contained genera or species related to other genera or species in each
of the other four groups. That I may be thoroughly understood, I will
quote the author's own words:--"In almost every group which has been
set before the reader, he must have perceived that one of the five
minor groups into which it is resolvable, bears a resemblance to all
the rest; or, more strictly speaking, contains types which represent
each of the four other groups, together with a type peculiar to
itself."[26] As far as my observation has extended, this is universally
the case; and whether the total number of groups be five or seven, I
think I am safe in asserting that the only possible way of making
these types, thus representing groups, approach such groups, is to
place the heterogeneous group in the centre, and the homogeneous
groups around it; taking care that the type peculiar to itself be its
very centre, its "heart's core." Such a heterogeneous group, then, is
Neuroptera: its characters as given,[27] I believe, perfectly correct;
and can any one say they are sufficient? Certainly not; but had I
described it thus--Class VII. Neuroptera, central, partaking of the
characters of all the others, I think a better character could not
have been given. This class contains a type peculiar to itself--the
genus Libellula of Linnæus: a genus so distinct, that several authors
have supposed it to constitute one of the primary divisions of
Insecta. It is, however, merely the Neuropterous type, the very
essence of the class; and many of its species, Anax Imperator for
instance, proclaim themselves by their imperial flight, their enormous
size, their richly variegated colours, their despotic and cruel
habits, emperors of the insect world. In this group we find the organs
of sight, manducation, and locomotion, carried to a greater degree of
perfection than we ever meet with, except in similar centres: like the
king of birds, the dragonfly is unrivalled among his kind. From
Libellula, the centre, we descend at once to Tinodes, or Psyche, on
the circumference of the circle. Supposing Psyche to be the
approaching genus to Lepidoptera, I think I need not enter very
diffusely on the similarities. Passing to the right, we find that
Diptera will next touch the central class; in which, after leaving the
Phryganeæ, we have now arrived among the next group, or sub-class,
Ephemeræ: and here, as we might expect, the inferior wings become much
diminished--at the point of contact obsolete.[28] The flight, instead
of being solitary, is in company, gracefully and gently rising and
falling. The parts of manducation are become obsolete; while, in habit
and appearance, the insect imitates the Tipulæ and Chironomi, so
exactly that the naturalist is foiled in his endeavours to distinguish
between them, as they joyously dance together by myriads in the rays
of the setting sun.
[26] Horæ Entomologicæ, p. 518.
[27] See the Table.
[28] In Cloëon.
We now approach mandibulated orders, and we shall see the loss of
mandibles in Phryganea and Ephemera, although apparently resulting
naturally enough from their distance from the type Libellula, has yet
another cause--the proximity of classes that have no mandibles: in the
city-building Ants, the mandibles are very perfect, and, therefore, we
may expect them, and we find them in the city-building Termites. The
opinion of philosophers, such as the authors of the _Introduction to
Entomology_, is always worth having, although I am doubtful of
assertions about insects, when unconfirmed by thorough entomologists;
and I believe as yet no entomologist is sufficiently acquainted with
the real history of white ants, to decide positively as to their
different stages of existence. The following quotation contains also a
corroboration of the propriety of this approach:--"The white ants,
though they belong to the Neuroptera order, borrow their instinct from
the hymenopterous social tribes, and, in conjunction with the ants,
(Formica,) connect the two orders. Their societies consist of five
descriptions of individuals:--workers, or larvæ; nymphs, or pupæ;
neuters, or soldiers; males and females."[29] The class Coleoptera now
approaches the Neuroptera, and on each side the boundary we find larvæ
digging pitfalls in the sand to catch their prey, and having tubular
mandibles to extract its juices when caught. We find them spinning
silken cocoons, in which they change into quiescent pupæ, incapable of
taking nutriment; which may fairly be supposed a symptom of approach;
but there is no insect whose imago I would venture to place on the
circumference of the neuropterous circle at the point.
[29] Introduction to Entomology, Vol. II. p. 32.
When we find an insect so doubtfully situated between two classes,
that Linnæus placed it in Neuroptera, Fabricius in Orthoptera,
Latreille, in two of his works, in Orthoptera, and in two others in
Neuroptera, MacLeay in Neuroptera, and Kirby and Spence in Orthoptera,
I think it but fair to conclude, that the orders must approach very
nearly to admit of this difference of opinion: such is Mantispa; and
Mantis-like as it really is, it only borrows that appearance from
being on the extreme circumference of the Neuropterous circle, and
touching the Orthopterous one where Mantis must evidently be situated.
Lastly, we see in Psocus the form, wings, and whole appearance of
Aphis, so exquisitely imitated, that practised entomologists often,
nay mostly, fail in separating them correctly: thus we find that class
VII. contains five natural orders, the contents of which have
been--and may be again, should the linear and dichotomous system
continue in vogue--placed either in the class to which they truly
belong, or respectively in classes I. II. III. V. and VI. at the mere
option and caprice of the systematist. I have already admitted that I
find no neuropterous insect sufficiently related, in its final state
to class IV. to warrant my placing it in contact with that class; and
that I may not be accused of assuming facts which exist only in my
imagination, I am perfectly willing to conclude that no such insect is
to be found; a conclusion that time and discovery, by falsifying, can
only add yet one more buttress to a tower, which nature seems to point
out as built by herself.
There are a few little insects which, like the spiders which crept
across Richard's brain, are somewhat perplexing to the naturalist, yet
he cannot dispose of them as the monarch did of his spiders; I mean
Pulex, Stylops, Thrips, Forficula. But, in truth, the first attempt
of the systematist should be to place classes properly, and these
disconnected species will, after a time, find appropriate places: they
were no more created without a design than man; and their Creator,
doubtless, has appointed them a station, although man, whose wisdom
is utter ignorance, has not yet been able to discover it. It is
impossible for the entomologist not to observe the general similarity,
the family likeness if I may so express it, which exists between these
genera; they appear a little way removed from Coleoptera, yet will
not harmoniously join that class. Thrips is evidently mandibulated,
although the dichotomists call it haustellated, and comes nearer to
Stylops[30] than any other known genus: its larva is, I believe,
unknown; but in March you may observe an active hexapod, lizard-like
animal, running about the flowers of Ranunculus ficaria on sunny
banks, and two or three months later you will find Thrips abundant
on the same flowers in the same spots: this is no proof of their
identity; but as the larva of Thrips and the imago of the said hexapod
are equally unknown, there may be a surmise expressed on the subject.
Mr. Kirby calls this hexapod Pediculus Melittæ, and has given a
description and plate of it in his _Monographia Apum_.[31] He there
asserts that De Geer considered it the larva of the Melöe
proscarabæus, and some observations of my esteemed friend, Mr.
Doubleday, who succeeded in obtaining the larva of Melöe from the egg,
certainly tended to corroborate De Geer. But I am rather wandering
from my subject, and, therefore, will consider these little creatures
also, wandering like comets in eccentric courses over the whole
system, now approaching Staphylinus, and anon Ichncumon, and, as they
draw near, borrowing a character from each: they may, on the other
hand, constitute disconnected links of some other mighty chain, the
intervening parts of which are for a time hidden from the sight of
man, and perhaps hereafter may be revealed; perhaps, again, they may
occupy some of the chasms I have been compelled to leave vacant: but I
deprecate, I detest the idea, of forcing any creature into a situation
which nature has not evidently pointed out as its appropriate one, for
the ignoble purpose of giving plausibility and imperfect perfection to
a scheme.
[30] For a beautiful and accurate figure and dissections of
this rare insect, see Curtis's Entomology, pl. 226: for a
_popular_ figure, _Professor-edly_ of the same insect, see
Insect Transformations, p. 67.
A little knowledge is a dangerous thing.
Drink deep, or taste not the Pierian spring.
[31] Monographia Apum, Vol. II. p. 168.
ON THE SUB-CLASSES, &c. OF LEPIDOPTERA.
It may be thought a strange propensity to grapple with difficulties,
that leads me to select Lepidoptera as a class, by which to exemplify,
in detail, the septenary and circular arrangement. There is no class
so puzzling to systematists, or for which science has done so
little--no class is at present so badly arranged, and in none are
barbarous combinations so much in vogue. Linnæus founded divisions at
the outset, on characters, "loose, vague, and insufficient:"[32] modern
genera have a little improved minor details, and but little, for their
places appear to have been assigned them by lot, and without the
slightest regard to similarity or approach: in a word, the arrangement
of Lepidoptera appears to have been conducted by collectors, who aimed
rather at a pretty picture than a related series; and all our writers
have rushed headlong by the same path, without staying an instant to
consider whether they were right or wrong, like boys playing at
follow-the-leader,[33] each occasionally leaping some wider gap, or
descending some more dangerous precipice than his predecessor, as
though for the very love of frolic and bravado. _One_, a talented
writer, an assiduous collector, a most accurate observer, hesitated
awhile, it is true, and it was thought he would have broken the line,
but no,--he kept precisely to the track of Linnæus and the rest of
them, through Papilio, Sphinx, Bombyx, Noctua, Geometra, Pyralis,
Tortrix, and Tinea; but, as he stood pledged to traverse no more than
five fields, he hit on the ingenious expedient of asserting roundly,
that the four last named were but one. In fact, the whole of this
immense class presents, at this hour, nothing but a vast chaos, which
seems to await the operation of some predicted spell to call it into
order.
[32] Particularly in the sections of Papilio.
[33] Linnæus.
[Illustration: SUB-CLASSES OF LEPIDOPTERA.]
These were apparent difficulties only; for, as no system existed to
direct, so none existed to encumber or perplex. Too much is known now
of Linnæan combinations, to assert, that he always thought correctly;
and since his day no one has thought at all. Now, if you cannot obtain
a nicely drawn plan, you prefer having a blank sheet of paper to one
covered all over with scorings and markings, and then you may set to
work and make your plan yourself. So, in natural history, contrariety
of opinion perplexes, while the absence of opinion leaves the
systematist perfectly unbiassed in the formation of his own. Again,
copious and well-named[34] collections of this favourite class are by
no means uncommon;[35] and through, the liberality of my friends, I had
often been permitted to inspect them, and had gained a sufficient
superficial knowledge of their contents, to be enabled, with the
assistance of my own specimens, to cluster them pretty well into seven
great families or sub-classes; and although, as I have noticed,
nothing available existed on the subject of arrangement of
Lepidoptera, either in essay, or treatise, or catalogue, or cabinet,
yet there was to be found, up and down, much valuable matter, in the
shape of what might be termed natural history of Lepidoptera. Finally,
I knew, that could I master this class, I could stand my ground,
because I had previously tried the experiment on the classes
Hymenoptera and Coleoptera, and had found that, at the word seven,
they fell into instant order, as at the touch of a magician's wand;
and, as for the other classes, we are in such innocent and blissful
ignorance of their contents, that were a scheme ever so futile, a
century at least must elapse before its futility could be proved by
Orthoptera, Hemiptera, or Diptera.
[34] I mean each species labelled with _a_ name.
[35] _British_ collections.
Whoever will give himself the trouble to examine thoroughly a
collection of British Lepidoptera, will find a very great majority of
them evincing very evident symptoms of relation to one or other of the
following species:--Papilio Machaon, Sphinx Ligustri, Pyralis
verticalis, Tinea pellionella, Noctua pronuba, and Geometra roboraria;
and should any form widely different from either of these occur, it
may, if the larva be known, be placed in the centre of a ring formed
by the groups, which we will suppose surrounding their six respective
types; or, if its larva be unknown, it must await the discovery of
that most unerring stage of its existence. I am persuaded, did
entomologists know how much depends on the form, habit, food, and
clothing of larvæ, they would not be so neglected as they are at
present. I have much to regret my own remissness in this respect, for
it has seldom happened that I have found the larva of any insect which
had not been previously well known, but it has tended to point out
some approaches that had never before been thought of,--approaches,
even when thus pointed out, totally irreconcilable with existing ideas
of arrangement and combination of groups, but which now open to my
view the most beautiful chains of affinities; and wonderfully but
indubitably prove, that a single individual may be related to three,
four, or even more apparently disconnected groups.
Perhaps no better genus was ever formed than Papilio of Linnæus; its
diurnal flight, its erect wings, and its clavated antennæ, at first
bid defiance to the systematist who attempts to bring any other group
into contact with it; indeed, in Britain we have nothing at all that
will avail us in this respect, which compels me to have recourse to
exotics, an assistance which I shall only avail myself of when I find
it quite impracticable to furnish the approaches from indigenous
species, the reference to which is attainable by every entomologist.
Among foreign Papiliones, especially among those groups which approach
our genera, Hesperia, Lycæna, Polyommatus, and Thecla, there appears
to be an almost infinite variety of form. Now it is but reasonable to
seize on any variations observable in genera or species from the
prominent or typical genus or order from which they may be supposed to
derive their more conspicuous character, and to employ such variations
in arrangement as connecting links between the group to which they
more decidedly belong, and the group to which, by such variation, they
evince an approach: a precisely intermediate species or genus between
two classes or sub-classes, or even orders, I have never met with,
notwithstanding the renowned Linnæan maxim, that _Natura saltus non
facit_; for did nature make no leaps, surely the question were
immediately at rest as to the existence of any other division than
species among created beings, a conclusion which even the most
strenuous supporters of the Linnæan dogma decidedly resist. Among the
Papiliones, this departure from the type may be looked for either in
the form of the antennæ, the position of the wings, or the time of
flight. The first is obviously the most tangible should it occur, and
it does occur. In Urania, the antennæ have become setaceous; the club
has entirely disappeared, yet the other peculiarities remain much as
in Papilio. This single deviation may be assumed as pointing out a
relation to Geometra, which the reader will perceive is supposed to
meet the sub-class Papilio at this point. A second peculiarity is to
be found in an insect figured by Godart, a Polyommatus in shape, but
with pertinated antennæ;[36] the genus he has very suitably named
Barbicornis. This deviation, it must be observed, is in favour of the
Bombyces, which we therefore suppose touching the sub-class at this
point. A third deviation, of a very different kind, is observable in
an insect which Latreille has figured in the Règne Animal, and placed
among the Sphinges: he calls it Coronis D'Urvillii. The antennæ in
this genus, as in Castnia, are gradually incrassated, and they may
probably be eventually both considered as Papiliones: of Coronis
D'Urvillii, I cannot entertain a doubt, as the wings are too
expansive, the antennæ too long, the abdomen too short for it ever to
retain its station among the Sphinges; the inferior wings are also
very decidedly caudate, a common formation among Papiliones, but
unknown among Sphinges; but, let this question be eventually decided
_pro_ or _con_, the approach between Hesperiæ and Sphinges is not
likely to be disputed, nor the fact that it takes place somewhere in
the neighbourhood of the genus Castnia.
[36] Latreille seems to think this to have been a deception,
and that the antennæ which Godart found on the insect did
not belong to it. I cannot suppose that the latter author
could have been so grossly deceived.
The next type is Sphinx Ligustri; and here again our British
collections are obliged to plead poverty; few, however, as they are at
present, I am compelled, if I purpose consulting nature, to reduce
them about half: the Ægeriæ and Zygænæ must be moved elsewhere; they
look like Sphinges, but are none. I will begin then with Castnia, of
which no more need be said. The next striking departure from the type
occurs in having the abdomen furnished with tufts or brushes, which
the insect spreads as it hovers over flowers, somewhat in the manner
of a bird's tail. The long porrected antlia also has a resemblance,
perhaps rather fancied than real, to the slender bill of a
humming-bird, whence the tribe has received with us the name of
English humming-birds. The genus Sesia I will place on the
circumference of the circle, not doubting but nearer approaches to the
Cossi may be discovered, or are even now known, but no better exists
among our own Sphinges. The next point of contact will be with
Pyralis; and here the genus OEgocera, figured in the Règne Animal,
seems to claim its station: it is a decided Sphinx, with the palpi of
Hypena proboscidalis, and Latreille has placed it between Sesia and
Zygæna, from which it will be seen that I differ only in making Zygæna
pass over the boundary line and into the next section.
We enter the third sub-class then at Pyralis, and find ourselves among
some of the most beautiful little creatures in existence--sylph-like
beings, which spend their lives in the brightest sunshine and among
the sweetest flowers. Linnæus considered them Sphinges, from what
character is not very apparent: the sub-character, applicable only to
this section, is certainly correct; they are truly "_larva diversæ_."
As for the antennæ being "_medio crassiores_," it is not the case,
unless the increase and decrease of pectination can be considered as
making them so. Of this particular tribe Latreille observes, "_Les
autres lepidoptères de cette division ont dans les deux sexes, des
antennes garnies d'un double rang de dents alongées ou bipectinées.
Ceux qui out une trompe distincte forment le genre Glaucopis; ceux où
cette organe manque ou n'est pas distinct celui d'Aglaope--ces
crepusculaires semblent se lier avec les Callimorphes._" The approach
of the genus Aglaope to Aglossa, rather than to Callimorpha, seems to
be presumable from the circumstance of its not possessing a tongue,
the genus Glaucopis having more similarity to our genus Pyrausta,
while some of its species, which appear to call for further generic
division of the order, are closely allied to our Botys literalis, &c.
The only British genera of this order are Zygæna and Ino; the latter,
however, appears to be merely a species of some extra-European genus,
as I have remarked several exotics of precisely similar form. The
insects of this order have a stout and rather hairy larva, much like
those of the generality of the sub-class, and in no respect allied to
that of the Sphinges. Early in the summer they spin a glossy silken
cocoon, generally attached to blades of grass, and remain but a few
days in the pupa state. A great proportion of the perfect insects have
hyaline spots and patches in their wings, and nearly all of them are
brilliantly coloured. It is known that Linnæus occasionally, as in
Tenebrio and the present instance, made his genera recipients of
species, which he found a difficulty in locating properly; but it is
really astonishing to find a naturalist like Latreille abiding by so
absurd a combination as the contents of the Linnæan genus Sphinx, and,
in servile imitation, calling creatures which nothing but an unclouded
sun ever tempts abroad--Crepuscularia.[37] It is no part of my present
plan to assign names to orders, or to describe their contents, except
in those particular instances in which the more immediate object of
this Essay may render it imperative. I will, however, just observe,
that I by no means consider Zygæna the type of the order, but merely
the nearest point of contact with Sphinx, and an evident departure
from its true type, which perhaps may be found in that ill-divided
genus Glaucopis, the form and appearance of which is altogether more
Pyralis-like than Zygæna. I am well aware that OEgocera and Zygæna do
not harmonize so beautifully as many other approaches, and fully
expect to see the connexion between these sub-classes much improved;
but I have seized on these genera as demonstrating a tendency in each
individual towards the sub-class to which it does not belong. The
circumstance of Zygæna having been so long considered a Sphinx will
warrant its situation on the very circumference of the circle which
contains its order, until a more appropriate occupant of that
situation can be found. At the central point of contact, the genus
Aglossa presents a very Bombyx-like appearance; its shape, its want of
the antlia, &c. indicate approach; and from the sub-class Tinea, the
division of Pyralis is at present an imaginary one: at this point,
after making what little comparison I am able, I am induced to place
Galleria, Melia, and Ilithya, in Pyralis; and Chilo, and Crambus in
Tinea.
[37] Volatu vespertino, _Lin._
The fourth sub-class, Tinea, far exceeds in numbers either of the
others, and probably all of them together; and where such a multitude
of species exists, great diversity in form and habit may be expected:
the Pterophori are a most singular tribe, and greatly resemble the
Tipulæ in many respects. I feel by no means certain that their
situation would not be better between the lepidopterous sub-class,
Tinea, and the dipterous sub-class, Tipulæ, thus throwing them
completely out of the lepidopterous circle; but this I leave. I am now
only sketching a rough and hasty outline from nature. If I attempt to
finish my drawing as I proceed, I shall find occupation sufficient for
a lifetime. I have observed that I considered the chain of relation
entering from the last sub-class at Chilo, or about that genus; the
same order must of course include Crambus, and its congeners; the next
order will contain Yponomeuta, which I will place at the point of
contact; and the next point being among the true Tortrices will drive
Halias fagana as a decided departure from their typical form to the
very circumference of the circle where it touches Noctua.