Part 4
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.
The fifth sub-class, Noctua, seems to be but one mighty genus: we will enter it from Halias fagana, an insect so nearly allied to Noctua in its larva, its pupa, and its imago, that for a long time I hesitated to which sub-class it belonged; again, in Cymatophora,[38] subtusa and retusa, I was fearful that by considering them Noctuæ, I might deprive the order Tortrices of a genus on which perhaps many curious combinations might depend, and I now only place them in Noctuæ until I may have an opportunity of examining their larvæ, which I have not yet been fortunate enough to meet with. Towards the central sub-class there appear to be many genera which approach the line of contact; Agrotis and Chareas for instance:[39] I prefer taking the latter, and must mention the species Graminis, as I am fearful of encumbering my system with species to which I not only never intended to refer, but should probably place in some distant order, or perhaps sub-class. At the approach to Geometra, the genus Catocala, from its looping larva, seems to have a right to be placed: this I, however, look on with suspicion, as the larva appears to me any thing but a guide in the connexion of sub-classes; but I here succumb to customary usage in making this genus the approach to the real loopers, objecting, however, to the intervention of Phytometra, Euclidia, and Brepha.
[38] Ochsenheimer places Oo in this genus, and I observe Mr. Stephens confines the genus to that one species. Mr. Curtis places Oo in the genus Bombycia: this confusion of genera is very puzzling, but I hope, by mentioning species, to make myself understood. Oo is not at all applicable to my purpose.
[39] Perhaps Noctua Lambda.
The sixth and last of the exterior sub-classes is Geometra, and we shall find one insect which is completely a Geometra, and yet in the larva has two additional feet, and the abdominal fringe of Catocala: this is Metrocampus margaritaria,[40] an insect, without which the connexion of these sub-classes would have been difficult to establish. The next species I am acquainted with seems to be Rumia cratægaria, and after it the Thorn moths, as they are termed (Crocallis?): these lead to Geometra[41] in the centre, which may be considered the farthest removed from any of the surrounding sub-classes; from the genus Geometra a line may be drawn through Biston, Nyssia, and Hybernia, to the point of contact with Phalæna in the centre, and another through Boarmia, Abraxas, and Ourapteryx to Urania, from which genus of Papiliones perhaps the reader will recollect we set out.
[40] Of Mr. Curtis's _Guide_. I cannot consider fasciaria, Mr. Curtis's next species, at all allied.
[41] Alcis. Curtis.
The seventh and central sub-class, Phalæna, now claims our attention. The mere circumstance of having taken a little tour round it gives but a very poor idea of its contents, and although my reader may assure me he knows them sufficiently well already, that assurance will by no means satisfy me that he and I are at all agreed either as to what those contents may be, or as to their relative situations. Before, however, I again set in earnest to the task of pointing out relations and approaches, I feel that some apology is due for attempting the restoration of a beautiful and euphonious name to that grand group of Lepidoptera, to which it was originally assigned by the eminent naturalist who was the first to define and name such groups.[42] I am fully aware this is an attempt at innovation for which I can never be forgiven by the scientific; for the merit of the present day seems to consist in the total neglect of grouping and classifying, and in making a host of imaginary genera and species, for the mere pleasure of overwhelming us with a "farrago" of barbarous and unutterable names,--a practice which my unsophisticated and old-fashioned notions will never dwell on with that deferential awe which such profound science has an undoubted right to expect.
[42] Linnæus.
Again, on the subjects of _orders_, a term I have already been induced to use now and then, I am quite aware that I here am guilty of another misdemeanour, and more especially as I call them natural orders, meaning thereby orders among the contents of which nature has established the similarity; and to the formation of which "the cunningly devised fables" of man have contributed but very little; and meaning also that nature has implanted in us all, more or less, the power of distinguishing such orders by a mere glance, and without any reference to our books.
Furthermore, the naming of orders which I have been obliged to mention by name, in the unscientific way which I have adopted, merely making them plurals of established names, of large and overgrown genera, I acknowledge to be a confession of ignorance not usual in this our day, especially as these old genera have almost in every instance the disadvantage of being euphonious, easily pronounced, expressive, and universally understood; and an opportunity once missed of coining names for three hundred new orders, (and each might have been a combination of consonants which no one could spell, or speak, or read, or understand,) alas! alas! may never occur again.
To return; I suppose the sub-class Phalæna to contain seven natural orders, a number precisely similar to that discovered from observations made on the larva by that most accurate and indefatigable naturalist, Dr. Horsfield;[43] and I may add, my own divisions are derived from the same source, together with the pupa and whole habit: the perfect insect has no characters, hitherto discovered, by which we can ascertain either sub-class or order, and from this circumstance I am compelled to omit those genera of whose larvæ I am ignorant,[44] and even to leave those as doubtful, of which I possess but a partial knowledge of that state.
[43] I regret not having Dr. Horsfield's work to refer to; but I believe I am perfectly safe in stating from memory that these seven he considered typed in the genera, Saturnia, Lasiocampa, Cossus, Cerura, Arctia, Laria, and Limacodes: two of these he manages to unite to other two, in order to reduce the number to five, but I forget which.
[44] As the genera which I must mention ought necessarily to be drawn entirely from one work, in consequence of authors differing as to their contents, I have adopted those in Mr. Curtis's _Guide_, invariably: below is a list of the genera he has given in this section, with my own idea of their situation attached to each, and the addition of six genera, which Mr. Curtis does not consider as belonging to the sub-class Phalænæ:
789 Trochilium 2 Cossi. 790 Ægeria 2 Cossi. 791 Hepialus 2 Cossi. 792 Cossus 2 Cossi. 793 Zeuzera 2 Cossi. 794 Stauropus 3 Notodontæ. 795 Pygæra 3 Notodontæ. 796 Clostera 3 Notodontæ. 797 Notodonta 3 Notodontæ? 798 Pterostoma 3 Notodontæ. 799 Petasia Sub-class Noctua. 800 Episema Sub-class Noctua. 801 Colocasia 6 Lariæ. 802 Dimorpha 3 Notodontæ? 803 Cerura 3 Notodontæ. 804 Ptilophora 3 Notodontæ? 805 Endromis Order uncertain. 806 Saturnia 7 Phalænæ. 807 Eriogaster 1 Bombyces. 808 Clisiocampa 1 Bombyces. 809 Lasiocampa 1 Bombyces. 810 Odenestis 1 Bombyces. 811 Gastropacha 1 Bombyces. 812 Hypogymna 6 Lariæ. 813 Orgyia 6 Lariæ. 814 Laria 6 Lariæ. 815 Arctia 6 Lariæ. 816 Arcturus 6 Lariæ? 817 Spilosoma 5 Arctiæ. 818 Phragmatobia 5 Arctiæ. 819 Penthophera Order uncertain. 820 Eyprepia 5 Arctiæ. 821 Eulepia 4 Lithosiæ. 822 Hypercampa 4 Lithosiæ. 823 Callimorplia 4 Lithosiæ. 824 Deiopeia 4 Lithosiæ. 825 Lithosia 4 Lithosiæ. 826 Nudaria Sub-cl. Phryganea. 827 Psyche Sub-cl. Phryganea. 828 Heterogena Order uncertain. 829 Limacodes Order uncertain. 854 Acronycta 5 Arctiæ. 942 Platypteryx 3 Notodontæ. 943 Drepana 3 Notodontæ. 944 Cilix 3 Notodontæ.
Natural Order--_Bombyces_. Has an elongate cylindrical downy larva, which rolls itself into a ring when touched; the pupa changes in a close gummy oval cocoon, remarkably small for the size of the imago. Among the exotic species of Lasciocampa, we find in the males particularly slender bodies, expansive wings, the inferior grooved to receive the abdomen, and diurnal flight, all of them characters so indicative of an approach to Papilio, that we scarcely hesitate a moment in assigning it the approaching station, not but I expect fully that time will eventually furnish us with a connexion on each side yet more conclusive.[45] The second genus of Bombyces is probably Odenestis, and the third Gastropacha, whose prominent and elongated palpi appear to point out an approach toward a tribe of insects with the same peculiarity, of which there are several to be found in the following order:
[45] See a Papilio with the antennæ of a Lasciocampa. Drury, Vol. III. pl. v.
Natural Order--_Cossi_. The larva is depressed; naked, except a very few scattered hairs; has sixteen feet; lives through one or more winters; never rolls itself in a ring when touched; feeds on the solid interior woody parts of vegetables. The pupa generally changes in a tough oval cocoon, interwoven with particles of its food. It has a double ring of raised denticulations of each segment of the abdomen, by means of which it is endowed with a considerable power of locomotion. The genus Zeuzera is very near the point of contact with the Bombyces. In Zeuzera there is much resemblance to the antennæ of Gastropacha. One genus, or group of genera, I expect will prove to be Stygia, a native of New-Holland. A second, at the point of contact with Sesia in Sphinx, must be Ægeria; thus retaining its place among British insects, immediately between Sesia and Cossus.[46] This is the first of a series of the most beautiful instances of approach, or rather, of what ought to be termed _relations of analogy_, that any system has ever previously disclosed. As a few words will again be necessary on this subject, I refrain from any further observation here, than merely requesting the reader to examine how minutely the Sphinx characters are appropriated by a true lignivorous Phalæna, which cannot be said, in any of its prior and principal states, to have the most distant approach to Sphinx. A third genus is, probably, the strange and paradoxical exotic Oiketicos, which has been minutely described in the _Linnæan Transactions_; and a fourth is Hepialus.[47] This genus has some slight points in which it differs from the others of the order already known, the larva being radicivorous only, seldom or never ascending internally the stems of plants: it changes in the earth.
[46] It is a most singular chance that these genera should have been placed so naturally, as the cause of this proximity has never before been even hinted at.
[47] Another type of Hepialus is figured in Drury, Vol. II. pl. xiii. 2.
Natural Order--_Notodontæ_. The larva is naked, has sixteen feet, and is, in different genera, furnished with excrescences, and apparent distortions in various parts of the body. The eighth or last pair of feet, and three last segments of the abdomen, are elevated; when the insect is at rest, the head and first segment are raised in a similar manner. In one genus (containing Camelina) the head and extremity of the abdomen nearly meet over the back, when raised in this singular manner. The posterior feet are frequently useless in walking; in some genera, entirely obsolete. The pupa is smooth, in a cocoon, mostly among dead leaves on the surface of the ground: sometimes it is glutinous, and interspersed with fragments of wood, like the last. I confess I am exceedingly puzzled both with the contents and extent of this order; but this arises from my having seen so few of the species in the larva state. Ptilophora plumigera, figured by Mr. Curtis,[48] I had always considered a Notodonta; but the larva evidently excludes it from the order, and, I should imagine, places it among the Noctuæ; where among them I know not, for I have not the slightest idea of any congeners, either of the larva or imago. The larva from which a collector of Lepidoptera could expect to obtain such an imago would be unicolourous, stouter in the middle, elevated in the penultimate segment, and more attenuated towards the head.[49] Pygæra appears doubtful at first, but when observed quite at rest, and in a perfectly natural position, elevates the head and tail, though in a much less degree than the typical genus. Mr. Curtis's genus Notodonta contains several good species, which may be considered as typing the order, as Ziczac, Tremula, and Dictæoides. The first species, Trepida (the Peridea serrata of Mr. Stephens,) seems more nearly related to Endromis. Both these may, however, probably belong to the order Notodontæ, and be situate near the approach to the central order Phalænæ. Petasia cassinea and Episema cærleocephala appear to be genuine Noctuæ, and very near Chareas graminis, and Rusina ferruginea, as far as my very imperfect knowledge of these four species will allow me to judge. Clostera is another departure from the type; but this may be accounted for, in some degree, by its close proximity to Hepialus, from which genus it borrows its remarkably short antennæ, and other peculiarities. It seems a strange perversion of judgment to place Platypteryx at the end of or among the Geometræ; but Linnæus did so, and that is enough. Hubner, Haworth, and a few others, positively ventured, in this glaring instance, to refer this genus to the Bombyces; but their ideas were thought to be wrong, and their judgment was, _nem. con._ reversed. I have elsewhere expressed a wish that my readers should convince themselves, and the frequent occurrence of the larvæ of Platypteryx and Cerura would afford any naturalist abundant opportunity of ascertaining, that they can be referred to but one order. The approach of Platypteryx and Cilix to the Pyralides, in assuming so much of their characters, is very interesting, and is a most striking departure from the typical form. These genera also approach the Lithosiæ, but not so nearly as some exotics.
[48] British Entomology, pl. 328.
[49] As the larva so decidedly forbids the introduction of this insect among the Notodontæ, and places it among the Noctuæ, it probably in some degree approaches Geometra pennaria in the adjoining sub-class.
Natural Order--_Lithosiæ_. The difference between Lithosiæ and Arctiæ is rather difficult to point out; yet a difference exists, which it is perfectly impossible not to detect. The larva of Lithosiæ has sixteen feet, is very active, is moderately hairy, does not readily roll itself in ring, but occasionally assumes that attitude. The pupa is smooth, changes in a slight web, in which the hairs are intermixed. The approach of Lithosia[50] to the genus Yponomeuta, in Tinea, scarcely need be pointed out. It will be observed, that Mr. Samouelle[51] was aware of this approach, and placed the genera Lithosia and Yponomeuta following each other. The splendid Callimorpha dominula, although, to all appearance, a real Arctia, must be included in this order, and placed in contact with the following one.
[50] See note for the genera of Lithosia.
[51] Ent. Useful Com. p. 249.
Natural Order--_Arctiæ_. Larva, with sixteen feet, generally very hairy, bear-like; rolls itself in a ring when touched; pupa smooth, in a slight web. Whether the whole of Mr. Curtis's genus Acronycta must be included in this order, I am not able positively to say: the genus Apatela of Mr. Stephens certainly must, and until I have obtained sufficient information to decide on Acronycta, we must bring Mr. Stephens's genus only into the order, leaving the remainder of the species undisposed of. The development of the antlia in Acronycta discovers as near an approach to Noctua, as Lithosia does to Tinea; but the bear-like, cocoon-spinning larva place these insects in close alliance with the true Arctiæ.
Natural Order--_Lariæ_. Larva, with sixteen feet, and furnished with various brushes, or fascicles of hair, on different parts of the body, but mostly on the anterior dorsal segments; it rolls itself in a ring when touched. The genus Porthesia of Mr. Stephens may be considered a near approach to Eriogaster, in the following order, Bombyces, in many of its peculiarities, as the abdominal hair with which it covers its eggs, in its antennæ, &c. Orgyia antiqua, on the other hand, is in habit, expansion of wing, slender body, and apterous female, a close approach to the Geometræ, near the genera Hybernia and Nyssia; in fact, were it not for the larva, that is, were the larva unknown, we should have no hesitation about placing this insect with the Geometræ.
Natural Order--_Phalænæ_. Larva, with sixteen feet; it has a circle of wart-like protuberances on each segment, from each of which spring a few strong bristles; pupa, smooth, with a few bristles at the tail; changes in a cocoon, which is singularly left partly open at one end. We have but one species of this order in Britain, Saturnia carpini;[52] but among exotics there is a great variety, some remarkable for the immense expanse of their wings.[53] Probably Phalæna Atlas of Linnæus is the centre of the group, and, if so, the centre and type of the class Lepidoptera.
[52] Saturnia carpini is the Pavonia minor of Linnæus, who, apparently, considered it a variety of a completely different species: the retention of a name thus originating in error is not justifiable.
[53] Drury has some fine figures of this order, particularly Vol. I. pl. xviii. 2; Vol. II. pl. v. 1, pl. vi. 2, pl. xi. 1, 2, pl. xiii. 2; Vol. III. pl. xix. pl. xxiv. pl. xxv. pl. xxxiv.