(L. J. S.)
HEMINGBURGH, WALTER OF,also commonly, but erroneously, calledWalter Hemingford, a Latin chronicler of the 14th century, was a canon regular of the Austin priory of Gisburn in Yorkshire. Hence he is sometimes known as Walter of Gisburn (Walterus Gisburnensis). Bale seems to have been the first to give him the name by which he became more commonly known. His chronicle embraces the period of English history from the Conquest (1066) to the nineteenth year of Edward III., with the exception of the years 1316-1326. It ends with the title of a chapter in which it was proposed to describe the battle of Creçy (1346); but the chronicler seems to have died before the required information reached him. There is, however, some controversy as to whether the later portions which are lacking in some of the MSS. are by him. In compiling the first part, Hemingburgh apparently used the histories of Eadmer, Hoveden, Henry of Huntingdon, and William of Newburgh; but the reigns of the three Edwards are original, composed from personal observation and information. There are several manuscripts of the history extant—the best perhaps being that presented to the College of Arms by the earl of Arundel. The work is correct and judicious, and written in a pleasing style. One of its special features is the preservation in its pages of copies of the great charters, and Hemingburgh’s versions have more than once supplied deficiencies and cleared up obscurities in copies from other sources.
The first three books were published by Thomas Gale in 1687, in hisHistoriae Anglicanae scriptores quinque, and the remainder by Thomas Hearne in 1731. The first portion was again published in 1848 by the English Historical Society, under the titleChronicon Walteri de Hemingburgh, vulgo Hemingford nuncupati, de gestis regum Angliae, edited by H. C. Hamilton.
The first three books were published by Thomas Gale in 1687, in hisHistoriae Anglicanae scriptores quinque, and the remainder by Thomas Hearne in 1731. The first portion was again published in 1848 by the English Historical Society, under the titleChronicon Walteri de Hemingburgh, vulgo Hemingford nuncupati, de gestis regum Angliae, edited by H. C. Hamilton.
HEMIPTERA(Gr.ἡμι-, half andπτερόν, a wing), the name applied in zoological classification to that order of the class Hexapoda (q.v.) which includes bugs, cicads, aphids and scale-insects. The name was first used by Linnaeus (1735), who derived it from the half-coriaceous and half-membranous condition of the forewing in many members of the order. But the wings vary considerably in different families, and the most distinctive feature is the structure of the jaws, which form a beak-like organ with stylets adapted for piercing and sucking. Hence the nameRhyngota(orRhynchota), proposed by J. C. Fabricius (1775), is used by many writers in preference to Hemiptera.
I., Frons.
II., Base of mandible.
III., Base of first maxillae.
IV., Second maxillae forming rostrum.
V., Pronotum.
Structure.—The head varies greatly in shape, and the feelers have usually but few segments—often only four or five. The arrangement of the jaws is remarkably constant throughout the order, if we exclude from it the lice (Anoplura). Taking as our type the head of a cicad, we find a jointed rostrum or beak (figs. 1 and 2, IV.b,c) with a deep groove on its anterior face; this organ is formed by the second pair of maxillae and corresponds therefore to the labium or “lower lip” of biting insects. Within the groove of the rostrum two pairs of slender piercers—often barbed at the tip—work to and fro. One of these pairs (fig. 2, II.a,b,c) represents the mandibles, the other (fig. 2, III.a,b,c) the first maxillae. The piercing portions of the latter—representing their inner lobes or laciniae—lie median to the mandibular piercers in the natural position of the organs. These homologies of the hemipterous jaws were determined by J. C. Savigny in 1816, and though disputed by various subsequent writers, they have been lately confirmed by the embryological researches of R. Heymons (1899). Vestigial palps have been described in various species of Hemiptera, but the true nature of these structures is doubtful. In front of the rostrum and the piercers lies the pointed flexible labrum and within its base a small hypopharynx (fig. 2, IV.d) consisting of paired conical processes which lie dorsal to the “syringe” of the salivary glands. This latter organ injects a secretion into the plant oranimal tissue from which the insect is sucking. The point of the rostrum is pressed against the surface to be pierced; then the stylets come into play and the fluid food is believed to pass into the mouth by capillary attraction.
I.,a, frons;b, clypeus;c, labrum;d, epipharynx.
I’., Same from behind.
II., Mandible.
III., 1st maxillae,a, base;b, sheath;c, stylet;c′, muscle.
IV., 2nd maxillae,a, sub-mentum;b, mentum;c, ligula, forming beak;d, hypopharynx (shown also from frontd′, and behindd″).
V., Prothorax,b, haunch;a, trochanter.
The prothorax (figs. 1 and 2, V.) in Hemiptera is large and free, and the mesothoracic scutellum is usually extensive. The number of tarsal segments is reduced; often three, two or only one may be present instead of the typical insectan number five. The wings will be described in connexion with the various sub-orders, but an interesting peculiarity of the Hemiptera is the occasional presence of winged and wingless races of the same species. Eleven abdominal segments can be recognized, at least in the early stages; as the adult condition is reached, the hinder segments become reduced or modified in connexion with the external reproductive organs, and show, in some male Hemiptera, a marked asymmetry. The typical insectan ovipositor with its three pairs of processes, one pair belonging to the eighth and two pairs to the ninth abdominal segment, can be distinguished in the female.
In the nervous system the concentration of the trunk ganglia into a single nerve-centre situated in the thorax is remarkable. The digestive system has a slender gullet, a large crop and no gizzard; in some Hemiptera the hinder region of the mid-gut forms a twisted loop with the gullet. Usually there are four excretory (Malpighian) tubes; but there are only two in theCoccidaeand none in theAphidae. “Stink glands,” which secrete a nauseous fluid with a defensive function, are present in many Hemiptera. In the adult there is a pair of such glands opening ventrally on the hindmost thoracic segment, or at the base of the abdomen; but in the young insect the glands are situated dorsally and open to the exterior on a variable number of the abdominal terga.
Development.—In most Hemiptera the young insect (fig. 3) resembles its parents except for the absence of wings, and is active through all stages of its growth. In all Hemiptera the wing-rudiments develop externally on the nymphal cuticle, but in some families—the cicads for example—the young insect (fig. 10) is a larva differing markedly in form from its parent, and adapted for a different mode of life, while the nymph before the final moult is sluggish and inactive. In the maleCoccidae(Scale-insects) the nymph (fig. 4) remains passive and takes no food. The order of the Hemiptera affords, therefore, some interesting transition stages towards the complete metamorphosis of the higher insects.
Distribution and Habits.—Hemiptera are widely distributed, and are plentiful in most quarters of the globe, though they probably have not penetrated as far into remote and inhospitable regions as have the Coleoptera, Diptera and Aptera. They feed entirely by suction, and the majority of the species pierce plant tissues and suck sap. The leaves of plants are for the most part the objects of attack, but many aphids and scale-insects pierce stems, and some go underground and feed on roots. The enormous rate at which aphids multiply under favourable conditions makes them of the greatest economic importance, since the growth of immense numbers of the same kind of plant in close proximity—as in ordinary farm-crops—is especially advantageous to the insects that feed on them. Several families of bugs are predaceous in habit, attacking other insects—often members of their own order—and sucking their juices. Others are scavengers feeding on decaying organic matter; the pond skaters, for example, live mostly on the juices of dead floating insects. And some, like the bed-bugs, are parasites of vertebrate animals, on whose bodies they live temporarily or permanently, and whose blood they suck.
The Hemiptera are especially interesting as an order from the variety of aquatic insects included therein. Some of these—theHydrometridaeor pond-skaters, for example—move over the surface-film, on which they are supported by their elongated, slender legs, the body of the insect being raised clear of the water. They are covered with short hairs which form a velvet-like pile, so dense that water cannot penetrate. Consequently when the insect dives, an air-bubble forms around it, a supply of oxygen is thus secured for breathing and the water is kept away from the spiracles. In many of these insects, while most individuals of the species are wingless, winged specimens are now and then met with. The occasional development of wings is probably of service to the species in enabling the insects to reach new fresh-water breeding-grounds. This family of Hemiptera (theHydrometridae) and theSaldidaecontain several insects that are marine, haunting the tidal margin. One genus ofHydrometridae(Halobates) is even oceanic in its habit, the species being met with skimming over the surface of the sea hundreds of miles from land. Probably they dive when the surface becomes ruffled. In these marine genera the abdomen often undergoes excessive reduction (fig. 5).
Other families of Hemiptera—such as the “Boatmen” (Notonectidae) and the “Water-scorpions” (fig. 6) and their allies (Nepidae) dive and swim through the water. They obtain their supply of air from the surface. TheNepidaebreathe by means of a pair of long, grooved tail processes (really outgrowthsof the abdominal pleura) which when pressed together form a tube whose point can pierce the surface film and convey air to the hindmost spiracles which are alone functional in the adult. TheNotonectidaebreathe mostly through the thoracic spiracles; the air is conveyed to these from the tail-end, which is brought to the surface, along a kind of tunnel formed by overlapping hairs.
a, Body of male Cicad from below, showing cover-plates of musical organs;
b, From above showing drums, natural size;
c, Section showing muscles which vibrate drum (magnified);
d, A drum at rest;
e, Thrown into vibration, more highly magnified.
Sound-producing Organs.—The Hemiptera are remarkable for the variety of their stridulating organs. In many genera of thePentatomidae, bristle-bearing tubercles on the legs are scraped across a set of fine striations on the abdominal sterna. InHalobatesa comb-like series of sharp spines on the fore-shin can be drawn across a set of blunt processes on the shin of the opposite leg. Males of the little water-bugs of the genusCorixamake a shrill chirping note by drawing a row of teeth on the flattened fore-foot across a group of spines on the haunch of the opposite leg. But the loudest and most remarkable vocal organs of all insects are those of the male cicads, which “sing” by the rapid vibration of a pair of “drums” or membranes within the metathorax. These drums are worked by special muscles, and the cavities in which they lie are protected by conspicuous plates visible beneath the base of the abdomen (see fig. 7).
Fossil History.—The Heteroptera can be traced back farther than any other winged insects if the fossilProtocimex siluricaMoberg, from the Ordovician slates of Sweden is rightly regarded as the wing of a bug. But according to the recent researches of A. Handlirsch it is not insectan at all. Both Heteropterous and Homopterous genera have been described from the Carboniferous, but the true nature of some of these is doubtful.Eugereonis a remarkable Permian fossil, with jaws that are typically hemipterous except that the second maxillae are not fused and with cockroach-like wings. In the Jurassic period many of the existing families, such as theCicadidae,Fulgoridae,Aphidae,Nepidae,Reduviidae,Hydrometridae,LygaeidaeandCoreidae, had already become differentiated.
Classification.—The number of described species of Hemiptera must now be nearly 20,000. The order is divided into two sub-orders, the Heteroptera and the Homoptera. The Anoplura or lice should not be included among the Hemiptera, but it has been thought convenient to refer briefly to them at the close of this article.HeteropteraIn this sub-order are included the various families of bugs and their aquatic relations. The front of the head is not in contact with the haunches of the fore-legs. There is usually a marked difference between the wings of the two pairs. The fore-wing is generally divided into a firm coriaceous basal region, occupying most of the area, and a membranous terminal portion, while the hind-wing is delicate and entirely membranous (see fig. 6). In the firm portion of the fore-wing two distinct regions can usually be distinguished; most of the area is formed by thecorium(fig. 6,co), which is separated by a longitudinal suture from theclavus(fig. 6,cl) on its hinder edge, and in some families there is also acuneus(fig. 9cu) external to and anemboliumin front of thecorium.After Marlatt,Bull.4 (N.S.)Div. Ent. U.S. Dept. Agr.Fig. 8.—Bed-bug (Cimex lectularius, Linn.).a, Female from above;b, From beneath;c, Vestigial wing;d, Jaws, very highly magnified (tips of mandibles and 1st maxillae still more highly magnified).Most Heteroptera are flattened in form, and the wings lie flat, or nearly so, when closed. The young Heteropteron is hatched from the egg in a form not markedly different from that of its parent; it is active and takes food through all the stages of its growth. It is usual to divide the Heteroptera into two tribes—the Gymnocerata and the Cryptocerata.After M. V. Slingerland,Cornell Univ. Ent. Bull.58.Fig. 9.—Capsid Leaf-bug (Poecilocapsus lineatus) N. America. Magnified—,cucuneus.Gymnocerata.—This tribe includes some eighteen families of terrestrial, arboreal and marsh-haunting bugs, as well as those aquatic Heteroptera that live on the surface-film of water. The feelers are elongate and conspicuous. ThePentatomidae(shield-bugs), some of which are metallic or otherwise brightly coloured, are easily recognized by the great development of the scutellum, which reaches at least half-way back towards the tip of the abdomen, and in some genera covers the whole of the hind body, and also the wings when these are closed. TheCoreidaehave a smaller scutellum, and the feelers are inserted high on the head, while in theLygaeidaethey are inserted lower down. These three families have the foot with three segments. In the curious littleTingidae, whose integuments exhibit a pattern of network-like ridges, the feet are two-segmented and the scutellum is hidden by the pronotum. TheAradidaehave two segmented feet, and a large visible scutellum. TheHydrometridaeare a large family including the pond-skaters and other dwellers on the surface-film of fresh water, as well as the remarkable oceanic genusHalobatesalready referred to. TheReduviidaearea family of predaceous bugs that attack other insects and suck their juices; the beak is short, and carried under the head in a hook-like curve, not—as in the preceding families—lying close against the breast. TheCimicidaehave the feet three-segmented and the forewings greatly reduced; most of the species are parasites on birds and bats, but one—Cimex lectidarius(figs. 3, 8)—is the well-known “bed-bug” which abounds in unclean dwellings and sucks human blood (seeBug). TheAnthocoridaeare nearly related to theCimicidae, but the wings are usually well developed and the forewing possesses cuneus and embolium as well as corium and clavus. TheCapsidaeare a large family of rather soft-skinned bugs mostly elongate in form with the two basal segments of the feelers stouter than the two terminal. The forewing in this family has a cuneus (fig. 9cu), but not an embolium. These insects are often found in large numbers on plants whose juices they suck.Cryptocerata.—In this tribe are included five or six families of aquatic Heteroptera which spend the greater part of their lives submerged, diving and swimming through the water. The feelers are very small and are often hidden in cavities beneath the head. TheNaucoridaeandBelostomatidaeare flattened insects, with four-segmented feelers and fore-legs inserted at the front of the prosternum. Two species of the former family inhabit our islands, but theBelostomatidaeare found only in the warmer regions of the globe; some of them, attaining a length of 4 to 5 in., are giants among insects. TheNepidae(fig. 6) or water-scorpions (q.v.)—two British species—are distinguished by their three-segmented feelers, their raptorial fore-legs (in which the shin and foot, fused together, work like a sharp knife-blade on the grooved thigh), and their elongate tail-processes formed of the abdominal pleura and used for respiration. TheNotonectidae, or “water-boatmen” (q.v.) have convex ovoid bodies admirably adapted for aquatic life. By means of the oar-like hind-legs they swim actively through the water with the ventral surface upwards; the fore-legs are inserted at the hinder edge of the prosternum. TheCorixidaeare small flattened water-bugs, with very short unjointed beak, the labrum being enclosed within the second maxillae, and the foot in the fore and intermediate leg having but a single segment. The hinder abdominal segments in the male show a curious asymmetrical arrangement, the sixth segment bearing on its upper side a small stalked plate (strigil) of unknown function, furnished with rows of teeth. On account of the reduction and modification of the jaws in theCorixidae, C. Börner has lately suggested that they should form a special sub-order of Hemiptera—the Sandaliorrhyncha.From Mariatt,Bull.14 (N. S.),Div. Ent. U.S. Dept. Agr.Fig. 10.—a, Nymph (4th stage) of Cicad, magnified;c,d, inner and outer faces of front leg, magnified—;b, teeth on thigh, more highly magnified.HomopteraThis sub-order includes the cicads, lantern-flies, frog-hoppers, aphids and scale-insects. The face has such a marked backward slope (see fig. 1) as to bring the beak into close contact with the haunches of the fore-legs. The feelers have one or more thickened basal segments, while the remaining segments are slender and thread-like. The fore-wings are sometimes membranous like the hind-wings, usually they are firmer in texture, but they never show the distinct areas that characterize the wings of Heteroptera. When at rest the wings of Homoptera slope roofwise across the back of the insect. In their life-history the Homoptera are more specialized than the Heteroptera; the young insect often differs markedly from its parent and does not live in the same situations; while in some families there is a passive stage before the last moult.After Weed, Riley and Howard,Insect Life, vol iii.Fig. 11.—Cabbage Aphid (Aphisbrassicae).a, Male;c, female (wingless). Magnified.bandd, Head and feelers of male and female, more highly magnified.After Howard,Year Book U.S. Dept. Agr., 1894.Fig. 12.—Apple Scale Insect (Mytilaspis pomorum).a, Male;e, female;c, larva magnified—;b, foot of male;d, feeler of larva, more highly magnified.TheCicadidaeare for the most part large insects with ample wings; they are distinguished from other Homoptera by the front thighs being thickened and toothed beneath. The broad head carries, in addition to the prominent compound eyes, three simple eyes (ocelli) on the crown, while the feeler consists of a stout basal segment, followed by five slender segments. The female, by means of her serrated ovipositor, lays her eggs in slits cut in the twigs of plants. The young have simple feelers and stout fore-legs (fig. 10) adapted for digging; they live underground and feed on the roots of plants. In the case of a North American species it is known that this larval life lasts for seventeen years. The “song” of the male cicads is notorious and the structures by which it is produced have already been described (see alsoCicada). There are about 900 known species, but the family is mostly confined to warm countries; only a single cicad is found in England, and that is restricted to the south.After Howard,Year Book U.S. Dept. Agr., 1894.Fig. 13.—Apple Scale Insect (Mytilaspis pomorum). a, Scale from beneath showing female and eggs;b, from above, magnified—;cande, female and male scales on twigs, natural size;d, male scale magnified.From Osborn (after Denny),Bull.5 (N.S.),Div. Ent. U.S. Dept. Agr.Fig. 14.—Louse (Pediculus vestimenti). Magnified.TheFulgoridaeandMembracidaeare two allied families most of whose members are also natives of hot regions. TheFulgoridaehave the head with two ocelli and three-segmented feelers; frequently as in the tropical “lantern-flies” (q.v.) the head is prolonged into a conspicuous bladder, or trunk-like process. TheMembracidaeare remarkable on account of the backward prolongation of the pronotum into a process or hood-like structure which may extend far behind the tail-end of the abdomen. Two other allied families, theCercopidaeandJassidae, are more numerously represented in our islands. The young of many of these insects are green and soft-skinned, protecting themselves by the well-known frothy secretion that is called “cuckoo-spit.”From Osborn (after Schiödte),Bull.5; (N.S.),Div. Ent. U.S. Dept. Agr.Fig. 15.—Proboscis of Pediculus. Highly magnified.In all the above-mentioned families of Homoptera there are three segments in each foot. The remaining four families have feet with only two segments. They are of very great zoological interest on account of the peculiarities of their life-history—parthenogenesis being of normal occurrence among most of them. The familiesPsyllidae(or “jumpers”) with eight or ten segments in the feeler and theAleyrodidae(or “snowy-flies”) distinguished by their white mealy wings, are of comparatively slight importance. The two families to which special attention has been paid are theAphidaeor plant-lice (“green fly”) and theCoccidaeor scale-insects. The aphids (fig. 11) have feelers with seven or fewer distinct segments, and the fifth abdominal segment usually carries a pair of tubular processes through which a waxy secretion is discharged. The sweet “honey-dew,” often sought as a food by ants, is secreted from the intestines of aphids. The peculiar life-cycle in which successive generations are produced through the summer months by virgin females—the egg developing within the body of the mother—is described at length in the articlesAphidesandPhylloxera. TheCoccidaehave only a single claw to the foot; the males (fig. 12a) have the fore-wings developed and the hind-wings greatly reduced, while in the female wings are totally absent and the body undergoes marked degradation (figs. 12,e, 13,a,b). In the Coccids the formation of a protective waxy secretion—present in many genera of Homoptera—reaches its most extreme development. In some coccids—the “mealy-bugs” (Dactylopius, &c.) for example—the secretion forms a white thread-like or plate-like covering which the insect carries about. But in most members of the family, the secretion, united with cast cuticles and excrement, forms a firm “scale,” closely attached by its edges to the surface of the plant on which the insect lives, and serving as a shield beneath which the female coccid, with her eggs (fig. 13a) and brood, finds shelter. The male coccid passes through a passive stage (fig. 4) before attaining the perfect condition. Many scale-insects are among the most serious of pests, but various species have been utilized by man for the production of wax (lac) and red dye (cochineal). SeeEconomic Entomology,Scale-Insect.AnopluraThe Anoplura or lice (seeLouse) are wingless parasitic insects (fig. 14) forming an order distinct from the Hemiptera, their sucking and piercing mouth-organs being apparently formed on quite a different plan from those of the Heteroptera and Homoptera. In front of the head is a short tube armed with strong recurved hooks which can be fixed into the skin of the host, and from the tube an elongate more slender sucking-trunk can be protruded (fig. 15). Each foot is provided with a single strong claw which, opposed to a process on the shin, serves to grasp a hair of the host, all the lice being parasites on different mammals. Although G. Enderlein has recently shown that the jaws of the Hemiptera can be recognized in a reduced condition in connexion with the louse’s proboscis, the modification is so excessive that the group certainly deserves ordinal separation.Bibliography.—A recent standard work on the morphology of the Hemiptera by R. Heymons (Nova Acta Acad. Leop. Carol.lxxiv. 3, 1899) contains numerous references to older literature. An excellent survey of the order is given by D. Sharp (Cambridge Nat. Hist.vol. vi., 1898). For internal structure of Heteroptera see R. Dufour,Mem. savans étrangers(Paris, iv., 1833); of Homoptera, E. Witlaczil (Arb. Zool. Inst. Wien, iv., 1882,Zeits. f. wiss. Zool.xliii., 1885). The development of Aphids has been dealt with by T. H. Huxley (Trans. Linn. Soc.xxii., 1858) and E. Witlaczil (Zeits. f. wiss. Zool.xl., 1884). Fossil Hemiptera are described by S. H. Scudder in K. Zittel’sPaléontologie(French translation, vol. ii. Paris, 1887, and English edition, vol. i., London, 1900), and by A. Handlirsch (Verh. zool. bot. Gesell. Wien, lii., 1902). Among general systematic works on Heteroptera may be mentioned J. C. Schiödte (Ann. Mag. Nat. Hist.(4) vi., 1870); C. Stal’sEnumeratio Hemipterorum(K. Svensk. Vet. Akad. Handl.ix.-xiv., 1870-1876); L. Lethierry and G. Severin’sCatalogue générale des hémiptères(Brussels 1893, &c.); G. C. Champion’s volumes in theBiologia Centrali-Americana; W. L. Distant’s Oriental Cicadidae (London, 1889-1892), and many other papers; M. E. Fernald’sCatalogue of the Coccidae(Amherst, U.S.A., 1903). European Hemiptera have been dealt with in numerous papers by A. Puton. For British species we have E. Saunders’sHemiptera-Heteroptera of the British Isles(London, 1892); J. Edwards’s Hemiptera-Homoptera of the British Isles (London, 1896); J. B. Buckton’sBritish Aphidae(London, Ray Society, 1875-1882); and R. Newstead’sBritish Coccidae(London, Ray Society, 1901-1903). Aquatic Hemiptera are described by L. C. Miall (Nat. History Aquatic Insects; London, 1895), and by G. W. Kirkaldy in numerous recent papers (Entomologist, &c.). For marine Hemiptera (Halobates) see F. B. White (Challenger Reports, vii., 1883); J. J. Walker (Ent. Mo. Mag., 1893); N. Nassonov (Warsaw, 1893), and G. H. Carpenter (Knowledge, 1901, andReport, Pearl Oyster Fisheries, Royal Society, 1906). Sound-producing organs of Heteroptera are described by A. Handlirsch (Ann. Hofmus. Wien, xv. 1900), and G. W. Kirkaldy (Journ. Quekett Club(2) viii. 1901); of Cicads by G. Carlet (Ann. Sci. Nat. Zool.(6) v. 1877). For the Anoplura see E. Piaget’sPediculines(Leiden, 1880-1905), and G. Enderlein (Zool. Anz.xxviii., 1904).
Classification.—The number of described species of Hemiptera must now be nearly 20,000. The order is divided into two sub-orders, the Heteroptera and the Homoptera. The Anoplura or lice should not be included among the Hemiptera, but it has been thought convenient to refer briefly to them at the close of this article.
Heteroptera
In this sub-order are included the various families of bugs and their aquatic relations. The front of the head is not in contact with the haunches of the fore-legs. There is usually a marked difference between the wings of the two pairs. The fore-wing is generally divided into a firm coriaceous basal region, occupying most of the area, and a membranous terminal portion, while the hind-wing is delicate and entirely membranous (see fig. 6). In the firm portion of the fore-wing two distinct regions can usually be distinguished; most of the area is formed by thecorium(fig. 6,co), which is separated by a longitudinal suture from theclavus(fig. 6,cl) on its hinder edge, and in some families there is also acuneus(fig. 9cu) external to and anemboliumin front of thecorium.
a, Female from above;
b, From beneath;
c, Vestigial wing;
d, Jaws, very highly magnified (tips of mandibles and 1st maxillae still more highly magnified).
Most Heteroptera are flattened in form, and the wings lie flat, or nearly so, when closed. The young Heteropteron is hatched from the egg in a form not markedly different from that of its parent; it is active and takes food through all the stages of its growth. It is usual to divide the Heteroptera into two tribes—the Gymnocerata and the Cryptocerata.
Gymnocerata.—This tribe includes some eighteen families of terrestrial, arboreal and marsh-haunting bugs, as well as those aquatic Heteroptera that live on the surface-film of water. The feelers are elongate and conspicuous. ThePentatomidae(shield-bugs), some of which are metallic or otherwise brightly coloured, are easily recognized by the great development of the scutellum, which reaches at least half-way back towards the tip of the abdomen, and in some genera covers the whole of the hind body, and also the wings when these are closed. TheCoreidaehave a smaller scutellum, and the feelers are inserted high on the head, while in theLygaeidaethey are inserted lower down. These three families have the foot with three segments. In the curious littleTingidae, whose integuments exhibit a pattern of network-like ridges, the feet are two-segmented and the scutellum is hidden by the pronotum. TheAradidaehave two segmented feet, and a large visible scutellum. TheHydrometridaeare a large family including the pond-skaters and other dwellers on the surface-film of fresh water, as well as the remarkable oceanic genusHalobatesalready referred to. TheReduviidaearea family of predaceous bugs that attack other insects and suck their juices; the beak is short, and carried under the head in a hook-like curve, not—as in the preceding families—lying close against the breast. TheCimicidaehave the feet three-segmented and the forewings greatly reduced; most of the species are parasites on birds and bats, but one—Cimex lectidarius(figs. 3, 8)—is the well-known “bed-bug” which abounds in unclean dwellings and sucks human blood (seeBug). TheAnthocoridaeare nearly related to theCimicidae, but the wings are usually well developed and the forewing possesses cuneus and embolium as well as corium and clavus. TheCapsidaeare a large family of rather soft-skinned bugs mostly elongate in form with the two basal segments of the feelers stouter than the two terminal. The forewing in this family has a cuneus (fig. 9cu), but not an embolium. These insects are often found in large numbers on plants whose juices they suck.
Cryptocerata.—In this tribe are included five or six families of aquatic Heteroptera which spend the greater part of their lives submerged, diving and swimming through the water. The feelers are very small and are often hidden in cavities beneath the head. TheNaucoridaeandBelostomatidaeare flattened insects, with four-segmented feelers and fore-legs inserted at the front of the prosternum. Two species of the former family inhabit our islands, but theBelostomatidaeare found only in the warmer regions of the globe; some of them, attaining a length of 4 to 5 in., are giants among insects. TheNepidae(fig. 6) or water-scorpions (q.v.)—two British species—are distinguished by their three-segmented feelers, their raptorial fore-legs (in which the shin and foot, fused together, work like a sharp knife-blade on the grooved thigh), and their elongate tail-processes formed of the abdominal pleura and used for respiration. TheNotonectidae, or “water-boatmen” (q.v.) have convex ovoid bodies admirably adapted for aquatic life. By means of the oar-like hind-legs they swim actively through the water with the ventral surface upwards; the fore-legs are inserted at the hinder edge of the prosternum. TheCorixidaeare small flattened water-bugs, with very short unjointed beak, the labrum being enclosed within the second maxillae, and the foot in the fore and intermediate leg having but a single segment. The hinder abdominal segments in the male show a curious asymmetrical arrangement, the sixth segment bearing on its upper side a small stalked plate (strigil) of unknown function, furnished with rows of teeth. On account of the reduction and modification of the jaws in theCorixidae, C. Börner has lately suggested that they should form a special sub-order of Hemiptera—the Sandaliorrhyncha.
Homoptera
This sub-order includes the cicads, lantern-flies, frog-hoppers, aphids and scale-insects. The face has such a marked backward slope (see fig. 1) as to bring the beak into close contact with the haunches of the fore-legs. The feelers have one or more thickened basal segments, while the remaining segments are slender and thread-like. The fore-wings are sometimes membranous like the hind-wings, usually they are firmer in texture, but they never show the distinct areas that characterize the wings of Heteroptera. When at rest the wings of Homoptera slope roofwise across the back of the insect. In their life-history the Homoptera are more specialized than the Heteroptera; the young insect often differs markedly from its parent and does not live in the same situations; while in some families there is a passive stage before the last moult.
TheCicadidaeare for the most part large insects with ample wings; they are distinguished from other Homoptera by the front thighs being thickened and toothed beneath. The broad head carries, in addition to the prominent compound eyes, three simple eyes (ocelli) on the crown, while the feeler consists of a stout basal segment, followed by five slender segments. The female, by means of her serrated ovipositor, lays her eggs in slits cut in the twigs of plants. The young have simple feelers and stout fore-legs (fig. 10) adapted for digging; they live underground and feed on the roots of plants. In the case of a North American species it is known that this larval life lasts for seventeen years. The “song” of the male cicads is notorious and the structures by which it is produced have already been described (see alsoCicada). There are about 900 known species, but the family is mostly confined to warm countries; only a single cicad is found in England, and that is restricted to the south.
TheFulgoridaeandMembracidaeare two allied families most of whose members are also natives of hot regions. TheFulgoridaehave the head with two ocelli and three-segmented feelers; frequently as in the tropical “lantern-flies” (q.v.) the head is prolonged into a conspicuous bladder, or trunk-like process. TheMembracidaeare remarkable on account of the backward prolongation of the pronotum into a process or hood-like structure which may extend far behind the tail-end of the abdomen. Two other allied families, theCercopidaeandJassidae, are more numerously represented in our islands. The young of many of these insects are green and soft-skinned, protecting themselves by the well-known frothy secretion that is called “cuckoo-spit.”
In all the above-mentioned families of Homoptera there are three segments in each foot. The remaining four families have feet with only two segments. They are of very great zoological interest on account of the peculiarities of their life-history—parthenogenesis being of normal occurrence among most of them. The familiesPsyllidae(or “jumpers”) with eight or ten segments in the feeler and theAleyrodidae(or “snowy-flies”) distinguished by their white mealy wings, are of comparatively slight importance. The two families to which special attention has been paid are theAphidaeor plant-lice (“green fly”) and theCoccidaeor scale-insects. The aphids (fig. 11) have feelers with seven or fewer distinct segments, and the fifth abdominal segment usually carries a pair of tubular processes through which a waxy secretion is discharged. The sweet “honey-dew,” often sought as a food by ants, is secreted from the intestines of aphids. The peculiar life-cycle in which successive generations are produced through the summer months by virgin females—the egg developing within the body of the mother—is described at length in the articlesAphidesandPhylloxera. TheCoccidaehave only a single claw to the foot; the males (fig. 12a) have the fore-wings developed and the hind-wings greatly reduced, while in the female wings are totally absent and the body undergoes marked degradation (figs. 12,e, 13,a,b). In the Coccids the formation of a protective waxy secretion—present in many genera of Homoptera—reaches its most extreme development. In some coccids—the “mealy-bugs” (Dactylopius, &c.) for example—the secretion forms a white thread-like or plate-like covering which the insect carries about. But in most members of the family, the secretion, united with cast cuticles and excrement, forms a firm “scale,” closely attached by its edges to the surface of the plant on which the insect lives, and serving as a shield beneath which the female coccid, with her eggs (fig. 13a) and brood, finds shelter. The male coccid passes through a passive stage (fig. 4) before attaining the perfect condition. Many scale-insects are among the most serious of pests, but various species have been utilized by man for the production of wax (lac) and red dye (cochineal). SeeEconomic Entomology,Scale-Insect.
Anoplura
The Anoplura or lice (seeLouse) are wingless parasitic insects (fig. 14) forming an order distinct from the Hemiptera, their sucking and piercing mouth-organs being apparently formed on quite a different plan from those of the Heteroptera and Homoptera. In front of the head is a short tube armed with strong recurved hooks which can be fixed into the skin of the host, and from the tube an elongate more slender sucking-trunk can be protruded (fig. 15). Each foot is provided with a single strong claw which, opposed to a process on the shin, serves to grasp a hair of the host, all the lice being parasites on different mammals. Although G. Enderlein has recently shown that the jaws of the Hemiptera can be recognized in a reduced condition in connexion with the louse’s proboscis, the modification is so excessive that the group certainly deserves ordinal separation.
Bibliography.—A recent standard work on the morphology of the Hemiptera by R. Heymons (Nova Acta Acad. Leop. Carol.lxxiv. 3, 1899) contains numerous references to older literature. An excellent survey of the order is given by D. Sharp (Cambridge Nat. Hist.vol. vi., 1898). For internal structure of Heteroptera see R. Dufour,Mem. savans étrangers(Paris, iv., 1833); of Homoptera, E. Witlaczil (Arb. Zool. Inst. Wien, iv., 1882,Zeits. f. wiss. Zool.xliii., 1885). The development of Aphids has been dealt with by T. H. Huxley (Trans. Linn. Soc.xxii., 1858) and E. Witlaczil (Zeits. f. wiss. Zool.xl., 1884). Fossil Hemiptera are described by S. H. Scudder in K. Zittel’sPaléontologie(French translation, vol. ii. Paris, 1887, and English edition, vol. i., London, 1900), and by A. Handlirsch (Verh. zool. bot. Gesell. Wien, lii., 1902). Among general systematic works on Heteroptera may be mentioned J. C. Schiödte (Ann. Mag. Nat. Hist.(4) vi., 1870); C. Stal’sEnumeratio Hemipterorum(K. Svensk. Vet. Akad. Handl.ix.-xiv., 1870-1876); L. Lethierry and G. Severin’sCatalogue générale des hémiptères(Brussels 1893, &c.); G. C. Champion’s volumes in theBiologia Centrali-Americana; W. L. Distant’s Oriental Cicadidae (London, 1889-1892), and many other papers; M. E. Fernald’sCatalogue of the Coccidae(Amherst, U.S.A., 1903). European Hemiptera have been dealt with in numerous papers by A. Puton. For British species we have E. Saunders’sHemiptera-Heteroptera of the British Isles(London, 1892); J. Edwards’s Hemiptera-Homoptera of the British Isles (London, 1896); J. B. Buckton’sBritish Aphidae(London, Ray Society, 1875-1882); and R. Newstead’sBritish Coccidae(London, Ray Society, 1901-1903). Aquatic Hemiptera are described by L. C. Miall (Nat. History Aquatic Insects; London, 1895), and by G. W. Kirkaldy in numerous recent papers (Entomologist, &c.). For marine Hemiptera (Halobates) see F. B. White (Challenger Reports, vii., 1883); J. J. Walker (Ent. Mo. Mag., 1893); N. Nassonov (Warsaw, 1893), and G. H. Carpenter (Knowledge, 1901, andReport, Pearl Oyster Fisheries, Royal Society, 1906). Sound-producing organs of Heteroptera are described by A. Handlirsch (Ann. Hofmus. Wien, xv. 1900), and G. W. Kirkaldy (Journ. Quekett Club(2) viii. 1901); of Cicads by G. Carlet (Ann. Sci. Nat. Zool.(6) v. 1877). For the Anoplura see E. Piaget’sPediculines(Leiden, 1880-1905), and G. Enderlein (Zool. Anz.xxviii., 1904).
(G. H. C.)
HEMLOCK(in O. Eng.hemlicorhymlice; no cognate is found in any other language, and the origin is unknown), theConium maculatumof botanists, a biennial umbelliferous plant, found wild in many parts of Great Britain and Ireland, where it occurs in waste places on hedge-banks, and by the borders of fields, and also widely spread over Europe and temperate Asia, and naturalized in the cultivated districts of North and South America. It is an erect branching plant, growing from 3 to 6 ft. high, and emitting a disagreeable smell, like that of mice. The stems are hollow, smooth, somewhat glaucous green, spotted with dull dark purple, as alluded to in the specific name,maculatum. The root-leaves have long furrowed footstalks, sheathing the stem at the base, and are large, triangular in outline, and repeatedly divided or compound, the ultimate and very numerous segments being small, ovate, and deeply incised at the edge. These leaves generally perish after the growth of the flowering stem, which takes place in the second year, while the leavesproduced on the stem became gradually smaller upwards. The branches are all terminated by compound many-rayed umbels of small white flowers, the general involucres consisting of several, the partial ones of about three short lanceolate bracts, the latter being usually turned towards the outside of the umbel. The flowers are succeeded by broadly ovate fruits, the mericarps (half-fruits) having five ribs which, when mature, are waved or crenated; and when cut across the albumen is seen to be deeply furrowed on the inner face, so as to exhibit in section a reniform outline. The fruits when triturated with a solution of caustic potash evolve a most unpleasant odour.
Hemlock is a virulent poison, but it varies much in potency according to the conditions under which it has grown, and the season or stage of growth at which it is gathered. In the first year the leaves have little power, nor in the second are their properties developed until the flowering period, at which time, or later on when the fruits are fully grown, the plant should be gathered. The wild plant growing in exposed situations is to be preferred to garden-grown samples, and is more potent in dry warm summers than in those which are dull and moist.
The poisonous property of hemlock resides chiefly in the alkaloidconineorconiawhich is found in both the fruits and the leaves, though in exceedingly small proportions in the latter. Conine resembles nicotine in its deleterious action, but is much less powerful. No chemical antidote for it is known. The plant also yields a second less poisonous crystallizable base calledconhydrine, which may be converted into conine by the abstraction of the elements of water. When collected for medicinal purposes, for which both leaves and fruits are used, the former should be gathered at the time the plant is in full blossom, while the latter are said to possess the greatest degree of energy just before they ripen. The fruits are the chief source whence conine is prepared. The principal forms in which hemlock is employed are the extract and juice of hemlock, hemlock poultice, and the tincture of hemlock fruits. Large doses produce vertigo, nausea and paralysis; but in smaller quantities, administered by skilful hands, it has a sedative action on the nerves. It has also some reputation as an alterative and resolvent, and as an anodyne.
The acrid narcotic properties of the plant render it of some importance that one should be able to identify it, the more so as some of the compound-leaved umbellifers, which have a general similarity of appearance to it, form wholesome food for man and animals. Not only is this knowledge desirable to prevent the poisonous plant being detrimentally used in place of the wholesome one; it is equally important in the opposite case, namely, to prevent the inert being substituted for the remedial agent. The plant with which hemlock is most likely to be confounded isAnthriscus sylvestris, or cow-parsley, the leaves of which are freely eaten by cattle and rabbits; this plant, like the hemlock, has spotted stems but they are hairy, not hairless; it has much-divided leaves of the same general form, but they are downy and aromatic, not smooth and nauseous when bruised; and the fruit ofAnthriscusis linear-oblong and not ovate.
HEMP(in O. Eng.henep, cf. Dutchhennep, Ger.Hanf, cognate with Gr.κάνναβις, Lat.cannabis), an annual herb (Cannabis sativa) having angular rough stems and alternate deeply lobed leaves. The bast fibres ofCannabisare the hemp of commerce, but, unfortunately, the products from many totally different plants are often included under the general name of hemp. In some cases the fibre is obtained from the stem, while in others it comes from the leaf. Sunn hemp, Manila hemp, Sisal hemp, and Phormium (New Zealand flax, which is neither flax nor hemp) are treated separately. All these, however, are often classed under the above general name, and so are the following:—Deccan or Ambari hemp,Hibiscus cannabinus, an Indian and East Indian malvaceous plant, the fibre from which is often known as brown hemp or Bombay hemp; Pité hemp, which is obtained from the American aloe,Agave americana; and Moorva or bowstring-hemp,Sansevieria zeylanica, which is obtained from an aloe-like plant, and is a native of India and Ceylon. Then there are Canada hemp,Apocynum cannabinum, Kentucky hemp,Urtica cannabina, and others.
The hemp plant, like the hop, which is of the same natural order, Cannabinaceae, is dioecious,i.e.the male and female flowers are borne on separate plants. The female plant grows to a greater height than the male, and its foliage is darker and more luxuriant, but the plant takes from five to six weeks longer to ripen. When the male plants are ripe they are pulled, put up into bundles, and steeped in a similar manner to flax, but the female plants are allowed to remain until the seed is perfectly ripe. They are then pulled, and after the seed has been removed are retted in the ordinary way. The seed is also a valuable product; the finest is kept for sowing, a large quantity is sold for the food of cage birds, while the remainder is sent to the oil mills to be crushed. The extracted oil is used in the manufacture of soap, while the solid remains, known as oil-cake, are valuable as a food for cattle. The leaves of hemp have five to seven leaflets, the form of which is lanceolate-acuminate, with a serrate margin. The loose panicles of male flowers, and the short spikes of female flowers, arise from the axils of the upper leaves. The height of the plant varies greatly with season, soil and manuring; in some districts it varies from 3 to 8 ft., but in the Piedmont province it is not unusual to see them from 8 to 16 ft. in height, whilst a variety (Cannabis sativa, varietygigantea) has produced specimens over 17 ft. in height.
All cultivated hemp belongs to the same species,Cannabis sativa; the special varieties such asCannabis indica,Cannabis chinensis, &c., owe their differences to climate and soil, and they lose many of their peculiarities when cultivated in temperate regions. Rumphius (in the 17th century) had noticed these differences between Indian and European hemp.
Wild hemp still grows on the banks of the lower Ural, and the Volga, near the Caspian Sea. It extends to Persia, the Altai range and northern and western China. The authors of thePharmacographiasay:—“It is found in Kashmir and in the Himalaya, growing 10 to 12 ft. high, and thriving vigorously at an elevation of 6000 to 10,000 ft.” Wild hemp is, however, of very little use as a fibre producer, although a drug is obtained from it.
It would appear that the native country of the hemp plant is in some part of temperate Asia, probably near the Caspian Sea. It spread westward throughout Europe, and southward through the Indian peninsula.
The names given to the plant and to its products in different countries are of interest in connexion with the utilization of the fibre and resin. In Sans. it is calledgoni,sana,shanapu,bangaandganjika; in Bengali,ganga; Pers.bangandcanna; Arab.kinnuborcannub; Gr.kannabis; Lat.cannabis; Ital.canappa; Fr.chanvre; Span.cáñamo; Portuguese,cánamo; Russ.konópel; Lettish and Lithuanian,kannapes; Slav.konopi; Erse,canaibandcanab; A. Sax.hoenep; Dutch,hennep; Ger.Hanf; Eng.hemp; Danish and Norwegian,hamp; Icelandic,hampr; and in Swed.hampa. The English wordcanvassufficiently reveals its derivation fromcannabis.
Very little hemp is now grown in the British Isles, although this variety was considered to be of very good quality, and to possess great strength. The chief continental hemp-producing countries are Italy, Russia and France; it is also grown in several parts of Canada and the United States and India. The Central Provinces, Bengal and Bombay are the chief centres of hemp cultivation in India, where the plant is of most use for narcotics. The satisfactory growth of hemp demands a light, rich and fertile soil, but, unlike most substances, it may be reared for a few years in succession. The time of sowing, the quantity of seed per acre (about three bushels) and the method of gathering and retting are very similar to those of flax; but, as a rule, it is a hardier plant than flax, does not possess the same pliability, is much coarser and more brittle, and does not require the same amount of attention during the first few weeks of its growth.
The very finest hemp, that grown in the province of Piedmont,Italy, is, however, very similar to flax, and in many cases the two fibres are mixed in the same material. The hemp fibre has always been valuable for the rope industry, and it was at one time very extensively used in the production of yarns for the manufacture of sail cloth, sheeting, covers, bagging, sacking, &c. Much of the finer quality is still made into cloth, but almost all the coarser quality finds its way into ropes and similar material.
A large quantity of hemp cloth is still made for the British navy. The cloth, when finished, is cut up into lengths, made into bags and tarred. They are then used as coal sacks. There is also a quantity made into sacks which are intended to hold very heavy material. Hemp yarns are also used in certain classes of carpets, for special bags for use in cop dyeing and for similar special purposes, but for the ordinary bagging and sacking the employment of hemp yarns has been almost entirely supplanted by yarns made from the jute fibre.
Hemp is grown for three products—(1) the fibre of its stem; (2) the resinous secretion which is developed in hot countries upon its leaves and flowering heads; (3) its oily seeds.
Hemp has been employed for its fibre from ancient times. Herodotus (iv. 74) mentions the wild and cultivated hemp of Scythia, and describes the hempen garments made by the Thracians as equal to linen in fineness. Hesychius says the Thracian women made sheets of hemp. Moschion (about 200B.C.) records the use of hempen ropes for rigging the ship “Syracusia” built for Hiero II. The hemp plant has been cultivated in northern India from a considerable antiquity, not only as a drug but for its fibre. The Anglo-Saxons were well acquainted with the mode of preparing hemp. Hempen cloth became common in central and southern Europe in the 13th century.
Hemp-resin.—Hemp as a drug or intoxicant for smoking and chewing occurs in the three forms of bhang, ganja and charas.
1.Bhang, the Hindustanisiddhiorsabzi, consists of the dried leaves and small stalks of the hemp; a few fruits occur in it. It is of a dark brownish-green colour, and has a faint peculiar odour and but a slight taste. It is smoked with or without tobacco; or it is made into a sweetmeat with honey, sugar and aromatic spices; or it is powdered and infused in cold water, yielding a turbid drink,subdschi.Hashishis one of the Arabic names given to the Syrian and Turkish preparations of the resinous hemp leaves. One of the commonest of these preparations is made by heating the bhang with water and butter, the butter becoming thus charged with the resinous and active substances of the plant.
2.Ganja, the guaza of the London brokers, consists of the flowering and fruiting heads of the female plant. It is brownish-green, and otherwise resembles bhang, as in odour and taste. Some of the more esteemed kinds of hashish are prepared from this ganja. Ganja is met with in the Indian bazaars in dense bundles of 24 plants or heads apiece. The hashish in such extensive use in Central Asia is often seen in the bazaars of large cities in the form of cakes, 1 to 3 in. thick, 5 to 10 in. broad and 10 to 15 in. long.
3.Charas, or churrus, is the resin itself collected, as it exudes naturally from the plant, in different ways. The best sort is gathered by the hand like opium; sometimes the resinous exudation of the plant is made to stick first of all to cloths, or to the leather garments of men, or even to their skin, and is then removed by scraping, and afterwards consolidated by kneading, pressing and rolling. It contains about one-third or one-fourth its weight of the resin. But the churrus prepared by different methods and in different countries differs greatly in appearance and purity. Sometimes it takes the form of egg-like masses of greyish-brown colour, having when of high quality a shining resinous fracture. Often it occurs in the form of irregular friable lumps, like pieces of impure linseed oil-cake.
The medicinal and intoxicating properties of hemp have probably been known in Oriental countries from a very early period. An ancient Chinese herbal, part of which was written about the 5th centuryB.C., while the remainder is of still earlier date, notices the seed and flower-bearing kinds of hemp. Other early writers refer to hemp as a remedy. The medicinal and dietetic use of hemp spread through India, Persia and Arabia in the early middle ages. The use of hemp (bhang) in India was noticed by Garcia d’Orta in 1563. Berlu in hisTreasury of Drugs(1690) describes it as of “an infatuating quality and pernicious use.” Attention was recalled to this drug, in consequence of Napoleon’s Egyptian expedition, by de Sacy (1809) and Rouger (1810). Its modern medicinal use is chiefly due to trials by Dr O’Shaughnessy in Calcutta (1838-1842). The plant is grown partly and often mainly for the sake of its resin in Persia, northern India and Arabia, in many parts of Africa and in Brazil.
Pharmacology and Therapeutics.—The composition of this drug is still extremely obscure; partly, perhaps, because it varies so much in individual specimens. It appears to contain at least two alkaloids—cannabinine and tetano-cannabine—of which the former is volatile. The chief active principle may possibly be neither of these, but the substance cannabinon. There are also resins, a volatile oil and several other constituents. Cannabis indica—as the drug is termed in the pharmacopoeias—may be given as an extract (dose ¼-1 gr.) or tincture (dose 5-15 minims).
The drug has no external action. The effects of its absorption, whether it be swallowed or smoked, vary within wide limits in different individuals and races. So great is this variation as to be inexplicable except on the view that the nature and proportions of the active principles vary greatly in different specimens. But typically the drugisan intoxicant, resembling alcohol in many features of its action, but differing in others. The early symptoms are highly pleasurable, and it is for these, as in the case of other stimulants, that the drug is so largely consumed in the East. There is a subjective sensation of mental brilliance, but, as in other cases, this is not borne out by the objective results. It has been suggested that the incoordination of nervous action under the influence of Indian hemp may be due to independent and non-concerted action on the part of the two halves of the cerebrum. Following on a decided lowering of the pain and touch senses, which may even lead to complete loss of cutaneous sensation, there comes a sleep which is often accompanied by pleasant dreams. There appears to be no evidence in the case of either the lower animals or the human subject that the drug is an aphrodisiac. Excessive indulgence in cannabis indica is very rare, but may lead to general ill-health and occasionally to insanity. The apparent impossibility of obtaining pure and trustworthy samples of the drug has led to its entire abandonment in therapeutics. When a good sample is obtained it is a safe and efficient hypnotic, at any rate in the case of a European. The tincture should not be prescribed unless precautions are taken to avoid the precipitation of the resin which follows its dilution with water.