text
stringlengths 1
16.9k
|
|---|
------ |
**The Anatomy of the Bee** |
------ |
BY R. E. Snodgrass |
_of the Bureau of Entomology, Washington, D. C._ |
------ |
The three parts of the body of the bee are well separated by constrictions. The head carries the eyes, antennae, and mouth parts; the thorax, the wings and legs; and the abdomen, the wax-gland and sting. |
The _head_ is flattened and triangular, being widest crosswise through the upper corners, which are capped by the large compound eyes. It carries the _autenne_, or feelers, on the middle of the face (Fig. 2, \(\Lambda\), \(\Lambda\)nt); the large _compound eyes_ (_E_) laterally; three small simple eyes or _vcelli_ (_O_), at the top of the face, and the _mouth parts_ (_Md_, _Mx_, and _Lb_) venturally. Each antenna consists of a long basal joint and of a series of small ones hanging downward from the end of the first. The antennae are very sensitive to touch, and contain the organs of smell. \(\Lambda\)t the lower edge of the face is a loose flap (Fig. 2, \(\Lambda,L\)m) forming an upper lip called the _bottom_. On its under surface is a small soft lobe called the _cippharynx_ on which are located the organs of taste. At the sides of the labrum are the two heavy jaws, or _mundibles_ (_Md_), which work sidewise. They are spoon-shaped at their ends in the worker, but sharp-pointed and toothed in the queen and drone. Those of the queen are largest, those of the drone smallest. Behind the labrum and the mandibles is a bunch of long appendages, usually folded back beneath the head, which together constitute the _propose_ (Fig. 2, \(\Lambda\), \(P\)_rb_). These organs correspond with the second pair of jaws, or _max-illire_, and the lower lip, or _labium_, of other insects. In Fig. 2 they are cut off a short distance from their bases, but are shown detached from the head and flattened out in Fig. 3, D. The middle series of pieces (_smt-Lb_) constitutes the labium, the two lateral series (_Ccl-Mx_) the maximise. The labium consists of a basal _submentum_ (_Smit_), and a _mentum_ (_Mt_), which supports distally the slender, flexible, tongue-like _glossa_ (_Gls_), the two delicate _paraglosse_ (_Pgl_), and the two lateral, jointed labial pair (_Lb_\(I^{\prime}\)_p_). Each maxilla is composed of a basal stalk, the _eardo_ (_Cd_); a main plate, the _slipes_ (_Sl_), and a wide terminal blade (_Mx_) called the _gate_. At the base of the galea is a rudimentary _maximillary pelpus_ (_MxP_?_p_), representing a part which in most insects consists of several slender joints. |
As before stated, the parts of the maximise and the labium together constitute the probocsis, which, as shown in Fig. 2, B, is suspended from a deep cavity (_PrbS_) on the lower part of the buck of the head having a membranous floor. The basal stalks (_Cd_) of the maximise are hinged to knobs on the sides of this cavity, while the labium is attached to the maxillary stalks by means of a flexible band called the _lorum_ (Fig. 3, D, _Lr_). |
When the bee wishes to suck up any liquid, especially a thick liquid like honey or syrup, provided in considerable quantity, the terminal lobes of the labium and maximize are pressed close together so as to make a tube between them. The labium is then moved back and forth between the maxillle with a pump-like motion produced by muscles within the head. This brings the liquid up to the mouth, which is situated above the base of the probocsis, between the mandibles and beneath the labium. The food is probably then taken into the mouth by a sueking action of the pharynx produced by its muscles. |
A more delicate apparatus is probably necessary, however, for sucking up minute drops of nectar from the bottom of a flower. Such a structure is provided within theglossa.** This organ (Fig. 3, D, _Gls_), ordinarily called the "tongue," is terminated by a delicate, sensitive, spoon-like lobe known as the labella (Fig. 3, A, B, and D, _Lbl_), and has a groove (\(k\)) running along its entire length on the ventral side. Within the glossa this groove expands into a double-barreled tube (Fig. 3, E, _Ltan_). A flexible chitinous rod (\(r\)) lies along the dorsal wall of this channel, which is itself provided with a still finer groove (\(l\)) along its ventral surface. Thus the very smallest quantity of nectar may find a channel suited to its bulk through which it may run up to the base of the glossa by capillary attraction. But since the glossal channels are ventral the nectar must be transferred to the dorsal side of the labium by means of the para-glosse, the two soft lobes (Fig. 3, D and F, _Pgl_) whose bases are on the upper side of the mentum, but whose distal ends underpin the base of the glossa, and thus afford conduits for the nectar around the latter to the upper side of the labium. The glossa is highly extensible and retractile by means of muscles attached to the base of its rod, and its movements when a bee is feeding are very conspicuous, and interesting to watch. |
The _thorax_ of any insect carries the wings and the legs. The two wings of the bee on each side are united to each other by a series of minute hooks so that they work together, and the four wings are thus practically converted into two. Each wing is hinged at its base to the back, and pivoted from below upon a small knob of the side wall of the thorax. The up-and-down motion of the wings is produced, not by muscles attached to their bases, but by two sets of enormous muscles, one vertical and the other horizontal, attached to the walls of the thorax, whose contractions elevate and depress the back plates of the thorax. Since the fulcrum of each wing is outside of its attachment to the back, the depression of the latter elevates the wings, and an elevation of the back lowers the wing. But the bee flies by,a propeller-like action, or figure-8 motion of the wings. This is produced by two other sets of much smaller muscles acting directly upon the wing bases, one before and the other behind the fulcrum of each. The combined result of all these muscles is that the down stroke of the wing is accompanied by a forward movement and a deflexation of the anterior edge, while the up stroke reverses this. |
The legs of the bee are too familiar to need any extensive description here. Their special characters, such as the antennae- and brushes on the last, are illustrated in Fig. 4. The tarsi are each provided with a pair of terminal _clave_ (_E_, _Cla_), by means of which the bee elings to rough objects, while between the claus is a sticky pad, the _cmpdum_ (_Emp_), which is brought into play when the bee aligits on or walks over any smooth surface like glass. |
The hint part of the thorax of i ees, wasi 8, and their allies is composed of a segment which, in other insects, is a part of the abdomen. It is known as the _propodum_. The middle division of the body of a bee, wasp, or ant, therefore, is not exactly the equivalent of the thorax of a grasshopper, fly, or butterfly. |
The _abdomen_ of the bee has no appendages corresponding with those of the head or thorax; but it bears two important organs, viz., the wax-glunds and the sting. The _vex-glunds_ are simply specially developed cells of the skin on the ventral surfaces of the last four visible abdominal segments of the worker. There are only six segments visible in the apparent abdomen; but remembering that the propoleum of the thorax is really the first, the wax-glunds occur, therefore, on segments four to seven inclusive (Fig. 1, IV-VII). The wax secreted by the glands is discharged through minute pores in the ventral plate of each segment, and accumulates in the form of a little scale in the pocket above the underlapping ventral plate of the segment next in front. |
The _sting_ is such a complicated organ that it is very difficult to describe it clearly in a few words. Fundamentally it consists of three slender, closely appressed pieces forming the sharp piercing organ that projects from the tip of the abdomen (Fig. 1, _Skn_), and of two soft finger-like lobes, sometimes also visible, all of which arise from three pairs of plates belonging to the eighth and ninth segments of the abdomen, but which are concealed within the seventh segment. |
Fig. 5 shows, somewhat diagrammatically, all the parts of the left side. The acute stinging shaft swells basily into a large bulb (_ShB_) which is connected by a basal arm on each side with two lateral plates (_Ob_ and _Tri_). The finger-like lobes, called the _pulpi of the sting_ (_SmPlp_) are carried also by the lower of these two plates (_Ob_) while the upper (_Tri_) carries the third and largest plate (_Qbl_) which partially overlaps the lower (_Ob_). |
## Anatomy of the Bee. |
A close examination of the sting proper shows that both the bulb and the tapering shaft are formed of three pieces. One is dorsal (_SbL_B and _SbL_S) while the other two (_Let_) are ventral (of course only one of the latter shows in side view). Furthermore, the basal arm on each side is formed of two pieces, one of which (_SbL_A) is continuous with the dorsal piece of the sting, while the other (_Let_) is continuous with the ventral rod of the same side. Since these ventral rods are partially enclosed within a hollow on the under side of the dorsal piece, the latter is called the _sheath of the sting_. It consists of the terminal _sheath_ of the sheath (_SbL_S), the _bulk_ (_SbL_B), and of a _basal arm_ (_StA_) on each side. |
The ventral pieces are slender sharp-pointed rods having bar-ed extremities, and are known as the _tuncts_. The shaft of the sheath is grooved along the entire length of its ventral surface, the groove enlarging into a spacious cavity in the bulb. The lanects lie close together against the ventral edges of the sheath, but slide freely upon minute tracks on the latter. The three parts, therefore, incluse between them a cavity which is tubular in the shaft, but enlarged into a wide chamber in the bulb. The great poison-sac (Fig. 8, _PsnSc_) of the acid-glands of the sting opens into the base of the bulb along with the smaller, the _poison_ is an acid liquid formed by the glands (Fig. 8, _AGl_, _AGl_, and _Bdl_). Two of these (_AGl_ and _AGl_) are simply small enlargements at the ends of two long coiled tubes (_AGl_D), which latter unite into a short single tube that opens into the anterior end of the great _poison-sac_ (_PsnSc_). The secretion of these glands is acid. The third gland (_BGl_) is a short, somewhat twisted tube opening into the bulb of the sting along with the poison-sac. Its secretion is alkaline. Carlet has shown that it is only the mixture of these two secretions that has the full strength in stinging properties. |
Figure 2: -Head of worker with parts of probes cut off a short distance from their buses. A anterior: B. posterior: \(a\), clypical suture: _Amt_, antenna: \(b\), plt in clypical suture marking anterior end of internal bar of head: \(c\), plt on occipital surface of head, markup posterior end of internal bar: _Cd_, cardio: _Urb_, Clypens: \(E\), compound eye: _Epr_, formsem magnuum: _Ft_, front: _Ge_, gen: _Gls_, glossion, or _tounge_: \(R\), ventral groove of glossion: _Lb_, labium: _LbP_, labial: palipsis: _Em_, labrum: _Md_, manlophic: _Md_, menu: _Mb_, nomuli: _Mr_, terminal blade of mr_, _MrPl_, muxiliary pulips: \(O\), occill: _Pw_, postgeman: _Pol_, praurons: _Phy_, base of probes: _PrbFs_, fossa of probes: _Sml_, sublumentum: _Sl_, stipes: _Ion_, sma! bar of teutourion arching over foramen magnuum: _Yr_, vertex. |
The _allimentary canal_ (Fig. 6) consists of a tube extending through the entire body, and coiled somewhat in the abdomen. The first part above the mouth in the head is widened to form the _pharynx_ (_Phy_). Then follows the long slender _esophagus_ (_C_), running clear through the thorax and into the front of the abdomen, where it enlarges into a thin-walled bag, called, in general, the _crop_, but which is known as the _hoiey-stomach_ (_IHS_) in the bee. Back of the honey-stomach is a short narrow _proventielus_ (_Prent_), which is followed by the large U-shaped stomach, or _eutriculus_ (_Fent_). Then comes the slender _small_ intestine (_SInt_) with the circle of _Mulplighian tubules_ (_Mol_) arising from its anterior end. Finally, forming the terminal part of the alimentary canal, is the _large_ intestine, or _rectum_ (_Rect_), consisting of an enormous sack, varying in size according to its contents, but often occupying a large part of the abdominal cavity. Six opaque longitudinal bands on its anterior end are known as the _rectal glands_ (_RGl_). |
The honey-stomach is of special interest in the worker because the nectar gathered from the flowers is held in it, instead of being swallowed on down into the stomach, and is regurgitated into the cells of the comb, or given up first to another bee in the hive. The upper end of the proventriculus sticks up into the lower end of the honey-stomach as a small cone with an X-shaped opening in its summit. This opening is called the _stomach-mouth_. Its four lips are very active, and take whatever food the ventriculus requires from the honey-stomach, for it must all go into the latter first, while at the same time it affords the bees a means of retaining nectar or honey in the honey-stomach. |
The natural food of bees consists of pollen, nectar, and honey. The first contains the nitrogen of their diet, and the other two the hydrogen, carbon, and oxygen. Observations made by the writer indicate that the pollen is not digested until it gets into the intestine, for masses of fresh-looking grains nearly always occur in the rear part of the ventriculus, which is otherwise filled with a brownish slime. On the other hand, the nectar and honey is very probably digested in the ventriculus, and in large part absorbed from it. |
The _saliency glands_, located in the back part of the head (Fig. 6, \(ar{\mathpzc{E}}\mathit{Gl}\)) and in the front part of the thorax (\(ar{\mathpzc{E}}\mathit{Gl}\)) open upon the upper part of the labium (Fig. 3, F, \(ar{\mathpzc{E}}\mathit{d}\mathit{D}\mathit{D}\mathit{D}\)). The saliva can thus affect the liquid food before the latter enters the mouth, or it can be allowed to run down the probosci upon hard sugar in order to dissolve it, for the latter is eaten with the probosci, not with the mandibles. |
The large glands (Fig. 6, \(\mathit{I}\mathit{Gl}\)) situated in the front part of the head are supposed, by some students of the bee, to form the white pasty brood food and the royal jelly. Others think that these substances come from the stomach. More investigation of the subject must be made, however, before the question can be decided; but the contents of the stomachs of workers have no resemblance to the brood food. |
The _circulatory_ system is very simple, consisting of a delicate, tubular, pulsating _heart_ (Fig. 1, \(\mathit{I}\mathit{U}\)) in the upper part of the abdomen, of a single long blood-vessel, the _aorta_ (_Ao_), extending forward from the heart through the thorax into the head, and of two pulsating membranes, the _diophra_\(\zeta\)_ms_ (_DDph_ and _VDph_), stretched across the dorsal and ventral walls of the abdomen, but leaving wide openings along their sides between the points of attachment. The heart consists of four consecutive chambers, _Iht-iht_, which are merely swellings of the tube, each having a vertical slit or _stisum_ (_Ost_) opening into each side. The _blood_ is the colorless liquid that fills the spaces about the viscera of the body cavity. The dorsal diaphragm and the heart pulsate forward. The blood in the cavity above the former enters the ostia of the heart, and is pumped forward through the aorta and out into the cavity of the head. From here it percolates back through the thorax and enters the space beneath the ventral diaphragm (_VDph_) of the abdomen. This membrane pulsates backward, and the blood is driven posteriorly and upward, through the lateral openings, around the abdominal viscera, and again into the dorsal or pericardial cavity of the abdomen, where it begins its circulation anew. In insects the principal function of the blood is to distribute the food which dissolves into it from the alimentary canal. |
The _respiratory system_ is very highly developed in the bee, consisting (Fig. 1) of large air-sacs (_Tvu_&_, _I-to_) in the head, thorax, and abdomen, and of tubes called trachene given off from them (_Tva_, _LTva_). Fig. 1 shows principally the parts in only the right side of the body. In the abdomen a large sac (_10_) lies on each side connected with the exterior by short tubes opening on the sides of the first seven segments. Three |
substances. This change is effected partly by the inhaled oxygen combining with the waste products, resulting in the formation of compounds of nitrogen which dissolve in the blood, and of carbonic acid gas which diffuses into the tracheal tubes and is exhaled. The nitrogen compounds are supposed to be removed by the _Molipidian tubules_ (Fig. 6, _Molt_), which are regarded as the kidneys of insects. |
The _nervous system_ consists of a series of small masses of nerve tissue called _ganglia_, lying along the median ventral line of the body cavity (Fig. 1, _1Gnq-7Gng_), the two of the thorax being much larger than those of the abdomen. Each two are connected by a pair of cords called _commissures_. Nerves are given off from these ganglia to the various organs and parts of the body, and to the legs and wings. In the head there are two ganglion lines. One is called the _brain_ (_Pey_) that swells positised into a large pouch known as the _bursta copulartz_ (_BQx_), opening to the exterior in the eighth segment beneath the base of the sting. |
During copulation the drone ejects the spermatozoa into the upper end of the vagina of the queen. The spermatozoa convisist of minute vibratory threads (Fig. 7, C), which, probably, by their own motion, make their way up through a small tube opening into the dorsal wall of the vagina, and so reach a globular sac (Fig. 7, _Spmn_) called the _spernatco_. Here they are held during the rest of the lifetime of the queen, to be extruded in small bundles, of about a hundred each, according to Breslaw, upon the eggs passing out of the vagina. Thus are the female eggs _fertilized_, the drone eggs developing without the addition of the nule element. |
Figure 5: Left side of string and its accessory plates, with alkaline gland (_BGI_) and base of poison-sue (_Pey_) attached. _BGI_, alkaline-poison giza: d; _Lct_, lancett: _Qth_, otolong plate: _Pey_, base of poison-sue holding secretion from acid-plant (see Fig. 8); _Qd_, underline state: _IX_S, medium part of ninth abdominalstorm (_ShA_, arm of sheath; _Shb_, bulb of sheath; _ShS_, short of sheath; _StntP_, palpus of string; _Trt_, tringular plate. |
Figure 11: \(\&\)-Alimentary causal and salivary glands of worker, dorsal. _Det_, salivary duct; _IG_, pharyngeal glands of heat supracerebral glands; _20I_, salivary glands of head postcerebral glands; _30I_, salivary glands of the thorax; _HS_, honey-stomach; \(M\), reservoir of thoracic salivary gland; _Mat_, Malipshian tubulie; \(G\), esophagus; _High_, pharynx; _Pront_, preventriculus; _Rect_, rectum; _Ryl_, rectal glands; _SInf_, small intestine; _Vev_, ventriculus. |
Figure 7: **A**, reproductive origins of drone, dorsal: B, inner view of dorsal wall of bulb of penis; O, group of spermatozoa; D, terminal segments of drone, lateral, showing penis (_P_o_) partly protruded; E, later level of penis and ejaculatory duct (_kJD_, _AcG_), accessory mucosa gland; B, bulb of penis; _Urb_, _AcG_, closing organs of ninth abdominal sternin; _Ten_, penis; _Frb_, but of penis; _VrIS-N_, seventh to ninth abdominal sternin; \(s\), gelatinations mass of inner wall of bulb of penis; _VrIS-N_, seventh to eighth abdominal sternin; \(s\), gelatinations mass of inner wall of bulb of penis; _Tes_, testifi; and, fortunnel to at least one of bulb of penis; \(e\), iodine-like plates of penis; _VrDef_, was deferenst; _Vr_, seminal vesicle; \(e\), _cr_, dorsal and ventricular plates in wall of penis; _pyv_, terminal chamber of penis through which the rest is everted; _zz_, court-tatory pouches of penis. |
_.11rounding Stevans..._.A swarm which leaves for parts unknown. |
_.21 daytime Frame..._13% inches long, 11% Inches deep. |
_.34 After Swarms._--Swarms which come after the first swarm. |
_.41 Albine Bec..._A very light-colored variety of the Italian bee. |
_.42 Alighing-board._--The projection before the entrance to a hive. |
_.43 American Frame..._12 inches long, 12 inches deep. |
_.44 Antenna._--Horns of the bee; are the organs of touch, and perhaps other senses. |
_.45 Anthers._--They double bags containh pollen in the male parts of flowers. |
_.46 apriori._--Helating to bees. |
_.47 apriori._--A bee-keeper. |
_.48 apriori._--A collection of bee-hives, colonies, appliances, usually on a spot of ground. |
_.49 apriori._--Bee-keeping. |
_.41 apriori._--The insect family to which bees belong. |
_.42 apri._--The genus to which honey-bees belong. |
_.43 apri._--Plant-louse which seerets honey-dew. |
_.44 artificial Fevenallation._--The impregnation of vir-gim quenes in confinement (never accomplished). |
_.45 apriori._--Fevenallation of virgin queen's non confined spaces (not correct term). |
_.46 rittelel Pasturage._--Plants purposely cuttle-vated for their bee-neetar. |
_.47 rittel Peltrue._--He meal or pea flour fed as a substitute for the pollen of flowers. |
_.48 rittel Swarm._--A swarm made by dividing a colony of bees. |
_.49 Axonception Frame._--The standard frame of the British Isles. 85x314 inches. |
_.41 Bellus alcet._--Cause of European't boul brood. (Che-shire). |
_.42 Bellus Guthierl._--Origin of sour broad. (Burri.) |
_.43 Bellus Larsee._--Cause of American fouid brood. |
_.44 (White.)_--Ballus a queen._--A mob of bees's lightly cluesing around a queen in an effort to kill her. |
_.45 Bar-frame._--The English name for Lang. frames. |
_.46 Bec-bread._--The pollen of flowers gathered by the bees and deposited in the comb. |
_.47 Bee-brush._--A brush used in removing bees from off their combs. |
_.48 Bec Culture._--The care of bees. |
_.49 Bec-dress._--a suit or dress to wear while work-lin with bees and preventing strings. |
_.40 Bec-escape._--A trap (or small pin) to allow bees to pass out of a super, but preventing their return. |
_.41 Rec-gloves._--Generally made of cloth or leather, to protect the hands from stings. |
_.42 Bec-gim._--A hollow log used for holding a swarm of bees. |
_.43 Bec-hive._--A box or other contrivance for holding a colony of bees. |
_.44 Bec-house._--a shelter for bee-hives. |
_.45 Bec-line._--The shortest distance between two points. |
_.46 Bec Metamorphosis._--The bee passes through three stages before becoming a perfect insect --first the egg, then the larva, and next the 17. |
_.47 Bec-motion._--A small moth which deposits its egg in combs. |
_.48 Bec Paradysis._--A disease which affects adult bees, cause unknown. |
_.49 Bec Plants._--Florcing plants which produce nectar for bees. |
_.40 Bec-post._--Fool brool. |
_.41 Bec Sipote._--From 'i to % of an inch. |
_.42 Bec-tent._--Used in covering a hive of bees while it is being operated upon. |
_.44 Bec-tent._--As sort of fat made by the bees and secreted in foids or pockets under thehd-men in the form of scatles, which are subsequently kneaded into comb. |
_.45 Bec-tree._--A hollow tree occupied by a colony of wild bees. |
_.46 Bec-vel._--A net well for protecting the head from the attacks of bees. |
_.47 Rittel._--A very fat of the honey bee from germany which is nearly black or dark brown and found wild in many parts of the U. S. Huber. |
_.48 Bettler._--The standard frame of the British Isles. 85x314 inches. |
_.49 Bectilus alcet._--Cause of European't boul brood. (Che-shire). |
_.40 Bectilus Guthierl._--Origin of sour broad. (Burri.) |
_.41 Bectilus Larsee._--Cause of American fouid brood. |
_.42 Bectilus a queen._--A mob of bees's lightly cluesing around a queen in an effort to kill her. |
_.43 Ber-frame._--The English name for Lang. frames. |
_.44 Bec-bread._--The pollen of flowers gathered by the bees and deposited in the comb. |
_.45 Bec-brush._--A brush used in removing bees from off their combs. |
_.46 Bec Culture._--The care of bees. |
_.47 Bec-dress._--a suit or dress to wear while work-lin with bees and preventing strings. |
_.48 Bec-escape._--A trap (or small pin) to allow bees to pass out of a super, but preventing their return. |
_.49 Bec-gloves._--Generally made of cloth or leather, to protect the hands from stings. |
_.40 Bec-gim._--A hollow log used for holding a swarm of bees. |
_.41 Bec-hive._--A box or other contrivance for holding a colony of bees. |
_.42 Bec-hive._--A shelter for bee-hives. |
_.43 Bec-line._--The shortest distance between two points. |
_.44 Bec Metamorphosis._--The bee passes through three stages before becoming a perfect insect --first the egg, then the larva, and next the 17. |
_.45 Bec-motion._--A small moth which deposits its egg in combs. |
_.46 Bec-Parysis._--A disease which affects adult bees, cause unknown. |