Chapter I: Preface

The number and variety of the insect pests which live on the plants of New Zealand, whether native or introduced, and the damage which they frequently do, form the excuse for the appearance of this work. The descriptions of these insects in the Transactions of the New Zealand Institute, or in works published in Europe and America, are not easily accessible to the general reader, and are also much scattered and fragmentary. It was thought therefore that the time had arrived when the information which might be useful to gardeners and tree-growers, as well as to students, might be summarized and brought together in a compendious form, and the present volume is an attempt towards this.

In order to render this work complete a second volume is necessary, which should include the large number of other destructive insects preying upon various plants. For example, the "pine-blight" (_Kermaphis_), the "American blight" (_Eriosoma_), the "black leech" (_Tenthredo_), the cabbage caterpillar, the turnip "fly," the various aphides on roses, geraniums, &c., the grass-grub (_Odontria_), the codlin-moth, the borers, weevils, wireworms, and a number of others are in different places damaging trees and plants, and it would be useful to collect in one volume information regarding them. The author has had in contemplation the preparation of such a volume, and it is hoped that it may be at some future time published.

Meanwhile the present is offered as, at least as far as it goes, a full description of one of the most general as well as the most noxious families of plant-parasites. The plates have been especially prepared with a double object: first, that gardeners and tree-growers might be able easily to recognize the kind of insect which might happen to be damaging their plants; and, secondly, that the student who should desire to know more of this curious family might have enough details indicated to guide him in his investigation. For the first purpose the figures have been coloured as near to nature as possible; for the second a few anatomical details have been introduced. The printing of these plates has been executed by Mr. Potts, lithographer to Mr. A. Willis, of Wanganui, and it is hoped that the reader may be well satisfied with the care and trouble which have been bestowed upon them.

The author is sensible that this volume may contain numerous imperfections; but these will not, he trusts, be attributed to culpable ignorance or carelessness.

EXPLANATION OF TERMS USED IN THE FOLLOWING PAGES.

_Abdomen._ The posterior half of the body of male or female, whether
joined to the anterior half or slightly separated, segmented or
not.

_Abdominal cleft._ A narrow slit in the extremity of the abdomen of
Lecanidinæ and the full-grown _Hemicoccidinæ_ only. (Plate ix.,
Fig. 1, _b_, _c_.) On the upper side of the body are seen the

_Abdominal lobes_, two minute, divergent, triangular or conical,
excrescences, one on each side of the cleft, in _Lecanidinæ_,
usually bearing one or more hairs. (Plate xi., Fig. 3, _b_, _c_.)

_Abdominal spike._ A more or less long, tubular or semi-tubular,
pointed process terminating the abdomen of the male in all
species, and serving as a sheath for the penis, which is a long,
white, soft tube with recurved hairs. (Plate ii., Fig. 3; Plate
xxi., Fig. 1, _k_.)

_Anal ring, anogenital ring._ An orifice situated near the abdominal
extremity of the female, either simple or compound, hairless or
bearing several hairs. (Plate ii., Fig. 1.)

_Anal tubercles._ Exhibited only by the _Coccidinæ_ and by the larvæ
of _Hemicoccidinæ_: two more or less conspicuous projecting
processes at the abdominal extremity of the female, without any
cleft, and in most instances projecting beyond the edge; usually
bearing setæ. (Plate ii., Fig. 2, _c_, _d_.)

_Antennæ._ Two jointed organs ("feelers") projecting from the
anterior portion of the body, of variable length. (Plate i.,
Figs. 9, 10, 11, types.)

_Apodous._ Without feet.

_Apterous._ Without wings.

_Bucca_, _buccal_. The mouth; belonging to the mouth.

_Carina_, _carinated_. A keel or raised-ridge; keeled.

_Cephalic region._ That part of the insect, male or female, which
bears the eyes, antennæ, and mouth, but not including the first
pair of feet.

_Clavate._ Club-shaped; somewhat knobbed.

_Claw._ The hooked terminating joint of the foot. (Plate i., Fig. 6,
_cl._, type.)

_Coxa._ The first joint of the foot, springing directly from the
under-side of the thoracic region. (Plate i., Figs. 6 _c_, 7
_c_.)

_Digitules._ Appendages observed on the feet, and often useful for
distinguishing species. Usually there are two pairs. The "upper
pair" spring from the upper side of the extremity of the tarsus,
and are generally long, fine hairs, terminating in a knob. The
"lower pair" spring from the base of the claw, and are usually
broader and more trumpet-shaped than the upper ones. (Plate i.,
Fig. 8, type.) Sometimes either pair, or both, may be absent.
In _Cœlostoma wairoense_ there are no "upper" digitules, and 24
"lower" ones on the foot of the male. (Plate xxi.)

_Dimerous._ Two-jointed.

_Dorsum._ The upper side of the body when the insect is in its
natural position.

_Dorsal._ On the upper side or dorsum.

_Eyes._ Two coloured, granular or simple, round organs on the
cephalic region of the female, near the base of the antennæ
(Plate xiv., Fig. 2, _k_.; Plate xx., _b_); two, or four,
coloured, granular, simple or facetted, on the head of the male
(Plate i., Figs. 14, 15; Plate xxi., Fig. 2, _b_).

_Femur._ The second joint of the feet, next the coxa, joined to it by
the false joint "trochanter." (Plate i., Figs. 6 _f_, 7 _f_.)

_Fringe._ A portion of the excreted substance, cotton or wax,
produced by the spinnerets on the edge of the body in certain
_Lecanidinæ_ and _Hemicoccidinæ_. It may be in the form of long
glassy threads (_Planchonia_) or of more or less broad flat
plates (_Ctenochiton_). (Plate vii., Figs. 2 _d_, 3 _a_; Plate
xii., Fig. 2, _a_, _b_, _c_.)

_Haltere._ A minute organ, situated just behind the wings of the
males, and of which the use, either in this family or in the
Diptera, has not been satisfactorily ascertained. It is often
termed the "balancer." In the house-fly it has been thought
to represent an organ of hearing. In Coccids it is furnished
with one or more hooked bristles, and Mr. Comstock affirms that
these are, probably for some purposes of flight, hooked into the
posterior edges of the wings.[A] (Plate i., Fig. 17; Plate xxi.,
Fig. 1, _m_.)

[A] Report of the Entomologist, U.S. Dep. of Agric. 1880, p.
277, note.

_Honeydew._ A substance of a glutinous character produced by many
species, and falling in spray from them on the leaves. (See
Chap. III.)

_Larva._ The first stage in the insect's life after emerging from the
egg.

_Lobes_, in the _Diaspidinæ_, are minute, flat, more or less rounded
projections, two or more, seen on the edge of the abdominal
extremity, usually interspersed with spines and hairs (Plate
iii., Figs. 1, 3, 4, 5, _l_); in the _Lecanidinæ_, are two
triangular or conical projections, usually bearing hairs, on the
dorsal side of the body, one on each side of the abdominal cleft
(Plate xi., Fig. 3, _b_, _c_).

_Mentum._ A kind of secondary rostrum, or "under-lip," not altogether
tubular, but rather a deepish trough, through which the rostral
setæ pass after leaving the rostrum. It may have one, two, or
three joints. It is not noticeable in the Diaspidinæ. (Plate i.,
Fig. 5, _b_.)

_Metamorphosis._ A change of form. For the number and characters of
these see Chap. II.

_Moniliform._ Like a string of beads.

_Monomerous._ With a single joint.

_Multilocular._ With several divisions: a term applied to the
spinneret orifices of some insects, distinguishing them from
"simple" orifices, which show only a single tube. Multilocular
orifices exhibit a bundle of tubes enclosed together. (Plate i.,
Fig. 4, _c_, _d_, _p_; Plate xviii., Fig. 2, _e_.)

_Nervure._ A strong vein which, starting from the attachment of the
wing of the male, runs along the anterior edge of the wing,
a little within it: at about half its length a branch runs
obliquely towards the posterior edge. (Plate i., 16; Plate xix.,
_f_; Plate xxi.)

_Normal._ According to rule--not exceptional.

_Ocelli._ Two, four, or six minute circular simple organs, on
the head of the male: probably organs of vision. In the
_Monophlebidæ_ they would seem to be replaced by a smooth
rounded protuberance behind the eye. (Plate i., Fig. 14, _oc._;
Plate viii., Fig. 2, _k_, _m_; Plate xxi., Fig. 2, _b_.)

_Ovisac._ The cottony bag or nest formed by certain species of
_Lecanidinæ_ and _Coccidinæ_ for the reception of their eggs.
(Plate xii., Fig. 1, _a_, _b_, _c_; Plate xix., _a_, _b_, _c_.)

_Peduncle_, _pedunculated_. A stalk; stalked.

_Pellicle._ The skin of an earlier stage, cast off at each
metamorphosis; used by the _Diaspidinæ_ and by one genus of
_Lecanidinæ_ in the formation of the puparium or test. (Plate
i., Fig. 3, _a_, _b_; Plate vii., Fig. 2, _b_.)

_Polymerous._ Many-jointed.

_Pupa._ The last stage of the male insect before emerging winged.

_Puparium._ The shield, covering, or "scale" of the _Diaspidinæ_.
(Plate i., Fig. 3, e; Plates iv., v., vi.)

_Rostral setæ._ Three or, in a few cases, four long, fine, curling,
tubular bristles springing from the rostrum, and often passing
through a mentum; used for insertion into the tissues of a plant
and sucking their contents. (Plate i., Fig. 5; Plate vi., only
one being here shown, from the smallness of the drawings.)

_Rostrum._ A more or less conical, tubular, projecting organ, or
beak, protruding from the under-side of the cephalic region, or
between the first pair of feet. It is absent in the adult female
_Cœlostoma_. It is the "mouth" of the insect. (Plate i., Fig. 5;
Plate iv., Fig. 5.)

_Sac._ The cottony, bag-like covering or nest produced by the
spinnerets and concealing the insect in many of the _Coccidinæ_
and some _Lecanidinæ_. (Plate xv., Fig. 1, _c_; Fig. 2, _b_.)

_Scale._ The shield or puparium of the _Diaspidinæ_. The word is
commonly used to designate the outward appearance of insects
of the whole family, which are indiscriminately called
"scale-insects," although many of them form no shield whatever.

_Secretion_ may be of various kinds. It is matter produced by
internal organs, and expelled through the "spinnerets." In the
_Diaspidinæ_ the secreted portion of the puparium (that is, all
except the pellicles) is made up of fine, closely-woven fibres,
forming the "scale." In the _Lecanidinæ_ it probably exudes
originally as fine fibres, but these become agglomerated in
some cases in a waxy or horny mass, or in others are loosely
collected as cotton. In the _Coccidinæ_ the secretion is
usually cottony, or powdery like meal. _Cœlostoma_ secretes all
three--wax, cotton, and meal. In some instances, as in _Carteria
lacca_, of Africa, the wax, called "shellac," is abundant enough
to be commercially valuable; or, as in the Chinese _Ericerus
Pe-la_ it can be used for making candles.

_Seta._ A bristle--a long stiff hair.

_Setose._ Bearing a few bristles.

_Spinnerets._ Organs observed in various parts of the body,
producing the waxy, cottony, or mealy matter. They consist
of cylindrical internal tubes, sometimes ending on the skin,
sometimes protruding outside it in the form of tubes, spines,
or conical hairs. In the former case the orifices show them to
be in some instances simple, and in others compound tubes.[B]
In the _Diaspidinæ_, besides being scattered over the body,
the spinnerets are arranged in groups on the last abdominal
segment, and these groups afford excellent characters for
specific distinctions. (Plate i., Fig. 4, for types of various
spinnerets; Plate iii., groups of spinnerets of _Diaspidinæ_.)

[B] Minute anatomical details are unsuitable for this work.
The student may consult Targioni-Tozzetti, "Studie sulle
Cocciniglie," cap. ii., p. 26.

_Spiracles._ "Breathing organs:" the orifices in the body of the
tracheæ or tubes conveying air to the blood. In the _Lecanidinæ_
they are usually four; simple circles, near the edge of the
body, and with a few strong spiny hairs near them. In the
_Coccidinæ_ they are often numerous. (Plate ii., Fig. 4; Plate
xx., _n_.)

_Spiracular spines._ Spiny hairs, usually three in number, of which
one is rather long, close to the spiracles, in the _Lecanidinæ_.

_Stigma_, _stigmatic spines_. Terms sometimes employed for spiracles,
&c.

_Tarsus._ The fourth joint of the feet, between the tibia and the
claw. Its consisting of one joint (monomerous) is a distinctive
character of the whole family. (Plate i., Fig. 6, _ta_.; Fig. 7,
_ta_.)

_Test._ The waxy, glassy, or horny covering produced through the
spinnerets and concealing the insect in many _Lecanidinæ_ and
some _Coccidinæ_. In this work it is not applied to the "scale"
of _Diaspidinæ_ or to cottony secretions.

_Thoracic band._ An appearance seen on the thoracic region in the
male, looking like a broad transverse ribbon.

_Thoracic region_, _thorax_. That part of the female or the male
which bears the three pairs of feet, when the feet are present;
or, if the feet are absent, the middle portion of the body,
segmented or not.

_Tibia._ The third joint of the feet, next the femur. (Plate i., Fig.
6, _ti_.; Fig. 7, _ti_.)

_Tracheæ._ Tubes ramifying throughout the body, conveying air to the
blood. Their orifices are the spiracles. The tracheæ, as in
other insects, appear as if constructed of a network of fine
spiral wires. (Plate ii., Fig. 4 _d_; Plate xx., _n_.)

_Trochanter._ A small articulation, not a distinct joint (something
like a knee-cap) of the feet, between the coxa and the femur.
(Plate i., Fig. 6, _tr_.; Fig. 7, _tr_.)

_Trimerous._ Three-jointed.

_Ventral._ On the under-side, the insect being in its proper
position.

NEW ZEALAND SCALE-INSECTS

(COCCIDIDÆ).