The adult Pteronarcys is nocturnal, flyi_A Text-book of Entomology Including the Anatomy, Physiology, Embryology and Metamorphoses of Insects for Use in Agricultural and Technical Schools and Colleges as Well as by the Working Entomologist

night, and Mr. Barnston observed it when on the wing, “constantly

dipping on the surface of the water”; by day it hides “in crevices

of rocks which are constantly wetted by the spray of falling water,

under stones and in other damp places.” It may thus be compared with

the Amphibians, Necturus and Proteus, whose gills are retained in

adult life. A similar large Chilian Perlid (_Diamphipnoa lichenalis_

Gerst.) differs in completely lacking the thoracic gills, though

there are four pairs on the abdomen, _i.e._ a pair on each of the

first four segments. In this form the number of individual filaments

in the largest tufts may amount to about 200.

Another Perlid (_Dictyopteryx signata_) is said by Hagen to have two

pairs of gill-tufts on the under side of the head; the first pair

situated on the base of the submentum, the second on the membrane

connecting the head and prosternum.

Kolbe states that in the imagines of _Perla marginata_ and _P.

cephalotes_ on the hinder edge of the thoracic stigmata arise three

very small chitinous plates, which, on their under side and on the

edges are beset with numerous short white filaments. These

completely correspond to the filaments of the tuft-like larval

gills. Persistent anal gills also occur in the imagines of Perla.

[Illustration:

FIG. 457.—Under side of _Pteronarcys regalis_, showing the situation

of the gills _(g_, _b_, _f_) and the sternal orifices: _A_, a

branchial filament showing the direction of the current of blood;

_c_, _d_, tracheæ. _B_, end of the abdomen enlarged.—After

Newport.

]

In _Nemoura lateralis_ and _cinerea_ the tracheal gills are

differently disposed. On each side of the anterior edge of the

prosternum arise delicate tightly twisted filaments, like those of

the larva. (Einführung, p. 536.)

Hagen also states that in the dragon-fly, Euphæa, the gills of the

nymphs are retained in the imago, and Palmén remarks that in Æschna

the rectal gills of the nymph persist in the imago, though not used

for respiration.

Palmén gives an instance of a caddis-fly (Hydropsyche, Fig. 448)

retaining its gills through the imago stage, but they are unfit for

respiration, as they are minute and shrunken.

A walking-stick (_Prisopus flabelliformis_) found in the mountains

of Brazil has the remarkable habit, according to Murray, of spending

“the whole of the day under water, in a stream or rivulet, fixed

firmly to a stone in the rapid part of the stream,” with its head

turned up stream; but leaving the water at dark. The under side of

the body, including the head, is hollowed so that the creature may

adhere, sucker-like, to smooth stones; the claws, claspers, and

flaps on the legs aid in retaining its hold, while the outer margin

of the legs is dentate and thickly fringed with hair to repel the

water.

Another form, closely related to Prisopus, from Borneo (_Cotylosoma

dipneusticum_) is said by Wood-Mason to be even more profoundly

modified for an aquatic life, since it has not only spiracles, but

also, as he claims, tracheal gills. From each side of the body, in

fact along the lower margins of the sides of the metathorax, there

stand straight out five equal, small, but conspicuous ciliated oval

plates, “which, when the insect is submerged and its stigmata are

closed, doubtless serve for respiration.” The author did not note

the actual presence of tracheæ in these plates.

LITERATURE ON THE ORGANS AND PHYSIOLOGY OF RESPIRATION

_a._ On the tracheal system in general

=Lyonet, P.= Traité anatomique de la chenille qui ronge le bois du

saule. (La Haye, 1760; 2d edit., La Haye, 1762, pp. 616, 18 Pls.)

=Treviranus, G. R.= Beiträge zur Anatomie und Physiologie der Tiere

und Pflanzen, 1816.

—— Das organische Leben. Bremen, 1831.

=Rengger, J. R.= Physiologische Untersuchungen über die tierische

Haushaltung der Insekten. Tübingen, 1817. (Germar’s Mag. f. Ent.,

1818, iii, pp. 410–413.)

=Dufour, L.= Recherches anatomiques sur les Carabiques et sur

plusieurs autres insectes Coléoptères. Organes de la respiration.

(Ann. Sc. nat., viii, 1826, pp. 19–27, 2 Pls.)

—— Études anatomiques et physiologiques sur les insectes Diptères de

la famille des Pupipares. Appareil respiratoire. (Ann. Sc. nat.

Zool., Sér. 3, iii, 1845, pp. 56–64, 1 Pl.)

—— Description et anatomie d’une larve à branchies externes

d’Hydropsche. (Ann. Sc. nat, Zool., Sér 3, 1847, viii, pp. 341–354.)

—— Études anatomiques et physiologiques, et observations sur les

larves des Libellules. Appareil respiratoire. (Ann. Sc. nat. Zool.,

Sér. 3, xvii, 1852, pp. 76–97, 3 Pls.)

—— Recherches anatomiques sur les Hyménoptères de la famille des

Urocerates. Appareil respiratoire. (Ann. Sc. nat. Zool., Sér. 4, i,

1854, pp. 203–209, 1 Pl.; see also p. 344.)

=Burmeister, H.= Handbuch der Entomologie, i, 1832, pp. 169–194,

416–436.

=Kirby, W., and W. Spence.= Introduction to entomology, 1833, iv, pp.

35–81.

=Bowerbank, J. S.= Observations on the circulation of blood and the

distribution of the tracheæ in the wing of _Chrysopa perla_. (Ent.

Mag., iv, 1837, pp. 179–185.)

=Platner, E. A.= Mitteilungen über die Respirationsorgane in der Haut

bei der Seidenraupe. (Müller’s Archiv f. Physiol., 1844, pp. 38–49.)

=Filippi, F. de.= Alcuni osservazioni anatomico-fisiologische sugl’

Insetti in generale, ed in particulare sul Bombice del Gelso. (Ann.

R. Acad. d’ Agricoltura di Torino, 1850, ii, p. 25, 1 Pl.; Transl.

by C. A. Dohrn, Stettin, Ent. Zeit., 1852, xiii, pp. 258–267; xiv,

pp. 124–132, 1 Pl.)

=Newport, G.= On the formation and the use of the air-sacs and dilated

tracheæ in insects. (Trans. Linn. Soc. London, 1851, xx, pp.

419–423.)

=Lubbock, J.= Distribution of tracheæ in insects. (Trans. Linn. Soc.

London, 1860, xxiii, pp. 23–50.)

=Landois, L.= Anatomie des _Phthirius inguinalis_ Leach. (Zeitschr. f.

wissens. Zool., xiv, 1864, pp. 1–26, 5 Taf.)

—— Anatomie des _Pediculus vestimenti_ Nitzsch. (Ibid., xv, 1865, pp.

32–55, 3 Taf.)

—— Anatomie des Hundeflohs (_Pulex canis_). (Nova Acta Leop.-Carol.

Akad. der Naturf., Dresden, 1866, xxxiii, 1867, pp. 67, 7 Taf.)

—— Anatomie der Bettwanze (_Cimex lectularius_ L.). (Ibid., xviii,

1868, pp. 206–224, xix, 1869, pp. 206–233, 4 Taf.)

=Meinert, Fr.= Campodeæ: en familie af Thysanurernes orden.

(Naturhistorisk Tidsskr., 3 Raek., iii, 1864–65, pp. 400–440, 1 Pl.)

=Reinhardt, H.= Zur Entwicklungsgeschichte des Tracheensystems der

Hymenopteren mit besonderer Bezeichung auf dessen morphologische

Bedeutung. (Berlin. Ent. Zeitschr., 1865, ix, pp. 187–218, 2 Taf.)

=Gerstaecker, A.= Bronn’s Klassen und Ordnungen des Tierreichs, v,

1866–1879. Organs of respiration, pp. 119–131.

=Pouchet, G.= Développement du système trachéen de l’Anophèle

(_Corethra plumicornis_). (Archiv zool. expérimentale, i, 1872, pp.

217–232, 1 Fig.)

=Graber, V.= Ueber eine Art fibrilloiden Bindegewebes der Insektenhaut

und seine lokale Bedeutung als Trachealsuspensorium. (Archiv f.

Mikroskop. Anat. x, 1874, pp. 124–144, 1 Taf.)

—— Die Insekten; München, 1877. Organs of respiration, pp. 346–369.

=Packard, A. S.= On the distribution and primitive number of spiracles

in insects. (Amer. Naturalist, viii, 1874, pp. 531–534.)

—— On the nature and origin of the so-called “spiral thread” of

tracheæ. (Amer. Naturalist, xx, 1886, pp. 438–442, 2 Figs., p. 558.)

=Wolff, O. J. B.= Das Riechorgan der Biene nebst einer Beschreibung

des Respirationswerkes der Hymenopteren, des Saugrüssels und

Geschmacksorganes der Blumenwespen. (Nova Acta d. kais. Leop-Carol.

Akad. der Naturf., xxxviii, 1876, pp. 1–251, 8 Taf.)

=Palmén, J. A.= Zur Morphologie des Tracheensystems. Leipzig, 1877,

pp. 140, 2 Taf.

=Moseley, H. N.= Origin of tracheæ in Arthropoda. (Nature, xvii, 1878,

p. 340.)

=Poletajew, Olga.= Quelques mots sur les organes respiratoires des

larves des Odonates. (Horæ Soc. Ent. Ross., xv, 1880, pp. 436–452, 2

Pls.)

=Viallanes, H.= Sur l’appareil respiratoire de quelques larves de

Diptères. (Compt. rend. Acad. Sc., Paris, 1880, pp. 1180–1182.)

=MacLeod, J.= La structure des trachées et la circulation

peritrachéenne. Bruxelles, 1880, pp. 70, 4 Pls.

=Hagen, H. A.= Beitrag zur Kenntnis des Tracheensystems der

Libellenlarven. (Zool. Anzeiger, 1880, pp. 157–162.)

—— Einwürfe gegen Palmens Ansicht von der Entstehung des geschlossenen

Tracheensystems. (Ibid., 1881, pp. 404–406.)

=Macloskie, G.= The structure of the tracheæ of insects. (Amer.

Naturalist, 1884, xviii, pp. 567–573, Fig.)

=Haase, E.= Das Respirationssystem der Chilopoden und Symphylen

(Scolopendrellen) vergleichen mit dem der Hexapoden. (Zeitschr. f.

Ent. N. F., ix, Breslau, 1884.)

—— Das Respirationssystem der Symphylen und Chilopoden. (Zool.

Beiträge, von A. Schneider, i, 1884, pp. 65–95, 3 Taf.; Zool.

Anzeiger, 1883, pp. 15–17.)

=Grassi, B.= I progenitori degli Insetti e dei Miriapodi. L’Japyx e la

Campodea. (Atti d. Accad. Gioenia d. Sc. Nat. Catania, 1885, Sér. 3,

xix, pp. 83, 5 Pls.)

—— I progenitori dei Miriapodi e degli Insetti. Anatomia comparata dei

Tisanuri. (Reale Accad. d. Lincei di Roma, Anno 284, 1887.)

=Meinert, Fr.= De eucephale Myggelarver. Sur les larves eucephales des

Diptères. (Vidensk. Selsk. Skrifter., 6 Raekke, naturvid. og mathem.

Afd. Kjöbenhavn, 1886, iv, pp. 369–493, 4 Pls.)

=Cajal, S. R.= Coloration par la méthode de Golgi des terminaisons des

trachées et des nerfs dans les muscles des ailes des insectes.

(Zeitschr. f. wiss. Microscopie, 1890, vii, pp. 332–342, 1 Pl.)

=Wistinghausen, C. v.= Ueber Tracheenendigungen in den Sericterien der

Raupen. (Zeitschr. wissensch. Zool., xlix, 1890, pp. 565–582, 1

Taf.)

=Stokes, Alfred C.= The structure of insect tracheæ, etc. (Science,

1893, pp. 44–46, 7 Figs.)

=Sadones, J.= L’appareil digestif et respiratoire larvaire des

Odonates. (La Cellule, xi, 1895, pp. 271–325, 3 Pls.)

=Holmgren, Emil.= Über das respiratorische Epithel der Tracheen bei

Raupen. (Festschrift Lilljeborg. Upsala, 1896, pp. 76–79, 2 Taf.)

See also Dewitz, p. 482; Kolbe, p. 482.

THE ORGANS OF REPRODUCTION

Insects are without exception unisexual, the male and female organs

existing in different individuals, no insects being normally

hermaphroditic. The reproductive organs are situated in the hind-body or

abdomen, especially near the end, the genital glands opening externally

either in the space between the 7th and 8th, or 8th and 9th, or 9th and

10th abdominal segments, but as a rule between the 8th and 9th segments

(Fig. 299).

The primary or essential male organs are the testes, those of the female

being the ovaries. As we shall see, the primitive number of seminal

ducts and oviducts was two, this number being still retained in Lepisma

and the Ephemeridæ. The reproductive organs of both sexes are at first,

in their embryonic condition, of the same shape and structure, becoming

differentiated in form and function before sexual maturity. These glands

and ducts have a paired mesodermal genital rudiment, the ends of the

ducts being often connected with corresponding ectodermal invaginations

of the cuticle.

The secondary sexual organs mainly comprise the external genital

armature of the male, and the egg-laying organs, or ovipositor of the

female. Besides these structures there are other more superficial

secondary sexual characters, such as differences in the size and

ornamentation as well as coloring of the body, or of parts of it.

The primary sexual organs of insects have been conveniently tabulated by

Kolbe, thus:—

I. _Male reproductive organs._

1. Two testes, with testicular follicles.

2. Seminal ducts (_vasa deferentia_).

3. Seminal vesicle.

4. Accessory glands.

5. The common seminal outlet, with the penis.

6. The copulatory apparatus.

II. _Female reproductive organs._

1. Two ovaries, with the egg-tubes.

2. Two oviducts.

3. Receptaculum seminis; bursa copulatrix.

4. Accessory sac.

5. The common oviduct, vagina, uterus.

6. The ovipositor.

The ducts of the sexual glands in Peripatus being transformed

nephridia or segmental organs, it has been inferred that this is

also the case with those of insects, though, as Lang states, there

is a considerable difference in the two cases, as the greater part

of the ducts in Peripatus arises out of the ectoderm, while in the

Myriopoda and insects they come from the mesoderm; but he adds that

in the Annelids the greater part of the nephridial duct is of

mesodermal origin.

While in insects there is but a single pair of genital outlets, the

serial arrangement of the testicular (Fig. 458) and egg-tubes (Fig. 459)

in some Thysanura (Campodea, Japyx, and Lepisma), where the tubes (5 to

7 on each side) open singly one behind the other in segmental

succession, indicates that in their ancestors these egg-tubes opened out

on different segments situated one behind the other. Each egg-tube

independently opens into one of the two oviducts, which extend through

the abdomen as straight canals. The two oviducts open externally by a

short unpaired terminal portion, which in Machilis is said to be

wanting, only the outer aperture of the two oviducts being in this case

common to both. In Campodea and in the Collembola the ovaries and testes

on each side are simply tubes. It is to be observed that in the young

Lepisma Nassonow found that the external openings of the two ejaculatory

ducts are paired (Fig. 458 _B_, _ed._).

[Illustration:

FIG. 458.—Male genital organs of Thysanura: _A_, Lepisma in which the

testes are segmentally arranged.—After Grassi. _B_, _Lepisma

saccharina_, young ♂: _vd_, vas deferens; _ed_, ejaculatory duct;

_ga_, external appendages,—After Nassonow. _C_, Machilis, the testis

lateral and separate, but not corresponding to the segments. _D_,

Japyx, with an undivided testicular tube on each side; _tt_, testes;

_cd_, vas deferens; _vs_, seminal vesicle; _ce_, ejaculatory

duct.—After Grassi, from Perrier.

]

In the Stylopidæ, also, though this may be the result of adaptation

to the singular parasitic habits of the females whose bodies are

mostly situated in the abdomen of their host, the ends of the

oviducts are formed by the invagination of the integument of the 2d,

3d, and 4th abdominal segments. In the 2d to 5th segments are

situated tubes which open in the cavity of the body with funnel-like

ends, so that the ducts have a close resemblance to the segmental

organs of worms. (Nassonow.)

[Illustration:

FIG. 459.—Ovaries of Thysanura: _A_, of Campodea. _B_, of Japyx.—After

Grassi. _C_, of Machilis.—After Oudemans, from Sharp.

]

[Illustration:

FIG. 460.—Female genital organs of _Lepisma saccharina_, adult: _ov_,

ovaries; _a_, part of the oviduct, corresponding to the calyx of

winged insects; _od_, oviduct; _vg_, vagina; _rs_, copulatory pouch;

_gg_, accessory glands; _m_, muscles; _n_, nervous cord.—After

Nassonow, from Perrier.

]

Among the winged insects the reproductive organs of the cricket (Fig.

466) are perhaps as simple as any. The testes are separate, and the vasa

deferentia very long. The seminal vesicles bear numerous large and short

utricles (_utriculi majores_ and _breviores_), the penis being simple

and dilated at the end; while in _Phyllodromia germanica_ the testes are

functional throughout life, and consist of four lobes each. In the

common cockroach (_P. orientalis_) (Fig. 461) the testes are functional

only in the young male; they afterwards shrivel and are functionally

replaced by the vesiculæ seminales and their appendages, when the later

transformations of the sperm-cells are effected. The accessory glands

are numerous and differ both in function and insertion. Two sets of

these glands (utriculi majores and breviores) are attached to the

vesiculæ seminales and the fore end of the ejaculatory duct, while

another appendage, called by Miall and Denny the _conglobate gland_,

opens separately on the exterior upon a double hook, which forms a part

of the external genital armature. The so-called penis is long, slender,

and dilated at the end, but is not perforated.

[Illustration:

FIG. 461.—_A_, male organs of the cockroach, ventral view: _Ts_,

testis; _VD_, vas deferens; _DE_, ductus ejaculatorius; _U_,

utriculi majores; _u_, utriculi breviores; 2, dorsal view; 3, _CG_,

conglobate gland and its duct. _B_, male organs, side view: _A_,

titillator; _B_, penis; other letters as in _A_.—After Miall and

Denny.

]

In the locusts (Acrydiidæ) the testes are, unlike those of most other

Orthoptera, closely united to each other so as to form a single mass of

tubular glands into which penetrate both simple and dilated tracheæ; the

entire mass is situated in the 3d, 4th, and 5th abdominal segments, and

above the intestine. The anterior end of the testicular mass is rounded

and held in place by a broad, thin band, one on each side; two similar

bands are situated a little behind the middle of the mass. From the

under side, and a little in advance of the middle of the mass, two

straight small ducts, as long as the testicular mass, pass obliquely to

the sides of the body, at the posterior end of the 7th segment of the

abdomen; these are the vasa deferentia. Each vas deferens, with its

mate, forms a convoluted mass of tubes, comprising twenty folded bundles

(_epididymis_ of Dufour), and two single, long, convoluted tubes, the

_vesiculæ seminales_, which are lobed in the 6th and 7th segments of the

abdomen. The two vesiculæ unite over the 5th abdominal ganglion, forming

a thick, very short canal (_ductus ejaculatorius_), which passes into a

large spherical muscular mass (præputium), behind which is the large

intromittent organ (_penis_), which forms a short chitinous cylinder,

quite complicated in structure, being armed with hooks and projections

and affording excellent specific characters. It can be seen in place

without dissection by drawing back the orbicular convex piece called the

_velum penis_.

In the Hymenoptera the reproductive system is quite simple, as seen in

Fig. 462.

[Illustration:

FIG. 462.—Male organs of saw-fly (Athalia centifoliæ): _a_, _a_,

testes; _b_, _b_, epididymis; _c_, _d_, vas deferentia; _e_,

vesiculæ seminales; _f_, ductus ejaculatorius; _h_, penis (see also

p. 180).—After Newport.

]

The general shape and relations of the female reproductive organs are

seen in Fig. 298, of the locust (Acrydiidæ). The ovaries consist of two

large bundles of tubes, each bundle tied to the other by slight bands,

with air-sacs and tracheæ ramifying among them. These tubes extend along

the intestine, passing into the prothorax. The ovarian tubes opening

into the oviducts unite to form the vagina, which lies on the floor of

the abdomen. (In the cockroach the vagina has a muscular wall and

chitinous lining.) Above the opening of the duct, and directly

communicating with it, is the copulatory pouch (_bursa copulatrix_), a

capacious pocket lined within with several narrow, longitudinal,

chitinous bands. Behind the bursa copulatrix lies, partly resting under

the fifth abdominal ganglion, the sebific, cement, or colleterial gland

(_colleterium_; compare Fig. 299, _sb_), which is flattened,

pear-shaped, a little over half as long as a ripe egg of the same

insect. From the under side, a little in advance of the middle, arises

the sebific duct, which, after making three tight coils next to the

ganglion, passes back and empties into the upper side of the bursa

copulatrix, dilating slightly before its junction with the latter.

The most primitive type of reproductive organs observed in insects is

that of the young Lepisma and the Ephemeridæ, in which the outlets of

the oviducts and of the vasa deferentia respectively are double or

paired, showing that insects have probably inherited these structures

from the segmental organs of their vermian ancestors.

Réaumur had already observed the process of oviposition and seen that

the female Ephemera had two openings near the end of the “6th” abdominal

segment, from which he saw two masses of eggs pass out at a time (Fig.

463). Eaton afterwards (1871) referred to the oviducts as terminating

between the 7th and 8th segments of the abdomen, and after him Joly; but

for a detailed monograph on the subject we are indebted to Palmén. He

found that the outlets of the sexual glands are paired, not only in the

larvæ of all stages, but also in the imagines, and in both sexes. In the

males the vasa deferentia pass on the ventral side of the 9th segment

through two external appendages, both reproductive organs, at whose tips

or sides the openings are situated. In the larvæ the female openings are

not formed until after the last moult. In the females the two oviducts

open on the ventral side of the hind-body between the 7th and 8th

segments.

[Illustration:

FIG. 463.—Upturned end of body of Ephemera, with two egg-masses (_o_)

issuing at the same time from the double oviducts; _q_, anus.—After

Réaumur.

]

Palmén suggests that the Ephemerids represent, in respect to the

reproductive system among insects, a very primitive type of

organization, and he concludes that the inner sexual organs of insects

are built up of two different morphological elements; _i.e._ (_a_)

internal primitive paired structures (testes with vasa deferentia,

ovaria with oviducts), and (_b_) integumental structures, such as the

ductus ejaculatorius and vagina.

In the younger larvæ the vasa deferentia form slender cords along which

are situated the seminal glands; these cords are inserted in the

integument on the hinder edge of the 9th sternite, where afterwards,

during the last moult, the copulatory organs grow out. In the older

larvæ the sperm collects in the cavities of these cords. Their walls

become expanded, and this section then functions as vesiculæ seminales.

The ends of the cords remain contracted and act as ductus ejaculatorii.

Common unpaired glandular structures are not present. At the last moult

the copulatory organs reach their complete development, and the ducts

become open externally.

The oviducts in the larva are at first slender, string-like, and bear

the egg-follicles. As soon as the eggs pass out of the follicles and

collect in the oviducts, the walls of the latter become stretched, and

this portion forms two uterus-like structures. The terminal division of

the two passages forms their vaginal portions. But since there is no

common vagina, there are no unpaired glands and no receptaculum seminis.

The two ducts become open after the last shedding of the skin.

Palmén adds that this paired or double nature of the sexual glands and

their external ducts in this group of insects occurs in some Myriopoda

(Fig. 3, _E_, _F_) and a few Arachnida (Fig. 3, _C_, _D_, the outlets

being in this class unpaired), numerous Crustacea, and most worms; and

as already stated it is very marked in Limulus, where the paired outlets

are in both sexes very simple and wide apart (Fig. 3, _A_). In the worms

the paired genital ducts are modified segmental organs. As we have seen,

in the young male Lepisma there are two male genital openings. Hence

this double nature of the genital passages in the may-flies seems to be

very primitive.

In the Dermaptera, also, the genus Labidura was found by Meinert to have

two independent ductus ejaculatorii, opening externally in double

external slit-like processes (_penes_). The two ducts arise from a

single seminal vesicle, which is either paired (_L. advena_), or forms a

common passage (_L. gigantea_). In Forficula (Fig. 464, _B_) only one

ejaculatory duct persists, the other is obliterated, and one of the

penes is atrophied, the other assuming a position in the middle line of

the body. Thus the single ejaculatory duct and seminal vesicle arise

from the primitive vasa deferentia, and not from the integument of the

body, as is the case in the following examples.

According to the researches of Dufour, Loew, etc., most species of

Orthoptera (Œdipoda), Libellula, Perla, Panorpa, Rhaphidia,

Myrmeleon, Sialis, and Trichoptera (Hydropsyche) have double vasa

deferentia and seminal vesicles, and two ejaculatory ducts. The male

genital passages of Rhaphidia have a double opening, Loew describing

“the two seminal vesicles as lying near each other and at last

uniting in a common passage, with an external opening, which,

however, must be very short, since I could only once clearly observe

it.” This opening is a deep invagination of the external integument,

at the bottom of which the two ducts open independently of each

other. In such insects, Palmén states that the single ejaculatory

duct morphologically arises by an invagination of the integument.

In another group, forming, as regards the genital apparatus, a step

next above the Ephemeridæ, viz. the Perlidæ, the oviducts open near

each other at the bottom of a median single “vagina,” situated

between the 7th and 8th abdominal segment; it is covered beneath by

a valve-like, enlarged sternite of the preceding segment, and Palmén

homologizes it with the ovi-valvula of some Ephemeridæ. He regards

this bell-shaped vagina as a cup-like, deep, intersegmental fold,

which projects into the body-cavity and there receives the two

ducts.

This differentiation in the Perlidæ may be regarded as the type for

several groups of insects. But in others occur a complication which

in some degree modifies the type. Thus the invagination arises out

from one segment alone, but several segments during metamorphosis

may become so reduced that the ventral portions of all may be

invaginated to form the vagina. Thus in the larva of Corethra,

according to Leydig, and also Weismann, the two testes are attached

by two cords to the integument; the hinder ones are inserted

independently, and share in the development of the outlets.

Graber has observed the same relations in the pupa of Chironomus,

the efferent genital tubes in both sexes being separate, so that

there are two vaginal passages and two penes present. Palmén

comments on these relations in the dipterous insects, remarking that

during metamorphosis certain parts of the terminal abdominal

segments are reduced, while others are hypertrophied; hence the

points of insertion of the cords referred to becoming the openings

of the vasa are carried within the abdomen; and this part of the

integument becomes an unpaired section. In these insects, also,

there is an unpaired vesicula seminalis, but its morphological

nature (whether formed from the integumental duct or the fused vasa

deferentia) can only be settled after special investigation.

In the Lepidoptera, also, it has been shown by Herold, Suckow,

Bessels, and recently with full details by Jackson, that the paired

larval oviducts are at first solid, but become tubular early in

pupal life. A little later, their cavities open into that of the

azygos or unpaired oviduct. The paired oviducts open in the female

caterpillars on the hind edge of the 7th abdominal segment,

afterwards uniting with the unpaired vagina of the 8th segment,

which is developed from the hypodermis.

Jackson adds that there are three stages traceable in the evolution

of the genital ducts of Lepidoptera: “an ephemeridal stage, which

ends towards the close of larval life; an orthopteran stage,

indicated during the quiescent period preceding pupation; and a

lepidopteran stage, which begins with the commencement of pupal

life.”

As a summary of these results it appears that the genital organs of

insects consist of two morphologically different elements: 1. the

primitive internal paired structures (testes with the vasa deferentia;

ovaries with the ovarian tubes), and 2. integumental structures (Fig.

464). In the most primitive winged insects (Ephemeridæ) the latter

structures are only represented by the two external sexual openings, the

entire reproductive system being paired. The paired parts become in the

more highly differentiated forms united into single parts, while, _a_, a

common integumental division, grows in, forming the ductus

ejaculatorius, or the vagina; or, _b_, the inner passages anastomose

together, _i.e._ the openings fuse together; or, _c_, both of these

cases occur at once; or, finally, we have _d_, where the superfluous

paired parts by reduction become single.

[Illustration:

FIG. 464.—Evolution of the unpaired from the paired sexual organs of

insects: _A-E_, male organs. The parts arising by invagination of

the integument indicated by thick black lines. _A_, an Ephemerid.

_B_, _Forficula auricularia_. _C_, nymph of Orthoptera in general.

_D_, Œdipoda. _E_, _Cetonia aurata_. _F_, female organs of

Æschna.—After Palmén, from Lang.

]

The male ducts open behind the 9th, the female passages of Ephemerids

behind the 7th abdominal segment, those of other insects behind the 8th,

except in the Stylopidæ (Strepsiptera), in which they open much in

front.

Figure 464 graphically shows their relation. In the Odonata (_F_) the

chitinous lining or integumental invagination extends inwards where the

two oviducts begin, in the Coleoptera (_E_) the vagina, bursa

copulatrix, and receptaculum seminis being lined by a thick chitinous

layer. While in Perla the two seminal ducts pass directly into the

copulatory organ, in the Coleoptera they open into the unpaired ductus

ejaculatorius at a distance from the copulatory organ.

The morphological results obtained by Palmén, and for the Lepidoptera by

Jackson, were apparently confirmed from an embryological point of view

by Nusbaum, from observations on the development of the sexual passages

in two genera of Pediculidæ, and are as follows:—

1. The prevalent impression that the larval ducts unite with each

other and give origin to the whole system of sexual ducts is

incorrect; they form only the vasa deferentia or the oviducts.

2. All other parts of the efferent apparatus (uterus, vagina,

receptaculum seminis, ductus ejaculatorius, penis, and appended

glands) develop from the hypodermis.

3. The connective tissue and the musculature of the efferent

apparatus are derived from mesoblast cells present in the

body-cavity.

4. The efferent ducts originate as paired rudiments. All unpaired

(azygos) parts (uterus, penis, receptaculum seminis, unpaired

glands, etc.) are at first paired. The unpaired efferent apparatus

of insects must therefore be regarded as morphologically a secondary

and more complicated form.[76]

5. The male and female efferent ducts are strictly homologous.

6. The cavities of the oviducts, uterus, vagina in the female, of

the vasa deferentia, appended organs, and ductus ejaculatorius of

the male arise independently, and come into connection secondarily.

The presence of two genital openings, viz. a bursa copulatrix or

copulatory pouch, and of the primitive oviducal orifice behind the

9th segment, is peculiar to Lepidoptera, and the inquiry naturally

arises whether they represent the outlets of two pairs of segmental

organs. The question has been fully set at rest, however, by

Jackson, who shows that the copulatory pouch is a secondary

invagination of the ectoderm, being derived from the hypodermis,

while the second aperture is a special adaptation. It is, however,

the partial homologue of the vaginal orifice in other orders of

insects. It opens behind the sternite of the 8th abdominal segment,

the typical position of the vaginal aperture as shown by

Lacaze-Duthiers. The lateral position of the bursa and its

separation from the azygos oviduct are probably late features in the

phylogenetic history of the Lepidoptera, subsequent even to the

closure of the furrow.

“The existence of a second or posterior aperture is probably to be

attributed to the advantage gained by a terminal position for the

aperture through which the ova are laid. The remarkable way in which

this aperture shifts backwards seems to point very distinctly to

this explanation, especially as the Lepidoptera are entirely devoid

of the outgrowths which form the ovipositor in some orders; _e.g._

most Orthoptera.”

The original condition of things appears to have been retained in a

moth, _Nematois metallicus_, which, according to Cholodkowsky,

possesses but a single external aperture, the bursa opening into the

dorsal wall of the unpaired oviduct.

_a._ The male organs of reproduction

Bearing in mind that the testes with their efferent ducts are, like the

ovaries and egg-tubes, primitive structures, there are various secondary

or adaptive structures which are either due (1) to modifications of the

male efferent ducts, or of the ovarian tubes, or (2) to various

accessory organs, mostly glandular, resulting from the invagination of

the ectoderm.

[Illustration:

FIG. 465.—_A_, diagram of male sexual organs of Carabus. _B_, of

Blaps. _C_, of Hydrophilus. The heavy black lines represent the

ectodermal organs; _t_, testis; _a. g._, accessory glands.—After

Escherich.

]

The male organs are, then, the following:—

1. Two testes (Figs. 465–469, _t_, _H_, _ho_).

2. The two seminal ducts (_vasa deferentia_, _v_, _sl_, _SL_), whose

lower or outer (distal) division becomes enlarged and acts as a seminal

vesicle (_vesicula seminalis_; Figs. 467–469, _bl_, _SB_).

3. The common ejaculatory duct (_ductus ejaculatorius_), with the penis

(Figs. 467–469, _ag_, _uSG_).

4. Accessory glands at the base of the vasa deferentia (_glandulæ

mucosæ_, Figs. 465–469, _a. g._, _dr_, _D_), whose secretion mixes with

the semen or serves for the formation of the seminal packets

(sematophores).

In his paper on the internal male organs of beetles, Escherich

states that those of the Carabidæ illustrate the simplest, most

primitive condition (Fig. 465). A simple blind tube on each side

produces spermatozoa, stores the elements, and secretes mucus. Each

of these tubes opens into a somewhat larger duct, and the two unite

in a common ejaculatory canal. The terminal portion in these beetles

is lined with chitin, and is therefore ectodermal, and not the

result of the union of the mesodermic vasa deferentia. The region

corresponding to the testes, vasa deferentia, and seminal vesicles

are mesodermic. Blaps (Fig. 465, _B_) is intermediate between the

Carabidæ and Hydrophilus (Fig. 465, _C_). The accessory glands (_a.

g._) are developed, and the seminal vesicles are situated in the

middle, and not at the lower end of the vasa deferentia, as in

Hydrophilus.

=The testes.=—Each testis is composed of follicles or corresponding

parts, which according to the group of insects in which they occur are

united in different ways; or each testis consists of a single hank or

skein-like blind tube which is enveloped by a membrane, as in the

Carabidæ, Dyticidæ, or Lucanidæ.

[Illustration:

FIG. 466.—_t_, testis; _v_, vas deferens; _g_, seminal vesicle of

_Acheta campestris_.—After Carus, from Gegenbaur.

]

[Illustration:

FIG. 467.—Male sexual apparatus of a bark-beetle: _sl_, vas deferens;

_ho_, testis; _bl_, seminal vesicle; _dr_, accessory gland; _ag_,

ductus ejaculatorius.—After Graber.

]

The number of testicular tubes is small in most Hemiptera, but very

great in the Cicadidæ, Orthoptera, Coleoptera, and many Hymenoptera.

Although the testes are usually separated from each other, they are

closely united in certain Orthoptera (Gryllotalpa, Ephippigera),

Coleoptera (Galerucella), in many Lepidoptera, and in a number of

Hymenoptera (Scolia, Pompilus, Crabro, and others).

The two testes of most Lepidoptera are so closely grown together or

coalesced into a single body that one might regard them as a single

testis. But in the different families there occur all grades, from the

unpaired testes of most Lepidoptera to Hepialus with separate testes.

Cholodkowsky therefore distinguishes four types:—

1. The embryonal or primitive type, with two testes, whose seminal

follicles are entirely separate. (Brandt.) These testes are

contained, as in all other Lepidoptera, in a well-developed thick

chitinous membrane or scrotum, analogous to that of the higher

vertebrates, which envelops each separate seminal follicle

(_Hepialus humuli_).

2. The larval type, with two testes, whose four follicles are

enclosed by a common scrotal membrane (_Bombyx mori_, _Gastropacha

quercifolia_, _Ichthyura anachoreta_ and _anastomosis_, _Saturnia

pyri_, _Aglia tau_).

3. The pupal type (since it first occurs in the pupa state), with a

single testis, which possesses an external median lace-like

covering. (Adela, Lycæna.)

4. The imaginal type, with a single testis enveloped by a lace-like

scrotum, within which the follicles are wound around the

longitudinal axis of the testis. (Most Lepidoptera.)

In Nematois there are twenty seminal follicles, the number of

ovarian tubes being the same. (Cholodkowsky.)

In many insects the testes are not composed of tubes (follicles),

but of button-like bodies, each of which has its own duct.

The color of the testes is usually white, but they may be orange

(Decticus), yellowish green (_Locusta viridissima_), or deep yellow

(Chrysopa).

The testes of Asilid flies are enveloped by a common dark-red

membrane rich in tracheæ, like that in Lepidoptera which clothes the

separate testicular follicles. The two testes of Calliphora are

enveloped by an orange-yellow capsule, outside of which is a special

membrane formed by the fat-body. (Cholodkowsky.)

In the honey-bee the testis has two envelopes, the outer of which is

formed by the fat-body, the inner coat of connective tissue. The

entire testis corresponds to a portion only of that of _Bombyx

mori_.

[Illustration:

FIG. 468.—Male organs of a weevil, _Hylobius abietis_: _H_, testis;

_SL_, vas deferens; _D_, slime gland; _SB_, seminal vesicle; _uSG_,

ejaculatory duct.

]

[Illustration:

FIG. 469.—Male organs of Tomicus. Lettering same as in Fig. 468.—This

and Fig. 468 from Judeich and Nitsche.

]

=The seminal ducts.=—The vasa deferentia are fine tubes, which vary much

in length; being short in many beetles and locusts, very short in many

Diptera (Syrphidæ, etc.), very long in Cicada and many beetles;

according to Burmeister, being in Dyticus about five times, in

Necrophorus and Blaps eight to ten times, in Cicada 14 times, in

_Cetonia aurata_ 30 times, as long as the body. They either resemble a

skein of silk, or form a tangled mass.

The distal or lower end of the vasa is in many insects dilated into a

sac or seminal vesicle, which serves for the reception and storage of

the seminal fluid after it passes through the vasa deferentia. In the

honey-bee the vas deferens is given off from the reservoir, forms loops

in and outside of the testis, and passes to the seminal vesicle. The

canal into which the vesicle narrows does not open into the ductus

ejaculatorius, but into the glandulæ mucosæ; its epithelial cells are

much vacuolated, and have, therefore, a spongy appearance.

(Koschewnikoff.)

[Illustration:

FIG. 470.—_A_, spermatozoön of a beetle (Copris), partly macerated to

show structure of flagellum, which consists of a supporting fibre

(_s.f_) and a fin-like envelope (_f_); _n_, nucleus; _a_, _a_,

apical body divided into two parts. _B_, anterior part of that of

Calathus, with barbed head and finmembrane.—After Ballowitz, from

Wilson.

]

=The ejaculatory duct= during coition conducts the sperm into the

copulatory pouch of the female. In consequence of the stretching of the

integumental membrane the end of the duct can be erected and again

withdrawn. For this purpose the end of the duct is thickened and is said

to be provided with powerful muscles. The evaginable terminal portion is

covered by a strong chitinous membrane forming the penis or intromittent

organ (Fig: 462, _h_), which is externally enveloped by a pair of

chitinous lobes, which in many beetles are converted into a capsule. The

ductus ejaculatorius of the honey-bee is inserted by two chitinous

branches into the point of union of the two glandulæ mucosæ; it and the

entire copulatory apparatus are devoid of muscles, though it is,

however, well developed beneath the mucous glands. (Koschewnikoff.)

=The accessory glands= of the vasa deferentia are tubes whose secretions

either directly mix with the semen, or in many cases form seminal

packets (_spermatophores_). In Coleoptera, Lepidoptera, and Diptera

there is usually one pair. In many insects there are several pairs, as

in Hydrophilidæ and Elateridæ; they are branched in Hemiptera, and in

Orthoptera bushy. The single glandular tubules are very long, and form a

skein-like mass. In Orthoptera, in the larger number of accessory

glands, two forms may be distinguished, which differ from each other in

their contents (Siebold). In the cockroach (Fig. 461) these glands form

the “mushroom” shaped gland of Huxley, which was at first regarded as

the testis.

=The spermatozoa.=—These very minute bodies, the sexual homologues of

the eggs, abound in the seminal fluid, and are formed in the follicles

of the testes from a germinal layer or epithelium, as are the eggs. They

are hair- or thread-like, usually consisting of a head, a body or

middle-piece, and a long, thread-like tail (flagellum), which vibrates

rapidly, causing the spermatozoön to move actively forwards (Fig. 470).

In beetles, according to Ballowitz, there are two main types of

spermatozoa, connected, however, by intermediate forms. There is a

double-tailed type, already described by Bütschli and v. la Valette

St. George, and there are others which are single-tailed. Bütschli

showed that in the double spermatozoön one tail-filament is straight

and stiff, the other being undulating and contractile. Ballowitz

describes this type in Calathus (Fig. 470, _B_), Chrysomela, and

Hylobius, etc., and shows that the straight or supporting portion of

the tail is elastic, but somewhat stiff, resistant to reagents, and

without any fibrillar structure, while the contractile fringe

consists of an extremely complicated system of fibrils (Fig. 470).

The single-tailed type of spermatozoön, as seen, _e.g._, in

Melolontha and Hydrophilus, has no supporting fibres. The tail is

twisted in a spiral, corresponds to the contractile fringe of the

double type, and exhibits a complicated fibrillar structure. The

fringed type works its way ahead like the screw of a steamer.

[Illustration:

FIG. 471.—_C_, anterior end of spermatid of a moth (Pygæra). _D_,

young spermatozoön of the same; _af_, axial filament; _c_,

centrosome; _m_, middle-piece or _mitosoma_; _n_, nucleus; _p_,

paranucleus; _e_, envelope of the tail.—After Platner, from Wilson.

]

Each spermatozoön is a modified but complete cell, and the nucleus

contains the chromatin, a deeply staining substance of the nuclear

network and of the chromosomes and the supposed bearer of heredity.

=Formation of the spermatozoön.=—It arises from a primordial germcell

called _spermatogonium_. This cell contains a large, pale nucleus and a

dark body, the accessory nucleus of Bütschli. The _spermatogonia_

subdivide, but at a certain period pause in their subdivisions, and

undergo considerable growth. “Each spermatogonium is thus converted into

a _spermatocyte_, which, by two rapidly succeeding divisions gives rise

to four spermatozoa, as follows: The primary spermatocyte first divides

to form two daughter-cells, known as spermatocytes of the second order,

or sperm mother-cells. Each of these divides again—as a rule without

pausing, and without the reconstruction of the daughter-nuclei—to form

two _spermatids_ or sperm-cells. Each of the four spermatids is then

directly transformed into a single spermatozoön; its nucleus becoming

very small and compact, its cytoplasm giving rise to the tail and to

certain other structures.... As the spermatid develops into the

spermatozoön, it assumes an elongated form, the nucleus lying at one

end, while the cytoplasm is drawn out to form the flagellum at the

opposite end.” (Wilson’s The Cell, from La Valette St. George.)

Henking finds that the primordial sperm-cells correspond to the

primordial ova, both forms of cells in the insect he studied containing

the characteristic number of twenty-four chromosomes.

The spermatogenesis of Laphria, according to Cholodkowsky, is very

peculiar, and strongly resembles that described by Verson in _Bombyx

mori_. In the blind end of the testicular tubes lies a colossal cell

visible to the naked eye, the spermatogone, from which the entire

contents of the testes originate. In Bombyx this spermatogone

appears in the larva state. Such colossal spermatogones also occur

in Lepidoptera of different families (Hyponomeuta, Vanessa, and in

the pupa of _Chareas graminis_), in Trichoptera, and in Hemiptera

(Syromastes); and Cholodkowsky inquires whether they may not be

typical of insects. Toyama has observed these colossal cells not

only in the testes but also in the ovaries of the silkworm. He

regards them as supporting cells.

The spermatozoa are inclined to remain in bundles, and in this state are

expelled during copulation. These bundles are either root-like, bushy,

string-like, sinuous, or worm-like.

Auerbach has observed the spermatozoa of _Dyticus marginalis_ in

their passage through the convoluted seminal vesicles. All those

arising from one testicular tube are united in a bundle. Each has a

very complex structure, bilateral but unsymmetrical. The right side

of the head is concave, the left convex; the whole head is

longitudinally curved to right or left; and on the posterior half of

the right side there is a projecting ridge bearing a hook-shaped

cyanophilous “anchor,” at the free end of which an erythrophilous

spherule appears. The most remarkable fact is that the spermatozoa

unite in pairs in a perfectly definite way, opposed and crossed in a

manner somewhat suggestive of a pair of scissors, with the right

sides of the heads in contact. During this conjugation, or

“dejugation” as Auerbach calls it, the anchors change their shape,

and the little spherules are lost. Hundreds of these double

spermatozoa are found together in little balls. The conjugation is a

temporary one, but it may permit a molecular exchange of substance,

perhaps with the result of mixing the hereditary qualities and

limiting variability. (Journ. Roy. Micr. Soc., 1893, p. 622.)

In many insects which lack a true penis, the bundle of spermatozoa are

united in the ejaculatory duct, forming packets which are enveloped by

the secretion of the accessory glands which stiffens into a hard case.

These packets are called _spermatophores_. They are either introduced

into the vagina of the female or simply remain outside. Graber has

repeatedly observed that the male crickets, in the absence of the

female, let their spermatophores fall to the earth; whether it is

afterwards made available is not known, because hitherto no case is

reported that females seeking impregnation search, as in the case of the

Isopod crustacean, Porcellio, for the spermatophores.

In the Gryllidæ and Locustidæ the spermatophore lies in a cup-like

cavity under the penis. This is called the “spermatophore cup”

(Chadima, 1871), into which the ejaculatory duct of the testis

opens.

According to the views of Schneider, the spermatophores, with their

capsule, usually consist solely of seminal filaments, which stick

closely to each other, and only exceptionally have a capsule formed

by a glandular secretion. In Locusta, however, and perhaps also in

Gryllus, the sperm is enveloped by the secretion of the accessory

glands of the seminal ducts; the spermatophores pass, still fluid,

out of the sexual opening of the male into that of the female, but

become chilled on the outer surface, so that the sperm, without

coming in contact with the air, passes into the receptaculum

seminis.

The mode of grouping of the spermatozoa of the Locustidæ as they

occur in the spermatheca of the female is remarkable. Their heads

lie so close to each other that they form a long shaft, while the

numerous threads are arranged so as to look like the two vanes of a

feather, the entire mass being like a very long heron’s feather.

(Siebold.)

In the honey-bee the spermatophore is likewise enveloped by the

secretion of the accessory glands, and thereby becomes a sort of

seminal cartridge. This is a peculiar oval body which is carried

during the marriage-flight into the air within the upper part of the

penis, the so-called penis-bulb. (Leuckart.)

_b._ The female organs of reproduction

The different parts of the female reproductive organs are the following:

1. The two ovaries.

2. The two oviducts.

[Illustration:

FIG. 472.—Female organs of generation of a saw-fly (_Athalia

centifoliæ_): _a_, _b_, _c_, the 18 ovarial tubes originating from

each of the two oviducts (_d_), and containing the immature eggs;

_e_, common oviduct; _f_, spermatheca; _g_, poison-sac; _h_,

poison-glands; 10, last ganglion.—After Newport.

]

3. The common egg-passage in nearly all insects (its distal or

hindermost part forming the uterus or vagina).

4. The receptaculum seminis, or spermatheca.

5. The bursa copulatrix, or copulatory pouch.

6. The accessory glands (cement, sebific, or colleterial glands, or “oil

reservoirs,” glandulæ sebaceæ, coleterium).

=The ovaries and the ovarian tubes.=—As in the testes, so each ovary

consists of a variable number of ovarian tubes, by some called

_ovarioles_, united by a thread at the distal end, and at the lower or

hinder end opening into the oviduct. Each ovarian or egg tube is divided

into three sections: (1) the terminal thread; (2) the terminal chamber,

and (3) the actual ovarian tube, or chambered main division, this

forming the longest part of the egg-tube.

The slender terminal thread serves to attach or suspend each egg-tube

near the dorsal vessel (not directly to the heart, as formerly

supposed), becoming lost in the fat-body.

[Illustration:

FIG. 473.—Ovarian tube of _P. orientalis_: _A_, section near the end;

_tf_, base of terminal filament. _B_, section lower down; _ec_,

egg-cells in egg-chamber.—After Brandt.

]

The terminal chamber contains undifferentiated cell elements, supposed

to be the remains of the ovarian rudiments. From these arise (either in

the embryo or larva) first, the follicle epithelium of the ovarian

tubes; and, second, the material for the formation of the new eggs, and

nutritive cells. “In the terminal chamber these cell-elements remain

undifferentiated, excepting when required for the removal of the

follicle epithelium, eggs, and nutritive cells in the adult insect.”

(Lang.) This portion of the ovariole is called the _germarium_. In

Blatta it is filled with protoplasm in which numerous small nuclei are

imbedded. (Wheeler.) The chambered main division of the egg-tube

contains the ripening eggs, one in each compartment, the tube appearing

like a string of beads.

The egg-tubes are of two types: (1) those without, and (2) those with

nutritive cells, the first kind being the simplest, and occurring in the

Synaptera (except Campodea) and in Orthoptera. As an example may be

cited that of the cockroach (Fig. 473), where in each tube there is a

simple continuous row of eggs from the terminal chamber to the oviduct.

The tube being constricted between these consecutive eggs, gives it a

beaded appearance.

In the cockroach (_Periplaneta orientalis_) each egg-tube has a

beaded appearance. Its wall consists of a transparent elastic

membrane, lined by epithelium, with an external peritoneal layer of

connective tissue. The terminal filament (_tf_) is filled with a

clear protoplasm, with a few nuclei. In the terminal chamber (_tc_)

are large nucleated cells, with separate nuclei, both entangled in a

network of protoplasm. In the third, or egg-chamber (_ec_), are

about twenty ripening eggs, arranged in a single row. “Between and

around the eggs the nuclei gradually arrange themselves into

one-layered follicles, which are attached, not to the wall of the

tubes, but to the eggs, and travel downwards with them. As the eggs

descend, the yolk which they contain increases rapidly, and the

germinal vesicle and spot (nucleus and nucleolus), which were at

first plain, disappear. A vitelline membrane is secreted by the

inner surface and a chitinous chorion by the outer surface of the

egg-follicle.

“The lowest egg in an ovarian tube is nearly or altogether of the

full size; it is of elongate-oval figure, and slightly curved, the

convexity being turned towards the uterus. It is filled with a clear

albuminous fluid, which mainly consists of yolk. The chorion now

forms a transparent yellowish capsule, which, under the microscope,

appears to be divided up into very many polygonal areas, defined by

rows of fine dots. These areas probably correspond to as many

follicular cells.” (Brandt, from Miall and Denny.)

In the second type, _i.e._ those egg-tubes with nutritive cells,

there are two kinds. In the first the egg-chambers and yolk- or

nutritive chambers alternate, each of the latter containing one or

more nutritive cells, which serve for the nourishment of the

ripening egg contained in the neighboring chamber. “The egg- and

yolk-chambers may be distinctly separated externally by

constrictions (Hymenoptera and many Coleoptera), or one nutritive

and one egg-chamber may lie in each section of the ovarian tube,

which is externally visible as a swelling (Lepidoptera, Diptera).”

In the second kind with nutritive cells, the actual tube consists

(Fig. 474, _C_) of ovarian chambers only; the nutritive cells here

remain massed together in the large terminal chamber. The single egg

in the tube is united with the terminal chamber by connective

strands (_d. s._), which convey the nutritive material to the eggs.

(Lang.)

Egg-cells, nutritive cells, and the cells of the follicle-epithelium

(epithelium of the chambers of the ovarian tubes) are, says Lang,

according to their origin, similar elements, like the egg and

yolk-cells of the flat worms (Platodes); division of labor leads to

their later differentiation. Only a few of the numerous egg-germs

develop into eggs, the rest serving as envelopes and as food for

these few.

Korschelt considers that all the chief elements of the egg-tubes,

viz. egg, nutritive, and epithelial cells, arise by a direct

transformation of the elements of the terminal chamber, and that the

last may be traced to the indifferent elements of the terminal

thread, the elements in question originating from the nuclear

elements by a breaking down of the syncytium (or masses of

protoplasm with nuclei scattered through it) composing it (Fig.

475).

The latest work is that of Wielowiejski (Zoologische Anzeiger, ix,

1886, p. 132), whose observations are based on a study of the

ovarian tubes and the growing eggs of the Hemiptera (Pyrrhocoris),

the Coleoptera (Telephorus, Saperda, Cetonia and Melolontha,

Carabidæ, and Hydradephaga), etc.

Wielowiejski divides the ovaries of insects into three groups:—

1. Comprising such ovaries in the ends of whose egg-tubes (terminal

filament) the embryonal cells in the early stages are accumulated,

and are transformed into egg-, yolk-, and epithelial cells

respectively. (Ovaries of Orthoptera, geodephagous and

hydradephagous Coleoptera, Lepidoptera, Diptera, and Hymenoptera).

2. Comprising ovaries whose ends above the egg-cells and egg-germs

(_Eianlagen_) possess throughout life a more or less voluminous

solid accumulation of cells (terminal chamber), but which stand in

no close relation with the first. (Ovaries of Coleoptera, with the

exception of the Geodephaga and Hydradephaga, and Aphidæ in part.)

[Illustration:

FIG. 474.—Various types of ovarian tubes, diagrammatic: _A_, ovarian

tube without nutritive cells. _B_, egg-tube with alternating

nutritive and egg-compartments. _C_, ovarian tubes in which the

terminal chamber (_ek_) is developed into a nutritive chamber,

with which the developing eggs remain connected by means of

threads (_ds_); _ef_, terminal filaments; _efa_, egg compartments

or chambers; _fe_, follicle epithelium; _df_, yolk-chambers.—After

Lang (_C_ from Claus).

]

[Illustration:

FIG. 475.—Upper portion of the ovary in Forficula, showing eggs and

nurse-cells; below, a portion of the nearly ripe egg (_e_) showing

deutoplasm-spheres and germinal vesicle (_gv_). Above it lies the

nurse-cell (n), with its enormous branching nucleus. Two

successively younger stages of egg and nurse-cell are shown

above.—After Korschelt, from Wilson.

]

[Illustration:

FIG. 476.—_A_, ovarian egg of a butterfly (Vanessa), surrounded by

its follicle; above are the nurse-cells (_n. c._), with branching

nuclei; _g.v_, germinal vesicle. _B_, egg of Dyticus, living; the

egg (_o.v._) lies between two groups of nutritive cells; the

germinal vesicle sends amœboid processes into the dark mass of

food-granules.—After Korschelt, from Wilson.

]

[Illustration:

FIG. 477.—A, lower portion of one of the two ovaries of _Sphinx

ligustri_, the four egg-tubes uniting to form the slightly

developed calyx (_ov_). The egg-tubes above contain ripe eggs

still surrounded by the follicle; _e. c_, the empty egg-chamber.

Beyond the empty egg-chambers (_e. c_) are three egg-chambers with

ripe eggs and the connecting cord. The whole tube is surrounded by

the peritoneal membrane and musculature.—After Korschelt.

]

3. Comprising ovaries whose ends above the egg-germs contain a

well-developed mass of cells functioning as a yolk-forming organ,

between whose special elements grow root-like offshoots of nearly

ripe egg-cells. (Hemiptera.)

[Illustration:

FIG. 478.—Ovary of a beetle, drawn somewhat diagrammatically: _o_,

egg-tube; _s_, stalk of the same; _c_, egg-calyx; _ov_,

oviduct.—After Korschelt.

]

When the egg is ripe the food-chamber disappears because its contents

have served for the formation of the egg below it. In Lepidoptera

especially, the egg-tubes resemble strings of pearls because most of the

numerous eggs ripen simultaneously and are likewise deposited at the

same period, which is naturally not the case in those insects whose eggs

gradually ripen (Fig. 477). In other cases the egg- or food-compartments

are transformed into each other, but only one egg- and one

food-compartment can be situated in the same dilatation of the ovarian

tube. Finally, there are insects in whose egg-tubes the egg-compartments

are arranged in a single row, while the capacious terminal chamber

contains a large mass of food-cells.

Egg-cells, nutritive cells, as well as the cells of the follicle

epithelium (epithelium of the chambers of the ovarian tubes), originate

as similar or homologous elements, division of labor leading to their

later differentiation. Only a few of the numerous egg-germs develop into

eggs, the rest serving as envelopes and also as food for these few.

(Lang.)

In many insects the egg-tubes open into an egg-calyx (Fig. 478, _c_), in

which the ripe eggs collect before passing into the oviduct (_ov_).

As the result of his investigations on the origin of the cellular

elements of the ovaries of insects Korschelt concludes:—

1. The different cell-elements of the egg-tubes, eggs, nutritive

cells, and epithelium arise from identical undifferentiated elements

situated in the contents of the earliest germ of the egg-tubes.

2. The first formation of the cellular elements present, and the

differentiation of the individual compartments of the egg-tube,

occur during embryonic and larval life.

3. The undifferentiated elements of the terminal chamber correspond

to the embryonic condition, while in post-embryonic time, and even

during imaginal life, a new formation of the different kinds of

cells takes place.

4. The mode of origin of the different kinds of cells from the

undifferentiated elements varies greatly in different insects.

5. From their histological nature, and from the mode of origin of

their elements, the most complex egg-tubes and those provided with

nutritive compartments are phylogenetically derived from those

without such nutritive compartments.

6. The nutritive cells in certain cases originate in the same way

and at the same time as the germ-cells, and are therefore to be

regarded as germ-cells which have abandoned the function of

egg-making, and exchanged it for the production of nutritive

material.

7. In the egg-tubes with numerous nutritive compartments the

nutritive cells can originate at the same place as the egg-cells,

and they afterwards still lie intermingled with these in the

beginning or upper part of the egg-tubes.

8. While the capability of egg-making of the germ-cells originally

situated in the extremity of the terminal chamber gradually becomes

transferred to those at the base of the terminal chamber, and the

first transform into nutritive cells, egg-tubes with nutritive

compartments at the base may be found.

9. The nutritive cells of certain forms arise independently of the

germ-cells and therefore could not have previously originated from

them.

10. The epithelium has in all forms nearly the same mode of

formation; it everywhere shows a close similarity to the

undifferentiated elements of the terminal chamber, out of which it

directly develops. As to the fact of formation of epithelium through

the germ-vesicles (_Keimblaschen_), nutritive-cell nuclei, or the

so-called “oöblasts,” I could not feel certain.

11. Neither the eggs of Hemiptera or of other insects arise through

the agency of “oöblasts,” but like the epithelial and nutritive

cells arise by a gradual differentiation from the indifferent

elements of the ovarian tubes.

12. The different elements of the egg-tubes, also the eggs, have the

morphological value of cells.

=Origin of incipient eggs in the germ of the testes.=—Heymons has

detected in the germ of the testes of the male larvæ of

_Phyllodromia germanica_ 7 mm. in length, young or incipient eggs,

similar to those seen in the ovarian tubes of the female larva of

the same size. In another male larva of the same size also occurred

short cylindrical tubes each with a terminal thread, which had the

appearance of rudimentary egg-tubes. Hence he thinks that every part

of the genital germs (_Anlagen_) in the male, which are not

concerned in the formation of testicular follicles, represents the

germ of a female genital gland. As is well known, no insects are

hermaphroditic, but this case of the practical origin of eggs and

egg-tubes in the lowest division of the male efferent passage, which

is homologous with the egg-producing division of the female ovarian

tubes, points back to hermaphroditic ancestors. And Heymons suggests

that the frequent occurrence of hermaphroditism in insects probably

confirms this view.

[Illustration:

FIG. 479.—Abdomen of queen bee, under side, × 8: _P_, petiole; _o_,

_o_, ovaries; _hs_, position filled by honey-sac; _ds_, place

through which the digestive canal passes; _od_, oviduct; _co.d_,

common oviduct; _E_, egg passing oviduct; _s_, spermatheca; _i_,

intestine: _pb_, poison-bag; _p.g_, poison-gland; _st_, sting; _p_,

palpi. _B_, vestigial ovaries of ordinary worker; _sp_, vestigial

spermatheca. _C_, partially developed ovaries of fertile worker;

_sp_, vestigial spermatheca.—After Cheshire.

]

=The bursa copulatrix.=—The copulatory pouch in most insects is a

special cup-shaped appendage of the vagina adapted for the reception of

the male organ during sexual union. Its mode of formation in the

cockroach is thus described by Haase:—

“By the retreat of the female sexual aperture, situated in the 8th

ventral plate, a considerable space, the genital pouch, is produced;

this is formed chiefly by the extended connective membrane between the

elongated 7th and 8th ventral plates. This serves for the development of

the egg-cocoon, which is retained by the internal appendages of the

posterior gonapophyses.”

The fertilization of the female takes place once for all a long time

previous to oviposition; the semen in the receptaculum seminis passes

out as the eggs slip down the egg-passage, and a spermatozoön gains

entrance into the interior of the egg through the micropyle. In

Œcanthus, according to Ayers, fecundation probably takes place while the

egg is passing into the vagina, “since it is hardly possible that the

male element could gain access to the follicles before the chorion is

secreted.”

In the Lepidoptera, as has been stated, the copulatory pouch opens

separately from the opening of the oviduct (vagina), but a slender canal

connects the pouch with the vagina (Fig. 310, _bc_). The outlet

(“vagina” of Burgess) of the copulatory pouch opens between the 7th and

8th segments, that of the oviduct (vagina) on the 9th segment being

“situated immediately below the anus and hardly separated from it,

between the lappets of the 9th segment.” (Burgess.) The opening of the

copulatory pouch is, as we have seen, the genuine or primitive sexual

opening.

[Illustration:

FIG. 480.—Spermatheca of the honey-bee, queen, × 40: _a_, space filled

by a clear fluid; _b_, mass of spermatozoa; _c_, duct; _d_, _d_,

active spermatozoa.— After Cheshire.

]

[Illustration:

FIG. 481.—Female sexual organs of Scolytus: _ER_, egg-tubes; _pEL_,

paired oviducts; _ST_, spermatheca; _BT_, copulatory pouch; _KD_,

cement-glands; _Sch_, vagina.—After Lindeman, from Judeich and

Nitsche.

]

=The spermatheca.=—This is a sac or pouch for the reception and storage

or preservation of the semen. While in most of the higher insects it

opens into the dorsal wall of the vagina (Fig. 472, _f_), in the

cockroach, locusts, and grasshoppers it opens into the bursa; but in

other European Orthoptera, as in most insects, it lies upon the dorsal

wall of the vagina. (Berlese.) In the cockroach, it is a short tube

dilated at the end and wound into a spiral of about one turn. “From the

tube a cœcal process is given off, which may correspond with the

accessory gland attached to the duct of the spermatheca in many insects

(_e.g._ Coleoptera, Hymenoptera, and some Lepidoptera). The spermatheca

is filled during copulation, and is always found to contain spermatozoa

in the fertile female. The spermatozoa are no doubt passed into the

genital pouch from time to time, and there fertilize the eggs descending

from the ovarian tubes.” In Meloë the spermatheca is exceedingly large.

(Miall and Denny, pp. 170, 171.)

=The colleterial glands.=—We have already briefly referred to these

glands. Those of the cockroaches form a number of long blind tubes

opening into the vagina. They furnish the material for the egg-capsule

or oötheca, viz. chitin and large crystals of oxalate of lime.

In _Phyllodromia germanica_ “these glands are glistening white till

the time of oviposition approaches, when they assume a yellow tint,

and the octahedral crystals are seen imbedded in a viscid substance

which fills their lumina. This viscid substance is soluble in

potassium hydrate, and is consequently not chitin. When excreted to

form the oötheca, it slowly hardens, deepens in color, and becomes

insoluble in potassium hydrate. Light has nothing to do with this

change, which is possibly produced by the oxygen in the air. It is

the same change which is undergone by the cuticula of the insect

itself immediately after ecdysis.” (Wheeler.)

=The vagina or uterus.=—This is simply the end of the common oviduct,

which, when dilated, is called the vagina, and, in the pupiparous forms,

the uterus.

In the cockroach the vagina opens by a median vertical slit situated in

the 8th sternite, into the genital pouch or bursa, upon the dorsal wall

of which the orifice of the spermatheca is situated. In the sheep-tick

the oviduct is enlarged to form the so-called uterus, which furnishes a

milk-like secretion for the nourishment of the larva during its

intra-uterine life.

In insects in general, the external opening of the vagina is simple, the

chitinous structures (valves) at the opening being adapted to receive

the male intromittent organ.

When the eggs are to be deposited deep below the surface of the earth,

or in wood, or in wood-boring larvæ, or in the body of caterpillars,

etc., they are inserted by the ovipositor (see p. 167).

_Signs of copulation in insects._—Leydig has collected, partly from

his own observations and partly from those of others, a number of

cases in which female insects bear traces of having had sexual

union, in the form of tags or plates attached to the body, and

apparently formed from material secreted by the male. Such probably

is the “pouch” on the abdomen of _Parnassius apollo_, and a somewhat

similar structure in _Fulgora laternaria_, and such is the plate

which is found on the hinder part of the abdomen of _Dyticus

latissimus_ and _D. marginalis_. Leydig compares these structures

with the white plate in _Astacus fluviatilis_, and with the little

white lid on the spider Argenna, and finds analogues among

vertebrates. (Arbeit. Zool. Zoot. Inst. Wurzburg, x, 1891, pp.

37–55, 2 Figs.)

LITERATURE ON THE ORGANS OF REPRODUCTION

_a._ General

=Hunter, J.= Observations of bees. (Phil. Trans. Roy. Soc. London,

1792, lxxxii, pp. 128–195.)

=Hegetschweiler, J. J.= Dissertatio inauguralis zootomica de

insectorum genitalibus. Turici, 1820, pp. 28, 1 Pl.

=Audouin, V.= Recherches anatomiques sur la femelle du Drile jaunatre

et sur le male de cette espèce. (Ann. Sc. nat., ii, 1824, pp.

443–462, 1 Pl.)

=Müller, Johannes.= Ueber die Entwickelung der Eier im Eierstock bei

den Gespenstheuschrecken. (Nova Acta Acad. Leop.-Carol., xii, 1825,

pp. 555–672, 6 Taf.)

=Dufour, L.= Recherches anatomiques sur les Carabiques et sur

plusieurs autres insectes coléoptères. Organes de la génération

(Ann. Sc. nat., vi, 1825, pp. 150–206, 6 Pls.; pp. 427–468, 4 Pls.).

—— Recherches anatomiques sur l’Hippobosque des cheveaux. (Ibid.,

1825, vi, pp. 299–322, 1 Pl.)

—— Recherches anatomiques sur les Labidoures. Appareil de la

génération. (Ibid., 1828, xiii, pp. 354–359, 2 Pls.)

—— Recherches anatomiques et considérations entomologiques sur

quelques insectes coléoptères, compris dans les familles des

Dermestins, des Byrrhiens, des Acanthopodes et des Leptodactyles.

Appareil génital. (Ibid., Sér. 2, Zool. i, 1834, pp. 76–82, 2 Pls.)

—— Résumé des recherches anatomiques et physiologiques sur les

Hémiptères. (Ibid., Sér. 2, i, pp. 232–239.)

—— Mémoire sur les métamorphoses et l’anatomie de la _Pyrochroa

coccinea_. Appareil génital. (Ibid., Sér. 2, Zool., xiii, pp.

337–339, 1 Pl.)

—— Histoire des métamorphoses et de l’anatomie des Mordelles. (Ibid.,

Sér. 2, xiv, pp. 235–238, 1 Pl.)

—— Anatomie générale des Diptères. Appareil génital. (Ibid., Sér. 3,

Zool., i, 1844, pp. 250–264.)

—— Histoire des métamorphoses et de l’anatomie du _Piophila

petasionis_. Appareil génital. (Ibid., Sér. 3, Zool., i, 1844, pp.

378–386.)

—— Études anatomiques et physiologiques sur les insectes diptères de

la famille des Pupipares. Appareil génital. (Ann. Sc. nat., Sér. 3,

Zool., iii, 1845, pp. 73–93, 2 Pls.)

—— Recherches sur l’anatomie et l’histoire naturelle de _l’Osmylus

maculatus_. Appareil génital. (Ibid., Sér. 3, Zool., ix, 1848, pp.

349–356, 1 Pl.)

—— Recherches anatomiques sur les Hyménoptères de la famille des

Urocerates. Appareil génital. (Ibid., Sér. 4, Zool., i, 1854, pp.

216–234, 1 Pl.)

—— Fragments d’anatomie entomologique. Sur les ovaires du _Nemoptera

lusitanica_. (Ibid., Sér. 4, viii, 1857, pp. 9–10, 1 Pl.)

—— Fragments anatomiques sur quelques Élatérides. (Ibid., Sér. 4,

viii, 1857, pp. 365–372, 1 Pl.)

—— Recherches anatomiques et considérations entomologiques sur les

Hémiptères du genre Leptopus. Appareil génital. (Ibid., Sér. 10,

1858, pp. 356–362, 1 Pl.)

—— Recherches anatomiques sur _l’Ascalaphus meridionalis_. Appareil

génital. (Ibid., Sér. 4, xiii, 1860, pp. 203–206, 1 Pl.)

—— Sur l’appareil génital male du _Coræbus bifasciatus_. (Thomson’s

Archiv Ent., 1857, i, pp. 378–381.)

=Suckow, F. W. L.= Geschlechtsorgane der Insekten. (Heusinger’s

Zeitschr. f. organ. Physik., 1828, ii, pp. 231–264, 1 Taf.)

=Rathke, M. H.= Miscellanea anatomico-physiologica. Fasc. 1. De

Libellarum partibus genitalibus. Regiomonti, 1832, p. 38, 3 Pls.

=Dutrochet, R. J. H.= Observations sur les organes de la génération

chez les pucerons. (Ann. Sc. nat., 1833, xxx, pp. 204–209.)

=Doyère, L.= Observations anatomiques sur les organes de la génération

chez la Cigale femelle. (Ann. Sc. nat., 1837, vii, pp. 200–206,

Fig.)

=Siebold, C. Th. E. von.= Ueber die weiblichen Geschlechtsorgane der

Tachinen. (Wiegmann’s Archiv f. Naturgesch., 1838, iv, pp. 191–201.)

—— Ueber die inneren Geschlechtswerkzeuge der viviparen und oviparen

Blattläuse. (Froriep’s Notizen, 1839, xii, pp. 305–308.)

—— Ueber das Receptaculum seminis der Hymenopteren-Weibchen. (Germar’s

Zeitschr. f. Ent., 1843, iv, pp. 362–388, 1 Taf.)

=Loew, H.= Beitrag zur anatomischen Kenntniss der inneren

Geschlechtsteile der zweiflügligen Insekten. (Germar’s Zeitschr. f.

Ent., 1841, iii, pp. 386–406, 1 Taf.)

—— Horæ anatomicæ, Abth. I. Entomotomien. Heft i-iii, Posen, 1841.

—— Beiträge zur Kenntniss d. inneren Geschlechtstheile der zweifl.

Insecten. (Germar’s Zeitschr. f. Entomologie, iii, 1841, pp.

386–406, 1 Taf.)

=Stein, F.= Vergleichende Anatomie und Physiologie der Insekten. I,

Monographie. Ueber die Geschlechtsorgane und den Bau des

Hinterleibes bei den weiblichen Käfern, Berlin, 1847, i, pp. 139, 9

Taf.

=Brauer, F.= Beitrag zur Kenntniss des inneren Baues und der

Verwandlung der Neuropteren. (Verhandl. d. zool. botan., Vereins in

Wien, 1855, pp. 1–26, 5 Taf.)

=Haliday, A. H.= Note on a peculiar form of the ovaries observed in a

hymenopterous insect, constituting a new genus and species of the

family Diapriadæ. (Nat. Hist. Review, 1857, iv, pp. 166–174, 1 Pl.)

=Laboulbène, A.= Recherches sur les appareil de la digestion et de la

reproduction du _Buprestis manca_. (Thomson’s Archiv Ent., 1857, i,

pp. 204–236, 2 Pls.)

=Lubbock, John.= On the ova and pseudova of insects. (Phil. Trans.

Roy. Soc., London, cxlix, 1860, pp. 341–369.)

=Landois, H.= Ueber die Verbindung der Hoden mit dem Rückengefäss bei

den Insekten. (Zeitschr. f. wissens. Zool., xiii, 1863, pp. 316–318,

1 Taf.)

=Leydig, F.= Der Eierstock und die Samentasche der Insekten. (Nova

Acta Acad. Leop.-Carol., xxxiii, 1867, pp. 88, 5 Taf.)

—— Beiträge zur Kenntniss des thierischen Eies im unbefruchteten

Zustande. (Spengel’s Zool. Jahrbücher, 1889. Abth. f. Anat., iii,

pp. 287–432, 7 Taf.)

=Bessels, E.= Studien über die Entwicklung der sexual Drüsen bei den

Lepidopteren. (Zeitschr. wissens. Zool., xvii, 1867, pp. 545–563.)

=Rajewsky.= Ueber die Geschlechtsorgane von _Blatta orientalis_, etc.

(Nachr. d. k. Gesellschaft d. Moskauer Universität, xvi, 1875.

Testes of cockroach. In Russian; for abstract, see Hoffmann u.

Schwalbe, Jahresbericht, 1875, p. 425.)

=Brehm, Siegfr.= Comparative structure of the reproductive organs in

_Blatta germanica_ and _Periplaneta orientalis_. (Horæ Ent. Soc.

Rossicæ, St. Petersburg, viii, 1880.) (In Russian, male organs

only.)

=Cholodkowsky, N. A.= Ueber die Hoden der Schmetterlinge. (Zool.

Anzeiger, iii Jahrg., 1880, pp. 115–117.)

—— Ueber den Bau der Testikel bei Schmetterlingen. (Zool. Anzeiger,

1880, iii, pp. 214–215.)

—— Ueber die Hoden der Lepidopteren. (Zool. Anzeiger, 1884, pp.

564–568.)

—— Ueber den Geschlechtsapparat von _Nematois metallicus_. (Zeitschr.

f. wissens. Zool., xliii, pp. 559–568, 1885.)

=Tichomirow, A.= Ueber den Bau der Sexualdrüsen und die Entwickelung

der Sexualprodukte bei _Bombyx mori_. (Zool. Anzeiger, iii, 1880,

pp. 235–237.)

=Nusbaum, F.= Zur Entwicklungsgeschichte der Ausführungsgange der

Sexualdrüsen bei den Insekten. (Zool. Anzeiger, v, 1882, pp.

637–643.)

——On the developmental history of the efferent passages of the sexual

glands in insects. Lemberg, 1884 (in Czech).

=Berlese, Ant.= Ricerde sugli organi genitali degli ortotteri. (Atti

della R. Acad. dei Lincei. Ser 3, xi, 1882.) (Genital organs of

European Orthoptera.)

=Balbiani, G.= Le Phylloxera du chêne et le Phylloxera de la vigne.

Paris, 1884, pp. 45, 11 Pls.

—— Contribution à l’étude de la formation des organes sexuel chez les

insectes. (Recueil Zool. Suisse, 1885.)

=Schneider, Anton.= Die Entwicklung der Geschlechtsorgane bei den

Insekten. Zool. Beiträge, Breslau, i, 1885.

=Beauregard, H.= Recherches sur les insectes vésicants. Suite.

(Journal Anat. Phys., Paris, 1887, xxii Année, pp. 528–548, 1 Pl.;

xxiii Année, pp. 124–163, 6 Pls.)

—— Les insectes vésicants. Paris, 1890. Chap. v, Appareil de la

génération, pp. 103–159, Pls. 10–12.

=Nassonow, N.= Études morphologiques sur les Lepisma, Campodea et

Podura. (Mém. Soc. Imp. Anthropologie et d’Ethn. Moscou, iii, 1887,

pp. 85, 2 Pls., 68 Figs.)

—— _Xenos rossii_; seine Anatomie und Entwicklungsgeschichte. (Bull.

de l’Université de Varsovie, 1892, pp. 74, 2 Taf.) (In Russian.)

—— Position des Strepsiptères dans le systeme selon les données du

développement post-embryonal et de l’anatomie, p. 11, Warsaw, 1892.

=Grassi, B. J.= Progenitori dei Miriapodi e degli Insetti. Memoria

vii, Anatomia comparata dei Tisanuri. (Atti d. R. Acad. de’ Lincei,

Cl. scienc. e fis., Serie 4, iv, 1888, pp. 435–606, 5 Pls.)

=Heymons, R.= Ueber die hermaphroditsche Anlage der Sexualdrüsen beim

Mannchen von _Phyllodromia germanica_. (Zool. Anzeiger, 1890, pp.

451–457.)

=Koschewnikoff, G.= Zur Anatomie der männlichen Geschlechtsorgane der

Honigbiene. (Zool. Anzeiger, xiv, 1891, pp. 393–396.)

=Verhoeff, C.= (See p. 186.)

=Ingenitzky, J.= Zur Kenntniss der Begattungsorgane der Libelluliden.

(Zool. Anzeiger, 1893, xvi Jahrg., pp. 405–407, 2 Figs.)

—— On the fauna and organization of dragon-flies of Russian Poland,

1893, 1 Pl. (In Russian.)

=Escherich, K.= Anatomische Studien über das männliche Genitalsystem

der Coleopteren. (Zeitschr. f. wissens. Zool., lvii, pp. 620–641,

1894.)

=Kluge, Max H. E.= Das männliche Geschlechtsorgan von _Vespa

germanica_. Inaug. Diss. Leipzig, 1895, pp. 1–45, 1 Taf.

=Verson, E.= La borsa copulatrice nei Lepidotteri (Atti e Mem. Accad.

Sc. Lett. ed Arti, Padova, 1896, xii, pp. 369–372, 4 Pls.).

=Klapálek, Fr.= Über die Geschlechtstheile der Plecopteren, mit

besonderer Rücksicht auf die Morphologie der Genitalanhänge.

(Sitzungsb. k. Akad. Wissens. Wien. Math.-Naturw. Cl., cv, 1896, pp.

56, 5 Taf.)

=Fenard, A.= Recherches sur les organes complémentaires internes de

l’appareil génital des Orthoptères. (Bull. Sc. France Belg., xxix,

1897, pp. 390–527, 528–533, 5 Pls.)

Consult also the Works of Ayres, Balfour, Burgess, Burmeister,

Bütschli, Claus, Dzierzon, Gensch, Henking, Honert, Huxley, Kluge,

Kramer, Landois, Leuckart (art. Zeugung), Leydig, Ludwig,

Metschnikoff, H. Meyer, Minot, Müller, Pfitzner, Schneider,

Seeliger, Scholz, Siebold, Suckow, Swammerdam, Tichomiroff, Wagner,

Waldeyer, Weismann, Wheeler, v. Wielowiejski, Will, Witlaczil, and

Ziegler.

_b._ Formation of the egg (oögenesis)

=Claus, C.= Beobachtungen über die Bildung des Insekteneies.

(Zeitschr. wissens. Zool., xiv, 1864, pp. 42–54.)

=Brandt, A.= Ueber die Eiröhren der _Blatta orientalis_. (Mém. Acad.

Imp. Scienc. de St. Petersbourg, Sér. 7, xxi, 1874, p. 30.)

—— Vergleichende Untersuchungen über die Eiröhren und die Eier der

Insekten. (Nachr. d. Gesellsch. Freunde d. naturwiss. Moskau, xxiii,

1876; also xxiv, 1877, pp. 77–79.)

—— Das Ei und seine Bildungsstatte. Ein vergleichenden-morphologischer

Versuch mit Zugrundelegung der Insecteneies. Leipzig, 1878.

=Kadyi, H.= Beiträge zur Vorgänge beim Eierlegen der _Blatta

orientalis_. Vorläufige Mittheilung. (Zool. Anzeiger, 1879, pp.

632–636.) (Formation of the egg-capsules of cockroach.)

=Brass, Arn.= Das Ovarium und der Eibildung und der ersten

Entwicklungsstadien bei viviparen Aphiden. Halle, 1883. (Zeits. f.

Naturwiss. in Halle, Jahrg. 1882.)

—— Zur Kenntniss der männlichen Geschlechtsorgane der Dipteren. (Zool.

Anzeiger, 1892, pp. 178–180.)

=Will, Ludvig.= Zur Bildung der Eies und des Blastoderms bei den

viviparen Aphiden. (Arbeiten Zool. Inst. Univ. Würzburg, vi, 1882,

pp. 217–258.)

=Korschelt, E.= Zur Frage nach dem Ursprung der verschiedenen

Zellenelemente der Insectenovarien. (Zool. Anzeiger, 1885, pp.

581–586, 599–605.)

=Wielowiejski, H. V.= Zur Morphologie des Insektenovariums. (Zool.

Anzeiger, 1886, ix Jahrgang, pp. 132–139.)

—— Zur Kenntniss der Eibildung bei der Feuerwanze (_Pyrrhocoris

apterus_). (Zool. Anzeiger, 1885, pp. 369–375.)

=Blochmann, F.= Ueber die Richtungskörper bei Insekteneiern. (Morph.

Jahrb., 1887, xii, ix 544.)

Also the writings of Leydig (p. 509).

_c._ On the spermatozoa

=Treviranus, G. R.= Ueber die organischen Körper des tierischen Samens

und deren Analogie mit dem Pollen der Pflanzen. (Zeitschr. f. d.

Physiologie, von F. Tiedemann, G. R. und L. C. Treviranus, 1835, v,

pp. 136–153, 2 Taf.)

=Siebold, C. Th. E. von.= Ueber die Spermatozoen der Crustaceen,

Insekten, Gasteropoden und einiger anderer wirbellosen Tiere.

(Müller’s Archiv f. Anatomie, 1836, pp. 13–52, 2 Taf.)

—— Fernere Beobachtungen über die Spermatozoen der wirbellosen Tiere.

(Ibid., 1836, p. 232; 1837, pp. 381–432, 1 Taf.)

—— Ueber die Spermatozoen der wirbellosen Tiere, iv. (Ibid. 1837, pp.

392–433.)

—— Lange Lebensdauer der Spermatozoen bei _Vespa rufa_. (Wiegmann’s

Archiv f. Naturgesch., 1839, v, pp. 107, 108.)

—— Ueber die Spermatozoiden der Locustinen. (Nova Acta Acad.

Leop.-Carol., 1845, xxi, pp. 249–274, 1 Pl.)

=Kölliker, A.= Beiträge zur Kenntnis der Geschlechtsverhältnisse und

der Samenflüssigkeit wirbelloser Tiere, nebst einem Versuch über das

Wesen und die Bedeutung der sogenannten Samentiere, Berlin, 1841,

pp. 88, 3 Taf.

—— Die Bildung der Samenfaden in Bläschen als allgemeines

Bildungsgesetz. (Neue Denkschr. d. allg. Schweiz. Ges., viii, 1847,

pp. 28, 3 Taf.)

—— Physiologische Studien über die Samenflüssigkeit. (Zeitschr. f.

wissens. Zool., vii, 1856, pp. 201–272, 1 Taf.)

=Yersin, A.= Observations sur le _Gryllus campestris_. (Bull. Soc.

Vaudoise sc. nat., 1853, iii, pp. 128.)

=Lespès, Ch.= Mémoire sur les spermatophores des grillons. (Ann. Sc.

nat., Sér. 4, iii, 1855, pp. 366–377, 1 Pl.; iv, pp. 244–249, 1 Pl.)

=Landois, H.= Entwicklung der büschelförmigen Spermatozoiden bei den

Lepidopteren. (Schultze’s Archiv f. Anat. u. Physiol., 1866, pp.

50–58, 1 Taf.)

=Bütschli, O.= Vorlaufige Mitteilungen über Bau und Entwicklung der

Samenfaden bei Insekten und Crustaceen. (Zeitschr. f. wissens.

Zool., xxi, 1871, pp. 402–415.)

=Bütschli, O.= Nähere Mitteilungen über die Entwicklung und den Bau

der Samenfaden der Insekten. (Ibid., xxi, 1871, pp. 526–534, 2 Taf.)

=La Vallette St. George, A. V.= Ueber die Genese der Samenkörper, III.

Mitteilung. (Archiv f. Mikroscop. Anat., 1874, x, pp. 495–504, 1

Taf.)

—— Spermatologische Beitrage: II. Mitteilung (Ibid., 1886, xxvii, pp.

1–122 Taf.). IV. Mitteilung (Ibid., 1886, xxviii, pp. 1–13, 4 Taf.)

V. Mitteilung (Ibid., 1887, xxx, pp. 426–434, 1 Taf.)

=Schneider, A.= Das Ei und seine Befruchtung, pp. 88, 10 Taf.;

Arthropoden, pp. 57–68 und 79. Taf. 8–10, 1883.

=Wielowiejski, H. de.= Observations sur la spermatogénèse des

Arthropodes. (Archiv Slav. de Biologie, 1886, ii, pp. 28–36.)

=Ballowitz, E.= Zur Lehre von der Struktur der Spermatozoen. (Anat.

Anzeiger, i Jahrg., 1886, pp. 363–376.)

—— Untersuchungen über die Struktur der Spermatozoen, zugleiche in

Beitrag zur Lehre von feineren Bau der kontraktilen Elemente. Die

Spermatozoen der Insekten. I. Coleopteren. (Zeitschr. f. wissensch.

Zool., 1, 1890, pp. 317–407, 4 Taf.)

—— Zu der Mittheilung des Herrn Professor L. Auerbach in Breslau über

merkwürdiger Vorgänger am Sperma von _Dytiscus marginalis_. (Anat.

Anzeiger, 1893, viii Jahrg., pp. 505–506.)

—— Die Doppelspermatozoen der Dyticiden. (Zeitschr. f. wissensch.

Zool., lxvi, 1895, pp. 458–499, 5 Taf.)

=Beauregard, H.= Note sur la spermatogénèse chez la cantharide.

(Compt.-rend. Soc. Biol., Paris, 1888, iv, pp. 331–333.)

=Gilson, G.= Étude comparée de la spermatogénèse chez les Arthropodes,

in La Cellule, Recueil de Cytologie et d’Histologie gén., i, 1888, 8

Pl.

=Verson, E.= Zur Spermatogenesis. (Zool. Anzeiger, xii Jahrg., 1889,

pp. 100–103, Fig.)

—— La spermatogenesi nel _Bombyx mori_. (Padova, 1889, 25 pp. und 3

Taf.)

—— Zur spermatogenesis. (Zool. Anzeiger, xii, 1889, pp. 100–103.)

—— Zur spermatogenesis bei der Seidenraupe. (Zeitschr. f. wissens.

Zool., lviii, 1894, pp. 303–313, 1 Taf.)

=Henking, H.= Ueber Reductionsteilung der Chromosomen in den

Samenzellen von Insekten. (Internat. Monatsschr. f. Anat. und Phys.,

1890, vii, pp. 243–248.)

—— I. Untersuchungen über die erste Entwicklungsorgänge in der Eiern

der Insekten. II. Ueber Spermatogenese und deren Beziehung zur

Eientwickelung bei _Pyrrhocoris apterus_. (Zeits. wissens. Zool.,

xlix, 1890, pp. 503–564; li, 1891, pp. 685–736.) III. Specielles und

Allgemeines. (Ibid., 1892, liv, pp. 1–274, 12 Taf.)

=Sabatier, A.= De la spermatogénèse chez les Locustides. (Comptes

rend. Acad. Paris, 1890, cxi, p. 797.)

=Cholodkowsky, N.= Zur Frage über die Anfangsstadien der

Spermatogenese bei den Insecten. (Zool. Anzeiger, 1894, pp.

302–304.) See also Zool. Anzeiger, 1892, p. 179.

=Auerbach, Leopold.= Ueber merkwürdige Vorgänge am Sperma von

_Dytiscus marginalis_. (Sitz. Ber. Akad., Berlin, 1893, pp. 185–203,

2 Figs.)

—— Zu dem Bemerkungen des Herrn Dr. Ballowitz betreffend das Sperma

von _Dytiscus marginalis_. (Anat. Anzeiger, viii Jahrg., 1893, pp.

627–630.)

=Toyama, K.= On the spermatogenesis of the silkworm. (Bull, ii, No. 3,

Coll. Agric. Imp. Univ. Tokyo, pp. 125–157, 1894, 2 Pls.)

=Wilcox, E. V.= Spermatogenesis of _Caloptenus femur-rubrum_ and

_Cicada tibicen_. (Bull. Mus. Comp. Zool., xxvii, 1895, pp. 32, 5

Pls.)

—— Further studies on the spermatogenesis of _Caloptenus

femur-rubrum_. (Ibid., xxix, 1896, pp. 193–202, 3 Pls.)

=Wilson, Edmund B.= The cell in development and inheritance. (New

York, 1896.) Also the writings of Platner, Waldeyer.

_d._ On the paired genital efferent passages

=Loew, H.= Abbildungen und Bemerkungen zur Anatomie einiger

Neuropterengattungen. (Linnæa Ent., 1848, pp. 345–385, 6 Taf.)

=Meinert, F.= Anatomia Forficularum, i, Kjöbenhavn, 1863, 1 Pl.

—— Om dobbelte Saedgange hos Insecter. (Naturhist. Tidsskrift, 3

Raekke, v, 1868, pp. 278–294.)

=Palmén, J. A.= Zur vergleichenden Anatomie der Ausführungsgänge der

Sexualorgane bei den Insekten. (Morph. Jahrb., ix, 1883, pp.

169–176.)

—— Ueber paarige Ausführungsgänge der Geschlechtsorgane bei Insekten.

Eine morphologische Untersuchung. Helsingfors, 1884, pp. 108 und 5

Taf.

=Nusbaum, J.= Zur Entwicklungsgeschichte der Ausführungsgänge der

Sexualdrüsen bei Insekten. (Kosmos, Lemberg, 1884, ix Jahrg., pp.

256–266, 393–408, 462–474, 2 Taf. In Polish with résumé in German.)

=Spichardt, C.= Beitrag zur Entwickelung der männlichen Genitalien und

ihrer Ausführgänge bei Lepidopteren. (Verhandl. d. naturwiss.

Vereins zu Bonn, 1886, xliii Jahrg., pp. 1–34, 1 Taf.)

=Jackson, W. H.= Studies in the morphology of the Lepidoptera. I.

(Zool. Anzeiger, xii Jahrg., 1889, pp. 622–626.) (See p. 389.)

=Lowne, B. Th.= On the structure and development of the ovaries and

their appendages in the blow-fly (_Calliphora erythrocephala_).

(Journ. Linn. Soc. London, 1889, xx, pp. 418–442, 1 Pl.)

See also Meinert (1897), Heymons (1897).

END OF PART I

A Text-book of Entomology Including the Anatomy, Physiology, Embryology and Metamorphoses of Insects for Use in Agricultural and Technical Schools and Colleges as Well as by the Working Entomologist · 第 11 / 16 章

The adult Pteronarcys is nocturnal, flying only at dewfall or in the