The remarkable mode of respiration by tracheal gills situated within the intestine of the nymphs of dragon-flies was first described by Swammerdam and afterwards by Réaumur. The most complete and best illustrated modern account is that of Oustalet. In these insects the large rectum is lined with six double longitudinal ridges, in Æschna bearing numerous delicate tubes or papillæ, each of which contains very numerous (by estimate 24,000) tracheal branches (Fig. 431); while in Libellula the gills are lamellate (Fig. 432). The tracheæ arise both from the main dorsal and visceral longitudinal trunks, which give rise to secondary branches passing into the walls of the rectum and sending into the branchial papillæ fine twigs, which, extending to the distal end of the papilla or lamella, recurve and anastomose with the efferent twigs.

The anal opening is externally protected by the suranal and lateral triangular chitinous plates, three to five in all. When open, the water passes into the rectum and bathes the rectal gills, where it may be forcibly expelled as if shot out from a syringe, thus propelling the insect forward. In Libellula the anus affords direct access to the intestinal cavity, but in Æschna Oustalet describes “a sort of vestibule separated from the rectum by a circular valvule.” He also states that the inspiration and the repulsion of water is produced at irregular intervals, and rather by the movements of the dorsal and sternal arches of the abdomen than by the contractions of the rectum, since the walls of this organ are less muscular than is supposed.

The nymph of Calopteryx (and probably of all the group Calopteryginæ) possesses rectal gills besides external caudal tracheal gills. There are three double rectal longitudinal folds or ridges, interpenetrated by tracheal twigs. (Dufour, denied by Poletaiew, but confirmed by Hagen.)

Dewitz claims that the caudal gills of the Agrionidæ are not their sole means of respiration, since he cut off the caudal tracheal gills of an Agrionid nymph, which continued to live for a week. Hence he thinks that there may be a rectal respiration, since under the microscope he saw a stream of water pass in and out of the end of the intestine.

Dewitz’ experiments prove that in young Ephemerids there may be besides branchial, both rectal and skin respiration. He saw under the microscope the anus for a while opened and then closed, causing the rectum to move; powdered carmine mixed with water was drawn into and then expelled from the rectum. There was, however, no enlargement and contraction of the abdomen as in the rectal respiration of Æschna. (Zool. Anz. 1890, p. 500.)

Eaton states that there is a rectal respiration in the nymphs of may-flies, and Palmén observed in young larvæ of Bætis and Cloëon that the rectum took in “by gulps” water colored by carmine and expelled the whole of it at once, in order to fill it again in the same way. “This rectal respiration therefore corresponds to that of Libellulid larvæ.”

Besides breathing by spiracles, by tracheal gills, as well as through the integument, the larva of Culex has been observed by Raschke to have a rectal respiration. At the anterior end of the rectum arises a countless number of fine tracheæ, which pass through the walls and, subdividing, end in numberless very fine twigs in the papilla-like folds situated within the rectum. The supply of tracheal twigs is greatest where the papillæ are largest. (Figs. 433, 434.)

In many aquatic insects respiration is carried on by tracheal gills. These are delicate, hollow, leaf-like or tubular outgrowths of the integument usually attached to the sides or end of the hind-body, and containing a trachea which usually sends off numerous minute branches, so that the exchange of gases readily takes place in them.

Palmén has shown that these tracheal gills, as he calls them, are not developed on the same segments as the stigmata, and that the two structures have no genetic connection with each other. It is evident that these gills are secondary, adaptive organs.

In some cases (see p. 475) the tracheæ are wanting, but as such gills are filled with blood, the air contained in the water must pass in through their delicate walls.

In the Plectoptera (Ephemeridæ) the tracheal gills are either foliaceous or filamentous; when foliaceous they form simple or double leaves, with or without branches, or with a fringe of tubules, or under the leaf-like cover-bearing tufts of filaments. They are situated on the (usually) basal seven abdominal segments, at their hinder edge (Figs. 435, 436). In Oligoneuria and Jolia a pair occurs on the under side of the head, attached to the maxillæ, while in Jolia there is a pair on the under side of the first thoracic segment at the insertion of each of the legs. In certain genera (Heptagenia, Oligoneuria, and Jolia), they are in the form of a flat cover, under which lies a tuft of respiratory tubes, or (Ephemerella) a small bifid cluster of very delicate leaves (Fig. 437, A). In Cœnis and Tricorythus the tracheal gills of the second pair are modified to form plates covering all the succeeding pairs, those of the first pair being nearly atrophied and well-nigh functionless. (Fig. 437, B.)

Finally, in the highly modified forms Bætisca and Prosopistoma the tracheal gills are entirely concealed and protected by mesothoracic projections so as to form a true respiratory chamber, to which the water has access either by an opening behind, as in Bætisca, or by three openings, two ventral and one dorsal (Fig. 441), as in Prosopistoma.

The slender cylindrical tracheal gills of Heptagenia in the third or fourth nymphal stage are 2–jointed, and the first abdominal pair in Cænis are said by Palmén to be finger-shaped and 2–jointed. In Polymitarcys virgo the gills do not appear until the eighth or tenth day after hatching.

Dewitz found that young nymphs of Ephemerids will well endure the amputation of their gills, while fully grown ones die. Amputation of the lateral gills hastens ecdysis. After the change of skin, the gills are smaller than before, and at first contain no tracheæ, but in a few weeks they develop as completely as in normal individuals. The caudal gills were also renewed.

In the nymphs of Perlidæ the tracheal gills are usually present, and are either foliaceous (Nemoura) or more commonly filamentous in shape (Fig. 442). They are situated either on the prosternum (Nemoura and Pteronarcys), or on each side of the thorax, or on the sides of the abdomen, or are restricted to a tuft on each side of the anus at the base of the caudal stylets (Pteronarcys and Perla). Unlike the Ephemeridæ the gills persist in certain genera throughout life.

The larvæ of the aquatic Neuroptera, Sisyra, Sialis, and Corydalus possess lateral pointed bristle-like tracheal gills, which in Sisyra are 2–jointed; those of Sialis are, in the living larva, curved upwards and backwards (Fig. 444). Corydalus is also provided with a ventral tuft of delicate filamentous gills, which, however, according to Riley, do not appear until after the first moult.

While the nymphs of Agrionidæ (which have rectal gills) respire chiefly by the large caudal foliaceous gills (Fig. 445), there are, according to Hagen, two genera of the Calopteryginæ (Euphæa, Fig. 445, and Anisopleura) whose nymphs possess seven pairs of external lateral tracheal gills, in shape like those of Sialis, besides three caudal and three rectal tracheal gills.^[74]

Hagen has also detected in the under side of the 5th abdominal segment of Epitheca and Libellula a pair of sacs of the shape of a Phrygian bonnet, each of which contains a smaller sac lined with epithelium,—as in Æschna they occur in the 5th and 6th, and in Gomphus in the 4th, 5th, and 6th segments. This serial arrangement appears to confirm Hagen’s suggestion that they are survivals of abdominal gills, which in Euphæa are completely evaginated.

In the Trichoptera, all of which, except Enoicyla, are apneustic, and most of which have tracheal gills, the latter are filamentous, and arise either from the dorsal and ventral sides of the abdominal segment, or they grow out from the sides; while in certain genera (Neuronia, Phryganea, etc.) the gills are represented by conical hooks on the sides of the 1st abdominal segment, which are evidently respiratory, as they contain numerous tracheæ. The tracheal gills are either single or more rarely form tufts (Figs. 447, 448).

In Hydropsyche (Fig. 448) the tracheal gills persist throughout life, while in other genera they only last through the pupal stage. When first hatched, the larva of Phryganea lacks gills. The larvæ of most of the Hydropsychidæ, Rhyacophilidæ, and Hydroptilidæ have no gills, though they appear well developed in the pupal stage. (Klapálek.)

The only lepidopterous larva known to be provided with tracheal gills is that of the pyralid genus Paraponyx. Its thread-like gills, arranged in tufts of three or four, arise from a common tubercle situated on the sides of nearly all the segments. Wood-Mason describes the East Indian P. oryzalis as “covered with a perfect forest of soft and delicate white filaments,” arranged in tufts disposed in four longitudinal rows. “The stigmata of the 2d, 3d, and 4th abdominal somites only are clearly discernible.” The caterpillar crawls “free and uncovered” over the submerged leaves of the rice plant “in the very midst of the water.” In a Brazilian species of Paraponyx described as Cataclysta pyropalis, by W. Müller, the tufts are reduced to simple unbranched filaments, and the case is more complex than in the European species (Fig. 449).

Of coleopterous larvæ breathing by tracheal gills there are but few. The larva of Gyrinus (Fig. 454) respires by 10 pairs of slender, hairy abdominal gills similar to those of Corydalus, and the stigmata are entirely wanting. Somewhat similar are the tracheal gills of Hydrocharis caraboides. Hydrobius has shorter setose gills, our American species having seven pairs of short setose gills. It has two spiracles at the end of the body, through which the air is taken by thrusting the body out of the water. The larvæ of two other aquatic coleopterous genera, Pelobius and Cnemidotus, also have gills; those of the former situated at the base of the coxæ, and brush-like, but containing no tracheæ, though filled with blood, while those of Cnemidotus are very long, bristle-like, jointed, and arising from the dorsal side of the thoracic and abdominal segments. The stigmata are wanting. (Schiödte.)

The larva of the dipterous genus Tanypus respires by two caudal papilliform processes, in each of which a trachea ramifies.

Certain larvæ with both stigmata and tracheal gills are enabled either to live in or out of water or on the surface, as in the case of certain beetles (Cyphonidæ, Elmidæ, Hydrophilidæ, Fig. 452), or the larval mosquito and Psychodes (Fig. 455); also the nymphs of dragon-flies.

The larvæ of the Cyphonidæ (Helodes, Cyphon, Hydrocyphon) possess but a single pair of stigmata, situated in the penultimate abdominal segment, while at the end of the abdomen are delicate tracheal gills. The two main tracheal trunks are much swollen. When on the surface of the water the larva breathes through the stigmata situated near the end of the abdomen; when floating in the water, the larva, like that of Gyrinus, carries along at the end of its body a bubble of air. The gills are only of use, as Rolph thinks, when the insect is compelled to remain a long time under water.

The larva of our native Prionocyphon discoideus (Say) is described by Walsh as “vibrating vigorously up and down a pencil of hairs proceeding from a horizontal slit in the tail”; this pencil is composed “of three pairs of filaments, each beautifully bipectinate. I presume it is used to extract air from the water.” When the larva is at the surface the pencil of hairs touches the surface of the water, and occasionally a bubble of air is discharged from the tail. “The general habit is to crawl on decayed wood beneath the surface, occasionally swimming to the surface, probably for a fresh supply of air.” (Proc. Ent. Soc. Phil., i, p. 117.)

The larvæ of the small water beetles of the family Elmidæ (Elmis, Potamophilus, Macronychus, and Psephenus) have similar habits. That of Elmis has ten dorsally situated pairs of spiracles, and on the end of the body bushy gills which are protruded at pleasure. The young larva is without spiracles, its tracheal system being closed. Macronychus and Potamophilus have similar habits. In the larva of the latter genus, which has nine pairs of spiracles, there are at the end of the body on each side three tufts of thread-like gills which are connected with the two main horizontal tracheæ, while the branches of the abdominal tracheæ are dilated into numerous (64) bladder-like sacs. The larva usually breathes through the caudal gills. When the water is low or dried up, the air is inhaled directly through the spiracles. (Kolbe.)

The larva of Psephenus lecontei, by its broad hemispherical body, is adapted to adhere to the smooth surface of rounded stones, in which situation we have found it. Although it is said by Rolph to have two pairs of spiracles, one pair on the mesothoracic and the other on the 1st abdominal segment, it probably rarely rises to the surface to breathe the air direct.

It possesses five pairs of gills on the under side of the 2d to the 6th abdominal segments. Each gill has finger-shaped processes on its hinder edge, which are “from their constant motion evidently connected with respiration.” Tracheæ may be seen, according to H. J. Clark, entering the gills, and “the circulation of water among the branchiæ is kept up by the flapping of the tail-pieces.” The larva of Helichus fastigiatus is said by Leconte to be “very nearly allied, while the remotely allied Stenelmis crenatus has no external branchiæ.”^[75]

The larva of the mosquito also has two modes of respiration, breathing either at the surface of the water through the two spiracles situated on the projection (siphon) at the hinder end of the body which is thrust out into the air; or when at the bottom respiring by tracheal gills. The pupa also has a double mode of respiration, either taking in air at the surface by the two thoracic horns with stigmatic openings, or when submerged using its tracheal gills.

Besides its long caudal tracheal air-tubes, the larval Eristalis is said by Chun to thrust out from the anus a number (20) of short tracheal filaments which float about in the water and serve to absorb the air.

An aquatic Brazilian larva of the family Psychodidæ has been found by Fritz Müller to take down under the water a large bubble of air (Fig. 455, C), the main tracheal trunk ending each in an opening at the end of the body (A, B); besides this, while at the bottom it breathes by three digitiform tracheal gills; another species having two pairs (C, a).

The remarkable larvæ of the Blepharoceridæ (represented in the United States by Blepharocera capitata), which live permanently in swift streams, attached by median suckers to stones, are apneustic, and breathe solely by leaf-like tracheal gills (Fig. 456, br) attached to the under side of the second to sixth abdominal segments. Those of the European Liponeura are said by Wierzejski to be branched, tree-like. Also immediately in front of the anus and behind the last sucker are four membranous sacs provided with tracheæ, but which are not capable of being withdrawn. These are said by Müller to be the same as what Dewitz states to serve as gills, and by Wierzejski they are homologized with the four anal gills of Chironomus.

The double mode of respiration in the larva of the horse bot-fly has been described by Scheiber. On the hinder end of the body are the stigmatic plates, which contain two lateral gill-plates and the middle stigmatal leaf. Besides this there is a pair of slightly developed prothoracic spiracles. The embryo and also freshly hatched larva of Gastrophilus equi do not possess these gill-plates, but on the end of the body are, according to Joli, two long thread-like gills. The freshly hatched larva of the allied Cephenomyia rufibarbis bears two caudal projections. (Kolbe.) As in shrimps and other Crustacea the gills are kept in constant motion, the water being driven over them by the rapid movements of the telson, so in the larval may-flies, and in the case-worm (Macronema), the gills move more or less rapidly. In case-worms as well as larval Perlidæ, Sialidæ, Paraponyx, and Hydrophilidæ the abdominal region is constantly moved to promote respiration. (Kolbe.)

Blood-gills.—Fritz Müller describes in trichopterous larvæ certain delicate anal tubular processes into which the blood flows, and which do not as a rule contain tracheæ, though occasionally very fine tracheal branches. Müller compares them with the gills of crabs and of shrimps. They are eversible finger-like tubules. They are used when the tracheal gills are temporarily not available. Their number varies even in the same genus. There are six in certain Rhyacophilidæ; five in different Hydropsychidæ; in Macronema there are four, and they are green when filled with the green blood of that insect, the tracheal gills being whitish. In the freshly hatched larva, while the tracheal gills are present, no anal blood-gills are visible. Similar blood-gills also occur in the pupæ of certain caddis-flies. (Pictet.)

Similar anal gills filled with blood occur in the larvæ of the fireflies (Lampyris, etc.), and perhaps, Kolbe thinks, serve for respiration, though other authors believe them to be adhesive organs.

The larva of Pelobius has true blood-gills. (Schiödte. See p. 461.)

The eversible ventral segmental sacs of Scolopendrella, Campodea, and Machilis, as well as the ventral tube (collophore) of Podura, Smynthurus, etc., may, as Oudemans and Haase have suggested, serve a respiratory purpose, though they lack tracheæ, and differ from blood-gills in containing no gases; yet the blood is forced into them, causing their eversion. Oudemans observed that Machilis everted its sacs when the vessel in which it was put was filled with warm, damp air. The sacs are only thrust out when the creature is completely at rest.

Structures referable to blood-gills also occur temporarily in the embryo of Orthoptera; Rathke observed them in the mole-cricket; Ayres observed them in Œcanthus niveus, where they form two stalked broad oval appendages on the first abdominal appendages, which he regarded as gills. Patten observed them in Phyllodromia germanica, as pear-shaped structures occurring in the same situation, but regarded them as sense-organs, as did Cholodkowsky. Graber found these structures in the embryo of the May-beetle, which looked like the other embryonic limbs, but survived after the disappearance of the latter, being longer and broader and unjointed. These disappeared shortly before birth. In Hydrophilus they remain, Graber states, after birth. Nussbaum has seen them in Meloë.

Finally, Wheeler has discussed at length these embryonic organs, which he regards as glandular structures, and calls pleuropodia, their primitive function having been that of limbs. He has detected them in the embryo of Periplaneta orientalis, Mantis carolina, Xiphidium ensiferum (Fig. 387); also in the Hemiptera (Cicada septemdecim, Zaitha fluminea), and in Sialis infumata. He discards the view that they were once gills or sense-organs, and concludes that they were glands. But, as we have suggested, their function once that of gills, and still respiratory in Synaptera, has perhaps become in the winged insects glandular and repugnatorial. Instead, then, of being modified abdominal limbs afterwards serving as glands, as Wheeler claims, we are inclined to believe that they functioned as blood-gills.

k. Tracheal gills of adult insects

Tracheal gills are known to be retained by a few insects in the imago stage, the nymphs in all stages breathing by them. The most notable example is the perlid genus Pteronarcys, in which, as Newport states, there are eight sets, comprising 13 pairs of branchial tufts distributed over the under surface of the thoracic and first two abdominal segments.

The first set, consisting of three pairs of tufts, partly encircling the neck like a ruff, arises from the soft membrane connecting the head and prosternum. The thoracic tufts originate between and behind the coxæ, as well as on the front margin of the meso- and metathoracic segments. The number of filaments in each tuft varies from about 20 to 50 or more, the densest tufts being those of the two hinder thoracic segments. Each filament is usually simple, though in a few cases they are branched (Fig. 457, A).

The adult Pteronarcys is nocturnal, flying only at dewfall or in the 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.

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 p. 437.

Also Gegenbaur’s Comparative Anatomy, Engl. Trans.

b. On the Stigmata

Loewe, C. L. W. De partibus quibus insecta spiritus ducunt. Diss. inaug. Halæ, 1814, pp. 28.

Sprengel, C. Commentarius de partibus quibus Insecta spiritus ducunt. Lipsiæ, 1815, pp. 38, 3 Taf.

Dufour, L. Recherches anatomiques sur l’Hippobosque des chevaux. (Ann. Sc. nat., 1825, vi, pp. 299–322, 1 Pl.)

—— Nouvelles observations sur la situation des stigmates thoraciques dans les larves des Bupresticides. (Ann. Soc. Ent. France, Sér. 2, 1844, ii, p. 203.)

Landois, H. Der Tracheenverschluss bei Tenebrio molitor. (Reichert u. Dubois-Reymond’s Archiv f. Anat., 1866, pp. 391–397, 1 Taf.)

—— und W. Thelen. Der Tracheenverschluss bei den Insekten. (Zeitschr. wissensch. Zool., xvii, 1867, pp. 187–214, 1 Taf.)

—— Der Stigmenverschluss bei den Lepidopteren. (Reichert u. Dubois-Reymond’s Archiv f. Anat., 1886, pp. 41–49, 1 Taf.)

Hagen, H. A. Beitrag zur Kenntnis des Tracheensystems der Libellen-Larven. (Zool. Anzeiger, 1880, pp. 157–162.)

—— Einwürfe gegen Palmén’s Ansicht von der Entstehung des geschlossenen Tracheensystems. (Ibid., 1881, pp. 404–406.)

Krancher, O. Der Bau der Stigmen bei den Insekten. (Zeitschr. wissensch. Zool., xxxv, 1881, pp. 505–574, 2 Taf.; Zool. Anz., 1880, pp. 584–588.)

Meinert, Fr. Spirakelpladen hos Scarabæ-Larverne. (Vid. Meddel. Nat. For. Kjöbenhavn (4), Aarg. iii, 1882, pp. 289–292.)

—— Noget mere om Spiracula cribraria og Os clausum. En Replik. (Ibid. (4), Aarg. v, 1884, pp. 68–91, Fig.)

Schiödte, J. G. Spiracula cribraria—os clausum: lidt om naturvidenskabelig Methode og Kritik. (Nat. Tidsskrift (3), xiii, 1883, pp. 427–473; also Jahresber. Neapel, 1883, p. 105.)

Verson, E. Il meccanismo di chiusura negli stimmati di Bombix mori. (Atti Istit. Veneto. Sc., 1887, p. 9, Pl.)

—— Der Bau der Stigmen von Bombyx mori. (Zool. Anzeiger, 1887, x Jahrg., pp. 561, 562.) See also Zool. Anzeiger, 1890, p. 116.

Haase, E. Die Stigmen der Scolopendriden. (Zool. Anzeiger, 1887, x Jahrg., pp. 140–142.)

—— Holopneustie bei Käfern. (Biolog. Centralbl., 1887, vii, pp. 50–53.)

Carlet, G. Note sur un nouveau mode de fermeture des trachées, “fermeture operculaire” chez les insectes. (Comp. rend. Acad. Sci. Paris, 1888, cvii, pp. 755–757.)

De Meijere, J. C. H. Über zusammengesetzte Stigmen bei Dipterenlarven [etc.]. (Tijd. Ent., xxxviii, 1895, pp. 65–100, 33 Figs.)

Also the other writings of Palmén, Dufour, Dewitz, Boas, Verson.

c. On tracheal gills and tracheal respiration

Pictet, F. J. Mémoires sur les larves des Némoures. (Annal. Sc. nat., 1832, xxvi, pp. 369–391, 2 Pls.)

—— Recherches pour servir à l’histoire et à l’anatomie des Phryganides. Genève, pp. 235, 20 Pls.

—— Histoire naturelle générale et particulière, des insectes Neuroptères. I, Monographie: Famille des Perlides, Genève, 1841, 1842, pp. 423, 53 Pls.

—— Histoire naturelle générale et particulière des insectes Neuroptères. II, Monographie: Famille des Ephémérines. Genève, 1843–1845, pp. 300, 47 Pls.

Dufour, L. Recherches anatomiques et considerations entomologiques sur les insectes Coléoptères des genres Macronychus et Elmis. (Ann. Sc. nat. Zool., Sér. 2, 1835, iii, pp. 151–174, 1 Pl.)

—— Description et anatomie d’une larve à branchies externes d’Hydropsyche. (Ibid., Sér. 3, 1847, viii, pp. 341–354, Fig.)

—— Recherches anatomiques sur la larve à branchies extérieures du Sialis lutarius. (Ibid., Sér. 3, 1848, ix, pp. 91–99, Fig.)

—— De diverses modes de respiration aquatique chez les insectes. (Compt. rend. Acad. d. Sc. Paris, 1849, xxix, pp. 763–770; Ann. and Mag. Nat. Hist., Sér. 2, 1850, vi, pp. 112–118.)

—— Études sur la larve du Potamophilus. (Ann. Sc. nat., Sér. 4, xvii, 1862, pp. 162–173, 1 Pl., Bericht v. Gerstaecker f. 1862, pp. 16, 17.)

Grube, A. E. Beschreibung einer auffallenden an Süsswasser-schwammen lebenden Larve (Sisyra). (Wiegmanns Archiv f. Naturgesch., 1843, ix, pp. 331–337, Fig.)

Schröder van der Kolk, J. L. G. Mémoire sur l’anatomie et physiologie de Gastrus equi. (Nieuwe Verhandl. d. K. Nederl. Instit. Amsterdam, 1845, ix, pp. 1–155, 13 Pls.; Erichson’s Bericht. f. 1845, p. 109.)

Scheiber, S. H. Vergleichende Anatomie und Physiologie der Œstriden-Larven. Respirationssystem. (Sitzungsber. Akad. Wissensch. Wien. Math.-naturw. Cl., 1862, xlv, pp. 7–39.)

Lubbock, J. On the development of Chloëon dimidiatum. (Trans. Linn. Soc. London, I, 1868, xxiv, pp. 61–78, 2 Pls.; II, 1866, xxv, pp. 477–492.)

Oustalet, E. Note sur la respiration chez les nymphes des Libellules. (Ann. Sc. nat. Zool., Sér. 5, xi, 1869, pp. 370–386, 3 Pls.)

Rolph, W. H. Beitrag zur Kenntnis eininger Insektenlarven. 1 Taf. Inaug. Dissertat. Bonn, 1873.

Chun, C. Ueber den Bau, die Entwicklung und physiologische Bedeutung der Rektaldrüsen bei den Insekten. Frankfurt a. M., 1875.

Haller, G. Die Stechmückenlarve. Kleinere Bruchstücke zur vergleichenden Anatomie der Arthropoden. I. Ueber das Atmungsorgan der Stechmückenlarven. (Archiv f. Naturgesch., xliv, 1878, pp. 91–96, 1 Taf.)

Vayssière, A. Recherches sur l’organisation des larves des Ephémérines. (Ann. d. Sc. nat. Zool., Sér. 6, xiii, 1882, pp. 1–137, 11 Pls.)

—— Monographie zoologique et anatomique du genre Prosopistoma Latr. (Ibid., Sér. 7, ix, 1890, pp. 19–87, 4 Pls.)

Eaton, A. E. Notes on some species of Cloëon. (Ann. Mag. Nat. Hist, Ser. 3, xviii, 1866, pp. 145–148.)

—— A revisional monograph of recent Ephemeridæ or may-flies. (Trans. Linn. Soc. London, 1883–1887, Ser. 2, iii, 63 Pls.)

Müller, Wilh. Ueber einige im Wasser lebende Schmetterlingsraupen Brasiliens. (Archiv f. Naturgesch., 1884, i Jahrg., pp. 194–212, 1 Taf.)

Vogler. Die Tracheenkiemen der Simulien-Puppen. (Mitteil. Schweiz Ent. Gesellsch., 1887, vii, pp. 277–282.)

Raschke, E. W. Die Larve von Culex nemorosus. Ein Beitrag zur Kenntnis der Insekten-Anatomie und Histiologie. (Archiv für Naturgesch., 1887, liii Jahrg., pp. 133–163, 2 Taf.; Zool. Anz., 1887, x Jahrg., pp. 18, 19.)

Klapálek, Fr. Untersuchungen über die Fauna der Gewässer Böhmens. I. Metamorphose der Trichopteren. (Archiv f. naturwissensch. Landesdurchforschung von Böhmen, Prag, 1888, vi, No. 5, pp. 63; No. 6, 1893, pp. 145, Figs.)

Müller, Fritz. Larven von Mücken und Haarflüglern mit zweierlei abwechselnd thätigen Atemwerkzeugen. (Ent. Nachr., 1888, xiv Jahrg., pp. 273–277; also Zool. Anzeiger, iv, 1881, pp. 499–502.)

Kolbe, H. J. Ueber den Kranzförmigen Laich einer Phryganea. (Sitzungsber. d. Gesellsch. naturforsch. Freunde in Berlin, 1888, pp. 22–26.)

Haase, Erich. Die Abdominalanhänge der Insekten mit Berücksichtigung der Myriopoden. (Morpholog. Jahrbuch, 1889, xv, pp. 331–435, 2 Taf.)

Dewitz, H. Einiger Beobachtungen, betreffend das geschlossene Tracheensystem bei Insectenlarven. (Zool. Anzeiger, xiii, 1890, pp. 500–504, 525–531.)

Miall, L. C. Some difficulties in the life of aquatic insects. (Nature, xliv, London, 1891, pp. 456–462.)

—— Natural History of aquatic insects, 1895, 116 Figs., pp. 1–395.

Weltner, W. (Note on Sisyra.) (Ent. Nachr., p. 145, 1894.)

Also papers by Hagen, Dewitz, Williams, Tömösváry (1884).

d. Literature on rectal respiration

Suckow, F. W. L. Respiration der Insekten, insbesondere über die Darmrespiration der Æschna grandis. (Zeitschrift f. d. organ. Physik, von Heusinger, 1828, ii, pp. 24–29, 4 Taf.)

Dufour, L. Sur la respiration branchiale des larves des grandes Libellules comparée à celle des poissons. (Compt. rend. de l’Acad. Sc. Paris, 1848, xxvi, pp. 301–303.)

—— Études anatomiques et physiologiques et observations sur les larves des Libellules. (Ann. Sc. nat. Zool., Sér. 3, 1852, xvii, pp. 76–97, 3 Pls.)

Gilson, G. and J. Sadones. Larval gills of Odonates. (Journ. Linn. Soc. London, 1897.)

e. Physiology of Respiration

Bonnet, Ch. Recherches sur la respiration des chenilles. (Mém. Math. des Savants Étrangers, Paris, 1768, v, pp. 276–303.)

Treviranus, G. R. Biologie, oder Philosophie der lebenden Natur, für Naturforscher und Aerzte. 6 Bände, Göttingen, 1802–1822. (Atmung, in Bd. iv.)

—— Die Erscheinungen und Gesetze des organischen Lebens. 2 Bände, Bremen, 1831–1833. (Atmung der Insekten in Bd. i.)

—— Versuche über das Atemholen der niederen Tiere. (Zeitschrift f. d. Physiologie, von F. Tiedemann, G. R. u. L. C. Treviranus, 1832, iv, pp. 1–39.)

Hausmann, J. F. L. De animalium exsanguinum respiratione commentatio. Hannover, 1803, vi, p. 70.

Spallanzani, L. Memoirs on respiration. London, 1804.

Sorg, F. L. A. W. Disquisitiones physiologicæ circa respirationem insectorum et vermium. Rudolstadt, 1805, Part II, p. 146.

Nitzsch, C. L. Commentatio de respiratione animalium. Vitebergæ, 1808, 4º, pp. 56.

—— Ueber das Atmen der Hydrophilen. (Reil’s Archiv f. Physiologie, 1811, x, pp. 440–458.)

Reimarus, J. A. H. Ueber das Atmen, besonders über das Atmen der Vögel und Insekten. (Reil u. Autenrieth, Archiv f. Physiologie, 1812, xi, pp. 229–236.)

Dufour, L. Anatomie de la Ranatre linéaire et de la Nèpe cendrée. (Annal. génér. Scienc. phys., Bruxelles, 1821, vii, pp. 194–213, 1 Pl.)

—— Mémoire pour servir à l’histoire du genre Ocyptera. (Annal. Scienc. natur., 1827, x, pp. 248–261, 1 Pl.)

—— Recherches sur quelques entozoaires et larves parasites des insectes Orthoptères et Hyménoptères. (Ann. Sc. nat. Zool., Sér. 2, 1836, vi, p. 55; Sér. 2, 1837, vii, pp. 5–20.)

—— Note sur le parasitisme. (Compt. rend. Acad. Sc. Paris, 1851, xxxiii, pp. 135–139; Rev. et Mag. de Zool., 1851, pp. 408–412.)

Dutrochet, R. J. H. Du mecanisme de la respiration des Insectes. (Ann. Sc. nat., 1833, xxviii, pp. 31–44; Mém. Acad. Sc. Paris, 1838, xiv, pp. 81–93.)

Newport, G. On the respiration of insects. (Phil. Trans. Roy. Soc., London, 1836, cxxvi, pp. 529–566.)

Coquerel, Ch. Note pour servir à l’histoire de l’Æpus robini. (Ann. Soc. Ent. France, Sér. 2, 1850, viii, pp. 529–532.)

Davy, J. On the effects of certain agents on insects. (Trans. Ent. Soc. London, 1851, pp. 195–212.)

Barlow, W. F. Observations of the respiratory movements of insects. (Phil. Trans. Roy. Soc. London, cxlv, 1855, pp. 139–148.)

Rathke, H. Anatomisch-physiologische Untersuchungen über den Atmungsprozess der Insekten. (Schriften d. k. phys.-ökon. Ges. Königsberg, i Jahrg., 1860, pp. 99–138, 1 Taf.)

Lubbock, J. On two aquatic Hymenoptera, one of which uses its wings in swimming. (Trans. Linn. Soc. London, xxiv, 1863, pp. 135–142, 1 Pl.)

Boyle, R. New pneumatical experiments about respiration. (Phil. Trans., 1870, v, No. 63, pp. 2051–2056.)

Lambrecht. A. Das Atmungsgeschäft der Bienen. (Bienenwirtschaftl. Centralblatt, vii Jahrg., 1871, pp. 20–25.)

—— Luftverbrauch eines Biens und die damit zusammenhängenden Lebensprozesse der Glieder desselben. (Ibid., 1871, pp. 115–120.)

Monnier. Sur la rôle des organes respiratoires chez les larves aquatiques. (Compt. rend. Acad. Sc. Paris, lxxiv, 1872, p. 235.)

Liebe, Otto. Ueber die Respiration der Tracheaten, besonders über den Mechanismus derselben und über die Menge der ausgeatmenten Kohlensäure. (Inaug. Diss. Chemnitz, 1872, pp. 28.)

Plateau, F. Recherches physico-chimiques sur les articulés aquatiques. (Bull. Acad. Roy. Belg., Sér. 2, xxxiv, 1872, pp. 271–321.)

—— Recherches expérimentales sur les mouvements respiratoires des Insectes. (Mem. Acad. Belg., 1884, xlv, pp. 219, 7 Pls., 56 Figs.)

—— Recherches physico-chimiques sur les articulés aquatiques. Part I. Action de sels en dissolution dans l’eau. Influence de l’eau de mer sur les articulés aquatiques d’eau douce. Influence de l’eau douce sur les Crustacés marines. (Mém. cour. et Mém. des savants étrang. de Belgique, xxxvi, 1871, pp. 68.) Part II. Résistance à l’asphyxie par submersion, action du froid, action de la chaleur, temperature maximum. (Bull. Acad. Roy. de Belgique, Sér. 2, xxxiv, 1872, pp. 271–321.)

—— Les Myriopodes marins et la résistance des Arthropodes à respiration aërienne à la submersion. (Journ. de l’anatomie et de la physiologie, 1890, xxvi, pp. 236–269.)

Bütschli, O. Ein Beitrag zur Kenntnis des Stoffwechsels, insbesondere die Respiration bei den Insekten. (Reichert und Dubois-Reymond’s Archiv f. Anatomie, 1874, pp. 348–361.)

Ritsema Cz., C. Acentropus niveus Oliv., in Zijne levenswijze en verschillende toestanden. (Tijdschr. voor Entom, 1876, xxi, separate, pp. 34, 2 Taf.)

Pott, Rob. Chemical experiments on the respiration of insects. (Psyche, ii, 1878.)

Sharp, D. Observations on the respiratory action of the carnivorous water-beetles. (Journ. Linn. Soc. London, xiii, Zoology, 1878, pp. 161–183.)

Krancher, O. Das Atmen der Biene. (Deutscher Bienenfreund., xvi Jahrg., 1880, pp. 49–51.)

Gissler, C. F. Sub-elytral air-passages in Coleoptera. (Proc. Amer. Assoc. Advanc. Sc. 29 Meet. (1881), 1881, pp. 667–669.)

Langendorff, O. Studien über die Innervation der Atembewegungen. 6. Das Atmungszentrum der Insekten. (Archiv f. Anatomie u. Physiol., Physiol. Abteil., 1883, pp. 80–87.)

Macloskie, G. Pneumatic functions of insects. (Psyche, iii, 1883, pp. 375.)

Chalande, J. Recherches sur le mecanisme de la respiration chez les Myriopodes. (Compt. rend. Acad. Sc. Paris, civ, 1887, pp. 126, 127.)

Comstock, J. H. Note on respiration of aquatic bugs. (Amer. Naturalist, 1887, xxi, pp. 577, 578.)

Fricken, W. v. Ueber Entwicklung, Atmung und Lebensweise der Gattung Hydrophilus. (Tagebl., 60, Versamml. deutscher Naturf. u. Aerzte, 1887, pp. 114, 115.)

Schmidt, E. Ueber Atmung der Larven und Puppen von Donacia crassipes. (Berlin. Ent. Zeitschr., 1887, xxxi Jahrg., pp. 325–334, 1 Taf.)

Dewitz, H. Entnehmen die Larven der Donacien vermittelst Stigmen oder Atemrohren den Luftraumen der Pflanzen die sauerstoffhaltige Luft? (Ibid., 1888, xxxii Jahrg., pp. 5, 6, Fig.)

Müller, G. W. Ueber Agriotypus armatus. (Spengel’s Zoolog. Jahrbücher. Abt. f. Systematik, etc., iv, 1889, pp. 1132–1134.)

—— Noch einmal Agriotypus armatus. (Ibid., v, 1890, pp. 689–691.)

Devaux, H. Vom Ersticken durch Ertrinken bei den Tieren und Pflanzen. (Naturwiss. Rundschau, vi Jahrg., 1891, p. 231; Compt. rend. Soc. de Biol., 1891, Ser. 9, iii, p. 43.)

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