shipments, . 110

from steady traffic, . 109

Dasijllis sacrator, . 392

Datana ministra, . 402

Date of hatching of the gypsy moth . 294

Daudeville on ravages of gypsy moth in France, .... 276

lxx

THE GYPSY MOTH.

PAGE

Davis, Miss R. L., observations on molting,
De Courval on tree pruning,

Defoliation of trees, .

Deudrolene, description of, ...

Dermestes ater, .

lardarius, .....
Des Cars on tree pruning, ....
Destruction of birds, folly of ,

of caterpillars, .

of egg-clusters. See Egg cluster,
of gypsy moth, methods for,
of pup® and moths, „ .
Destructiveness of the gypsy moth, .

of introduced insects, ....

. 305

. 178

8-28, 85, 86, 273-284
. 135

. . . 385

384, 385
179, 186
205

58, 59, 87, 126, 165

117

194

23, 40, 57,

273-284

250

Dexter elm, the, .

. 247

Digestion of birds, ....

204

of eggs of the gypsy moth by birds,

. 239

Digestive system,of gypsy moth,

. 369

Diglochis omnivorus, ....

. . . . 375

Dimorphism, sexual, of gypsy moth, .

. . . . 272

Dill, J. P. , statement of ,

. 16, 26

Dionychopus niveus, ....

. 341

Diptera, predaceous, ....

. 392

Dipterous parasites .

336, 376, 385

how reared, .

. 386

Dei, Apelle, on ravages of gypsy moth in Europe,

. 2-79

Director of field work, inspection of infested region by, ... 46

visit to Washington by,

83

recommendations of entomologists considered by, ... 69

report of, to committee,

69

visit to Amherst by,

46

Description of different stages of the gypsy

moth,

288, 300, 333, 336

of dipterous parasites, .

. 387

Disease among caterpillars,

280, 405

Distance females can assemble males,

240, 351

travelled by caterpillars,

. 310

Distribution of the gypsy moth, .

94

affected by extermination, .

113

affected by food supply,

. 95, 97

affected by natural causes,

97

a study of methods and routes,

106

as caterpillars, ....

98

as eggs, .

98, 103, 239

by animals, .

103

by birds, .....

. 98, 215, 231, 235, 239

by man, .

by traffic, .

102-105, 109, 345

by travelling of caterpillars, .

. 310

by wind, .

98, 278, 301

compared with that of other insects,

97

in other countries, ....

INDEX.

lxxi

PAGE

Distribution of the gypsy moth, peculiarities of, ... 9S, 99

period of greatest, .......... 104

primary, . 104

relation of population to, . 99

results of study of methods, . 107

secondary, ........... 104

District infested by gypsy moth. See Infested region.

Dohrn, Dr. , on parthenogenesis, . ....... 366

on vitality of larv®, ......... 278

Donitz on singing Lepidopteron, . 341

Donovan on occurrence of gypsy moth in England, .... 268

Douglass and Scott on breeding Heteroptera, . 394

Dowd, Mrs. John, statement of, . 22

Downy woodpecker attacking the gypsy moth, .... 207,221

Drassus sp. attacking the gypsy moth, . 405

Drew, C. II., statement of, ......... 59

Dry abates pubeseens. See Downy woodpecker.
villosus. See Hairy woodpecker.

Dryocampa rubicunda, .......... 402

Dubois on ravages of the gypsy moth in Belgium, .... 279

E.

Ebermayer, Dr., on birds v. the gypsy moth, . 209

Eck raupenleim machine, ......... 133

Effects, injurious, of arsenic (Appendix F), .... 161,162

of extermination on distribution, . 113

of insecticides on foliage, . 159, 489

Egg-clusters of the gypsy moth, advantage of destruction of, 84, 117, 284

age of, how determined, . 95

comparison of number destroyed annually, . 93

destruction of, ... . 63, 117

destruction of, in Europe, ........ 284

distribution of, by streams, . 98

how laid, . 363

number of caterpillars from, . 94, 297

number destroyed in 1891, . 54

of unfertilized females, ....... 290, 367

old distinguished from new, . 95

size of, . 289

treated with acids, . 63, 123, 413, 415

treated with creosote, ....... 63, 123, 410

where found, . 98, 126, 289

Egg-feeding birds, value of, . 229

Egg-gathering and fall inspection, . 60

Eggs of the gypsy moth, birds which may eat, .... 228.229

burning of, . 57,119,284

danger from transportation of, . Ill

description of, . 288

destruction of, ... 35, 39, 53, 63, 69, 78, 84, 125, 195

distributed by birds, . . 230, 239

lxxii

THE GYPSY MOTH.

Eggs of the gypsy moth, effects of digestive processes
effects of extremes of temperature on,
experiments with insecticides on,
hatching of, how accomplished,
how covered,

implements used in search for,
number of, deposited, .
number of, in female, .
number of, laid by poorly fed females,
of dipterous parasites, .
removed by dissection, .
scattering of, ...
time required for fertilization,
vitality of,

Eichorn raupenleim machine,

Elacliiptera dispar.

Electric insecticide,

Elm, the Dexter, ....

trees attacked by Chrysomela scalaris,

Elms attacked by gypsy moth, .

“ Elphona,” .

Embryo, development of,

Emerging, process of, .

Emerton, J. H., spiders identified by,

Empidonax minimus,

Employees, number of, yearly, .

uniform of, .

Emulsion, kerosene, use of,

Enemies, natural. See Natural enemies.

England, extermination of gypsy moth in,
occurrence of gypsy moth in,

English sparrow attacking the gypsy moth
importation of, into America,

Eutachina larvarum, ....

of birds upon

PAGE

239
292
4.07
297
289
125
94, 289
364
95
385
364

17, 239, 290, 363
343
279, 291
131
390

482
247
235
277

483

88, 294, 295
336
404
207
89-91
114
163, 485

. 269

267, 268
08, 231, 234
233, 234
392

Entomological adviser, Prof. C. H. Fernald appointed, ... 57

opinion of, in regard to extermination, ..... 67

Entomologists, recommendations of, . 69

conference of, . 45

infested region inspected by, . 69, 79

reports of (Appendices D and E).

spraying recommended by, . 45

Enwright, Wm. J., statement of, . 40

Epeira strix, . 405

Epiblemum scenicum, .......... 405

Escape of the gypsy moth, statements in regard to, ... 4

Essex County Agricultural Society, petition presented by, . . 36

Eupelmus bifasciatus, . . 377

Europe, distribution of gypsy moth in, . 267

methods of destroying the gypsy moth in, . 117,284

European birds attacking gypsy moth eggs, . 231

birds, introduction of, . 232

INDEX.

lxxiii

European dipterous parasites,

food plants, .

hymenopterous parasites,
methods for destroying the gypsy moth,
predaceous beetles, • .

Eurytoma abrotani, .

Everett, petition presented by selectmen of,

Eversman, Professor, on ravages of gypsy moth in Orenboorg,
Examination of stomachs of various birds, . . . 212,2

of stomach of toad,

Excresences from bad pruning, .

Exhibit at Atlanta Exposition,
at Mechanics Fair,
at World’s Columbian Exposition,

Exorista sp., parasitic, on gypsy moth in America and Europe,
Experiment station, ....

Experiments, amount of food consumed,
assembling, .....
birds v. gypsy moth eggs,
cotton as a food plant, .
destruction of eggs,
distance travelled by caterpillars,
effects of light on caterpillars,
extremes of heat and cold oh caterpillars,
extremes of heat and cold on eggs,
fertilization of female moths,
food plants, ....
food selection,

insecticide, ....... 55, 69

insecticides on foliage,
parthenogenesis, .
trapping caterpillars,
trapping male moths, .

Exterminated colonies,

Extermination, advice of State Board of Agriculture
aid given by birds,
by burlapping and hand killing
circumstances favoring,
effect on distribution, .
how accomplished, . .

in orchards, ....
in outer towns,
in woodland, ....
local success of,
measures urged to provide for,
obstacles to, .

opinions of entomologist in regard to,
progress of, .
results of efforts toward,
spraying not successful as a means of,

Exterminative measures, numbers of caterpillars reduced by,
External anatomy of moth, .......

PAGE

392
325
377
284
385
377
36
2S0
15, 231
405
177
201
201
200
387, 392

87, 406

315
345
229
324
122
310

310
327
292
343

316
485

87, 407, 417, 477
489
365

311
357

70, 248
70
238
64

244
113
127
248
115

88, 248
247

35

245
67

244
70

62, 138
60
339

56,

lxxiv

THE GYPSY MOTH.

PAGE

Fall hatching, .

False alarms, places from which received, .

. 201

Farlow, Dr., on vegetable parasites, ....

. 405

Farmers, distribution of moth by, ....

109

methods most useful for, .

. 194

Feeding habits of gypsy moth, .

. 311

time of, .

. 311

Fells, Middlesex, colonies of the gypsy moth found in,

86

condition of, .

87

control of by Metropolitan Park Commission,

78

Felt, E. P., experimental work by, ....

57

observations on chipping sparrow,

215

observations on Dermestes lardarius ,

. 384

on whale-oil soap, .

163

on mites, .

. 404

Female gypsy moth, abdomen, hair of,

. 342

anatomy of, ........

. 339

attacked by ants, .......

. 380

attraction of males by .

. 240

birds feeding on, .

217, 228

description of, .

. 337

distribution of, by birds, .

. 239

does not fly, .

97,

112, 344

eggs laid by infertile, ......

. 365

eggs removed by dissection of, .

. 364

eggs scattered by, .

. 290

lack of fat in, .

. 373

length of life, .

343, 362

mating of, .......

342

number of eggs deposited by, ....

. 94, 95

polygamous, .

. 343

reproductive system of, .

. 375

unfertilized, eggs laid by, .

. 290

Fences, comparison of yearly work on,

93

Fenton, Mrs. M. F., statement of, ...

9, 30, 42

Fernald, Dr. H. T., report of (Appendix D).

Fernald, Mrs. C. H., identification of gypsy moth by,

32

Fernald, Prof. C. H., advice concerning egg killing, .

119

advice concerning field work, ....

57

appointed entomological adviser, ....

57

at conference on gypsy moth (Appendix A),
consultation with, .

46

experiments by, . .

field work examined by, .

. 34, 57

invitation to entomologists to visit infested region,

69

recommendations of entomologists considered by,

69

recommendation of policy of State work, .

251

record of introduction of gypsy moth, .

. 3

report of, to committee, .

69

INDEX.

lxxv

» PAGE

Fertility of scattered eggs, ....

291

Fertilization, time required,

. 343

Fertilized females, assembling by,

. 3G3

Field force discharged, ....

. 63, 84

organization of, .....

50

reductions of, .

. 60, 64, 79

operations criticised by Professor Riley,

56

pupation of the gypsy moth in the,

. 335

work begun, .

47

work, discontinuance of,

. 68, 78, 84

Fifleld, Mrs. George, on migration of caterpillars,

13

Fifleld, W. W., statement of,

. 21, 44

Fingerling, Prof. Max on egg killing,

. 118

Fire, aid furnished by, ....

. 7, 166

caterpillars destroyed by,

. 58, 59, 87, 126

eggs destroyed by, ....

57, 118, 119

numbers of moths destroyed by, .

92

Fires, rules concerning (Appendix B).

First destructive appearance of the gypsy moth,

. . . 7

Fish-oil soap, use of, .

Fitchburg Railroad, inspection of,

in

Flicker attacking the gypsy moth,

221, 227

Flight habits of gypsy moth,

97, 112, 342, 344

Flinn, Mrs. J. W., statement of,

8, 22, 25, 27

Flood, M. J., observations on blue-jay,

. 214

Fly-catchers attacking the gypsy moth,

. 7, 207

219, 226, 227, 236

Foliage, area of, on trees, ....

. 494

destruction of, by caterpillars,

. 8-28,

59, 85, 96, 273-284

effect of insecticides on,

159, 489, 494

Follansbee, Mrs. S. J., statement of, .

. 17, 27

Food, amount consumed by caterpillars,

. 315

amount necessary for birds, .

. 204

distribution of the gypsy moth from lack

of,

95

existence of caterpillars without, .

. 325

plants of the canker worm, .

97

plants of the gypsy moth,

58, 246, 316

plants of the gypsy moth, cotton as, .

324

plants of the gypsy moth in Europe, .

325

plants of the tent caterpillar,

97

selection by gypsy moth caterpillars, .

. 485

Forbush, E. H., director, lectures on gypsy moth by,

. 200

on colors of animals of British Columbia,

. 271

on feeding habits of crows, .

. 394

report on birds v. gypsy moth,

203-243

suggestions concerning caterpillar traps by,

. 311

Force, field. See Field force.

Forests attacked by gypsy moth,

97, 274

possible danger to, from gypsy moth, .

. 70, 87

Formica subsericea, .

. 381

Foster, F. E., statement of,

. 18, 29

Fowls affected by arsenic, ....

162

lxxvi

THE GYPSY MOTH.

PAGE

Fowls feeding on gypsy moth caterpillars, ...... 222

France, ravages of the gypsy moth in, ... 274-276, 283

Fraxinus excelsior, exempt from ravages of gypsy moth, . . . 282

Freezing mixtures, .......... 293

French, J. N., statement of, . 27, 30, 31

Frisch, J. L., on injuries by gypsy moth, . 274

Frost, H. L., on food plants of the gypsy moth, .... 316

on predaceous bugs, . ■ . • • 395

Fruit crop increased by spraying, . 60

loss of, . . . • . 26, 41

poisoned by spraying, . 161

trees in Europe attacked by gypsy moth, . 271

trees how sprayed, . 158

Fiirst, Hermann, quoted on birds attacking caterpillars, . . . 208

Gr.

Galeruca xanthomelcena, increase of, due to sparrows, . . . 235

Garden crops destroyed, . 26

Gases for destroying eggs, . 125

Gaurax anchora, . 387

Gazen on ravages of gypsy moth in Kirsanov, ..... 282

Genitalia, description of, . 339

Germany, ravages of the gypsy moth in, . . 274

Gerstiicker, Dr., on the killing of trees by gypsy moth, . . .277

Gibson, It., statement of, . 20

Glands, accessory, of gypsy moth, . . 375

Glass, binocular, use of, . 125

Glover, Townend, on insectivorous birds, . 207

Glucose, use of, . 55, 142

Godart, on injuries by gypsy moth, . 275

Goodell, Pres. II. H., aid of, in securing assistants, . ... 46

letter to Governor-elect Brackett by, . 35

Goodwin, F. M., statement of, . 12, 19

Goodwin, J. O., description of movements of gypsy moth caterpil¬
lars, . 13

statement of, . 21, 31

Gordon, Miss Carrie, observations on molting, . 304

Gould, L. S., at conference on gypsy moth (Appendix A), . . 45

Gould pumps, . 150

Grackle, purple, attacking the gypsy moth, . 207

Grseser on distribution of gypsy moth, . 267

Graff, V. E., on ravages of gypsy moth in Kiazan, .... 281

Grafting wax, use of, in pruning trees, . 177

Grain attacked by gypsy moth in Europe, . 283

Grass eaten by gypsy moth caterpillars, . . . . . 58, 282

Great-crested flycatcher attacking gypsy moth caterpillars, . . 207
Great titmouse attacking other birds, ....... 233

Green, I. C., observations on the redstart, . 219

Green, Paris. See Paris green.

Grimm on feeding habits of birds, . 208, 222

INDEX.

lxxvii

Grosbeak, rose-breasted, attacking gypsy moth,
Grote, Prof. A. R., on systematic position of dispar ,
Gulls as insect destroyers, .

Gypsy motli, acclimation of,

act to provide against depredations by
annual increase of,
area occupied by, ....
attacked by parasites,- .
attacked by predaceous insects, .
bibliography of, . . . .

caterpillars. See Caterpillars of the gypsy motl
colonies of, exterminated,
committee, appointment of,
committee, meeting of, with Metropolitan Park
committee, name of, changed,
comparison of numbers destroyed yearly
common names of,

conditions favoring rapid increase of,
description of caterpillar,
description of eggs,
description of imago, .
description of pupa,
destruction of, by birds,
destruction of, by burlapping
destruction of, by burning
destruction of, by spraying
destructiveness of,
distribution of. See Distribution,
efforts of citizens to destroy,
egg-clusters. See Egg-clusters,
exterminative methods to reduce number of,
female. See Eemale.
first destructive appearance of,
food plants of,
form in which imported,
hermaphrodites,
hibernation of,
history in America,
histoi'y in the Old World,
identification of,

in America, occurrence of, recorded by
in England, .....
in England, how exterminated,
in Europe, .....
in Europe, methods for destroying,
increase of, checked,
increase of, due to English sparrow,
increase of, retarded by fires,
increase of, retarded by isolation,
injuries of, in Old World,
injuries of, to woodland,

Commission,

Profess o

Riley,

7,

PAGE

207, 219
256
206

94
47

95
94, 103

375, 3S5
381, 392
. 257

i 65
49

76
93
256
. 95

. 300

. 288
. 336

. 333

96, 209, 272
167
119, 127
58

23, 40, 57, 70
34, 68, 77, 84

60

7

97, 318
4

339
245
3

273
32

3

268

272

274
284

94
235
7
6

273
88

58,

lxxviii

THE GYPSY MOTH.

6,

15,

57,

96,

Gypsy moth, introduction of into America by Leopold Trouvelot,
introduction of, recorded by Professor Fernald,

Japanese, size of, .

males. See Male moth,
means of preventing spread of, caterpillars,
means taken to find new colonies,
migration of, in search of food, .
natural enemies of,
number of, colonies exterminated,
number of, destroyed by Are,
number of, destroyed by spraying,
number of eggs deposited by,
numbers of, in populated districts,
origin of isolated colonies, .
outbreak of, in 1889,

parasites of, .

peculiarities of the distribution of,
period of greatest distribution,
plants destroyed by the,
possible spread of, ...
pupae. See Pupae,
rapid development of, .
ratio of increase of,
ravages of, first noticed,
result of the transportation of,
seasons favorable for the increase of,
second brood of, .
secondary distribution of,

spread of, compared with that of canker worm,
statements from citizens concerning escape of,
study of the distribution of,
swarming of the male, .
systematic positiou of, .
v. English sparrow,
weather favorable for the increase of,

PAGE

3

3

338

63
105
13, 97
203, 375
70
92
92

94
99

103
10

375, 385
98, 99

104
70, 318

250

86

95
32

102
95, 96
86, 295
104
97

4
94
86

256
234
84

H.

Habia ludoviciana, . 207

Habits, feeding, of gypsy moth caterpillars, . . . . .311

of flight of gypsy moth, . 344

of the gypsy moth, observations on the, ..... 87

spinning, of gypsy moth caterpillars, .... 279, 330, 332

Hair deposited by the gypsy moth in laying, .... 342, 364

Hairs, aerostatic, of caterpillars, . 301

Hairy caterpillars, immunity of, from birds, .... 208, 210

covering of nests, . 289

woodpecker attacking the gypsy moth, .... 207, 221

Hamlin, Mrs. I. W., statement of, . . . . . .11, 20, 30

Hand-killing of caterpillars, efficiency of, . 64

Harlow, J. W., statement of, . 25, 28

INDEX.

lxxix

PAGE

Harmon, Win. B., statement of, ....... 26, 30, 41

Harpalus caliginosus, ......... 382, 385

pennsylvanicus, ........ 382, 384

Harris, Dr. T. W., on occurrence of gypsy moth in England, . . 268

on use of burlap, . . . . . . . . . .171

Hartig, Dr. It., on raupenleim . 130

on tree pruning, .......... 180

infested region visited by, ........ 79

Harvey, Prof. F. L., report of (Appendix E).

Hatch Experiment Station Bulletin, introduction of gypsy moth re¬
corded in, . 3

Hatching of gypsy moth caterpillars, date of, . 294

fall, . 2S5

Hauenstein raupenleim machine, . . . . . . .133

Haushalter, F. H , statement of, . . . . . . . . 21

Haworth on occurrence of gypsy moth in England, .... 268

Heat, effect of, on gypsy moth caterpillars, . 327

effect of, on gypsy moth eggs, ...... 119,293

fall hatching produced by, . 296

Hermaphrodites, gypsy moth, . 339

Hemiptera, predaceous, - . 392

Hemiteles fulvipes, .......... 378

Henry, Professor, on egg-killing, . 118

on ravages of the gypsy moth in France, . 283

Henshaw, Samuel, appointed entomologist to first commission, . 38

on enemies of gypsy moth, ........ 405

Hericart, F., Viscount, on ravages of gypsy moth, .... 276

Hess, Dr. Richard, on means of destroying the gj^psy moth, . . 285

Hibernation of the gypsy moth, ........ 245

of parasites, ........... 377

of predaceous bugs, . 403

Highways, caterpillars of gypsy moth found along, .... 99

inspection of, . 197

History of gypsy moth in America, ....... 3

of gypsy moth in the Old World, . 273

Hochleim raupenleim machine, . . . . . . . .132

Hofmann, Dr., on disease of nun moth, . 405

Holland, occurrence of gypsy moth in, . 268, 283

Homeyer on distribution of gypsy moth, . 267

Hornets, predaceous, . 378

Hose, Eck raupenleim, . 133

for spraying, ........... 147

House swallows driven away by sparrows, ..... 234

House wren attacking the gypsy moth, ..... 208,227

Howard, L. O., opinions of, on gypsy moth work (Appendix E).

Hutchins, John, statement of, ........ 43

Hyannis tobacco mixture as insecticide, . 483

Hydrochloric acid on eggs, . 413

Hydrocyanic acid gas, eggs treated with, . 410

Hydrogen arsenide, eggs treated with, . 412

sulphide, eggs treated with, . . . . . . . .412

lxxx

THE GYPSY MOTH.

PAGE

Hylan, J. P., on assembling of gypsy moth, ..... 345

on leaf area of trees, . 495

Hyla pickeringii, . 404

Hymenoptera attacking the gypsy moth, . 375

Hymenopterous parasites destroyed by flycatchers, . . 220, 241, 376

Hyphantria cunea, .......... 402

Hypogymna dispar, . 255

I.

Ichneumon disparts, . 378

grandis, hibernation of, . 377

Ichneumons captured by birds, . 220, 241, 376

Icterus galbula. See Baltimore oriole.

Imago of gypsy moth. See Female moth ; male moth.

Implements used in searching for eggs, . 125

Importation of birds, . 232

of English sparrow, . 233, 234

of gypsy moth, form of, . 4

of parasites, . 288, 406

Imported insects, damage from, . 270

In-and-in breeding, . . 368

Increase of the gypsy moth, . 94

conditions favoring rapid, ........ 95

due in some measure to sparrows, ...... 235

influences that retarded . 5

normal rate of, in isolated colonies, ...... 95

on neglected lands, . . .31

ratio of, . 95

retarded by climate, . 5

retarded by isolation, . . 6

weather favorable for the, ........ 84

Indigo bird attacking gypsy moth, . 207, 219

Infestation, centres of, . 104

Infested estates, account kept of, . 52

localities, birds frequenting, ....... 223

localities designated on maps, . 50, 52

region appointed to inspectors, ....... 49

region, colonies found in 1891 outside of, ..... 70

region, condition in 1891, . 53

region, description of, ........ 100, 101

region, extent of, . 53, 108

region, how inspected, . 196

region, inspection of belt around, . 108

region of 1891, moth rai’ely found outside of, . . . 6-1

region, proportion of population in, . 101

region, railroads running through . 101

region visited by Agricultural committee, ..... 36

region visited by entomologists, . 69, 79

towns, proportionate numbers of the gypsy moth in, . . . 99

INDEX.

lxxxi

PAGE

Infested woodlands, . 116

woodlands, known area of, ........ 87

Information, bulletin of, . 34,200

of the public, measures for, ...... 34, 198, 200

Injuries by gypsy moth in Old World, . 273

severity of, . 58

spread of, ........... 59

to man and animals from spraying (Appendix F), . . . 161

to woodland by the gypsy moth, . . . . .85, 88, 273-284

Ink, printers’ used in destroying the gypsy moth, .... 34

Insectary, description of, ......... 406

Insecticides, contact, . 57, 58, 163, 485

danger from arsenical (Appendix F).

experiments with, . . . . 55, 69, 407, 477

for destroying caterpillars, . 417, 477

Insectivorous vertebrates (other than birds), ..... 404

Insect lime. See Raupenleim.

Insects, birds as destroyers of, ........ 204

imported, danger from, ........ 270

Inspection, annual, .......... 196

force insufficient for, . 79, 81

of belt around infested region, . 106

of Boston, result of, . . . . .80

of outside territory, ........ 110, 111

of outside towns, result of, . 65, 70

ctf railroads, . Ill

of wooded region, . 66, 87

Inspections of 1891, ......... 52,60,99

Inspectors, observations reported by, . 51

town-sections allotted to, ........ 50

Internal anatomy of gypsy moth, . 368

Introduction of English sparrow, ...... 233, 234

of European birds, . 232

of European parasites, . 288,406

of gypsy moth into America by Leopold Trouvelot, ... 3

of gypsy moth into England, ....... 269

of gypsy moth, recorded by Professor Fernald, .... 3

Investigating committee, appointment of, urged by gypsy moth

committee, . 68, 77

Isolated colonies of the gypsy moth, . 103

injury from, ........... 95

normal rate of increase in . 95

Italy, ravages of the gypsy moth in, . 279

J.

Jliger, Dr., on diseases of nun moth, . 405

Japan, occurrence of gypsy moth in, ....... 267

Japanese gypsy moth, size of, . . 338

Jay, blue, attacking the gypsy moth, . 6, 207, 225

attracted by meat, . 229

lxxxii

THE GYPSY MOTH.

Jay, blue, destroying predaceous insects, .

distributing the gypsy moth, ....
feeding habits of, .

Joly, M. N., on ravages of the gypsy moth,

Jones, F. H., preparation of soap powder emulsion by,

PAGE

241
. 236
210, 231
. 276
. 163

K.

Kazan, ravages of the gypsy moth in, . 281, 283

Kearly, George, on increase of insects following destruction of

birds, . 205

on scarcity of gypsy moth in England, . 269

Kelly, Mrs. Daniel, statement of, ....... 22

Keppen, Theodore, note on cuckoo . 208

on gypsy moth in Russia, . 268, 280

Kerosene emulsion, use of, . 163, 485

for destroying caterpillars, . 126

for destroying eggs, . 416

Kharkov, ravages of gypsy moth in, . 281

Kiev, ravages of the gypsy moth in, . 281

King birds attacking the gypsy moth, .... 207,226,227

Kinglet attracted by meat . 229

Kirby, Catalogue Lepidoptera Heterocera, . 255

Kirkland, A. H , cages for breeding beetles, . 384

observations on wood pewee, ....... 220

on assembling of gypsy moth, . . . . . . . 345

on fall hatching, .......... 296

on food selection by larvae, . . . 485

on garden toad, . .... 404

on internal anatomy of gypsy moth, . 368

on predaceous Hemiptera, . . . 392

on leaf area of trees, ......... 494

Kirsanov, ravages of gypsy moth in, . 282

Kishenev, ravages of gypsy moth in . 280

Klausen, experiments of, with wadding bands, . 286

Knapsack pump, . 149

Knives, cleaning . 126

Ivollar, Vincent, on egg killing, . 118

on use of burlap, . 171

Kornauth, Wachtl and, on diseases of nun moth, .... 405

Kulagin, N., on injuries of gypsy moth in Russia, .... 280

L.

Labodsky on bands for trees, . 285

Lacy, Sylvester, statement of, . 17

Larches attacked by gypsy moth, . 277

Larch saw-fly, damage from, . 270

Laria dispar, . 255

Larv® of gypsy moth. See Caterpillars of gypsy moth.

INDEX.

lxxxiii

PAGE

Law for protection of birds, need of enforcement of, . . . 242

Lawrence, Gen. S. C., testimony of, . 10

Lawrence, Mrs. C. A., statement of, ....... 29

Lead, arsenate of. See Arsenate of lead.

Leaf area of trees, . . . . . . , . . . . 494

Least flycatcher attacking the gypsy moth, ..... 207

Leaves, how injured by arsenical poisons, . 494

Legislature, petition for extermination of gypsy moth presented to, 36

Length of life of imago, . 343, 362

larvae without food, ........ 278, 325

Lepidoptera attacked by predaceous bugs, . 393

Lepidopteron, singing, . 341

Lettuce, quantity eaten by gypsy moth, ...... 315

Lexington, area of woodland infested in, . 87

Light, caterpillars attracted to, ....... 310

Limbs, large, removal of, ... 184

Lime, insect. See Raupenleim.

Limenitis Ursula, ........... 402

Lindens attacked by gypsy moth, . 274

Lines of travel, relation of distribution to, ..... 108

Lintner, Dr. J. A., infested region visited by, . 69

report of (Appendix D), .

Liparis dispar, . . 255

monacha, damage by, ........ 130

use of raupenleim against, ..... 132

Literature on gypsy moth . 257-267

Lithobius forficatus, . 405

Livonia, occurrence of gypsy moth in, . 267, 268

Local extermination, success of, . 247

Localities, infested, birds frequenting, ...... 223

Locusts destroyed by bii’ds, . 205

Locli on vitality of caterpillars, . 327

Loeftler, E., statement of, . 42

London purple, . 140, 417, 477

Leech, J. H., on Japanese gypsy moth, . 338

Lycosa sp. attacking the gypsy moth, . 405

Lymantria monacha, aerostatic hairs of, . . . . . .301

disease of, . 405

M.

Macharcca serriventris, . 392

Machines for burning eggs, . 119

raupenleim, . 131

spraying . 149-156

Majorca, island of, occurrence of gjrpsy moth in, .... 267

Malden, office removed to, ......... 55

petition presented by city officials of, ...... 36

trees defoliated by gypsy moth in, 57

Male gypsy moth, anatomy of, . 339

attracted by pupae, . . 363

lxxxiv

THE GYPSY MOTH.

PAGE

Male gypsy moth, birds feeding on, ...... 228-240

description of, . 336

digestive system of, . 371

distance over which female attracts, . 240, 351

experiments in trapping, . 69, 357

flight of, . 344, 345

length of life of, .......... 343

mating of, . 342

polygamous . 343

presence of fat in, ......... 373

reproductive system of, . 373

Malpighian vessels of gypsy moth, structure of, .... 370

Man, distribution of the gypsy moth by, . 99, 100-103

Maps, section, . 50

Market gardeners, distribution of moth by . 109

Marptusa familiaris, . 405

Martin, Dr. Pearl, appointed commissioner, . 38

Martins driven away by sparrows, . . 234

Maryland yellow-throated warbler attacking the gypsy moth, . . 208

Massachusetts Agricultural College, students of, as assistants, . 46

Horticultural Society, action of, . 36

Mating of gypsy moth, . 342

Maynard, C. J., note on bird digestion, . 204

Maynard, Prof. S. T., recommendation concerning painting trees, . 178

Mayo, Mrs. Thomas F., statement of, . 15, 22, 24

McCarty, Miss K. A., statement of, . 19, 25

McGowen nozzle, . . . . . . • . . .152

McKee, George W., bark shave invented by, . 190

McLaughlin, Wm., statement of, . 44

Medford, brick shipments from, . 110

centre of infestation, ......... 99

colonies of gypsy moth discovered in woods of, . . . . 85

description of section 8 (Appendix C).

distribution of caterpillars from, . 112

gypsy moth fought by municipal authorities of, . . . . 33

measures taken to destroy the pest in, . 34

“Mercury,” description by J. O. Goodwin of movements of

caterpillars in, ......... 13

residence of Trouvelot in, . 4

selectmen of, petition for extermination of gypsy moth pre¬
sented to Legislature by, . 36

statement of citizens as to escape of gypsy moth, ... 4

trees defoliated by gypsy moth in, . 57

woodland burned in, . 166

Meeting of Board of Agriculture, special, ... . . . . 49

opponents to spraying, . 56

Meigenia bisignata, .......... 392

Melrose, outbreak of the gypsy moth in, . 58

Men, examination and training of, ....... 68, 85

largest force of, . 85

Menecles insertus, ........... 393

INDEX.

lxxxv

PAGE

Mephitis mcphitica, . 404

Method of pruning, . 177

of rearing predaceous insects, ...... 384, 394

of testing insecticides, . 418

pursued in outside inspecting, ....... 60

Methods for destroying the gypsy moth, ...... 164

in Europe, ........... 284

most useful to the farmer, ........ 194

Metropolitan Park Commission, gypsy moth committee hold meet¬
ing tvith, . 78

location of territory controlled by the, ..... 78

reservation, moths found in the, ....... 86

“ Mercury,” Medford, description of movements of caterpillars in, . 13

Merrill, Mrs. E. E , statement of, ....... 42

Merula migrcitoria, . . . . . . . . . .216

Mesochorus, species parasitic on gypsy moth in Europe, . . . 378
Microgaster species, parasitic, on gypsy moth in Europe, . . . 377

value of certain species in Europe, . 288

Micropyle, description of, . . . . . . . . . 289

Middlesex Fells, colonies of gypsy moth found in the, ... 86

condition of, ........... 87

Migration of the gypsy moth in search of food, .... 97

Milk inspectors, information furnished by, ..... 107

peddlers, distribution of gypsy moth by, ..... 109

Miller, J. C., statement of, . 13, 42

Minott, C. W., experiments by, . 418

observations on feeding habits, ....... 311

observations on vitality of larvae, ...... 299

observations on creosote oil, ....... 416

Mirror, use of, .......... 125

Mites attacking eggs, .......... 404

Mixter, C. S., statement of, ........ 41

Molting of the gypsy moth, ........ 308

Molts of gypsy moth larvae, . 304

time between, .......... 305

Mongoose, importation into Jamaica, . 233

Monteiro, Dr. A. A. C., on egg-killing, ...... 118

Morton, Hon. .T. Sterling, matter of appropriation presented to, . 83

Moscow, occurrence of gypsy moth in, .... 268, 283

Mosher, F. H , experiments by, . 418

observations on blue-jay, . 214

observations on crow, ......... 217

observations on cuckoo, . 212

observations on flight of female, . . 344

observations on hairy woodpecker, ...... 221

observations on tree frog, . 404

observations on vitality of larvae, ...... 299

Moth, gypsy. See Gypsy moth.

gypsy, female. See Female gypsy moth,
gypsy, male. See Male gypsy moth,
traps,

358, 300

lxxxvi

THE GYPSY MOTH.

PAGE

Moth, tussock, increase due to sparrows . 235

Moulton, F. C., analyses by, ........ 474

experiments by, . 142, 407

on cyanides, ........... 485

Myiarchus crinitus, .......... 207

]sr.

Names of gypsy moth, . 255, 256

Naphtha burner for destroying caterpillars, .... 122, 126
Nason, Prof. F. L., inventor of dendrolene, ..... 135

Nasonov, Dr. N., on egg-killing, . 118

on methods of destroying the gypsy moth, ..... 284

on ravages of gypsy moth in Poland, ...... 283

Native birds driven away by sparrows, ...... 234

Natural enemies of gypsy moth, . 95, 06

birds, . 203

Coleoptera, . . . . . . . . . . .381

Diptera, . . 385

Hemiptera, . 392

Hymenoptera, .......... 375

spiders, . 404

vertebrates, ........... 404

selection, effect on gypsy moth in England, .... 273

selection, influence on colors of gypsy moth, .... 272

selection, influence on flight of males, ...... 345

Neitner, gypsy moth found in Ceylon by, ...... 267

Nematus erichsonii, damage from, . 270

ribesii, damage from, ........ 270

Nervous system of gypsy moth, ........ 373

Neville, T. J. , statement of, ........ 23

Nicholson, C., on extermination of the gypsy moth in England, . 270

Nitric acid for destroying eggs, . 123

Nitrogen dioxide for destroying eggs, . 413

Noctua-c-nigrum , .......... 400-402

Nolken on distribution of gypsy moth, . 268

Norcross, J. Henry, efforts of, to secure an appropriation, . . 36
Nothrus sp. attacking gypsy moth, ....... 404

Nozzle, cyclone, for burning, ........ 120

gem, used for contact insecticides, ...... 163

Nozzles for spraying, . 147, 149, 150, 154

Number of caterpillars from single egg-clusters, .... 297

Nun moth, aerostatic hairs of, ........ 301

damage by (see Lymantria (Liparis) monacha), .... 130

Nursery stock, where shipped, . . . . . . . .108

Nuthatch attracted by meat, . 229

feeding habits of, . . . . . . . . .231

white-breasted, attacking the gypsy moth, . 208

Nymphcea oclorata, . . . . .317

INDEX.

Ixxxvii

o.

PAGE

Oak attacked by gypsy moth in Europe, . . . 274-277,281-283

leaf, area of, . 495

Obstacles to extermination, . 245

Ochsenheimer, “ Schmett. v. Europa,” ...... 255

Ocneria dispar, . . 255

act to provide against depredations by . 47

See Gypsy moth.

Ocneria rubea, peculiar structure on fore wings of, . . . . 342

studies on, . 256

Odoriferous glands of bugs, . 394

Oil, creosote, for destroying eggs, . 63, 123, 410

hose, . 120

paraffine gas, used for burning, . 120

paraffine gas, used on eggs, ........ 417

rape, with tar for banding trees, . 285

spray, burning with, . 59

Old World, injuries of gypsy moth in, ...... 273

Orchards attacked by gypsy moth . 274

extermination of moth in, . 248

Orenboorg, ravages of gypsy moth at, . . . . . 280

Organization of committee, . 38, 49

of field force, . <50

of second commission, ......... 45

Orgyia definita, influence of environment on, . 273

leucostigma, . 402

compared with gypsy moth, . 272

destroyed by spraying, . 140

increase due to English sparrows, . 235

Oriole, Baltimore, attacking the gypsy moth, . . 6, 213, 225, 227, 237

Osborn, Prof. Herbert, identification of mites, ..... 404

Outbreaks of the gypsy moth checked by birds, .... 205

of the gypsy moth in 1889, . 10

Oven bird attacking the gypsy moth, . 208, 219

Oviposition of gypsy moth, . 363

Ovipositor of gypsy moth, . 342

P.

Packard, Dr. A. S., infested region visited by, .
report of (Appendix D).

Paint and creosote tube .

for use in marking trees, . . . .

for use on wounds on trees, . . . .

town section bounds marked with,

Paleacrita vernata, .

food plants of the, .

Palpi, labial, used in spinning, . . . .

of imago, .

69

124
51, 124
. 178

50
402
97

. 332

. 339

lxxxviii

THE GYPSY MOTH.

PAGE

Panzer on ravages of gypsy moth, . 275

Paraffine gas oil for burning . 120

gas oil on eggs, . 417

Parasitized pupae, per cent, of, . 336

Parasites of gypsy moth, . 375

aid given by, in Europe, . • . . . 284

breeding, on many hosts, . 377

destroyed by birds, . 220, 241, 376

dipterous, . 385

hymenopterous, . 375

importation of, . 406

on eggs, . 63

vegetable, ........... 405

Parexorista sussurans, .......... 392

Paris green, . 39, 56, 58, 59, 80, 137, 138, 417, 419, 473

analyses of, . 492

Paris green and lime, analyses of, . . . ... . . 492

comparative effects of, ......... 473

experiments with, . 436

on foliage, ........... 491

Parcisitigena segregata, . 392

Park, Franklin, Boston, colony of gypsy moths found in, . . 70

reservation, Metropolitan, moths found in, .... 86

Parks„possible danger to, . 87

Parthenogenesis, . 365

Parus atricapillus. See Chickadee.

major, . 233

Passerina cyanea, . 207

Pearce, W. J., on parthenogenesis, . 367

Peddlers, routes of, . 108

Pedestrians, distribution of the gypsy moth by, .... 103

Pekin, gypsy moth occurring at, . 268

Penza, ravages of the gypsy moth in, . 281

Pergande, Theo., identification of ants by, . 381

Perillus circumcinctus, .......... 393

Perkins, Dr. G. H., infested region visited by, . 79

report of (Appendix E), .

Perry, A. P., statement of, . 21

Pesomachus hortensis, . . . . . . . . . .378

Petition by city officials of Malden, ....... 36

by city officials of Somerville . 36

by Essex County Agricultural Society, . 36

by executive committee of the State Board of Agriculture, . 36, 78

by Massachusetts Horticultural Society, . 36

by selectmen of Arlington, . 36

by selectmen of Everett, . 36

by selectmen of Stoneham, ........ 36

by selectmen of Wakefield, . . 36

by selectmen of Winchester, . . . 36

by State Board of Agriculture, . 36

Petroleum, use of, on eggs, . 119, 288

INDEX.

lxxxix

PAGE

Pewee, wood, attacking the gypsy moth, .

207, 227

destroying parasites, .

220, 376

Phalcena ( Bombiyx ) dispar, .

. 255

Plialangium dorsatum, ......

. 404

Phenol on eggs, .

123, 414

Phidippus galathea, .

. 405

Phidippus tripunctatus, ......

. 404

Phloeothrips, .

. 404

Phoebe attacking the gypsy moth,

207, 227

Phora incisuralis., .......

. 387

scalaris, .

. 387

setacea, .......

. 391

Phorocera, .

. 387

Phorocera concinnata, ......

. 392

Phosphoric acid deposits in caterpillar,

. 370

Pierce, G. T., statement of, ....

41

Pierce, Richard, statement of,

21, 29, 43

Pierce, W. A., at conference on gypsy moth (Appendix A),

45

Pieris rapce, damage from, .

270

Pimpla Jlavicans, .......

. 378

instigator, .

. 378

pedalis, .......

375, 377

tenuicornis, ......

. 375

Pines attacked by the gypsy moth,

86, 277

attacked by the gypsy moth in Europe,

282

Pipilo erythrophthalmus, .....

. 207

Piranga erythr omelas, .

. 207

Pitch, trees banded with, .

. 285

Plants attacked by the gypsy moth, .

. 58, 70, 3

LG, 318, 323

in Europe, .

. 325

not attacked by the gypsy moth, .

. 323

Plaster of Paris, use of, on trees,

188

Platynus limbatus, ......

. 384

Plummer, Mrs. A. H., statement of, .

29, 31. 42

Podisus cynicus, .......

. 392

serieventris, .

. 393

early stages of, .

. 396

Poisoned larvae, analyses of, ...

. 474

Poland, ravages of the gypsy moth in forests of,

. 283

Police regulations, enforcement of,

. 54, 55

Polistes pallipes, .

. 378

Poltava, ravages of the gypsy moth in,

. 281

Polygamy of the gypsy moth, ....

. 343

Pomerania, insect outbreak in, .

. 205

Pontederia cordata, .

. 317

Population of Massachusetts, proportion of, in infested

region

101

relation of, to distribution, ....

99

Porchinsky, Dr. J., on means of distributing the

gypsy moth, .

. 286

on ravages of the gypsy moth in the Crimea,

279

Porthetna dispar, .

systematic position of ( see Gypsy moth),

. 256

xc

THE GYPSY MOTH.

PAGE

Post offices, frames placed in, .

Potassic cyanide on eggs, .

Potato beetle killed by arsenate of lead,

Pratt, Augustus, elected a member of the committee,

Predaceous Coleoptera, .

Diptera, . ........

Hemiptera, .

Hemiptera attacked by crows,

Hemiptera, how reared, .

Hymenoptera, .

insects, aid given by, ......

insects destroyed by birds, .

insects, Dr. Altum on importation of, .

Press, State, assistance given by, ....
Primary distribution of the gypsy moth,

Printers’ ink used in protecting trees from gypsy moth,

Process of emerging, .

of molting, ........

of pupation, ........

Progress of extermination, ......

Protection of birds, law for, .....

Protoparce celeus, granules ifi, .

Pruning, effects of improper, .

infested trees, .

season for, ........

Preyssler, on ravages of the gypsy moth, .

Pteromalus borccheanus, . . . . ...

halidayanus, ......

pint .

Ptinus brunneus, ........

Pumps, Gould, .

how repaired, .

knapsack, ........

Pupae of the gypsy moth, arsenic found in,

assembling by, .

attacked by parasites, ......

birds feeding on, .

comparison of number of, destroyed annually, .
description of, .......

destruction of, .

emerging of imago from, .....

parasites reared on .

per cent, parasitized, ......

size of, .........

time spent in, .

Pupation in the field, . . . . . .

process of, ........

Purple grackle attacking the gypsy moth, .

Pyroligneous acid on eggs, .

Pyrophila pyramidoides, ......

Pyrrharctia Isabella, .

191)

. 413

. 144

76

. 381

. 392

. 392

. 394

. 394

. 378

284
241

. 288
199
104
34

. 336

. 308

. 332

. 244

206, 242
. 370

175
172
179
. 275

. 377

. 377

. 377

. 385

150
156
149
. 476

. 363

. 376

. 7, 208, 228
93

. 333

. 58, 59, 194
. 336

. 386

. 336

. 333

. 333

. 335

. 332

. 207

. 416

402
. 377

INDEX.

xci

Q.

PAGE

Quercus pedunculata attacked by gypsy moth, ..... 282

rubra, leaf area of, ......... 495

Quiscalus quiscula, .......... 207

R.

Railroad sidings, inspection of, .

trains obstructed by gypsy moth,

Railroads running through the infested district,

Rana silvatica, .....

Ransom, Miss M. M., statement of, .

Ratzeburg on ravages of the gypsy moth,

Raupenleim bands,
composition of,
on eggs, .
trees banded with,

Ravages of the gypsy moth in Massachusetts,
of the gypsy moth in Old World, .

Rawson, W. W., appointed commissioner, .

Reaumer on birds destroying the gypsy moth,

Red-eyed vireo attacking gypsy moth,

Redstart, American, attacking the gypsy moth,
Reduction of infested area,

Region, infested. See Infested region.

Regulations concerning the gypsy moth (Appendix B).
Reid, II. N-, experiments by,
on trapping males,

Reply of State Board to order of Representative W

Reports of inspectors, .

of State Board of Agriculture, extracts from,
of visiting entomologists (Appendix E),
Reproductive powers of gypsy moth, .

system of gypsy moth, .

Respiratory system of gypsy moth,

Restriction of distribution of gypsy moth,

Retractile tubercles of gypsy moth larva,
secretion from,

Rhynchagrotis alternata ,

Riazan, ravages of gypsy moth in,

Richardson, D. M., statement of,

Riegel, on ravages of gypsy moth,

Riley, Prof. C. V., at conference on
infested district visited by, .
on assembling in the bombycidm,
on insectivorous birds, .
on occurrence of gypsy moth in America, .
Rimrod, C. J., on ravages of gypsy moth, .
Ritzema-Boz, Dr. J., on gypsy moth in Holland,

Road commissioners of Medford, meeting of, .

Ill

. 280
101, 102
404
20, 27, 29
. 277

129-135
135

125, 284, 285, 417
64, 69, 136
. 7-44

. 273

38
232
207, 216
208, 219, 227
. 245

?ypsy

moth (Append

J. D. Bu

lock

65-67, 78

x A)

418
357
73
51, 52
81, 82

245
373
372
114
302
304
400, 402
281
12, 27
277
45
56
357
207
3

275
268, 283
33

XC11

THE GYPSY MOTH.

PAGE

Roads, destruction of eggs along, . 63

isolated colonies found along the, . 54

Robert, M., on tree scraping, . 191

Robin, American, attacking the gypsy moth, . . . 208, 216, 227

destroying predaceous insects, ....... 241

destruction of silk worms by, . 6

experiments on, .......... 204

Rogers, J. H., statement of, . 17

Romanoff on distribution of gypsy moth, . 268

Rose-breasted grosbeak attacking the gypsy moth, . . . 207, 219

Routes of transportation, study of the, ...... 106

Rowe, C. H., on predaceous beetles, . 381, 382, 385

Rubbish, destruction of, . 193

Rudzky, on egg destruction, ........ 285

Rules and regulations concerning the gypsy moth (Appendix B),

Russell, G. C., statement of, . 21

Russell, Gov. Wm. E., removal of salaried commission by, . . 45

Russell, Mrs. E. M., statement of, . 21

Russia, occurrence of gypsy moth in, . 268

ravages of gypsy moth in, . 279, 280

Ryder, Mrs. P. N., statement of, ....... 43

s.

Salisbury on occurrence of gypsy moth in England, .... 268

Samara, ravages of gypsy moth in, . 281

Samuels, E. A., record of destruction of silkworms by birds, . . 6

on value of birds, . 205

Sanderson, L. B., notes on wood thrush, ...... 236

statement of, .......... 59

Sap, circulation of, in trees, . . . . . . . .175

Saratov, ravages of gypsy moth in, . 281, 282

Sarcophaga, parasitic . 387, 389

Sarcophaga affinis, . 392

Sargent, Dr. C. S., translation of Des Cars’ “ Tree Pruning” by, . 179

Sargent, F. W., elected member of the committee, .... 76

Saugus, gypsy moth found in, . 53, 86, 87

Saxony, ravages of gypsy moth in, . 274

Sayornis phcebe. See Phoebe.

Scales of gypsy moth wings, form of . 341, 342

Scarlet tanager attacking the gypsy moth, . 207, 227

Scattered eggs, . 63, 117, 363

eggs, fertility of . 239

Scattering of caterpillars, . . . . . . . . .114

Sclueffer, J. C., on ravages of gypsy moth in Saxony, . . . 274

Scheffer, M., on use of burlap, . . . . . . ... 171

Scheuerlen, Dr., on disease of nun moth, ...... 405

Schmidberger on egg-killing, . 117

Schrader, F. C., experiments by, . 360, 418

Schrank “ Fauna Boica,” . 255

Scolytidfe, attacking trees, . 190

INDEX. xciii

PAGE

Scolytus destructor attacking trees in England, ..... 192

Scraping of eggs from trees, method of, discarded, .... 63

of eggs from trees, recommended by Europeans, . . . 292

of trees, . 189

of trees, value of, . 172

Scudder, Samuel, at conference on gypsy moth (Appendix A), . 45

Season for pruning., . 179

larval, distribution in, . 110

Second brood of the gypsy moth, . 86, 295

“ Section ” books, record of infested estates kept in, ... 52

Section 8, Medford, description of (Appendix C).

Sections, towns divided into, ........ 49

Seitz, raupenleim machine . 133

Seopru, Georg, on ravages of gypsy moth in the Crimea, . . . 280

Sessions, Hon. Wm. R., appointed member of committee, . . 49, 76

at conference on gypsy moth (Appendix A).

chosen chairman of committee, . 49

Medford visited by, ......... 34

member of committee sent to Washington, ..... 83

Sex differentiation in larvae, . 374

Sexual dimorphism of gypsy moth, ....... 272

Shade trees, how sprayed, . 158

Slialer, Prof. N. S., appointed member of committee, ... 49

assistance given by, . 72

at conference on gypsy moth (Appendix A), .... 45

interview with Mr. Trouvelot, ....... 4

resignation of, .......... 72

Shaw, H. J., moth trap invented by, . 360

observations on red-eyed vireo, . 221

Shellac, use of, in pruning, . 177

Sherman, J., statement of, ......... 20

Sherman, Walter, statement of, ....... 20, 26

Shipov, ravages of gypsy moth in, . 282

Sialia sialis. See Blue bird.

Siberia, occurrence of the gypsy moth in, . . . . 267, 268, 280

Sidings, railroad, inspection of, . Ill

Siebold on parthenogenesis, ........ 366

Silk, amount spun by gypsy moth caterpillars, ...... 331

glands of caterpillars, . 370

Silkworms destroyed by bii’ds, . 6

Silpha quadripunctata, .......... 287

Simbeersk, ravages of gypsy moth in, . 281, 283

Sinea diadema, . . 405

Size of imago, variation in, . 338

Skunk attacking the gypsy moth, . 404

Smith, Prof. J. B., infested region visited by, ..... 69

on insectivorous birds, ......... 207

on raupenlein, . 135

on systematic position of dispar, . . 256

report of (Appendix D).

Smith, J. W., data furnished by, concerning wind, .... 350

XC1V

THE GYPSY MOTH.

S,

Snowdon, W. H., statement of, .

Soap powders, use of, as contact insecticide,

Soda, arsenate of, experiments with, .

Somerville, petition presented by city officials o
Sorauer, Dr. Paul, on tree pruning,

South, Richard, on extermination of gypsy moth in England,
Spain, occurrence of gypsy moth in,

Sparrow, chipping, feeding on gypsy moth caterpillar
English, attacking the gypsy moth,

English, feeding on gypsy moth eggs, .

English, introduction of,

Sparrows feeding on gypsy moth,

Speyer on distribution of gypsy moth
Sphinx drupiferarum, .

Spiders attacking gypsy moth,

“ Spiegel,” destruction of, .

Spines on wings of gypsy moth,

Spinney, Mrs. F. T. , statement of,

Spinning habits of caterpillars,

Spiny area on wings, .

Spizella socialis, .

Spray, burning with oil,

Spraying against gypsy moth,
apparatus,

benefit to fruit crops from,
burlapping substituted for,
caterpillars distributed by,
caterpillars killed by,
danger from (Appendix F),
distribution lessened by,
poisons for use in,

not effectual as an exterminative method,
number of moths destroyed by,
prejudices against,

recommended by entomologists (Appendix A),
rules concerning (Appendix B).

system of, .

time of, ...
with arsenate of lead, .
with arsenate of lead, effectiveness of,
with arsenical insecticides, failure of, as a means of

tion, .

with contact insecticides,
with Paris green. See Paris green,
with Paris green, opposition to, .
outfits, ......

Spread of gypsy moth, comparison with that of canker worm
efforts to prevent the, .
in twenty years,
in woods,

slow, ....

PAGE

13, 18, 25, 30
163, 485
143
36

. 181
. 269

. 268
07, 215, 226, 227
. 208
231, 239
233, 234
219, 228
. 267

. 383

404, 405
. 284

. 341

12, 18, 29, 32
02, 278, 330, 332
. 341

207, 215
59

exter

145

57

64

55, 417, 477
56
92

157
156
60
64
113
58, 64

18, 199
45, 55

56
156, 157

87
80

62

57

56
55, 140
97
79
5
115
245

INDEX.

XCY

PAGE

Squirrels, eggs scattered by, . 231

Starling attacking nun moth in Europe, ..... 208, 209

State Board of Agriculture. See Board of Agriculture.

Statements of citizens concerning the gypsy moth (Appendix G), 7, 8-10,

11-13, 14-32, 33, 40-44, 59

Station, experiment, erection of, . 87, 406

Staudinger on distribution of gypsy moth, . 267

Steatocla borealis, . 405

Stephens, “ Illustrations of British Entomology,” .... 255

on occurrence of gypsy moth in England, ..... 269

Stephenson, Dr. F. B., translation of Bussian works on gypsy moth

by, . 268

Stetson, John, statement of, ........ 10

Stetson, S. S., elected a member of the gypsy moth committee, . 84

Stockholm, occurrence of gypsy moth at, . 267

Stomach examination of cuckoo, . 212

examination of toad, . . 405

of gypsy moth larva, . . . . . . . . .369

Stoneham, petition presented by selectmen of, ..... 36

Stone walls, comparison of yearly work on, . 93

St. Petersburg, non-occurrence of gypsy moth at, . . . 268

Streams, caterpillars distributed by, . 98

Studies on systematic position of dispar, ...... 256

Study of the methods and routes of transportation, .... 106

Sulpho-naphthol, ........... 484

Sulphur dioxide on eggs, . 416

Summer pruning, ........... 184

Swallows, house, driven away by sparrows, . 234

Swampscott, outbreak of the gypsy moth in, . 58

Sweden, occurrence of gypsy moth in, . 267

Swill-takers, distribution of the moth by, . . . . . .109

Swinton on sound producing insects, . 341

Syrphus sp. attacking the gypsy moth, . 405

Systematic position of dispar, . 256

T.

Tachina, European parasites of gypsy moth, ..... 392

Tachinids captured by birds, . 241

parasitic, . 387

Tambov, ravages of the gypsy moth in, . 281

Tanager, scarlet, attacking the gypsy moth, .... 207, 227

Tangl, Dr., on disease of nun moth, . 405

Tar and rape oil bands, . 285

bands, . 127, 285, 286

coal, use of, in tree pruning, . 177, 182, 186

used on eggs, . 125,414

Tarred burlap, use of, on trees, . 188

paper, trees banded with, . 28

Taylor, Wm., statement of, . . . . . . . 8, 19, 25, 28, 31

XCY1

THE GYPSY MOTH.

PAGE

Teaming from infested region, ....

108

Telea polyphemus, .

401, 402

Tent caterpillars attacked hy warblers,

. 219

caterpillars destroyed by Baltimore oriole, .

. 213

caterpillars destroyed by spraying,

140

caterpillars killed by arsenate of lead, .

144

Terns as insect destroyers, .

. 206

Territory infested. See Infested region.

Thaxter, Dr., on vegetable parasites, .

. 405

Thelymorpha vertiginosa, .

. 392

Theronia melanocephala, .

. 375

destroyed by wood pewee, ....

220, 376

habits of, .

. 376

Thomixus sp. attacking the gypsy moth,

. 405

Thrush, brown, feeding on the gypsy moth,

208, 225

wood, feeding on the gypsy moth,

208, 236

Tideman on ravages of the gypsy moth in Kazan,

2S1

Time between molts, ......

. 305

in pupa stage, .

. 333

of feeding, .

. 311

of hatching, .

. 294

record of men’s .

52

required for emerging, .

. 336

spent in laying, .

. 364

spent in mating .

. 342

spent in spinning, .

. 332

Tin, use of, on trees, .

189

Tiresias serra, .

385

Titmouse attacking the gypsy moth in Europe, .

209,

232, 233

attracted by meat, .

. 229

great, attacking other birds ( see chickadee),

. 233

Toad attacking the gypsy moth, ....

222, 404

Tobacco mixture as an insecticide,

. 483

Tolype velleda, .

. 402

Torches, kerosene, for burning caterpillars,

39

Tortricids, British, dark color of,

. 271

Tortrix fiimiferana attacked by Pimpla pedaJis,

. 377

Tower, W. L., notes on caterpillars, .

169, 329

on predaceous Hymenoptera,

. 379

Towhee bunting, feeding on gypsy moth imagoes,

225, 227

Towns and cities from which false alarms have been received,

. 201

divided into sections, .

50

efforts concentrated in outlying, .

53

infested, citizens from, present at hearings,

84

infested, proportionate numbers of gypsy moths in,

99

inner, increase of the moths in, .

92

inspected beyond infested area, .

198

necessity of inspecting apparently cleared, .

80

worst infested, destruction of eggs in,

69

Traffic, danger from, .

. 109

distribution of the gypsy moth by,

102

INDEX.

xcvii

PAGE

Traffic, ratio of distribution by, . 109

study of, . 109

Transportation, a study of the methods and routes of, . . 106

by freight, . 110

Trapping of male moths, results of, . 80, 357

Traps, caterpillar, . 311

moth, . 358, 360

Travel, danger from, to Boston, . 107

direction of, from infested centre, . 107

lines of, . 108

Travelling of young larvae, . 310

Treadwell, Professor, experiments on robins, ..... 204

Tree creepers attracted to meat, . 229

Tree ink, trees banded with, . 64, 128

pruning, . 172

Trees, alarming condition of, in 1889, ...... 33

banded . • . 126, 195

banded with burlap, . 69, 85, 167

banded with raupenleim, . 64

banded with tarred paper, . 28

banded with tree ink, . 64

comparison of yearly work on, ....... 92, 93

defoliated by the gypsy moth, . 57, 85

destroyed by the gypsy moth, . 23, 70, 274

hollow, treatment of, . 63, 187

infested, location of, ......... 99

infested, marked with white paint, . 51

leaf area of, . 494

per cent, of pupae in, . 335

saved by contact insecticides, ....... 58

scraping of, . 189

Trogus flavatorius, . 378

Trombidium bulbipes, .......... 404

Trouvelot, Leopold, interview with Prof. N. S. Shaler, ... 4

introduction of the gypsy moth into America by, ... 3

residence in Medford . 4

Tube, paint and creosote, . 124

Tubercles, larval, . 300

retractile . 303, 304

Tubeuf, Dr., on disease of nun moth, . 405

Turpentine for destroying eggs . 123, 416

Tussock moth destroyed by spraying, . 140

increase of, due to sparrows, . 235

Tutt, J. W., on the extermination of the gypsy moth in England, . 270

Tuttle, Mrs. R., statement of, . n i6, 25

Tyrannus tyrannus, . 207

XCV111

THE GYPSY MOTH.

u.

Uhler, Prof. P. R. , description of Poclisus serieventris,

. 399

determination of Hemiptera by, ....

. 400

Unfertilized females, eggs laid by, ....

290, 365, 367

United States Senate, resolve passed by the,

83

Urates, presence of, in malpighian vessels of larvae, .

. 370

Useful birds, .

insects v. birds, .

Utah, cricket ravages in, .

206

Y.

Value of egg-eating birds, . ■ . .

229

Vanessa antiopa, ........

400, 402

Variation in size of imago, .

Vegetable parasites, .

288, 405

Vehicles inspected by police, .

54

transportation of the gypsy moth by, .

39, 102, 103, 107

Vertebrates, insectivorous, . .

. 404

Vespa consobrina, ........

. 378

germanica , ........

. 378

maculata, ........

. 378

Villages, inspection of, .

197

Vireo, red-eyed, attacking gypsy moth caterpillars, .

207, 216, 225

white-eyed, attacking the gypsy moth,

208

yellow-throated, attacking the gypsy moth,

208, 217, 227

Vitality of dipterous larvae, .

. 386

of gypsy moth eggs, .

279, 291

of caterpillars, .......

299, 325

of predaceous bugs, ......

. 393

Volsk, ravages of the gypsy moth in, .

282

Voronezh, ravages of the gypsy moth in, .

. 281

AV.

Wachtl and Kornauth on disease of nun moth, . ... 405

Wadding bands, Klausen’s experiments with, . 286

Wakefield, petition presented by selectmen of, . '36

Walker, J. J., on the distribution of the gypsy moth, . . . 268

Wallace, Mrs. B., statement of , ........ 44

Walls, stone, comparison of yearly work on, . 93

Warbler, black and white, attacking the gypsy moth, . . 208, 225

black-throated green, attacking the gypsy moth, . . . 208

chestnut-sided, attacking the gypsy moth, . 208

creeping, feeding on the gypsy moth, ...... 227

Maryland yellow-throated, attacking the gypsy moth, . . 208

yellow, attacking the gypsy moth, . 208, 227

Ward, A. H., suggestions on insecticides by, ..... 142

Ware, E. C., directions concerning care of sprayiug machines, . 155

INDEX.

xcix

PAGE

Warsaw, occurrence of the gypsy moth in,

. 283

Wasps, predaceous, .......

. 378

Water birds as insect destroyers, ....

. 206

distribution of the gypsy moth by,

98, 105

Wax, grafting, use in pruning trees, ....

. 177

Weather, effect of, on the moth, . ....

. 84, 96

egg destruction hindered by the, ....

78

influence on assembling, .....

. 346

Webster, Prof. F. M., spraying v. bees,

157

Weed, Prof. Clarence M., infested region visited by,

69

on feeding habits of the gypsy moth, .
report of (Appendix D).

215

Weijnbergh on parthenogenesis, ....

. 366

Weir, J. Jenner, ou the extermination of the gyps3r moth in England, 270

Wellington, Dr. Chas., on Paris green and lime,

. 491

Wellington, J. E., statement of, .....

30

Weston, S. F., statement of, .

. 30, 43

Whale-oil soap, use of, .

163, 485

Wheeler, J. G. , statement of, .

. 20, 28

White-breasted nuthatch attacking the gypsy moth, .

. 208

White-eyed vireo attacking the gypsy moth,

208

Wiggiu, Mayor, at conference ou gypsy moth (Appendix

A), .

. 45

Wild, Miss Helen T., statement of, ...

. 13, 21

Wilkes on occurrence of the gypsy moth in England,

. 268

Williston, Dr. S. W., determination of dipterous parasites by, .

. 387

Winchester, outbreaks of the gypsy moth in,

. 58

petition of selectmen, ......

36

Wind, distribution of caterpillars by,

98, 301

influence of, on assembling, .....

. 346

Wingelmuller, C., on flying of female,

. 344

Wings, atrophy of female Orgyia, ....

. 273

effects of shellac on, ......

351

form of scales of, .......

342

markings of, ......

. 337

not necessary to mating, .

. 356

sound producing apparatus on, ....

. 341

spiny area of, .......

. 341

“ Winning” colony, pupation in, ....

. 335

second brood at, ......

. 295

Winter oaks attacked by the gypsy moth, .

282

pruning, .

. 181

Woburn, area of infested woodland in,

87

woodland burned at, .....

165

Wodzicld, Count, gypsy moth ravages on estate of, .

. 232

Wood, C. E., observations by, ou the yellow-throated vireo,

217 222

Wood, E. W., elected chairman of committee, .

76

Wooded region, inspection of, .....

66

Woodland, area of, infested, .....

87

birds in infested, . .

223

burning of, .

165

colonies found in .

70

c

THE GYPSY MOTH

Woodland, area of, defoliated by the gypsy moth,
extermination of the gypsy moth in, .
injury done to, by the gypsy moth,

Woodpeckers attacking the gypsy moth, .

attracted by meat, .

eggs scattered by, .

feeding habits of, .

Wood pewee attacking parasites, ....

attacking the gypsy moth, .

Woods, explanation of colonies in,

inspection of, .

moth checked in, .

result of search of, .

Wood thrush attacking the gypsy moth,
distributing gypsy moth caterpillars, .

Work, cost of, increased by delayed appropriations, .

delayed by snow storms, .

done annually, comparison of,

field, advice of Professor Fernald concerning, .

of 1891, ., .

of 1892, .

of 1893, .

of 1894, .

of 1895, .

of four years, summary of, .

World’s Columbian exposition, exhibit at, .

Wounds from pruning, how healed, ....
Wren, house, attacking the gypsy moth, .

driven away by sparrows, .

European, destroying eggs of the gypsy moth, .
Wright, Walter, note on liberation of English sparrows,

PAGE

85

. 248

88
207
. 229

230, 231
. 210
220, 376
. 207

. 107

87

88
80

. 208
. 236

78

. 63, 85
. 92, 93
57

. 45

62
68
72
83
91

. 200
177
208, 227
. 234

232
234

Y.

Yaroschev on ravages of the gypsy moth, . 282

Yellow-billed cuckoo destroying the gypsy moth, . . . 207,212
Yellow-throated vireo attacking gypsy moth caterpillars, . 208, 217, 227
Yellow warbler attacking the gypsy moth, . 208

z.

Zinc, arsenate of, experiments with, .

use of, on trees, ....
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