Chapter XXXVI: Part III: The Metamorphoses of Insects (7)

In 1870 I observed these sense-pits in the antennæ and also in the
cercopoda of the cockroach (_Periplaneta americana_). I counted about
90 pits on each cercus. They are much larger and much more numerous
than similar pits in the antennæ of the same insect. I compared them
to similar pits in the antennæ of the carrion-beetles, and argued that
they were organs rather of the smelling than hearing. (Amer. Nat.,
iv., Dec. 1870.) Organs of smell in the flies (Chrysopila) and in the
palpi, both labial and maxillary, of Perla were described in the same
journal (Fig. 270). Compare Vom Rath’s account of the organs in the
cercopods of Acheta (Fig. 271); also the singular organ discovered by
him on the end of the palpus of butterflies, in which a number of
hair-like rods (_sh_) are seated on branches of a common nerve (_n_,
Fig. 272).

Footnote 49:

Forel, however (_Recueil Zoologique Suisse_, 1887), denies that these
tympanic organs are necessarily ears, and thinks that all insects are
deaf, with no special organs of hearing, but that sounds are heard by
their tactile organs, just as deaf-mutes perceive at a distance the
rumbling of a carriage. But he appears to overlook the fact that many
Crustacea, and all shrimps and crabs, as well as many molluscs, have
organs of hearing. The German anatomist Will believes that insects
hear only the stridulation of their own species. Lubbock thinks that
bees and ants are not deaf, but hear sounds so shrill as to be beyond
our hearing.

Footnote 50:

Weismann, Die nachembryonale Entwicklung der Musciden. Zeitschr. für
wissen. Zoologie, xiv, p. 196, 1864.

Footnote 51:

Plateau (1877) states that the digestive fluid of insects, as well as
of Arachnids, Crustaceans, and Myriopods, has no analogy with the
gastric juice of vertebrates; it rather resembles the pancreatic sugar
of the higher animals. The acidity quite often observed is only very
accessory in character, and not the sign of a physiological property.
“Farther, I have found it in insects; Hoppe-Seyler has demonstrated in
the Crustacea, and I have proved in the spiders, that the ferment
causing the digestion of albuminoids is evidently quite different from
the gastric pepsine of vertebrates; the addition of very feeble
quantities of chlorhydric acid, far from promoting its action, retards
or completely arrests it.” (Bull. Acad. roy. Belgique, 1877, p. 27.)

Footnote 52:

The word _grès_ we translate as the layer of gum. Not sure of the
English equivalent for _grès_, I applied to Dr. L. O. Howard, U. S.
Entomologist, who kindly answers as follows: “I have consulted Mr.
Philip Walker, a silk expert, who writes me the following paragraph:
‘_Grès_, as I understand it, is the gum of the silk fibre, hence the
French name for raw silk, _grèye_, which is in distinction to the silk
that has been boiled out in soap after twisting, or throwing, as it is
called. As I understand it, the silk fibre is composed of the _grès_
and fibroin. The former is soluble in alkali, like soap water, and the
latter is not.’” While Blanc considers the _grès_ as the product of a
special secretion of the wall of the reservoir, Gilson regards its
production as simultaneous with that of the silk or of the fibroin
(_l.c._ 1893, p. 74).

Footnote 53:

On cytological differences in homologous organs. Report 63d meeting of
British Assoc. Adv. Sc. for 1893. 1894. p. 913.

Footnote 54:

See also Giard, Bull. Soc. Ent. France, p. viii, 1894.

Footnote 55:

“The contents of the Malpighian tubules may be examined by crushing
the part in a drop of dilute acetic acid, or in dilute sulphuric acid
(10 per cent). In the first case a cover-slip is placed on the fluid,
and the crystals, which consist of oblique rhombohedrons or derived
forms, are usually at once apparent. If sulphuric acid is used, the
fluid must be allowed to evaporate. In this case they are much more
elongated, and usually clustered. The murexide reaction does not give
satisfactory indications with the tubules of the cockroach.” (Miall
and Denny, The cockroach, p. 129, footnote.)

Footnote 56:

“There is a curious analogy between the excretory organs of these
insects and the mesonephros of some vertebrates, where a second,
third, etc., generation of tubules is added to the primitive metameric
series. When the embryonic number of Malpighian vessels persists in
insects, the demand for greater excreting surface is supplied by a
lengthening of the individual vessels.”

Footnote 57:

For the mode of adhesion of Cynips eggs, see Adler in Deutsche Ent.
Zeits. 1877, p. 320.

Footnote 58:

Mercaptan is a mercury, belonging to a class of compounds analogous to
alcohol, having an offensive garlic odor. Methyl mercaptan is a highly
offensive and volatile liquid.

Footnote 59:

Embryonic or temporary glands, the “pleuropodia” of Wheeler, viz. the
modified first pair of abdominal legs, occur in Œcanthus, Gryllotalpa,
Xiphidium, Stenobothrus, Mantis (occasionally a pair on the second
abdominal segment, Graber); Blatta, Periplaneta, Cicada, Zaitha,
Hydrophilus, Acilius, Melolontha, Meloë, Sialis, Neophylax. (See
Wheeler, Appendages of the First Abdominal Segment, etc., 1890.)

Footnote 60:

These midges owe their phosphorescence to bacteria in their bodies
during disease.

Footnote 61:

Untersuchungen zur Anatomie und Histologie der Tiere, 1884, p. 72.

Footnote 62:

Zelle und Gewebe, 1885, p. 43. (See also our p. 217.)

Footnote 63:

Studien über die Lampyriden, Zeits. für wiss. Zool., xxxvii, 1882.
Both Wielowiejski and M. Wistinghausen have completely disproved the
view of Schultze, that the tracheæ end in star-like cells, where
respiration takes place, as the “star-like cells” are simply net-like
expansions of the peritoneal membrane of the tracheæ.

Footnote 64:

The following summary compiled from Krancher, is translated, with some
minor changes, from Kolbe’s work.

Footnote 65:

Miall and Denny state that in the cockroach the abdominal spiracles
are permanently open, owing to the absence of a valve, but
communication with the tracheal trunk may be cut off at pleasure by an
internal occluding apparatus.

Footnote 66:

Zur Entwicklungsgeschichte der Biene, Zeitschr. wissens. Zoologie, xx,
p. 519, 1870.

Footnote 67:

Die Entwicklung der Dipteren im Ei, Zeitschr. wissens. Zoologie, xiii,
1863.

Footnote 68:

Amer. Naturalist, May, 1886, p. 438.

Footnote 69:

Zeitschr. wissens. Zoologie, xl, 1884, Taf. xix, Fig. 8, _T_.

Footnote 70:

_Science_, 1893, pp. 44–46.

Footnote 71:

Art. Thorax, Todd’s Cycl. of Anat. and Phys.

Footnote 72:

The mesothoracic stigmata are open in Carabus, Potamophilus, Elmis,
Macronychus, Buprestis, Elater, Lampyris, Lycus, Triphyllus,
Eucinetus, Dascillus, Psephenus, Ergates, Micralymna, and probably
many others. The metathoracic stigmata are open in Lycus and Elmis.

Footnote 73:

In the Hymenoptera the two pairs on the meso- and metathoracic
segments are open in the Aculeata, also in the Siricidæ, among which
sometimes that on the third segment is closed. In Pimpla and
Microgaster (fully grown larvæ) only the mesothoracic stigmata are
open.

Palmén adds that most dipterous larvæ are amphipneustic; Cecidomyia,
the Mycetophilidæ, Bibionidæ, and Stratiomys are typically
peripneustic. (p. 92.)

Moreover, a single insect, as Sialis, may be apneustic as a larva,
peripneustic as a pupa, and holopneustic in the imago stage.

Footnote 74:

Mr. J. W. Folsom, who has made the accompanying sketch of the nymph of
_Euphæa splendens_ in the Cambridge Museum, finds only seven pairs of
gills, there being no traces of them on segments 1, 9, and 10. A stout
trachea, he writes us, enters the base of each gill, and subdivides
into several long branches, which course along the periphery. Hagen in
his original account said there were eight pairs on segments 1–8
respectively.

Footnote 75:

Harris, Correspondence, p. 226, Pl. III., Fig. 7.

Footnote 76:

Nusbaum’s view has been questioned by Heymons, who, from his studies
on the embryology of the cockroach (Periplaneta and Phyllodromia),
Forficula, and Gryllus, concludes that the ectodermal ends of the
sexual outlets owe their origin to an unpaired median hypodermal
invagination, and that it is quite doubtful whether the ectodermal
portions of the sexual passages of insects were ever paired (p. 104).
On the other hand he appears, even throwing out the case of Ephemera,
to have overlooked Nassonow’s discovery of paired outlets in the young
of Lepisma.

Footnote 77:

Acta Acad. German., xxxiii, 1867, No. 2, p. 81. Quoted by Dr. Sharp,
Insecta, p. 142.

Footnote 78:

Journ. Morph., iii, Boston, pp. 299, 300.

Footnote 79:

Proc. Boston Soc. Nat. Hist., xi, pp. 88, 89.

Footnote 80:

In the following general account of the embryology of insects, I have
closely followed the admirable arrangement and description of
Korschelt and Heider, in their Lehrbuch der vergleichenden
Entwicklungsgeschichte der wirbellosen Thiere, pp. 764–846, often
translating their text literally, though not omitting to state the
results of other writers.

Footnote 81:

Korschelt and Heider state that no cellular embryonal membranes are
present in Synaptera, Uljanin finding none in the Podurids. In the
embryo of _Isotoma walkerii_ we, however, observed a membrane which we
compared to the larval skin of many Crustacea, and both Sommer and
Lemoine have detected in eggs of the same group a cuticular larval
skin which is provided with spines for rupturing the chorion. The
amnion is also wanting in Proctotrupids (Ayers), and is rudimental in
Muscidæ (Kowalevsky, Graber), in viviparous Cecidomyidæ, according to
Metschnikoff, who also states that in certain ants of Madeira the
envelopes are represented only by a small mass of cells in the dorsal
region.

Footnote 82:

In Diptera the stomodæum may be dorsal, Dr. Pratt tells us.

Footnote 83:

Will (Aphis) and also Cholodkowsky’s statement (Blatta), as well as
Balfour and Schimkewitch’s statements that the brain is at first
disconnected from the ventral cord, are apparently erroneous.

Footnote 84:

The description perhaps applies not only to the cockroaches, but, as
seen from the similar but fragmentary notices of Heider and of Wheeler
on the Coleoptera, may be common to insects in general.

Footnote 85:

Report on the Rocky Mountain locust, etc. Ninth Annual Report U. S.
Geol. and Geogr. Survey of the Territories for 1875, pp. 633, 634.

Footnote 86:

Orthoptera Europæa, 1853, p. 37.

Footnote 87:

In his Für Darwin (1863), Fritz Müller gives his reasons for the
opinion that the so-called “complete metamorphosis” of insects was not
inherited from the primitive ancestor of all insects, but acquired at
a later period.

Footnote 88:

For further details see the 1st Report of the U. S. Entomological
Commission, 1878, pp. 279–281.

Footnote 89:

See Köppen ueber die Heuschrecken in Südrussland, 1862, pp. 22, 23.

Footnote 90:

In Samouelle’s The Entomologist’s Useful Compendium, 1819. See
Westwood’s Class. Insects, i, p. 2; Leach’s Ametabolia comprised the
Thysanura (Synaptera) and the lice.

Footnote 91:

From the Greek μανός, scanty; μεταβολή, change.

Footnote 92:

Greek, ἤρεμα, quiet; μεταβολή, change.

Footnote 93:

At the same date (March, 1869) we independently suggested that the
insects had originated from some form like the hexapodous young of
Pauropus and Podura. In November, 1870, we suggested that the
Thysanura and the hexapodous Leptus may have descended from some
Peripatus-like worm. Afterwards (1871) we proposed for the ancestral
form the term _leptiform_, which was later abandoned for Brauer’s term
_Campodea-form_.

Footnote 94:

Amer. Naturalist, i, p. 85, 1867.

Footnote 95:

First Rep. U. S. Ent. Commission, p. 281–283.

Footnote 96:

Trans. Ent. Soc. London, iii, p. xv. See also Ashton, R. J., Trans.
Ent. Soc. London, iii, 1841–43, pp. 157–159.

Footnote 97:

Proc. Bost. Soc. Nat. Hist., x, 1866, p. 283.

Footnote 98:

See Max Braun’s article entitled Ueber die histologischen Vorgange bei
der Hautung von _Astacus fluviatilis_, with a full bibliography, in
Semper’s Arbeiten aus dem Zool. zoot. Institut in Würzburg, ii, pp.
121–166. Also Semper’s Animal Life, p. 20. Trouvelot also discovered
the moulting fluid. (Amer. Nat., i, p. 37.)

Footnote 99:

American Naturalist, xvii, May, 1883, pp. 547, 548.

Footnote 100:

Le Pelletier. A. M. L., Bulletin de la Société Philomathique, Paris,
April, 1813.

Footnote 101:

Heineken, Carl. Observations on the reproduction of the members in
spiders and insects. (Zool. Journ., 1829, vi, pp. 422–432.)

Footnote 102:

Bees and Bee-keeping, pp. 21, 22.

Footnote 103:

Butterflies, their structure, changes, and life-histories. New York,
1881, pp. 37–42. Butterflies of the Eastern United States and Canada,
1888, 1889. Also, Frail children of the air, 1895, pp. 232, 233 _a_.
Dr. Chapman, however, finds that this piece in micropupæ has no
connection whatever with the head or eye, but belongs rather with the
prothoracic segment. (Trans. Ent. Soc. London, 1893, p. 102.) We have
been able to confirm his statements, but still this piece is peculiar
to the pupal state.

Footnote 104:

Rep. Ent. U. S. Dept. Agr., 1879, pp. 228, 229, Pl. IV, Fig. 4.

Footnote 105:

Monograph of bombycine moths, Pt. I, 1897. Figs. 24, 28, 29, 33, 34,
40, 77.

Footnote 106:

Amer. Naturalist, xii, pp. 379–383.

Footnote 107:

_Hybocampa milhauseni_, Dr. Chapman tells me, has a pupal spine
(imperfectly present in Cerura) with which it cuts out a lid of the
cocoon.

Footnote 108:

Riley’s Report for 1892, p. 203.

Footnote 109:

Philosophy of the pupation of butterflies, and particularly of
Nymphalidæ, by Charles V. Riley. (Proc. Amer. Assoc. Adv. Science,
xxviii, Saratoga Meeting, August, 1880, pp. 455–463.)

Footnote 110:

The homology of the suranal plate of the larva with the cremaster of
the pupa, established by Riley in 1880, is also affirmed by Jackson
(1888) and by Poulton, and for some years we have been satisfied that
this is the correct view; Professor Hatchett-Jackson discovered it, he
states, in 1876.

Footnote 111:

In his remarkable studies on the morphology of the Lepidoptera,
Professor W. Hatchett-Jackson states his belief that Riley’s homology
of the sustentors with the soles or plantæ of the anal prolegs, and
the sustentor ridges with their limbs, is wrong, and that the
eminences on either side the anal furrow, or the “anal prominences,”
as they are termed by Riley, represent the prolegs, and that the
sustentor ridges and sustentors are probably peculiar developments of
the body of the 10th somite, found only in some Lepidoptera. From our
examination of pupa of different families of moths, we are satisfied
that Jackson’s view is the correct one. We have not found the
sustentors and their ridges in the pupæ of the more generalized moths,
but the vestiges of the anal legs are almost invariably present, their
absence in the pupa of Nola and Harrisina being noteworthy.

Footnote 112:

We copy from Kirby and Spence their abstract of Herold’s conclusions:
“The successive skins of the caterpillar, the pupa-case, the future
butterfly, and its parts or organs, except those of sex, which he
discovered in the newly excluded larva, do not preëxist as germs, but
are formed successively from the _rete mucosum_, which itself is
formed anew upon every change of skin, from what he denominates the
_blood_, or the chyle after it has passed through the pores of the
intestinal canal into the general cavity of the body, where, being
oxygenated by the air-vessels, it performs the nutritive functions of
blood. He attributes these formations to a _vis formatrix_ (bildende
Kraft).

“The caul or epiploon (_fett-masse_), the _corps graisseux_ of
Réaumur, etc., which he supposes to be formed from the superfluous
blood, he allows, with most physiologists, to be stored up in the
larva, that in the pupa state it may serve for the development of the
imago. But he differs from them in asserting that in this state it is
destined to two distinct purposes: first, for the production of the
muscles of the butterfly, which he affirms are generated from it in
the shape of slender bundles of fibres; and, secondly, for the
development and nutrition of the organs formed in the larva, to effect
which, he says, it is dissolved again into the mass of blood, and
being oxygenated by the air-vessels, becomes fit for nutrition, whence
the epiploon appears to be a kind of concrete chyle.”
(Entwickelungsgeschichte der Schmetterlinge, pp. 12–27.) It seems that
Herold was right in deriving the pupa and imago from the hypodermis
(his _rete mucosum_), but wrong in denying that the germs did not
preëxist in the young caterpillar, and wrong in supposing that the
latter originated from the blood, also in supposing that the muscles
owe their origin to the fat-body. Swammerdam, and also Kirby and
Spence, were correct in supposing that the imago arose from “germs” in
the larva, though wrong in adopting the “emboîtement” theory.

Footnote 113:

In the regions where the imaginal buds are not present (dorsal aspect
of the prothorax, and abdomen), the epithelium (hypodermis) may
proliferate independently of these buds.

Footnote 114:

We shall translate portions and, when the text allows, make an
abstract of parts of Gonin’s clear and excellent account, often using
his own words.

Footnote 115:

C. Herbert Hurst, The Pupal Stages of Culex.

Footnote 116:

Lowne on the Blow-fly, new edit., pp. 2, 41, Fig. 7.

Footnote 117:

Miall, Natural History of Aquatic Insects, pp. 136–138. Also Trans.
Linn. Soc. London, V, Sept., 1892.

Footnote 118:

This account is translated from Korschelt and Heider, with some
omissions and slight changes.

Footnote 119:

Westwood in his excellent account of this group remarks: “Hence, as
well as from the account given by Jurine, it is evident that the pupa
of the Stylops is enclosed in a distinct skin, and is also in that
state enveloped by the skin of the larva, contrary to the suggestion
of Mr. Kelly.” (Class. Insects, II. 297.) This is all we know about
the supernumerary larval stages.

Footnote 120:

Some facts towards a life history of _Rhipiphorus paradoxus_. Annals
and Magazine of Natural History for October, 1870.

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TRANSCRIBER’S NOTES

● P. 316, changed “abdominal cells” to “absorbent cells”. ● Silently corrected typographical errors and variations in spelling. ● Archaic, non-standard, and uncertain spellings retained as printed. ● Enclosed italics font in _underscores_. ● Enclosed bold font in =equals=. ● Superscripts are denoted by a caret before a single superscript character or a series of superscripted characters enclosed in curly braces, e.g. M^r. or M^{ister}. ● Subscripts are denoted by an underscore before a series of subscripted characters enclosed in curly braces, e.g. H_{2}O.