The pine moth of Nantucket, Retinia frustrana

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THE

PINE MOTH OF NANTUCKET

— BETINIA FRUSTRANA —

BY

SAMUEL H. SCUDDER.

BOSTON:
A. WILLIAMS AND COMPANY,

1883.

PUBLICATIONS

OP THE

lassacltts^tts Bm\^ for t\t ^xamim at ^griculturt

THE

PINE MOTH OF NANTUCKET

— RETINIA FRUSTRANA —

BY

SAMUEL H. SCUDDER.

BOSTON:

A. WILLIAMS AND COMPANY,

283 Washington Street.

1883.

Copyright, 18S2,
By Samuel H. Scudder.

University Press :
John Wilson and Son, Cambridge.

THE PINE MOTH OF NANTUCKET.

The pines on the island of Nantucket (Pinus rigida Miller),
set out some twenty or thirty years ago, are fast dying in large
numbers from a cause hitherto unknown. A great many have
already perished, and most of the living trees look sickly. On
the " Old South Road," from Nantucket to Siasconset, all the
trees on one side of the road are quite dead, or fast dying,
while upon the opposite they are comparatively healthy-look-
ing, although seriously affected.

On Sept. 19, 1876, I went to this spot to discover, if pos-
sible, the difficulty. I chose first a dead tree on Mr. Crosby's
land, and cut it down, carefully examining the trunk, boughs,
twigs, bark, and roots ; there was no sign of the work of any
insect sufficient to have caused the death of the tree, — none
more than would be found on any healthy tree. Next, I selected
a tree that was nearly dead, the uppermost boughs only being
in leaf, and a few bunches of needles appearing at different
points on the trunk. I cut this down, and examined the trunk,
boughs, bark, and roots as before, with negative results ; but
when I searched the living twigs I found, always at the extreme
tips, a great many recently dead needles, and in connection
with them a small lepidopterous insect, and in such numbers,
both here and on hundreds of trees afterwards examined, as
to leave no room for doubt that this insect is the sole cause of
the trouble. The only other insect at all common was the
larva of a geometrid moth, which had nibbled the leaves ex-
tensively, but not enough to cause serious damage, or to strike

4 THE PINE MOTH OF NANTUCKE^T.

at all at the life of the tree ; wherever the mark of the blight
was found upon living trees, the first-mentioned insect was
present in vast numbers, and very nearly all the damage that
had been inflicted was directly traceable to its devastations. It
is a minute moth of the family of Tortricidae, referable to the
genus Retinia (or Coccyx of some authors), and may be de-
scribed as follows :

Retinia frustrana nov. sp. (Fig. l.)

Head covered, especially above, with hoary tipped, smoky
brown scales, giving it a speckled appearance ; palpi rather
longer than the head, the middle joint expanding into a com-
pressed, disk-like plate, half as large as the head, and covered
with silvery gray scales, which are dusky toward the base, the
apical joint minute, slender, dusky ; antennae equally and nar-
rowly annulated with dark brown and white. Thorax and
patagia of much the same color as the summit of the head,
but the front portion of each tinged with pale umber, while the
hinder portion inclines to silvery gray, sometimes to a decided
degree.

The ground color of the front wings is divided between a
dull yellowish umber and a deep reddish umber, deepening at
points to a bright ferruginous. The former prevails in the
lower half of the outer two-thirds of the wing, and in an ob-
lique subapical band, subparallel to the outer margin. The
latter elsewhere, but becoming subinfuscated in the basal third
of the wing ; the brightest parts of this tint are found in a large
quadrate patch depending from the middle of the costa, and
an oblique, slightly arcuate streak, directed inward from the
apex, and often continued a little out of line over the lower
half of the wing, breaking the lower pale patch in the middle
of the outer half of the wing. Both of these umber tints are
overlaid by frequent transverse, perfect or broken stripes of
lustrous pearly gray, which, with the diversity of the ground
color, give the insect a very variegated appearance. Nearly
all of these pearly stripes run at right angles to the costa, and
are distributed as follows : The most important and persistent
are the two broadest, which divide the wing into nearly equal

THE PINE MOTH OF NANTUCKET. 6

thirds, the outer striking the inner angle of the wing, where
the fringe terminates ; another, nearly as constant, crosses the
wing a little beyond the middle, is slightly bowed outward,
and united at the middle with the outer of the two already
mentioned, forming with it an H, with one straight and one
bowed leg ; often, on the left wing, it more nearly resembles
a K ; besides these there are numerous, often partially con-
fluent, short bars or stripes on the upper half of the wing, and,
next the inner margin, very brief similar bars, increasing in
size toward the base, and on the basal third forming a dull
pearly patch. The whole of the basal third or fourth of the
wing is traversed irregularly by transverse pearly lines, often
nearly or quite confluent ; and in some individuals the whole
basal half is of a nearly uniform pearly hue. Many of these
pearly scales appear to have fuliginous bases, so that where
the patches are broadest, the color is usually duller. The
outer edge of the wing is marked by scattered black scales,
edged within, and sometimes without, by a delicate white line ;
and the fringe, which is very long, especially below, is pearly
fuliginous, often deepening apically to black, and with all the
scales minutely white tipped, forming transverse lines of white
upon the darker ground.

Hind wings very pale silvery gray, slightly infuscated, the
fringe infuscated only at base, outside of a silvery hue. Legs
silvery gray, the tarsi infuscated above at the base of all the
joints. Abdomen silvery gray, more or less infuscated above,
or sprinkled with brownish fuscous scales.

Expanse of wings, 12-14 mm. ; length of body, 4.75-5.75
mm. ; length of antennae, 3.5 mm. Described from twenty
specimens.

There seems to be no colorational distinction between the
male and the female, but considerable general variation both
in the markings and in the tints of this beautiful but destruc-
tive insect. Some individuals occur in which the deeper col-
ors are intense, while, at the other extreme, the pearly scales
have spread so widely, and at the same time the more brilliant
tints have become so subdued, as to give the whole insect a

6 THE PINE MOTH OP NANTUCKET.

drab appearance. The two shades of umber, also, grade into
each other in all cases, being seldom sharply separated. The
markings as above described are those most prevalent.

The larva (fig. 4) is slender, cylindrical, slightly depressed,
of a pale brown color above, the thoracic segments slightly
darker, with a faint pale mediodorsal line, which broadens
and becomes somewhat yellowish on the two hinder segments,
on the last occupying nearly the whole breadth of the segment ;
the lower part of the sides and the under surface are dirty
luteous. The head varies from castaneous to pitchy castane-
ous, is broader than long, obscurely subcordate, the lateral
hemispheres being tumid above, and separated b}'- a deep and
narrow groove ; the antennae and most of the mouth parts are
pale luteous, the ocelli black. The prothoracic shield is of the
color of the head, transversely obovate, more than twice as
broad as long, and divided by a pale mediodorsal stripe ; the
hinder margin is broadly rounded, the front margin nearly
straight, and the lateral margins rounded subangular, posteri-
orly melting into the hind margin. The anal plate is scarcely
darker than the body, small, almost semicircular, but less than
twice as broad as long, and slightly tumid. The legs are of
the color of the under surface of the body, but are marked with
fuscous, the claws reddish ; the prolegs are also fuscous, and
the spiracles edged with piceous. The body is uniformly, but
rather sparsely, clothed with microscopic hairs, scarcely per-
ceptible with a good lens ; and besides these has longer and
stouter, but still delicate, pale hairs, about as long as the width
of the body, scattered over the upper surface, arising, one
each, from minute piceous warts, which are definitely arranged
on both sides of the body : — two on a segment in a dorso-
pleural row, two on a segment in a ventro-pleural row, and one
on a segment in a stigmatal row. There are similar hairs
scattered more irregularly on the head and prothoracic shield.

Length, 13 mm. ; breadth, 2 mm.

The chrysalis (figs. 2, 2 a, 3, 3 a') is almost uniformly castane-
ous, -with wing-cases, eye-covers, antennae, and sometimes some

THE PINE MOTH OF NANTUCKET. 7

of the liinder edges of the dorsal scuta of the abdomen dusky.
The rostrate prolongation of the anterior extremity of the body
(fig. 2) is bent downward at a slight angle, preserving above
the curve of the head, pretty strongly and uniformly compressed,
docked apically, triangular as viewed laterally, the sides hol-
lowed, and the upper surface slightly sulcate, its lateral edges a
little elevated or margined, and all the ridges marked with black.
The pronotum is depressed below the surface of the head, but
bounded posteriorly by a sharp, elevated, backward directed
ridge, higher than the mesosternum. All the abdominal seg-
ments behind the first (fig. 2 a) are furnished with anterior and
posterior dorsal transverse rows of minute, sharp, conical tuber-
cles or points, the rows nearly equidistant, those of the movable
segments longer than the others, and with the points directed
backward. The anterior row is a little more extended than
the other, and is formed on most of the segments of larger and
more distant points ; in advance of it, at the line to which the
posterior edge of the preceding segment reaches, is a shorter,
delicate, fine-edged ridge ; and a similar but blunter ridge
continues the posterior row of tubercles around the body. The
very tip of the abdomen (fig. 3 a), which is truncated and blunt,
bears a slight coronet of points similar to those of the trans-
verse rows.

Length, 6 mm. ; breadth, 1.25 mm. '

The eggs seen were not described.

The moth appears to be most nearly allied to the European
species R. duplana Hiibn. and R. sylvestrana Curtis. From
specimens of the former, which Professor Zeller was kind
enough to send me from Germany, it differs by its much
smaller size, and the much greater irregularity of its mark-
ings, these being almost always clustered into four or five
narrow, equidistant, transverse belts in R. duplana ; a tendency
to such a transverse disposition of the markings exists also in
R, frustrana, as indicated above, but mostly confined to two
comparatively broad belts. From R. sylvestrana, as far as I
can judge by descriptions, and by a pair of English specimens

8 THE PINE MOTH OF NANTUCKET.

sent me for comparison by Professor Fernald, it differs by its
slightly lesser size, the color of the head and palpi, the differ-
ent disposition of the markings of the wing, and their more
brilliant and more highly variegated tints ; in R. sylvestrana
the stripes are numerous, very slender, and tend toward con-
fluence on the basal half of the wing, giving it a somewhat
hoary appearance, in which respect it resembles R. duplana
rather than R. frustrana. The pupa of R. frustrana also agrees
with that of R. duplana, and is distinguished from that of other
Retiniae (that of R. sylvestrana is not known) in the rostrate
prolongation of the anterior extremity of the body (see figs. 2,
3) ; the close affinity of R. frustrana to the two above-men-
tioned species will therefore be readily granted.

Although I have not been able to follow the history of this
insect completely, it is probably double-brooded, and differs
therein from the European species which it most resembles.
R. duplana flies in Germany once a year only, appearing by the
end of March or the beginning of April, and living some time
into May ; the larva is full grown by the end of June or the
beginning of July, when it changes to pupa, and in this con-
dition continues eight months in the year. R. sylvestrana is
said to appear on the wing in England in June and July, and
has a similar history to the preceding, excepting in its later
changes. R. frustrana appears in Nantucket between these
two periods, or toward the end of April,i and flies at least
during May ; probably most of the brood has emerged by the
end of the first week in May. Eggs were seen in one instance
May 15, and a nearly grown larva on June 18. Caterpil-
lars may be found fully grown, together with an occasional
chrysalid, in the middle of July ; a little later chrysalids only
can be found ; and again, several years ago, I found larvae in
great abundance, with an occasional chrysalid, about the mid-

1 The earliest specimens obtained one year from chj'salids only a week or
two in confinement in a warm room appeared on April 25th ; the earliest of
those kept the same year in a cellar appeared May 8th. A single living moth,
and another just dying, were discovered among the twigs confined in a box as
late as June 23d ; how long they had been out of chrysalis there were no means
of judging, but not impossibly several weeks.

THE PINE MOTH OF NANTUCKET. 9

die of September. Soon after that all change to chrysalids ;
for, in a subsequent year, Mr. S. Henshavv, who visited the
island September 17-19, and examined the trees carefully,
found not more than one sixth in the larval state, the rest in
chrysalis. In all probability, then, the insect is double-brooded,
flying in May and August, and wintering in chrysalis.

Curious as this difference in the number of broods between
these allied species in Europe and America may seem, it is
quite in accordance with what occurs in other Lepidoptera,
where analogous species are found upon the two continents.
I have not studied this subject in the nocturnal Lepidoptera,
but among butterflies I have found that nearly all the species
which are identical, or very closely allied, on the two conti-
nents have at least one brood per annum more in North
America than in Europe. Specifications of half a dozen of
these cases will be found in the American Naturalist, Yol. X.
pp. 603, 601. This seems to be largely due to climatic causes;
and it naturally follows that, when an injurious insect is im-
ported from Europe to America, its ravages here are likely to
surpass anything charged to it in its proper home, — a point
which should be taken into account by students of economic
entomology.^

Retinia, the genus into which this insect falls, is represented
in Europe by no less than eleven species, four or five of which
are common, and four were found by Ratzeburg more than
forty years ago doing extensive injury.^ They all feed upon
coniferous trees, perhaps exclusively upon pines, and all live
upon the twigs ; according to Ratzeburg again, all are single-
brooded with a single exception (R. resinella), where a gene-
ration of moths appears only once in two years. When I first

1 Mr. C. V. Riley (2d Rep. Entora. Missouri) asserts that destructive insects
introduced from America into Europe make no headway against their more
"highly developed" allies on that continent; while the reverse is true of Eu-
ropean pests introduced here, "the stronger and more favorably organized spe-
cies overpowering and starving out from time to time their less vigorous and
less favorably organized competitors." Unfortunately he gives no facts to sup-
port this highly organized theory.

2 Three of these four have now been found on the Pacific coast of the United
States.

10 THE PINE MOTH OF NANTUCKET.

observed the injury at Nantucket, no species of this genus had
been found in this country ; but since then one or two have
been found in this section, and doing a considerable amount of
injury to pines.^ Now that attention has been drawn to them,
no doubt other notices will follow, showing that we have to
deal with a whole group of insects specially destructive to
pines both in Europe and America ; but our Nantucket species
proves much more dangerous than the European R. duplana
and R. sylvestrana.^

The different species of this genus attack the trees in some-
what different methods, but they all agree in selecting the ten-
derest growing shoots for their ravages, and in destroying this
sensitive and essential part by boring into the heart, and de-
vouring the sappiest and pulpiest portion at the base of the nee-
dles. Some, like a species recently found by Mr. Comstock of
the Agricultural Department in Washington upon Pinus inops,^
live a part of the time, at any rate, outside of the twig, for
their webs may be seen enclosing the base of the bud and the
surrounding new leaflets ; but most of them, like R. frustrana,
live entirely within the shoot from the moment they have bored
their way into it, and undergo therein their transformations.

The injury done by R. frustrana to the pitch pine (Pinus
rigida) of Nantucket is soon detected in the months between
May and September by noticing the dead needles at the very

1 A brief notice of these will be found in the Appendix.

2 Fernald's Catalogue of Tortricidte (1882) gives eight species, of which, how-
ever, only three, including K. frustrana, are found in the eastern United States.
Of the five found on the Pacific slope, where the insect fauna has, as is known, a
decidedly European aspect, four are believed to be identical with European spe-
cies, and among them R. duplana and R. sylvestrana occur.

^ Since this was written Mr. Comstock has published his notices of this spe-
cies (Eep. U. S. Dept. Agric, 1879, pp. 236, 237, pi. 5, fig. 2), which he consid-
ers, on Professor Fernald's authority, to be the same as that here described.
There can be no doubt of their very close relationship, but the difference in the
habits of the larvae in the two localities, botli during active life and when about
to undergo metamorphosis, would be very singular if they belong to the same
species. The specimens carefully studied by him, also, were found on a differ-
ent species of pine. I have made no comparison, but only desire here to call the
attention of those who may hereafter study this insect to this fact. For further
account of Mr. Comstock's observations, see the close of this paper.

THE PINE MOTH OP NANTUCKET. 11

tip of a shoot otherwise of a fresh green color, or only partially
withered near the dead needles. The egg must be laid, as
Ratzeburg presumes it to be in the European species, between
the scales of the bursting bud, from whence the caterpillar eats
its way at birth into the very heart of the bud near the extreme
tip ; for to this part are the youngest caterpillars confined. From
this point the growing caterpillar burrows down the stem, often
for from four to six centimeters, and thus eats the very life out
of the tree ; for with one of these insects at nearly every bud,
as was the case in the tree I cut down, and in the accessible
branches of many others examined at different times, the tree
must speedily perish. As the caterpillar works downward, one
by one the needles find their supply of nourishment cut off,
cease their further growth, lose their color, and wither, — the
change in coloration of the needles showing the progress of the
pest. Fig. 6 shows the appearance of one of these twigs in
which the caterpillar has bored a couple of centimeters. Some
of the terminal needles, as may be seen by comparison with
fig. 5, which represents an unharmed twig of the same tree,
have scarcely had a chance to grow at all before being robbed
of their means of support, and have turned quite yellow ; fur-
ther down the stem, where also they are wholly withered, they
are a little longer ; still further they are longer yet, and only
partially withered, showing more recent attack ; and it is not
until the wholly green and fresh needles are reached that they
are of the normal length. The difference between an uninjured
twig and one that has been attacked is really greater than ap-
pears by comparison of figs. 5 and 6 ; for, as will be seen on
comparing the lower normal needles of each, fig. 5 represents
a shoot with much shorter needles than fig. 6 would normally
have had throughout. The dome-shaped contour of the needle
tips in the healthy shoots is well represented in fig. 5, and the
contrast to this which fig. 6 exhibits is very marked, and tells
the story of the damage done. The specimen represented in
fig. 6 was chosen rather to exhibit this point, being perhaps
more marked than usual. Generally the whole shoot is un-
naturally swollen and disfigured by the pitch that has exuded
from the injuries caused by the caterpillars, as may be seen on

12 THE PINE MOTH OF NANTUCKET.

removing the needles ; tins appears in fig. 9 of the plate, to
compare with which a healthy shoot with the needles removed
is shown in fig. 7.

As the insect is probably double-brooded, the second genera-
tion has to attack shoots already grown, or nearly grown, in
which case, of course, the change of contour of the tip, seen
on comparing fig. 6 with fig. 5, does not ensue ; but the with-
ered needles are all of nearly the full length, as shown in fig. 8.
In this figure the stem has been cut longitudinally, to show the
nature and extent of the borings of the caterpillar. The mid-
dle of the stem is found pierced by a slender cylindrical pas-
sage as far as the dead needles continue ; the passage is lined
with silk and foul with excrement, which has been removed
from the specimen drawn. As far as the boring has been car-
ried, the withered needles fall from their position on being
touched, having nothing but a shell for their support.

When the caterpillar is fully grown it selects a place within
its burrow wherein to change to chrysalis ; this is usually at
the bottom of the burrow, but, in a thick shoot, may be in any
part, even toward the tip, where it can push a lateral passage
obliquely toward the base of one of the needles. Such a bur-
row, vertical in this case and not oblique, may be seen in fig.
8 on the right hand of the regular burrow at the tip of the
shoot. Several indeed may occupy different parts of the same
shoot ; the place selected is slightly enlarged to form a lon-
gitudinal cell, at the upper or outer end of which a passage is
eaten into the open air, which may generally be seen with-
out difficulty from the outside, if looked for near the base of
the needles, while the nest is uninjured. The holes left by the
fallen needles must not be taken for these outlets ; these never
seem to be taken advantage of, for from them usually exudes
more or less pitch, closing the opening. To find on emergence
from chrysalis that the means of egress of the moth was gone
would prove disastrous to its life. Half through the eaten open-
ing the chrysalis forces its way when about to change to the
imago.

It appears then that this insect, by selecting for its food in
the larval state the point where the greatest amount of nour-

THE PINE MOTH OF NANTUCKET. 13

ishment exists, has chosen well for itself but ill for the tree ;
the very richness of the nourishment of which it robs the tree
tends to the immense abundance of the insect, which, attack-
ing the tree at every growing point, effectually puts an end to
its life. The nearly dead tree I cut down was not more than
seven and a half centimeters in diameter, and perhaps four
metres high ; all but the very topmost boughs were dead, and
here the foliage was extremely scanty, yet I could certainly
have obtained forty or fifty caterpillars and chrysalids from
this one tree.

At first sight, certainly, there seems nothing to prevent this
insect from continuing its ravages, and destroying every pine
on the island. The only encouragement in this view is, that
then, for want of pines, the moth must die. In the hope of
finding some natural means of its destruction, I have sought
for parasites which might at least keep it in check. One such
I found the first day, feeding upon a larva ; and by enclosing
many infested twigs in a tight box I have obtained three kinds
of hymenopterous parasites, — one a species of Bracon proper,
another a minute Perilampus, both apparently undescribed.
The latter is far the more abundant, but neither appears to be
sufficiently common for us to place much reliance upon them,
although they unquestionably serve, to a certain extent, to re-
duce the numbers of the moth. The only possible method of
combating this evil is directly to destroy the Retinia in some
one of its stages. Bonfires every day at dusk in the vicinity of
the woods, during the last week in April and the first week in
May, would doubtless destroy great numbers of moths laden
with eggs, and would give healthy employment and no small
delight to the small boys of the island. But apparently the
only effectual means of destruction is one indicated by the his-
tory of the insect, but which would be useless on the main
land, or without concerted action on the part of the inhabitants
of the island. As already stated, the affected are speedily dis-
tinguished from the uninjured shoots soon after the caterpillar
has commenced its work, by the presence of dead needles at
the apex of an otherwise green shoot ; the presence of the

14 THE PINE MOTH OF NANTUCKET.

enemy is thus infallibly disclosed. The month of June then
is the time for operation ; and the work to be done can he done
once for all hy breaking or cutting from every pine-tree on the
island evei'y affected shoot.

To be of any radical use this must be done during a single
year, to leave none for propagation ; for the same reason it
must be done to every tree, great or small, from the topmost
boughs of the tallest trees to seedlings just springing from
the ground ; every scattered tree or seedling upon the island
must be searched. I examined one isolated tree about a metre
high, growing a kilometer or thereabouts from the woods on
the south shore, and it was thoroughly infested. To leave such
a tree would be to have the labor and expense of the proposed
assault in vain. The work must be completed within the month
of June, since it is at this time that the caterpillar is only partly
grown in its burrow, and will infalHbly die if the shoot is re-
moved from the tree ; its sustenance will be gone, and it cannot
crawl about sufficiently to find and enter another tree. This is
not a part of its accustomed line of action, and it could not re-
cover from so rude a shock as robbery of its home. There would
be no absolute need of burning the broken shoots, but this might
be done where there is any danger of their falling near seedlings,
which it is possible the wandering outcasts might enter ; and it
should certainly be done if the operation has to extend into July,
when the caterpillar might be ready to change to chrysalis, which
it could do in its burrow whether the shoot were attached to the
tree or fallen to the ground. Since some more advanced cat-
erpillars might as early as June undergo such transformation,
doubtless the most thorough way would be to have the work fin-
ished before the end of June, and to burn every broken shoot ;
to cut off any suspected shoot rather than to leave one affected,
or even to remove every growing shoot.^ But anything less

1 I am told by good botanists that the tree would probably recover from this
Caesarian operation, and it might be easier and more rapid than to select the
affected shoots. It certainly would be safer. Dr. G. L. Goodale has called my
attention to the following passage, which seems to him to indicate that the tree
would survive. " The pitch pine, says Smith, differs from other trees of this
family, its stump throwing up sprouts the spring after the stem has been felled,
but these do not attain any considerable height. The fallen trunk throws out

THE PINE MOTH OP NANTUCKET. 15

radical than the means here suggested would be wasted labor.
Leave them alone and the pine woods of Nantucket are doomed
to destruction ; to plant new trees would be to add fuel to
flames. There is no possible escape but in some radical and
concerted action such as is here suggested ; and this is possi-
ble only because of the isolation of Nantucket, and the com-
paratively small extent of its little forest. Ten men, each
armed with a pair of hedge shears, and ladders of some sort,
ought to accomplish it in the month. Whether it will " pay"
is for the Nantucket people to decide. But if they will not do
it, their next best plan is to cut down the entire forest, sell the
wood, and burn the brush, leaving not even a seedling any-
where ; then to pasture the sheep upon the spot for two years,
and carefully destroy every seedling that springs up outside
the fences which confine the sheep. After that it would be
safe to plant again by seed.

Will the good people of Nantucket take all this trouble to
rid themselves of this pest ? It seems extremely doubtful,
especially since concerted action on the part of all the land-
owners would be necessary. Just here our impotence, under
republican institutions, seems to be manifest. " Any single-
minded and prolific worm," President Eliot has happily said,
" is more than a match for man." But this is mainly because
we fight it single-handed. No great success is to be expected
in checking the ravages of insects in this country until the
people are , far better and more generally acquainted than at
present with the simplest rudiments of the history of insects.
I do not believe that five per cent of the people of Massachu-
setts above the age of twelve years can correctly state the

sprouts in the succeeding summer ; and the bundles of leaves of both are re-
markable for issuing from the axil of a single leaf, in the same manner as in the
young plant." — MicHAux, iV. Amer. Si/lva, Vol. III. pp. 89, 90, note (1853).

Mr. George B. Emerson also says of the same tree : " Its stump throws up
sprouts the spring after the stem has been felled. These continue to flourish,
■with apparent vigor, for several years ; but I have never seen them attain any
considerable height. The fallen trunk itself throws out sprouts in the succeed-
ing summer ; and the bundles of leaves of both are remarkable for issuing from
the axil of a single leaf, in the same manner as is observed in the young plant."
— Emerson, Trees and Shrubs of Mass., State ed., p. 73. Svo, Boston, 1846.

16 THE PINE MOTH OF NANTUCKET,

general features of transformations in insects, or know tliat,
practically speaking, all their growth comes by feeding in the
larval stage. Without such knowledge one has not the means
of learning how to prevent the ravages of an insect never be-
fore met with, but each specific case must be treated hap-
hazard.

Good results would also flow from proper legislative action,
but such action seems curiously abhorrent to the republican
mind. Why our people should not protect themselves in this
particular, as well as the more paternal governments of Europe
guard the interests of their agriculturists, it would be hard to
say ; but it is probably owing to our not being awake to the
real extent of the injuries done by insects, and the need in
resisting them of concerted action, which only State authority
can enforce. An enlightened public opinion in this matter is
too far away. In towns immediately adjoining Boston one
may every year see orchards completely overrun by caterpil-
lars, while adjoining nurseries, properly cared for, are exempt.
Why should the owner of the neglected plantation be allowed
to put his neighbor to the additional pains and cost his neglect
has caused ? If he will not care for his trees, he should at
least cut them down, and not make them special breeders of
pests. By act of legislature such a man should be required to
take all reasonable pains to prevent the increase of the insects
which damage his own and his neighbor's property, and pen-
alties should be rigidly enforced. Such legislation should
certainly be restricted to enemies already known . to be very
harmful, and to such as bid fair to become generally danger-
ous. The decision of what should be included, especially in
the latter class, and what means should be taken to prevent
the increase and spread of insect pests, ought to be in the
hands of a scientific commission, created by the State, com-
posed of persons who are familiar with insects, and who should
protect the interests of the agriculturist, the gardener, and the
nurseryman, — just as the fish commissioners protect the fish
supply, see that proper laws are framed, and that these are
duly regarded and enforced.

The insect here considered may be taken as an example of

THE PINE MOTH OF NANTUCKET. 17

the necessity of such laws and such a commission. It has prac-
tically destroyed the timber of Nantucket, but has never yet
been found on the adjoining main land, or in any other part of
the State. A careful examination of the pitch pines at Wood's
HoU, during the height of its devastations at Nantucket,
revealed no trace whatever of this insect's operations. Should
it once gain a foothold there, as it probably will, there is no
apparent reason why it should not extend to the Penobscot, or
as far as the pitch pine flourishes. The landed proprietors
everywhere in Massachusetts have then a personal interest in
preventing the advent of such an enemy, and may rightly com-
pel the people of Nantucket to take, at their own cost, active
measures for the destruction of this pest.

The time will certainly come when the people of Massachu-
setts will demand some such legislative action as is here indi-
cated ; the sooner it is reached the better for the material
welfare of the Commonwealth.

As this paper was written three years ago, I have added, in
an Appendix, an account of what has since appeared in print
concerning the moths of this genus in the United States, as
observed by Professor J. H. Comstock.

It may be added, in conclusion, that there is another boring
larva, evidently belonging to the same family of Tortricidae,
also found in the shoots of this Nantucket pine, which, on ac-
count of its greater size, would do far more damage than Re-
tinia frustrana were it at all common. I have not succeeded
in raising it, and have never seen more than six or eight speci-
mens. It too has its insect foe, — a parasite belonging to the
genus Campoplex, one of the Ichneumonidae.

APPENDIX.

In the Report of the Entomologist to the United States Depart-
ment of Agriculture for 1879, as published in the Report of the
Department for the same year, pp. 233-238, pi. 5, figs. 1, 2, Pro-
fessor J. H. Comstock gives an account and descriptions of three
species of Retiuia, all attacking the pitch pine.

The first, described by Professor Fernald as Retinia corastocki-
ana, was found in the a^ icinity of Ithaca, N. Y., boring into the twigs
and small branches, and causing an exudation of resin. They often
cause the death of the twig, especially when, as in many cases,
more than one larva lives in a single twig; but the j^rincipal dam-
age done was in disfiguring the shape of the tree by the destruction
of the terminal shoots. They pass the winter in the larval state,
and there are, apparently, two broods a year.

A second species, Retinia rigidana Fernald, was found in the
same place, and on the same tree ; but no account is given of its
habits, further than that they are "similar" to those of the next
species, and that the larva inhabits terminal shoots.

As the third species is considered by Professor Fernald to be
the same as that described in this paper (but see above, p. 10,
note), I append the account entire. A twig, the moth, larva, and
chrysalis are figured in the Report, pi. 5, fig. 2.

" Infesting the new growth of Pinus in ops and P. rigida (and
perhaps of other species) spinning a delicate web around the termi-
nal bud, and mining both the twig and. the bases of the leaves;
one or several small yellowish larvae, which transform within gray-
ish cocoons, either in their burrows or fastened to the twigs, and
become small copper-colored moths, with wing expanse of 12 mm.
(.47 inch)."

APPENDIX. 19

" Aoout the middle of May, 1879, the scrub-pines (Pinus inops)
in Virginia, near Washington, were found to be greatly injured
by small lepidopterous larvae. On many trees there was scarcely
a new shoot to be found which was not infested at its tip by fi-ora
one to four yellowish black-headed caterpillars. They were so
completely concealed while at work that their presence Avould
scarcely be noticed, and the effect of their work was hardly visible
until the twig was almost completely destroyed. Upon close exam-
ination a delicate web was seen inclosing the base of the bud and
the surrounding new leaflets, resembling much the nest of a small
spider. When this web was removed, one or several little yellow
caterpillars were seen either retreating into a mine in the bud or
into the bases of the leaves, which were also mined, or, not infre-
quently, they dropped from the twig, suspending themselves by a
silken thread. The bud was often so hollowed that it dropped to
pieces almost at a touch.

" At the time when they were first noticed larvae of> almost all
sizes were to be found. Some wei^e apparently almost full-grown,
while others had evidently not been long hatched. The nearly
full-grown specimens measured 8 mm. (.31 inch) in length. The
first pupae were obtained early in June. Most of the larvae trans-
formed within the burrows which they had made, first spinning
more or less of a silken envelope about themselves. Others, how-
ever, issued from their mines, and spun rather tough grayish
cocoons between the leaves. The pupae were short, stout, and
brown in color, with each segment furnished dorsally with two
serrated lines, one consisting of large, and one of fine teeth.

" The first moths issued June 13, the pupae having previously
worked their way, by means of the spines just mentioned, into
such positions that they could give forth the moths without injury
to the latter, and a few weeks later almost every shoot had one
or more of the empty pupa skins protruding from it. Speci-
mens of the moths were sent to Professor Fernald, who deter-
mined them as identical with Mr. Scudder's manuscript species,
Retinia frustrana. In August Mr. Sciulder gave a short account
of this insect before the entomological section of the American
Association for the Advancement of Science, at Saratoga. He
had found it in such numbers upon the island of Nantucket in the
young trees of Pinus rigida, planted there some years ago to re-
pair the damage done by burning during the war of 1812, as to
seriously threaten the success of the experiment. Mr. Scudder

20 APPENDIX.

intends publishing an account of the workings of the insect in
that locality very shortly.

" In the latter j^art of July specimens of the twigs of Pinus
rigida were received from Mr. S. H. Gage, of Ithaca, which had
evidently been infested by the same insect, although no living in-
habitants were to be found. In Sej^tember other specimens were
received from the same gentleman, and this time two pupae and
one larva Avere found. According to Mr. Gage, the insect is not
very common in that locality.

" In the latter part of August, individuals of the second brood
were very abundant in the scrub-pine in the vicinity of "Washing-
ton. As before, they were found in almost every stage of growth,
and the difference was even moi-e marked. In one instance five
larvae of greatly differing sizes were found in one shoot. The
smaller ones were boring into the bases of the leaves, and the
larger ones into the twig proper. The largest of the five had made
quite a long channel from the tip of the bud down into the heart
of the twig. Pupae were also found at this time, which did not
give forth the moth till late in the winter.

" The usual mode of hibernation is in the pupa state. A thor-
ough search in January in the field showed only pupae. The
pupae collected in August and September did not begin to give
forth the moths in the breeding cages before early January, though
this was continued at intervals through January, February, and
March, and was greatly hastened without doubt by the heat of the
room. On February 15, however, a few twigs were collected,
from one of which, on February 28, a full-grown larva had emerged,
and was found crawling about the cage. This would seem to in-
dicate occasional larval hibernation.

" As to remedies, the only one which I can suggest at present
is that involving the somewhat arduous task of picking off the
infested twigs in early winter and burning them. Whether the
salvation of the trees will be worth this labor in greatly infested
regions will depend entirely upon their value to those interested.

" As Mr. Scudder has prepared descriptions of all stages, we
will not trespass upon his ground by appending further descrip-
tions than we have already given. Our figure will assist in the
recognition of the species."

ANALYSIS.

PAGE

Outward aspect of affected trees 3

Description of moth 4

Description of caterpillar 6

Description of chrysalis 6

Resemblance of the moth to other species of Retinia 7

Life history of Retinia frustrana 8

Its appearance on the wing oftener in America than in the allied species of

Europe is in keeping with what is seen in other insects 9

Habits of the European species of Retinia 9

Description of the injuries caused by Retinia frustrana 10

Its mode of hibernation 12

Its parasites, and various modes of attacking it 13

The only effective remedy against the ravages of the insect to destroy its

means of subsistence, and after proper delay plant again 14

Legislative enactments for the protection of agricultural and arboricultural

interests 16

Appendix : Professor Comstock's account of our native species of Retinia . 18

Explanation of the plate 22

EXPLANATION OF THE PLATE.

[The original drawings, both plain and colored, were made by Mr. J. Henry-
Blake of Cambridge. The reproduction by chromolithography is the work of
Messrs. Thos. Sinclair and Sons, of Philadelphia.]

Retinia frustrana and Pinus rigida.

Fig. 1. The moth, enlarged three diameters.

" 2. Side view of clirysalis, enlarged three diameters. 2 a. One of the ab-
dominal joints, enlarged nine diameters, to show the rows of spines
and ridges.

" 3. Front view of chrysalis, enlarged three diameters. 8 a. The terminal
joints of the abdomen, enlarged nine diameters, to show the arrange-
ment of spines and hairs at the tip of the body.

" 4. Full-grown caterpillar, enlarged four diameters.

" 5. Terminal shoot of the pine in an uninjured, natural condition.

" 6. Terminal shoot which has been attacked by the insect when the apical
leaves were only partly grown ; away from the tip the needles have
nearly or quite attained their full growth before the mining opera-
tions of the caterpillar had sapped their supply of nourishment.

" 7. Terminal shoots in a healthy condition, stripped of its needles, to con-
trast with fig. 9.

" 8. An infested shoot cut open to lay bare the mine of the caterpillar in its
latest stage ; the refuse which nearly fills it has been removed. The
length of the terminal needles shows this shoot to have been well
advanced in its growth before it was attacked.

" 9. A shoot similar to that represented in fig. 7, but which has been dis-
torted by the attacks of the insect.

J Henry Blake, ad r.ai. 1' SincLair&aon.l'ith Phlla.

THE PINE -MOTH OF .VWrrCKET .