Article beginning on page 108.
Psyche 6:108-109, 1891.

Full text (searchable PDF)
Durable link: http://psyche.entclub.org/6/6-108.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

TWO NEW LEPIDOPTEROUS BORERS.
BY OTTO LUGGER, ST. ANTHONY PARK, MINN.
To the long list of injurious borers
infesting cultivated and wild plants two new species must be added which, in
Minnesota, are of especial interest, as
they cause great damage to some of our
trees, and even threaten to destroy them entirely in some regions.
All visitors to the Twin Cities admire
our groves of oaks, chiefly composed of
peculiarly branched and gnarled burr-
oaks, and dark and straight red-oaks.
The former, though badly infested by
numerous species of insects, seems to be proof against any lasting injury by them. The tree is in fact so well protected with a corky bark, even found upon the young-
est twigs, that both insects and intense cold seem to be powerless. This is
quite different, however, with our red-
oak, a tree of much quicker growth and
but slightly protected by thin and glossy dark bark, at least when still young and not wrinkled by old age. Nature seems
to have endowed the former, like a good
mother, with a warm and enduring coat
against insects and the inclemencies of
winter, and to have treated the red-
oak like the stepmother so much fabled
about. The red-oak seems to have a
very great attraction for all kinds of
boring insects, but notwithstanding its
wonderful power to repair injuries and
to heal wounds made upon its bark and
wood -a power not shared by the burr-
oak - the tree is a doomed one, provid-
ing no steps are taken to protect it as
well as it deserves. But all advice to
protect any of our native trees is usually received with a smile that is more or
less unpleasant to the true lover of nature, as it contains the elements of contempt, ridicule and derision for the adviser.
Among the worst borers of the red-
oak are several lepidopterous larvae, but chiefly those of P~ionoxystus pe~ci-
$erda (F'itch), P. ~obiniae (Peck) and
T~ochiliunz l~gge~i. The first (pl. 3,
figs. I and 2) , as well as the second spec- ies, are insects described long ago ; the latter, and the most injurious one in this regior, has been described by H. Ed-
wards, our authority in this family of
insects. Below is his description, illus- trated by pl.3, fig. 3,
Tvocfiz'Zi~m Zuggevz'n. sp. Upper side of head black, orbits of eyes bright lemon yellow. Face black. Palpi black at the base. otherwise lemon yellow. Thorax with the disk black, with short erect downy hairs. Collar, patagia, spot at the base of the wings, and a broad streak at base of thoraxconspicuou.sly lemon- yellow. Antennae chestnut brown above, dull orange beneath. Tibiae orange, tarsi some- what of a darker shade. Abdomen black,
anal tuft pale orange, with bright yellow band at the posterior edge of all segments, those of the posterior segments much
widened. Forewings thinly clothed with
scales the costa narrowlydulIorange as is also the oblique rather indistinct discal mark at the end of the cell. The space from vein 2 to vein 5 clear of scales behind the cell. Hind



================================================================================

P~yche, 1891, vol. 6.
Plate 3.
I I




================================================================================

wings with the anterior mxrgin dull orange. Fringe of both wings brownish. Under side of forewings with the costa lemon-yellow. Length of body 20 mm. Exp. of wings 35
mm.
The moth issues towards the end of
May, and fresh p~~pal skins can be ob-
served till towards the close of June.
Some trees harbor hundi-eds of these in- sects, and consequently suKer greatly ;
the trunk and all the larger limbs are
equally infested. In only one instance
a pupal case was seen projecting from
the trunk of a sinall bmi* oak.
A second and equally injurious borer
is destroying our ash-trees in the wind- breaks surro~mdirig farm houses located
in the open prairies, 'and also those
planted in the parks or as shade trees
along the streets in our villages.
As a
genci-a1 rule only the smaller trees are infested, but these to such an extent that they break dow~ entirely. Professors
Aldrich and Orcutt have given the life-
history of this insect in a late bulletin. But even old and very large trees do not escape entirely, as 1 have seen trees two feet in diameter, and appre~~tly quite
healthy, whose bark was perforated
with numerous holes made by this in-
sect. In these cases the trees did not
suffer to any visible extent, b ~ ~ t death is always the consequence in stnaller trees where the borer cuts 0.K entirely the
circulation of sap, and enters deeper
into the solid wood.
T~rochiZiuin f~axitzi, n. sp. The head is grizzled black above, with the base, palpi and antennae dark orange. Coxae black, tibiae and tarsi orange, the posterior portion of the tibiae broadly banded with black. Thorax with the disk black, with rather long and erect black hairs. Collar, patagia, a large spot at the base of each wing, and a narrow streak over the posterior part of scutellun~ lemon-yellow ; all these spots witli the excep- tion of those at base of wings are edged in fl-ont with dark orange. Abdomen black7
banded with yellow at the posterior end of each segment; sides of posterior 5 segments orange, the orange extending almost over the whole s~~rfkce of the three last ones. Forewings covered with scales, except a
narrow portion from base to cell, and some very small spaces itntnediately behind the cell. Costa a ~ d internal margin coppery brown. Outer n~m-gin broadly brown7 shaded with purplish copper. Discal mark large7 alnlost rounded. At the base all the veins are stained with bright scarlet orange, and there are some scales of the same color below the costa. Beneath the forewings are lemon- color on the costa, shading into orange to- wards the centre of the wing, and into brown on the outer margin. Discal mark orange. Hind wings with a coppery sheen., Fringes of both wings brown. Length of body 15
mm.
Exp. of wings 30 mm.
In pl. 3, fig. 4, this species is sliown ; it resembles very strongly a Polistes.
This species resembles very closely
the injurious moth Podosesia sy~z'egae
(Harr.), but belongs to a dityerent
genus.
EXPLANATION OF PLATE 3.
Fig. I. Prionoxystus querciperda,
8 and 9 imago, and empty pupal case ;
natural size.
Fig. 2.
The same, la~va; natural
size.
Fig. 3. Trochilium luggeri, im-
ago, empty pupal case and hinder ex-
tremity ; the last enlarged, the others of natural size.
Fig. 4. Trochilium fraxini, imx-
go ; natural size.




================================================================================