Chapter XX: Part I: Morphology and Physiology (16)

We not infrequently find in myriopods (Polydesmidæ, Julidæ, and
Glomeris) repugnatorial or the so-called cyanogenic glands, which
are either paired, opening on the sides of the body, or form a
single row along the median line of the under side of the body.
Leidy describes and figures the spherical glands of _Julus
marginatus_, of which there are 50 pairs. These glands have been
regarded as modified nephridia, but are more probably coxal glands,
and the homologues of the parapodial glands of annelid worms.

FIG. 358.—Sternite of _Machilis maritima_, with the pair of coxal sacs
(_cb_) on the right side everted; _hs_, coxal appendages; _m_,
retractor muscles.—After Oudemans, from Lang.
]

=Eversible coxal glands.=—True coxal glands occur in _Scolopendrella immaculata_ on the 2d to 11th segment, on the inner side of the base of the legs (Fig. 15, _c.g._). Homologous glands also occur in the same position in _Campodea staphylinus_ (also in _C. cookei_ and _C. mexicana_) on the 1st to 8th abdominal segments, and Oudemans has described a pair of eversible sacs on each side of segments one to seven of Machilis. These eversible sacs in the synapterous insects are evidently modified coxal glands, and are probably repugnatorial as well as respiratory in function.

The apparatus consists of an eversible gland, composed of hypodermic cells, usually retracted by a slender muscle and with an efferent passage, but the glands vary greatly in shape and structure in different insects. In some cases these fœtid glands appear not to be the homologues of the coxal glands, but simply dermal glands.

These repugnatorial glands are of not infrequent occurrence in the lower or more generalized winged insects, and in situation and appearance are evidently the homologues of the coxal glands of the Symphyla and Synaptera.

_Fœtid glands of Orthoptera._—In the ear-wigs (Forficula and Chelidura) Meinert has detected a pair of what he calls fœtid glands at the posterior margin of the dorsal plates of the 2d and 3d abdominal segments.

Vosseler also describes the same glands as consisting of a retort-shaped sac, in whose walls are numerous small hypodermal cells and large single glandular cells provided with an efferent passage, the fluid being forced out by the pressure of the dermal muscles, one acting specially to retract the gland. The creature can squirt to a distance of 5 and even 10 cm. (4 inches) a yellowish-brown liquid or emulsion with the odor of a mixture of carbolic acid and creosote.

The large eversible dorsal glands of the Blattidæ, since they contain numerous hairs, which, when everted, are fan-like or like tufts, serve, as in the spraying or scent apparatus, to disseminate the odor, and might be classified with the alluring unicellular scent-glands or _duftapparat_ of other insects, as they are by some authors; but as the glands are large and compound they may prove to be the homologues of the coxal glands rather than of the dermal glands.

Evaginable organs in the Blattids were first observed by Gerstæcker in both sexes of Corydia; they are yellowish white, covered with hairs, and are thrust out from between the dorsal and ventral plates of the 1st and 2d abdominal segments.

_Fig. 359._—Under side of end of Aphlebia, showing the two eversible
sacs; _V-X_, five last abdominal segments; _A_, portion showing the
hairs; _B_, showing origin of a hair in its follicle.—After Krauss.
]

In the cockroach (_P. orientalis_) Minchin detected two pouch-like invaginations of the cuticle, lying close on each side of the middle line of the body between the 5th and 6th tergites of the abdomen. They are lined by a continuation of the cuticle, which forms, within the pouches, numerous stiff, branched, finely pointed bristles, beneath which are a number of glandular epithelial cells. In the male nymph of _P. decorata_ he also found beside these glandular pouches “an additional gland, opening by a tubular duct under the intersegmental membrane between the 5th and 6th terga above the glandular pouch of each side, and extending forward into the body cavity. The gland and its duct are proliferations of the hypodermis, and there is no invagination of the cuticle.” These eversible glands are most complicated in _Phyllodromia germanica_. While it is absent in the female, in the male it is relatively of enormous size, extending over the 6th and 7th somites, as well as projecting far into the body cavity (Minchin). Haase states that these glands become everted by blood-pressure and give out the well-known disagreeable smell of these insects. He states that in the male of _P. germanica_ the dorsal glands in the 6th and 7th abdominal segments are without hairs and produce an oily secretion; they function as odoriferous organs in sexual union.

In the male of another Blattid (_Aphlebia bivittata_) of the Canary Islands, Krauss has detected two yellowish dorsal sacs 1.5 mm. in length, opening out on the 7th abdominal segment, and filled full of long yellowish hairs, the ends directed towards the opening, where they form a thick tuft. These eversible glands lined with hairs appear to be closely similar to the long slender eversible hairy appendages or scent organs of certain Arctian and Syntomid moths. (Fig. 359.)

FIG. 360.—External flaps (_gl_) of glands of Platyzosteria.
]

We have found the external median wart with lateral lids or flaps in between the 5th and 6th tergites of _Platyzosteria ingens_ Scudder, a large wingless Blattid living under the leaf scars of the cocoanut tree in Southern Florida (Fig. 360), but were unable to detect them in Polyzosteria or in the common Blabera of Cuba, or in another genus from Cordova, Mexico.

In another group of Orthoptera, the Phasmidæ, occur a pair of dorsal prothoracic glands, each opening by a pore and present in both sexes. In the walking-stick, _Anisomorpha buprestoides_, ♂ and ♀, these openings are situated on each side of the prothorax at its upper anterior extremity, situated at the bottom of a large deep pit. When seized it discharged a “milky white fluid from the pores of the thorax, diffusing a strong odor, in a great measure like that of the common Gnaphalium or life everlasting” (Peale in Say’s American Entomology, i, p. 84). Boll states that the females when captured “spurt from the prothorax, somewhat after the manner of bombardier beetles, a strong vapor, which slightly burnt the skin; when the females were seized by the males a thick fluid oozed from the same spot.” Scudder describes these glands in another Phasmid (_Autolyca pallidicornis_) as two straight, flattened, ribbon-like bodies, with thick walls, broadly rounded at the end, lying side by side and extending to the hinder end of the mesothorax. In _Anisomorpha buprestoides_ the glands are of the same size and shape (Scudder). In _Diapheromera femorata_ the repugnatorial foramina are very minute, and the apparatus within consists of a pair of small obovate or subfusiform sacs, one on each side of the prothorax, about 1 mm. in length, with a short and very slender duct opening externally at the bottom of the pit (Scudder).

In the Mantidæ these seem to be genuine coxal glands, as there is a pair situated between the coxæ of the first pair of legs. An evaginable organ like a wart, with a glandular appearance, occurs on the hind femora of the Acrydiidæ in a furrow on the under side, into which the tibia fits, about one-fourth from the base (Psyche, iii, p. 32).

In the male cricket, the anal odoriferous glands are small lobes opening into a reservoir on each side of the rectum (Dufour). Homologous glands also occur in the Coleoptera (Fig. 302, _l_ and 317, _s_).

FIG. 361.—Glands (_g_) of Lachnus; _h_, “honey” wart.—Gissler _del._
]

Most Hemiptera or bugs send out a fœtid or nauseous odor due to a fluid secreted by a single or double yellow or red pear-shaped gland, situated in the middle of the mesothoracic segment, and opening between the hinder or third pair of coxæ. In Belostoma Leidy describes these glands as consisting of two rather long cœcal tubes situated in the metathorax, beneath the other viscera, extending backwards into the abdomen, and opening between the coxæ of the third pair of legs. Locy states that the smell arising from these glands is pleasant, resembling that of well ripened pears or bananas. Other bugs, moreover, emit an agreeable odor, that of Syromastes resembling that of a fine bergamot pear. (Siebold.) The fluid given out by the European fire-bug (_Pyrrhocoris apterus_) has a sweetish smell, like ether. In the nymph there are three pairs of dorsal glands, on abdominal segments 2–5, which are atrophied in the mature insect. In the bed-bug, the nymph has three odoriferous glands each with paired openings in the three basal abdominal segments respectively, and situated on the median dorsal line, being arranged transversely at the edge of the tergites; but after the last moult these are aborted, and replaced by the sternal metathoracic glands (Künckel). Gissler has detected a pair of glands in _Lachnus strobi_ (Fig. 361).

=Anal glands of beetles.=—Certain beetles are endowed with eversible repugnatorial glands. _Eleodes gigantea_ and _E. dentipes_ of both sexes are said by Gissler to possess these glands. When teased “they stand on their anterior and middle legs, holding the abdomen high up and spurting the contents of the glands right and left.” The glands (Fig. 366, 1) are two reddish brown, somewhat bilobed sacs, and extend from the base of the last up to the middle of the 2d abdominal segment, with an average length of 6.5 mm. The liquid stains the human skin, has an acid reaction, with a peculiar, “intensely penetrant odor, causing the eye to lachrymate. It is soluble in water, alcohol, and ether. Boiled with concentrated sulphuric acid and alcohol an ethereal aromatic vapor is produced, indicating the presence of one or more organic acids, though neither formic or acetic acid could be detected.” Williston has observed the same habits in seven other species of Eleodes, all ejecting a pungent vile-smelling liquid, one species (_E. longicollis_) ejecting a stream of fluid from the anal gland, backwards sometimes to the distance of 10 cm. or more, and he regards these beetles as “the veritable skunks of their order.” Leidy briefly describes the odoriferous glands of _Upis pennsylvanica_.

The anal glands consist, according to Meckel and also Dufour, of two long, simple, flexuous cœca with reservoirs having two short excretory ducts situated near the anus (Siebold).

Glands like those of Eleodes found in _Blaps mortisaga_ are described in detail by Gilson (Fig. 366, 2). They form two pouches or cuticular invaginations situated in the end of the abdomen on the sides of the end of the intestine and unite on the median line underneath the genital organs, forming a very short tube with a chitinous wall, continuous with the cuticle of the last abdominal segment. Into each pouch open a large number of fine slender lobules varying in shape, giving a villous aspect to the surface. These lobules are composed of as many as fifty unicellular glands, each of which is composed of four parts: (1) A radiated vesicle, (2) a central sac, giving rise (3) to a fine excretory tube, and (4) a sheath near the origin of the excretory tube. These are all modifications of the cytoplasm of the cell with its reticulum; the nucleus with its chromosomes is also present, but situated on one side of the central sac. The fine excretory tubules form a bundle passing down into the mouth of each lobule.

Similar glands, though usually smaller, which have not been
carefully examined, occur in Carabus (Fig. 300, 3) and Cychrus,
which eject from the vent a disagreeable fluid containing butyric
acid (Pelouse). The bombardier beetle Brachinus, with its anal
glands, ejects a jet of bluish vapor accompanied with a considerable
explosion, which colors the human skin rust red; it is caustic,
smells like nitrous acid, and turns blue paper red. Westwood states
that individuals of a large South American Brachinus on being seized
“immediately began to play off their artillery, burning and staining
the flesh to such a degree that only a few specimens could be
captured with the naked hand, leaving a mark which remained for a
considerable time.” The fluid ejected by another species, in
Tripoli, blackened the fingers of the collector. “It is neither
alkaline nor acid, and it is soluble in water and in alcohol.”
(Kirby and Spence, iv, p. 149.)

Species of other genera (Agonum, Pheropsophus, Galerita, Helluo,
Paussus, Ozæna) are also bombardiers, though less decidedly so than
Brachinus. A Paussid beetle (Cerapterus) ejects explosively a fluid
containing free iodine (Loman), while Staphylinus, Stenus, Ocypus
olens, Lacon, etc., have similar anal fœtid glands, the liquid being
more or less corrosive. The secretion of _Mormolyce phyllodes_ is so
corrosive that it is said to paralyze the fingers for 24 hours
after. (Cuénot.)

FIG. 362.—Median section through the femoro-tibial joint of leg of
Coccinella, showing at _o_ the opening through which the blood oozes
out; _f_, femur; _t_, tibia; _e_, extensor muscle of the tibia: _s_,
sinew of the same; at _ch_, chitinized; _h_, articular membrane;
_v_, tibial process.—After Lutz.
]

The two pairs of remarkably large, soft, eversible, forked, orange-yellow glands of the European genus Malachius, are thrust out from the side of the 1st and the 3d thoracic segments. They are everted by blood-pressure, and retracted by muscles. The larva of _Hydrophilus piceus_ ejects by the anus a black, fœtid fluid.

Claus has shown that the larva of _Lina populi_ and other Chrysomelidæ possess numerous minute, eversible glands in each of the warts on the upper surface of the body, each gland containing a whitish, repellent fluid smelling like the oil of bitter almonds and containing salicylic acid derived from its food-plant, which issues as pearl-like drops. Candèze thinks the fluid may contain prussic acid. The fluid is secreted by a variable number of glandular cells, each provided with an efferent duct. The larvæ of saw-flies, notably _Cimbex americana_, also eject droplets of a clear fluid from non-evaginable glands situated near each stigma (Chlolodkovsky).

=The blood as a repellent fluid.=—In this connection it may be mentioned that though there are no special glands present, many beetles emit drops of blood from the femoro-tibial joints of their legs as a means of defence. Such are the oil-beetles (Meloë), Cantharis, Lytta. The cantharadine secreted by these beetles, according to Beauregard, is an efficient means of defence, as birds, reptiles, and carnivorous insects will not usually attack them. This substance is formed in the blood and also in the genital organs, and is so extremely caustic that scavenger insects which feed upon their dead bodies will leave untouched the parts containing cantharadine, and if May-beetles or mole-crickets are washed with the blood of Meloë or with cantharidate of potassa, it will for several days render them safe from the attacks of the carabids which usually prey upon them. The eggs even after deposition are strongly vesicant, and are thus free from the attacks of egg-eating insects (Cuénot). The Coccinellidæ are also protected by a yellow, mucilaginous, disagreeable fluid oozing out of the ends of the femora; in our common, two-spotted lady-bird (_C. bipunctata_) the yellow fluid is disagreeable, smelling like opium. Lutz has found that the blood in Coccinellidæ passes out through a minute opening situated at the end of each femur (Fig. 362). The blood is very repellent to insectivorous animals.

The Dyticidæ eject from the anus a colorless, disagreeable fluid, while these beetles, and especially the Gyrinidæ, when captured send out a milky fluid which appears to issue from the joints of the body. The Silphidæ throw out both from the mouth and vent a fœtid liquid with an ammoniacal odor. They possess but a single anal gland, the reservoir opening on one side of the rectum (Dufour).

Other malodorous insects have not yet been investigated; such are the very persistent odors of lace-winged flies (Chrysopa).

More agreeable secretions, but probably formed by similar glands, is the odor of rose or hyacinth given out by Cicindelæ, or the rose fragrance exhaled by the European _Aromia moschata_.

=Eversible glands of caddis-worms and caterpillars.=—Gilson, while investigating the segmentally disposed thoracic glands of larval Trichoptera, has found in the larva of _Limnophilus flavicornis_ that the sternal prothoracic tubercle gives exit to an underlying tubular gland. In _Phryganea grandis_ each thoracic sternum affords an exit to an eversible gland. Many caterpillars, as our subjoined list will show, are very well protected by eversible repugnatorial glands situated either in the under or upper side of the body. Since the time of De Geer (1750) the fork-tailed larva of Cerura has been known to throw out a secretion, which was described by Bonnet in 1755 as a true acid, sharp, sour, and biting. This spraying apparatus in _Cerura (Harpyia) vinula_ has been well described by Klemensiewicz (Fig. 366, 4), though Rengger in 1817 noticed the general form of the secretory sac, and that it opens out in two muscular eversible tubes, out of which the secretion is ejected.

The fork-tailed larva of _Macrurocampa marthesia_, which is much like that of Cerura, when teased sends out a jet of spray to the distance of nearly an inch from each side of the neck. While examining the very gayly-colored and heavily-spined caterpillars of _Schizura concinna_ we observed that when a fully-grown one was roughly seized with the forceps or fingers it sent out a shower of spray from each side of the prothoracic segment, exactly like that of Cerura and Macrurocampa.

In the European _Cerura vinula_ the apparatus consists of a single sac, which opens by a narrow transverse slit on the under side of the neck, out of which is rapidly everted four lateral tubes, two on each side (Fig. 366, 4, _t_), which are withdrawn within the opening by the contraction of several fine muscles. The apparatus in the American _C. multiscripta_ is as in the European _C. vinula_. In a living specimen the large secretory sac was seen to be of the same size and shape as in Macrurocampa, and of the color of raw silk. The sac when distended extends back to a little behind the middle pair of legs, and is nearly two-thirds as wide as the body. The caterpillar sent out the fluid when handled, but we could not make it spray.

In the larva of _Macrurocampa marthesia_ the cervical or secretory gland (Fig. 366, 5) is situated in the 1st and 2d thoracic segments, extending to the hinder edge of the latter and lying between the nervous cord and the œsophagus and proventriculus, and when empty the bulk of it lies a little to one side of the median line of the body. It is partly held in place by small tracheæ, one quite large branch being sent to it from near the prothoracic spiracle. The short, large duct, leading from it to the transverse opening in the membrane between the head and prothoracic segment, is a little narrower than this opening, and is kept distended by tænidia, or a series of short, spiral threads which are pale, not honey-yellowish, in color. This duct lies on one side of the prothoracic ganglion, resting just under the commissures passing up to the brain; it is also situated between the two silk ducts.

The very distensible sac (Fig. 366, 5) is rendered elastic by a curious arrangement of the cuticle, the tænidia of the duct itself being represented by very thickly-scattered, irregular, separate, sinuous, chitinous ridges, which stand up from the cuticular lining of the wall of the sac (Fig. 366, 6). The secretory cells of the walls of this sac in _Cerura vinula_ are said by Klemensiewicz to be large hexagonal cells, resembling those of silk-glands, having like them large branched nuclei.

The fluid thrown out is said by Poulton to be formic acid; it causes violent effervescence when allowed to fall upon sodium-bicarbonate, and colors blue litmus paper red. It also appears from the researches of Latter that these creatures in the imago state secrete free potassium hydroxid, a substance for the first time known to exist in the animal kingdom.

In the caterpillar of _Astyanax archippus_ (_Limenitis disippus_) a dark, bladder-like sac is everted, but the lateral tubes appear to be wanting, and no spray is sent out; it occurs in the larvæ of many Nymphalidæ and other butterflies and moths.

These glands are functionally active in Perophora, but obsolete (at least the external openings) in Lacosoma.

=The osmeterium in Papilio larvæ.=—The caterpillars of the swallowtailed butterflies (Papilio, Doritis, and Thais), as is well known, when irritated thrust out from a transverse slit on the upper part of the prothoracic segment a large orange-yellow V-shaped fleshy tubular process (the osmeterium), from which is diffused a more or less melonlike but disagreeable, in some cases insufferable, odor; the secretion is acid and reddens litmus paper. The mechanism has been described and figured by Klemensiewicz.

When at rest, or retracted, the osmeterium lies in the upper part of the body in the three thoracic segments, and is crossed obliquely by several muscular bundles attached to the walls of the body, and by the action of these muscles the evagination of the osmeterium is strongly promoted. After eversion the tubes are slowly retracted by two slender muscles inserted at the end of each fork or tube, and arising from the sides of the 3d segment behind the head, crossing each other in the median line (Fig. 366, 7 _r.m._). The secretion is formed by an oval mass of glandular cells at the base of the forks; in the glandular mass is a furrow-like depression about which the secretory cells are grouped. The secretion collects in very fine drops on the side of each furrow opposite the glandular cells.

According to C. D. Ash the larva of an Australian Notodontid (_Danima banksii_ Lewin) protrudes from the under side of the prothoracic segment a Y-shaped red organ like that of Papilio; no fluid or odor is given out.

=Dorsal and lateral eversible metameric sacs in other larvæ.=—The showy caterpillars of Orgyia and its allies have a conspicuous coral-red tubercle on the back of the 6th and also the 7th abdominal segment, which on irritation are elongated, the end of the tubercles being eversible. When at rest the summit is crateriform, but on eversion the end becomes rounded and conical. These osmeteria are everted by blood pressure, and retracted by a muscle. Fig. 366, 9, represents a section of an osmeterium of _Orgyia leucostigma_ when retracted by the muscle (_m_); at the bottom of the crater are the secreting or glandular cells (_gc_), being modified hypodermal cells. These doubtless serve as terrifying organs to ichneumons and other insect enemies, and though we have been unable to detect any odor emanating from the tubercles, yet possibly they give out a scent perceived by and disagreeable to their insect assailants.

FIG. 363.—Freshly hatched larva of _Hyperchiria io_, with its two
pairs of eversible glands (_g_).
]

FIG. 364.—Young larva of _Megalopyge crispata_, enlarged, showing the
seven pairs of lateral processes (_lp_): _sp_, spiracle; _abl′_,
_abl^6_, six pairs of abdominal legs besides the anal pair.
]

In the Hemileucidæ there is a pair of lateral osmeteria, on the 1st and on the 7th abdominal segments, which however, are not highly colored (Figs. 363, 366, 10). In Megalopyge (Lagoa, Fig. 364) there is a lateral row of singular pale permanently everted processes which appear to be the homologues of the osmeteria of larvæ of other lepidopterous families. As these are repeated on seven segments, their metameric arrangement is obvious. The relation of these curious glands to the viscera is seen in Fig. 297, _lgp_, and their minute structure in Fig. 365.

At _A_, the lumen (_l_) is a deep narrow cavity, with the secretion
(_secr._), collected at the mouth of the cavity, composed of a thin,
mucus-like, coagulated fluid, containing granules of varying degrees
of fineness, which take the stain readily. Outside of these are
collected fine nuclei (_bc_), stained dark, and enveloped in a
slight, transparent, pale, protoplasmic envelope, which may be blood
corpuscles. The glandular cells themselves are simply modified
hypodermal cells, as seen at _C_. In some of the nuclei, indistinct
nucleoli are seen, and deeply stained granules, especially around
the periphery of the nuclei. At _B_ is represented a section on one
side of the middle, but still showing the spacious lumen. In the
section represented by _C_, the knife passed through the process
still nearer the outer edge, and near the base; at _C^1_, three of
the glandular cells, with their large, deeply stained nuclei, are
drawn. A transverse section at _D_ shows the large lumen or cavity
(_l_).

As to the function and homologies of these structures, it is
difficult to decide. We have never noticed that they give off any
odor, though they may prove to be repugnatorial; they are not
visible in the fully grown, living insect, being concealed by the
long, dense hairs clothing the body; they are not spraying organs,
as they are imperforate at the end, not ending as the lateral,
eversible glands of _Hyperchiria io_, etc., in a crateriform
orifice.

They may be permanently everted glands, or osmeteria, which have, by
disuse, lost their power of retraction and their crateriform
opening, as well as the power of secreting a malodorous fluid.

FIG. 365.—Section of lateral processes of larva of Megalopyge.
]

In certain of the butterflies, the Heliconidæ (Colænis, Heliconius, Euides, and Dione), there is thrust from the end of the abdomen a pair of large, irregular, rounded, eversible glands, which give out a disagreeable odor, and are consequently repellent, and which seem to be the homologues of the odoriferous glands of other butterflies.

The large, soft, rounded, eversible glands, looking like puff-balls
or a rounded pudding (Fig. 366, 12), are everted, when the
butterflies are roughly seized, from the dorsal side of the
penultimate segment of the abdomen. The males possess two smaller
tubercles on the inside of the anal claspers or lobes. Müller also
detected, in the females of various species of the Heliconidæ
enumerated above, a pair of club-shaped processes like the balancers
of flies, which are thrust out on each side of and under the
odoriferous puff-balls of the hinder edge of the penultimate segment
(Fig. 366, 13). The club or head is armed with hairs or bristles,
which, in Heliconius, are like the scales of a butterfly.

FIG. 366.—Scent-glands of insects: 1. Anal eversible glands of
Eleodes.—After Gissler. 2. Anal eversible glands of Blaps.—After
Gilson. 3. Anal glands (_agl_) of _Carabus hortensis_: _rs_,
reservoir; _d_, excretory duct; _i_, intestine; _r_, rectum.—After
Kolbe. 4. Prothoracic spraying apparatus of _Cerura vinula_: _gl_,
the gland; _d_, its duct, with tænidia; _t_, the spraying tubes;
_m_, muscles; _rm_, retractor muscles.—After Klemensiewicz. 5. The
thoracic glandular sac of _Macrurocampa marthesia_: _gl_, the
glandular sac; _d_, its duct; _e_, peritracheal epithelium; _t_, the
spiral threads or tænidia. 6. Irregular separate masses of chitinous
ridges on the cuticular lining of the wall of the sacs of
_Macrurocampa marthesia_. 7. Osmeterium (_os_) of the larva of
_Papilio machaon_ at rest: _rm_, the retractor muscles at the ends;
_m_, the numerous oblique muscles; _dm_, dorsal longitudinal
muscles; _t_, trachea; _oe_, œsophagus; _gang_, brain; 1, head; 2,
3, 4. thoracic segments. 8. Osmeterium (_os_) of one side, enlarged:
_g_, glandular portion at the base; _d_, depressions in the cuticula
of the glandular portion; _t_, trachea.—This and Fig. 7 after
Klemensiewicz. 9. Eversible dorsal glands (_ev. gl_) of larva of
_Orgyia leucostigma_ in Stage II: _gc_, glandular cells at bottom of
the crater-like depression; _m_, retractor muscle; _p_, poison
gland-cells of the root of the seta (_s_); _c_, cuticula; _hyp_,
hypodermis; _A_, portion of the cuticle and hypodermis enlarged. 10.
Lateral eversible gland of _Hyperchiria io_, Stage II: _rm_,
retractor muscle; _oen_, œnocytes. 11. The same as Fig. 10, but
representing a section through one side of the eversible gland. 12.
_A_, end of body of _Colænis julia_; _ev_, eversible anal gland;
_oa_, odoriferous appendages; _B_, the same in _Heliconius
apseudes_, side view; _C_, odoriferous appendages of _Colænis dido_
in fresh condition; _D_, tested with alcohol and benzine. 13.
Odoriferous appendages of _Heliconius eucrate_, head cleansed.—Figs.
12, 13, after F. Müller. 14. Odoriferous glands (_ogl_) in the pupa
of _Vanessa io_: _r_, rectum; _h_, the folds of hypodermis which
forms the terminal papilla of the abdomen; _ov_, oviduct.—After
Jackson.
]

In the caterpillars of certain blue butterflies (Lycænidæ) is an internal osmeterium, being a very minute sac which is everted from a transverse slit on the top of the 7th abdominal segment. Its function is quite the opposite of those of the caterpillars of other families, since the sac exudes a sweet fluid very attractive to ants, which may be diffused more widely by the delicate spinulose bristles crowning the summit. W. H. Edwards states that in several species of Lycæna, besides that on the 7th abdominal segment, there is on the 8th segment a pair of minute dorsal evaginable tubercles.

A pair of small ramose odoriferous glands are said by Siebold, who regarded them as alluring glands, to occur in Argynnis, Melitæa, and Zygæna, to be situated near the orifice of the oviduct, and Scudder has detected them near the anus of the female pupa of _Danais archippus_. The appearance of the odoriferous glands in the pupa of _Vanessa io_ is well shown by Jackson (Fig. 366, 14). They develop as two tubular ingrowths of the hypodermis, perfectly distinct one from the other, each having its own separate aperture to the exterior. In Fig. 366, 14 the condition of parts is nearly as in the imago, the glands being situated below the rectum and opening of the oviduct. In both sexes of another Brazilian butterfly (_Didonis biblis_) on the median line of the abdomen between the 4th and 5th segments are two roundish vesicles covered with short gray hairs, which emit a disagreeable smell.

It is possible that the dark-green fluid in Parnassius, secreted by
an evaginable gland, and which is moulded into shape by the
scimetar-shaped peraplast (Scudder), is formed by the homologues of
the anal glands of other butterflies.

Distribution of repugnatorial or alluring scent-glands in insects[59]

_A._ LARVAL INSECTS

_a._ _Each thoracic segment; sternal. Phryganea grandis._

_b._ _Prothoracic, sternal, discharging a lateral jet of spray; with a single large internal sack._

LEPIDOPTERA

Family TINEIDÆ

_Hyponomeuta evonymella._

Family NOCTUIDÆ

_Bryophila_, _Cucullia formosa_, _C. scrophulariæ_, _Habrostola_, _Cleophana linariæ,_ Catocala (sp.), _Aporia cratægæ_, _Aplecta nebulosa_, _Leucania staminea_, _L. hispanica_, _L. nonagrioides_, _Plusia gamma_.

Family NOTODONTIDÆ

_Pheosia rimosa_, _Schizura concinna_, _Danima Banksii_ (Australia), _Macrurocampa marthesia_, _Heterocampa pulverea_, _Cerura vinula_, _C. furcula_, _C. borealis_, _C. multiscripta._

Family NYMPHALIDÆ

Probably all the species.

_c._ _Prothoracic, dorsal; sending out a_ V-_shaped odoriferous organ_ (osmeterium).

Family PAPILIONIDÆ

All the species as a rule.

_d._ _Thoracic sternal, evaginable glands._

Family PEROPHORIDÆ

_Lacosoma chirodota_, _Perophora melsheimerii_.

Family NOLIDÆ

In three, and probably in all the species of Nola.

_e._ _Lateral, abdominal, non-eversible glands, one near each spiracle, emitting a clear fluid._

Family TENTHREDINIDÆ

_Cræsus septentrionalis_, _C. varus_, _Cimbex americana_, _C. betulæ, Trichiosoma_.

_f._ _Lateral, abdominal, partly eversible glands emitting neither moisture nor odor, but flesh-colored._

Family _Tineidæ_

Phyllocnistis? (eight pairs.)

Family HEMILEUCIDÆ

_Hyperchiria io_ (two pairs, viz. on 1st and 7th segments), _H._ sp. (Mexico), _Hemileuca yavapai_, _pamina_, _H. maia_, _H. artemis_, _Pseudohazis eglanterina_.

_g._ _Lateral, abdominal, permanently everted, metameric glands, not known to secrete a fluid, nor to be odoriferous._

Family MEGALOPYGIDÆ

_Megalopyge crispata._

_h._ _Medio-dorsal, partly eversible glands, emitting a spray of liquid but no odor(?), and colored coral-red or orange-yellow (P. auriflua), but usually in the European species yellowish._

Family LIPARIDÆ

All the species except those of Demas.

_i._ _A single, median, abdominal, dorsal gland, emitting a fluid attractive to ants, on 7th segment; with a pair of minute, index glands on the 8th segment._

Family LYCÆNIDÆ

All the species.

_j._ _Protrusile organs near the anus._

_Myrmeleon_ larva (Hagen? Dimmock).

_B._ NYMPH OF HETEROMETABOLOUS INSECTS

_a._ _Paired, dorsal glands, on abdominal segments 1, 2, and 3._

_Cimex lectularius_ (Künckel).

_b._ _The same on abdominal segment 5._

_Lachnus strobi._

_C._ PUPA OF CERTAIN BOMBYCES

_At anterior end of certain pupæ, internal glands to moisten threads of the cocoon for exit of moth._

_D._ ADULT INSECTS

_a._ _Occurring on the prothorax only; strongly repugnatorial, best developed in_ ♂.

_Anisomorpha buprestoides_, _Autolyca pallidicornis_, _Phasma putidum_, _Phyllium_ (sp.), _Heteropteryx_ (sp.), _Diapheromera femoratum_ (probably in all the species of the family), _Mantis carolina_.

_b._ _Occurring on the pro- and mesothorax, and on the middle of the abdomen, orange-yellow, fleshy tubercles or evaginations._

_Malachius bipustulatus_, _Anthocomus equestris_, _Evæus thoracicus_.

_c._ _Segmental, eversible glands, homologues of the coxal glands of other Arthropods, occurring on all, or nearly all, the abdominal segments._

_Scolopendrella immaculata_ (coxal glands on 3d to 11th pair of legs), _Campodea staphylinus_ (a pair of coxal glands on 1st to 8th abdominal segments), _Machilis maritima_ (eversible, coxal glands on segments 1–7).

_d._ _Occurring in the abdomen._

_d^1._ _In the two first abdominal segments._

_Corydia carunculigera_ ♂ and ♀.

_d^2._ _Alluring (?) organs situated on the dorsal side of the abdomen, in the 6th, or 6th and 7th, abdominal segment._

_Periplaneta americana_ ♂, _P. orientalis_ (nymph), _P. decorata_ ♂ (nymph), _Ectoblatta germanica_ ♂, _Ectobia lapponica_ ♂, _Phyllodromia_ ♂, _Aphlebia bivittata_ ♂, _Platyzosteria ingens_ (on seventh segment).

_e._ _At the end of the body._

_Colænis julia_ ♀ (F. Müller), _Heliconius apseudes_ (F. Müller).

LITERATURE ON DEFENSIVE OR REPUGNATORIAL GLANDS

=Aldrovandus, U.= De animalibus insectis libri septem cum singulorum
iconibus ad vivum expressis. (Denuo impress: Bonon. apud Clementem
Ferronium, 1638, p. 273. The first edition was in 1602.)

=Moufet, T.= Insectorum sive minimorum animalium theatrum, etc.
London, 1634, pp. 185, 186.

=Gœdart, J.= Metamorphosis naturalis sive insectorum historia, etc.
Amstelodami, 1700, Pars ii, p. 136. (French ed. of 1700, ii, p. 162;
Lister’s Latin ed., London, 1685, p. 60.)

=Réaumur, R. A. F.= Mémoires pour servir à l’histoire des insectes,
etc. Paris, 1736, ii, pp. 266–269, Pls. 21, 22. [ii, partie ii, pp.
21–23, of the Amsterdam ed. of 1737–1748.]

=De Geer, C.= Observation sur la propriété singulière qu’ont les
grandes chenilles à quatorze jambes et à double queue, du saule, de
seringuer de la liqueur. (Mém. sav. étrang, Paris, 1750, i, pp. 530,
531, Pl.; Goetze und Bonnet, etc., Auserlesene Abhandlungen, 1774,
p. 220.)

=Schaeffer, J. C.= Neuendeckte Theile an Raupen und Zweyfaltern, etc.
Regensburg, 1754.

=Sulzer, J. H.= Die Kennzeichen der Insekten, etc. Zürich, 1761, pp.
65–67, Taf. 5, Fig. 34.

=Müller, O. F.= Pile-larven med dobbelt Hale, og dens Phalæne, etc.
Kjöbenhavn, 1772, pp. 53–56, Pl. 2, Figs. 3–5.

=Bonnet, C.= Mémoire sur une nouvelle partie commune à plusieurs
espèces de chenilles. (Mém. math. d. savants étrang., Paris, 1755,
ii, pp. 44–52; Collection complète des œuvres de C. Bonnet, 1779,
ii, pp. 3–16.)

—— Mémoire sur la grande chenille à queue fourchue du saule, dans
lequel on prouve, que la liqueur que cette chenille fait jaillir,
est un véritable acide, et un acide très-actif. (Mém. math, de
savants étrang., Paris, 1755, ii, pp. 267–282; Collection complète
des œuvres de C. Bonnet, 1779, ii, pp. 17–24.)

=Amoreux, P. J.= Notice des insectes de la France, réputés venimeux,
etc. Paris, 1789, pp. 282–285.

=Schwarz, C.= Neuer Raupenkalender. Nürenberg, 1791, Abth. i, p. 59.

=Petzhold, C. P.= Lepidopterologische Beyträge. (L. G. Scriba’s
Beiträge zu der Insekten-geschichte, Frankfurt am Main, 1793, Heft
3, pp. 230–251.)

=Nouvelle Dictionnaire d’Hist. Nat.=, xv, p. 487. (Larva of
Hydrophilus ejects with a slight noise a fœtid and blackish fluid.)

=Rengger, Johann Rudolph.= Physiologische Untersuchungen über die
thierische Haushaltung der Insecten. Tübingen, 1817. (In the chapter
entitled Abgesonderte Säfte bei den Raupen, he speaks of the
glandular apparatus of the larva of _B. vinula_, noticing the
general form of the secretory sac, that it opens out in two muscular
evertible points, out of which the secretion is ejected.)

=Dufour, L.= Mémoire anatomique sur une nouvelle espèce d’insecte du
genre Brachinus. (Ann. de mus. d’histoire nat., xviii, 1811, pp.
70–81.)

—— Recherches anatomiques sur les carabiques et sur plusieurs autres
coléoptères. (Ann. d. Sci. Nat., 1826, viii, pp. 5–54.)

—— Mémoire sur les métamorphosis et l’anatomie de la _Pyrochroa
coccinea_. Glande odorifique. (Ibid., ii sér. Zoologie, xiii, 1840,
pp. 340, 341.)

—— Recherches anatomiques sur les Diptères. 1851, pp. 195, 313.
(Alimentary canal of Sepsis contains the seat of a “glande
odorifique.”)

=Kirby and Spence.= Introduction to entomology, etc. (2d ed., i, 1815;
London, 1818, ii, pp. 238, 239.)

=Lyonet, P.= Recherches sur l’anatomie et les metamorphoses de
différentes espèces d’insectes. Ouvrage posthume. Paris, 1832.

=Morren, C.= Mémoire sur l’émigration du puceron du pêcher (_Aphis
persicæ_), et sur les caractères et l’anatomie de cette espèce.
(Ann. Sci. Natur. Zool., 1836, vi, pp. 65–93, Pls. 6, 7.)

=Ratzeburg, J. T. C.= Die Forstinsekten, etc. (Theil i, Die Käfer,
etc., 1837, p. 246.)

=Aubé, C.= Note sur une sécrétion fétide d’_Eumolpus pretiosus_. (Ann.
Soc. Ent. Fr., 1837, i, vi; Bull., p. 58.)

=Lacordaire, J. S.= Introduction à l’entomologie. 1838, ii, p. 45.

=Meckel, von Hemsbach, Johann Friedrich.= Mikrographie einiger
Drüsenapparate der niederen Thiere. (Anat. Phys. u. wiss. Med.,
1846, pp. 1–73, Taf. 1–3; p. 46, Müller’s Archiv.)

=Stein, Friedrich.= Vergleichende Anatomie und Physiologie der
Insekten. Berlin, 1847.

=Leidy, Joseph.= History and anatomy of the hemipterous genus
Belostoma. (Journ. Acad. Nat. Sci. Philadelphia, Ser. 2, 1847, i,
Part i, pp. 57–67, Pl. 1.)

—— Odoriferous glands of invertebrata. (Proc. Acad. Philadelphia,
1849, iv, 234–236, 1 Pl.; Ann. and Mag. N. H., Ser. 2, 1850, v, pp.
154–156.)

=Chapuis et Candèze.= Catalogue des larves des coléoptères, etc. (Mém.
Soc. Sci. de Liège, 1853, viii, pp. 351–653, Pls. 1–9, pp. 611,
612.)

=Siebold, Carl Theodor.= Lehrbuch der vergleichenden Anatomie der
wirbellosen Thiere, 1848. (Burnett’s transl., Boston, 1854.)

=Burnett, Waldo Irving.= Translation of Siebold’s Anatomy of the
Invertebrates, 1854. (Note on the osmeteria of _Papilio asterias_,
which he regards as an odoriferous and defensive, rather than
tactile, organ, p. 415.)

=Karsten, H.= Bemerkungen über einige shaarfe und brennende
Absonderungen verschiedener Raupen. (Müller’s Archiv für Anat. Phys.
u. wiss. Med., 1848, pp. 375–382, Taf. 11, 12.) Describes the
poison-glands at the base of the spines of Saturnia larvæ.

—— Harnorgane des _Brachinus complanatus_. (Müller’s Archiv, 1848, pp.
367–376, Taf.)

=Laboulbéne, Alexandre.= Note sur les caroncules thoraciques du
Malachius. (Annales de la Soc. Ent. de France, 3^e Sér., vi, 1858,
pp. 521–528.)

=Saussure, Henri de.= Recherches zoologiques de l’Amerique centrale et
du Mexique. (6^e Partie, Études sur les Myriopodes et les Insectes,
Paris, 1860.)

=Gerstaecker, C. E. A.= Ueber das vorkommen von ausstülpbaren
Hautanhängen am Hinterleibe an Schaben. (Archiv f. Naturgesch.,
1861, xxi, pp. 107–115.)

=Liegel, Hermann.= Ueber den Ausstülpungsapparat von Malachius und
verwandten Formen. Inaug. Diss., Göttingen, pp. 31, 1 Taf. (n. d.,
since 1858 and before 1878.)

=Leydig, F.= Zur Anatomie der Insecten. (Archiv f. Anat. Phys. u.
wiss. Med., 1859, pp. 33–89, 149–183, Taf. 2–4, pp. 35 and 38.)

—— Ueber bombardier Käfer. (Biolog. Centralbl., x, 1890, pp. 395,
396.)

=Claus, C.= Ueber die Seitendrüsen der Larve von _Chrysomela populi_.
(Zeits. f. wissens. Zool., xi, 1861, pp. 309–314, Taf. xxv.)

—— Ueber Schutzwassen der Raupen des Gabelschwanzes. (Würzburger
Naturw. Zeitschrift, 1862, iii, xiv; Sitz. am., 28 Juni, 1862.)

=Rogenhofer, Alois.= Drei Schmetterlingsmetamorphosen. (Verhandlungen
der k. k. zoolog.-bot. Gesellschaft, Wien, xiii, 1862, pp.
1224–1230.)

=Fitch, Asa.= Eighth report on the noxious and other insects of ...
New York. (Trans. N. Y. State Agric. Soc., 1862, xxii, pp. 657–684),
p. 677. (Separate.)

=Guenée, Achille.= D’une organe particulier que présente une chenille
de Lycæna. (Annales Soc. Ent. de France, Sér. 4, 1867, pp. 665–668,
Pl. 13.)

=Landois, L.= Anatomie der Bettwanze, _Cimex lectularius_, mit
berücksichtigung verwandter Hemipterengeschlechter. (Zeitsch. f.
wissens. Zool., 1868, xvii, pp. 206–224, 218–223, Taf. 11, 12.)

=Studer, Theodor.= Mittheilungen der naturforsch. Gesellschaft in
Bern, 1872–1873, No. 792–811, p. 101.

=Candèze, E.= Les moyens d’attaque et de défense chez les insectes.
(Bull. Acad. royale de Belgique, 2 Sér., xxxviii, 1874, pp.
787–816.)

=Mayer, Paul.= Anatomie von _Pyrrhocoris apterus_. (Reichert und du
Bois-Reymond’s Archiv f. Anat. Phys., etc., 1874, pp. 313–347, 3
Taf.)

=Scudder, Samuel Hubbard.= Odoriferous glands in Phasmidæ. (Psyche, i,
pp. 137–140, Jan. 14, 1876; Amer. Nat., x, p. 256, April, 1876.)

—— Prothoracic tubercles in butterfly caterpillars. (Psyche, i, pp.
64, 168, 1876.)

—— Organs found near the anus of the ♀ pupa of Danais, which recall
the odoriferous organs mentioned by Burnett, transl. Siebold’s Comp.
Anat. as occurring in Argynnis and other genera. (Psyche, iii, p.
278, 1882, p. 453, note 22.)

—— Glands and extensile organs of larvæ of blue butterflies. (Proc.
Bos. Soc. Nat. Hist., xxxiii, pp. 357, 358, 1888.)

—— Butterflies of Eastern United States. i-iii, 1889.

—— New light on the formation of the abdominal pouch in Parnassius.
(Trans. Ent. Soc. London for 1892, January, 1893, pp. 249–253.)

=Müller, Fritz.= Die Stinkkölbchen der weiblichen Maracujáfalter.
(Zeitschr. f. wissens. Zool., 1877, xxx, pp. 167–170, Taf. 9.)

=Plateau, Félix.= Note sur une sécrétion propre aux coléoptères
dytiscides. (Ann. Soc. Ent. Belg., 1876, v, xix, pp. 1–10.)

=Edwards, William H.= Notes on _Lycæna pseudargiolus_ and its larval
history. (Can. Ent., x, Jan., 1878, pp. 1–14. Fig.)

—— On the larvæ of _Lycæna pseudargiolus_ and attendant ants. (Can.
Ent., x, July, 1878, pp. 131–136.)

—— Butterflies of North America, i-iv. Many Pls. Phil., 1868—.

=Voges, Ernst.= Beiträge zur Kenntniss der Juliden. (Zeitsch. f.
wissens. Zoologie, xxxi, p. 127, 1878. The scent-glands are
retort-shaped bodies, the necks of which open into _foramina
repugnatoria_.)

=Rye, E. C.= Secretion of water-beetles. (Ent. Month. Mag., xiv,
1877–1878, pp. 232, 233.)

=Forel, A.= Der Giftapparat und die anal Drüsen der Ameisen. (Zeits.
f. wissens. Zool., 1878, xxx, Suppl., pp. 28–68, Taf. 3, 4.)

=Saunders, William.= Notes on the larva of _Lycæna scudderi_. (Can.
Ent., x, Jan., 1878, p. 14.)

=Weismann, A.= Ueber Duftschuppen. (Zool. Anzeiger, 26th Aug., 1878,
Jahrg., i, pp. 98, 99.)

=Gissler, Carl Friedrich.= On the repugnatorial glands in Eleodes.
(Psyche, ii, Feb., 1879, pp. 209, 210.)

—— Odoriferous glands on the 5th abdominal segment in nymph of
_Lachnus strobi_. (Fig. 273, p. 804, of Packard’s Report on Forest
and Shade Tree Insects, 1890.)

=Brunner von Wattenwyl, K.= Ueber ein neues Organ bei den Acridiodeen.
(Verhandl. k. k. Zool. Bot. Gesells. Wien., 1879, xxix;
Sitzungsber., pp. 26, 27.)

—— Verhandl. k. k. Zool. Bot. Gesells. Wien. (A peculiar organ on hind
femora of Acridiidæ.)

=Rougement, P.= Observations sur l’organe détonnant du _Brachinus
crepitans_ Oliv. (Bull. Soc. Sci. Nat. Neuchâtel, 1879, xi, pp.
471–478, Pl.)

=Goossens, Th.= Sur une organe entre la tête et la première paire de
pattes de quelques chenilles. (Ann. Soc. Ent. France, ix, p. 4,
1809; Bull., pp. 60, 61.)

—— Des chenilles vésicantes. (Ann. Ent. Soc. France, vi, pp. 461–464,
1887.)

=Coquillett, D. W.= On the early stages of some moths. (Can. Ent.,
March, 1880, xii, pp. 43–46.)

=Chambers, Victor Tousey.= Notes upon some Tineid larvæ. (Psyche, iii,
July, 1880, p. 67. Certain retractile processes “from the sides of
certain segments of the larva.”)

—— Further notes on some Tineid larvæ. (Psyche, iii, p. 135, Feb. 12,
1881. Larva of Phyllocnistis has eight pairs of lateral pseudopodia
on first eight abdominal segments.)

=French, G. H.= Larvæ of _Cerura occidentalis_ Lint, and _C. borealis_
Bd. (Can. Ent., July, 1881, xiii, pp. 144, 145.)

=Passerini, N.= Sopra i due tubercoli abdominali della larva della
_Porthesia chrysorrhœa_. (Bull. Soc. Ent. Ital., 1881, xiii, pp.
293–296.)

=Klemensiewicz, Stanislaus.= Zur näheren Kenntniss der Hautdrüsen bei
den Raupen und bei _Malachius_. (Verhandlungen d. Zool. Bot.
Gesellsch. Wien., xxxii, pp. 459–474, 1882, 2 Taf.)

=Weber, Max.= Ueber eine Cyanwasserstoffsäure bereitende Drüse.
(Archiv für Mikr. Anat., xxi, pp. 468–475, xxiv, 1882.)

=Bertkau, Philip.= Ueber den Stinkapparat von _Lacon murinus_ L.
(Archiv f. Naturg., 1882, Jahrg., xlviii, pp. 371–373.)

=Dimmock, George.= Organs, probably defensive in function, in the
larva of _Hyperchiria varia_ Walk. (_Saturnia io_ Harris). (Psyche,
iii, pp. 352, 353, Aug. 19, 1882. Account of lateral eversible
glands on 1st and 7th abdominal segments; they emit neither moisture
nor odor.)

—— On some glands which open externally on insects. (Psyche, iii, pp.
387–399, Jan. 15, 1883. Treats of poison-glands, glandular hairs,
eversible glands of Cerura, etc.)

=Coleman, N.= Notes on _Orgyia leucostigma_. (Papilio,
November-December, 1882, Jan., 1883, ii, pp. 164–166.)

=Müller, F.= Der Anhang am Hinterleibe der _Acræa_-weibchen. (Zool.
Anzeiger, 6th Aug., 1883, Jahrg., vi, pp. 415, 416.)

=Dewitz, H.= Ueber das durch die Foramina repugnatoria entleerte
Secret bei Glomeris. (Biol. Centralblatt, iv, pp. 202, 203, 1884.)

=Williston, S. A.= Protective secretion of Eleodes ejected from anal
gland. (Psyche, iv, p. 168, May, 1884.)

=Poulton, Edward Bagnall.= Notes in 1885 upon lepidopterous larvæ and
pupæ, including an account of the loss of weight in the
freshly-formed lepidopterous pupæ. (Trans. Ent. Soc., London, June,
1886, pp. 156, 157, 159.)

—— Notes in 1886 upon lepidopterous larvæ, etc. (Trans. Ent. Soc.,
London, Sept., 1887, pp. 295–301.)

—— Notes in 1887 upon lepidopterous larvæ, etc. (Trans. Ent. Soc.,
London, 1888, p. 597.)

=Künckel-d’Herculais, J.= La punaise de lit et ses appareils
odoriférants. (Comptes rendus, ciii, 1886, pp. 81–83; Annals & Mag.
Nat. Hist., 5th Ser., xviii, 1886, pp. 167, 168.)

—— Étude comparée des appareils odorifiques dans les differents
groupes d’Hemiptères hétéroptères. (Compt. rend. Acad. Sc., Paris,
cxx, pp. 1002–1004.)

=Packard, A. S.= The fluid ejected by notodontian caterpillars. (Amer.
Nat., 1886, xx, pp. 811, 812.)

—— An eversible “gland” in the larva of Orgyia. (Amer. Nat., 1886, xx,
p. 814.)

—— Fifth Rep. U. S. Ent. Comm. Insects injurious to forest and shade
trees, p. 136, 1890.

—— Hints on the evolution of the bristles, spines, and tubercles of
certain caterpillars. (Proc. Boston Soc. Nat. Hist., xxiv, 1890, p.
551.)

—— Notes on some points in the external structure and phylogeny of
lepidopterous larvæ. (Proc. Bost. Soc. Nat. Hist., xxv, 1890, pp.
83–114.)

—— A study of the transformations and anatomy of _Lagoa crispata_, a
bombycine moth. (Proc. Amer. Phil. Soc., Philadelphia, xxxii, 1893,
pp. 275–292, 7 Pls.)

—— The eversible repugnatorial scent glands of insects. (Journ., N. Y.
Ent. Soc. iii, 1895, pp. 110–127; iv, p. 896; pp. 26–32, 1 Pl.)

=Loman, J. C. C.= Freies Jod als Drüsensecret. (Tijdschr. Neder.
Dierk. Ver. Deel 1, 1887, pp. 106–108.)

=Riley, Charles Valentine.= Proc. Ent. Soc., Washington, March 13,
1888, i, pp. 87–89.

—— Notes on the eversible glands of larvæ of _Orgyia_ and _Parorgyia
leucopæa_ and _P. clintonii (achatina)_. (See 5th Rep. U. S. Ent.
Comm., p. 137.)

=Denham, Ch. S.= The acid secretion of _Notodonta concinna_. (Insect
Life, i, p. 147, 1888; hydrochloric acid.)

=Michin, Edward A.= Note on a new organ, and on the structure of the
hypodermis, in _Periplaneta orientalis_. (Quart. Journ. Micros. Sc.,
Dec., 1888, xxiv, 1 Pl.)

—— Further observations on the dorsal gland in the abdomen of
Periplaneta and its allies. (Zool. Anz., 27 Jan., 1890, pp. 41–44.)

=Maynard, C. L.= The defensive glands of a species of Phasma,
_Anisomorpha buprestoides_. (Contributions to Science, i, April,
1889.)

=Schaeffer, Cæsar.= Beiträge zur Histologie der Insekten. (Zool.
Jahrb. Morph. Abth. iii, pp. 611–652, Taf. xxix, xxx, 1889; treats
of the ventral glands in prothorax of caterpillars; scales and hairs
are secretions from the very greatly enlarged hypodermic cells.)

=Gilson, G.= Les glandes odorifères der _Blaps mortisaga_ et de
quelques autres espèces. (La Cellule, v. pp. 1–21, 1 Pl., 1889.)

—— The odoriferous apparatus of _Blaps mortisaga_. (Rep. 58th Meeting
Brit. Assoc. Adv. Sc., 1889, pp. 727, 728.)

=Haase, Erich.= Ueber die Stinkdrüsen der Orthoptera. (Sitzgsber. Ges.
Naturf. Freunde, Berlin, pp. 57, 58, 1889.)

—— Zur Anatomie der Blattiden. (Zool. Anz., xii Jahrg., pp. 169–172,
1889.)

=Herbst, Curt.= Anatomische Untersuchungen an _Scutigera coleoptrata_.
Ein Beitrag zur vergleichenden Anatomie der Articulaten. Dissert.,
Jena, pp. 36 (Hautdrüsen, Coxal-Organ.); p. 1, 1889.

=Wheeler, William M.= Hydrocyanic acid secreted by _Polydesmus
virginiensis_ Drury. (Psyche, v, p. 422.)

—— New glands in the hemipterous embryo. (Amer. Nat., Feb. 1890, p.
187; odorous(?) glands.)

=Jackson, W. Hatchett.= Studies in the morphology of the Lepidoptera,
Pt. i. (Trans. Linn. Soc., London, 2 Ser., Zoöl., v, May, 1890.)

=Krauss, Hermann.= Die Duftdrüse der _Aphlebia bivittata_ Brullé
(Blattidæ) von Teneriffa. (Zool. Anz., xiii Jahrg., 1890, pp.
584–587, 3 Figs.)

=Fernald, H. T.= Rectal glands in Coleoptera. (Amer. Nat., xxiv, pp.
100, 101, Pls. 4, 5, 1890.)

=Verson, E.= Hautdrüsen system bei Bombyciden (Seidenspinner). (Zool.
Anzeiger, 1890, pp. 118–120.)

=Vosseler, Julius.= Die Stinkdrüsen der Forficuliden. (Arch. Mikr.
Anat., xxxvi, 1890, pp. 565–578, Taf. 29.)

=Carrière, J.= Die Drüsen am ersten Hinterleibsringe der
Insektenembryonen. (Biol. Centralblatt, xi, pp. 110–127, 1891.)

=Borgert, Henry.= Die Hautdrüsen der Tracheaten. Inaugural Diss.,
Jena, 1891, pp. 1–80.

=Lang, Arnold.= Lehrbuch der vergleichende Anatomie, English Trans. by
Henry M. and Matilda Bernard, 1891, pp. 458, 459.

=Kennel, J. von.= Die Verwandtschaftverhältnisse der Arthropoden.
(Schriften herausgegeben von der Naturforscher Gesellschaft bei der
Universität Dorpat, vi, Dorpat, 1891.)

=Patton, W. H.= Scent-glands in the larva of Limacodes. (Can. Ent.,
xxiii, Feb. 1891, pp. 42, 43; eight pairs of glands with pores along
the edges of the back.)

=Batelli, Andrea.= Di una particolarita nell integumento dell’
_Aphrophora spumaria_. (Monitore Zoöl. Ital. Anno 2, pp. 30–32,
1891. Dermal glands in the hindermost segment.)

=Ash, C. D.= Notes on the larva of _Danima banksii_ Lewin. (Ent.
Month. Mag., Sept. 1892, p. 232, Fig.) notodontian larva protrudes
from under side of prothoracic segment a Y-shaped, red organ like
that of Papilio; no odor or fluid given out.

=Bernard, Henry M.= An endeavor to show that the tracheæ of the
Arthropoda arose from setiparous sacs. (Spengel’s Zool., Jahrbuch,
1892, pp. 511–524, 3 Figs.)

=Latter, Oswald.= The secretion of potassium hydroxide by _Dicranura
vinula_, and the emergence of the imago from the cocoon. (Trans.
Ent. Soc. London, 1892, 287, also xxxii; Prof. Meldola adds that the
larva of _D. vinula_ secretes strong, formic acid, and is the only
animal known to secrete a strong, caustic alkali.)

—— Further notes on the secretion of potassium hydroxide by _Dicranura
vinula_ (imago), and similar phenomena in other Lepidoptera. (Trans.
Ent. Soc. London; Nature, 1895, p. 551, March 20, 1895.)

=Zograff, Nicolas.= Note sur l’origine et les parentes des
Arthropodes, principalement des Arthropodes trachèates. (Congrès
Internationale de Zoologie, 2^e Session à Moscow, Aug. 1892; Part i,
Moscow, 1892, pp. 278–302, 1892; cyanogenic glands in Myriopods, p.
287.)

=Swale, H.= Odor of _Olophrum piceum_. (Ent. Month. Mag., v, Jan.
1896, pp. 1, 2.)

=Cuénot, L.= Moyens de défense dans la série animale, Paris, n. d.
(1892); the ejection of blood as a means of defence by some
Coleoptera. (Comptes rendus, Acad. Sc. France, April 16; Nature,
April 26, 1894.)

—— Sur la saignée réflexe et les moyens de défense de quelques
insectes. (Arch. Zool. expér. (3), 1897, iv, pp. 655, 679, 680.)

=Holmgren, Emil.= Studier öfverhudens och de körtelartade hudorganens
morfologi hos skandinaviska macrolepidopterlarver. (K. Svenska
Vetenskaps-Akademiens Handlingar, xxvii, No. 4, Stockholm, 4º 1895,
pp. 82, 9 Pls.)

=Lutz, K. G.= Das Blut der Coccinelliden. (Zool. Anzeiger, 1895, pp.
244–255, 1 Fig.)

=Gilson, Gustav.= Studies in insect morphology. (Proc. Linn. Soc.
London, March 5, 1896; Nature, p. 500.)

—— On segmentally disposed thoracic glands in the larvæ of the
Trichoptera. (Journ. Linn. Soc., London, xxv. 1897.)

=Cholodkowsky, N.= Entomotomische Miscellen, v, Ueber die
Spritzapparate der Cimbiciden Larven, pp. 135–143, 2 Taf. Ibid., vi.
Ueber das Bluten der Cimbiciden Larven, pp. 352–357, 1 Fig. (Horæ
Soc. Ent. Rossicæ, xxx, 1897.)

Also the writings of Darwin, Wallace, Poulton, Weir, Beddard, Butler,
Busgen, (pp. 365–367), Girard, Kolbe, Locy.

THE ALLURING OR SCENT-GLANDS

It is difficult to draw the line between repelling and alluring glands. Attention was first definitely called to the alluring odors of Lepidoptera by Fritz Müller, who showed that the males of certain butterflies are rendered attractive to the other sex by secreting odorous oils of the ether series. He pointed out that the seat of the odor is the androconia (see p. 199), while either repellent or pleasant odors are exhaled from abdominal glands.

Those of _Pieris napi_ yield a scent like that of citrons, _Didonis
biblis_ gives off three different odors from different parts of the
body, besides having a distinctly odorous spot on the hind wings.
Both sexes have a sac between the fourth and fifth abdominal
segments which exhales a very unpleasant (protective) odor, while
the males have on the succeeding segment a pair of glands from which
proceeds an agreeable odor like that of the heliotrope. _Callidryas
argante_ throws off a musky odor. In _Prepona laertes_ the odor is
like that of a bat, in _Dircenna xantho_ it is vanilla-like, the
androconia being situated on the front edge of the hind wings. In
_Papilio grayi_ the odor is said to be as agreeable and intense as
in flowers. Certain sphingids are known to exhale a distinct odor,
which Müller has traced to a tuft of hair-like scales at the base of
the abdomen, and which fits into a groove in the first segment, so
as to be ordinarily invisible.

_Fig. 367._—Scent-tufts: 1, of _Leucarctia acræa_; 2, of _Pyrrarctia
isabella_.—After Smith.
]

In the noctuid genus, Patula, the costal half of the hind wing is
modified to form a large scent-gland, and in consequence the
venation has been modified. The still greater distortion of the
veins in the allied genus, Argida, was attributed by the author to
its once having possessed a similar scent-gland, now become
rudimentary by disuse. (Hampson.)

Peculiar white or orange-colored, hairy, thread-like processes have
been found protruding from narrow openings near the tip of the
abdomen of Arctian moths (Fig. 367), which throw off, according to
J. B. Smith, “an intense odor, somewhat like the smell of laudanum.”
We have perceived the same unpleasant odor emanating from the males
of _Spilosoma virginica_ and _Arctia virgo_, as well as _Leucarctia
acræa_.