British Bees / An Introduction into the Studies of the Natural History and Economy of the Bees Indigenous to the British Isles

by William Edward Shuckard

All the legs comprise the coxa, or hip-joint; the trochanter, which is a small joint forming the connection between this and the next joint the femur, or thigh; the tibia, or shank; and the tarsus, or foot. The latter consists of five joints, declining in length from the first, which is generally as long as all the rest united together; the first, in the anterior pair, being called the palmæ, or palms; and in the four posterior plantæ, or soles; the other joints are called the digiti, or fingers, or tarsus collectively; at the extremity of the terminal one are the two claws, which are sometimes simple hooks, but usually have a smaller hooklet within; they have both lateral and perpendicular motion, and between their insertion is affixed the pulvillus, or cushion. The coxæ in their occasional processes exhibit very useful specific characters, as do the markings and form of the remaining joints of the leg and foot, which in several genera furnish generic peculiarities. The four anterior tarsi have each a moveable spine, or spur, at their apex within, which can be expanded to the angle at which the insect wishes to place the limb, and to which it forms a collateral support; the posterior tibiæ have two each of these spurs, excepting in the genus Apis, which has none to this leg. Attached to this spur on the anterior tibiæ of all the bees, there is, within, a small velum, or sail, as it has been called; this is a small angular appendage affixed within the spur by its base. At the base of the palmæ of the same legs, and opposite the play of this velum, there is a deep sinus, or curved incision, the strigilis, called thus or the curry-comb, from the pecten, or comb of short stiff hair which fringes its edge. Upon this aperture the velum can act at the will of the insect, and combined they form a circular orifice. The object of this apparatus is to keep the antennæ clean, for the insect, when it wishes to cleanse one or the other of them, lays it within this sinus of the palma, and then, pressing the velum of the spur upon it, removes, by the combined action of the comb and the velum, all excrescences or soilure from it, and this process it repeats until satisfied with the cleanliness of the organ: and this it may be frequently seen doing. This arrangement proves how essential to the well-being of the insect is the condition of its antennæ, the sinus, or strigilis, or curry-comb, as it may be called, being always adapted in size to the thickness of the antennæ, for insects being always both right- and left-handed, they therefore use the limb on each side to brush the antenna of that side. The palmæ and other joints of the tarsus of the fore legs are greatly dilated in many males, or fringed externally with stiff setæ, which give it as efficient a dilatation as if it were the expansion of its corneous substance. The anterior tarsi of the females are likewise fringed with hair, to enable them to sweep off and collect the pollen, and to assist also in the construction and furnishing of their burrows. The intermediate tarsi are as well often very much extended in the males, being considerably longer than those of the other legs. The use of the claws at the apex of the tarsi is evidently to enable the insect to cling to surfaces.

The manner in which the bee conveys either the pollen, or other material it purposes carrying home, to the posterior legs, or venter, which is to bear it, is very curious. The rapidity of the motions of its legs is then very great; so great, indeed, as to make it very difficult to follow them; but it seems first to collect its material gradually with its mandibles, from which the anterior tarsi gather it, and that on each side passes successively the grains of which it consists to the intermediate legs by multiplicated scrapings and twistings of the limbs; this then passes it on by similar manœuvres, and deposits it, according to the nature of the bee, upon the posterior tibiæ and plantæ, or upon the venter. The evidence of this process is speedily manifested by the posterior legs gradually exhibiting an increasing pellet of pollen. Thus, for this purpose, all the legs of the bees are more or less covered with hair. It is the mandibles which are chiefly used in their boring or excavating operations, applying their hands, or anterior tarsi, only to clear their way; but by the constructive or artisan bees they are used both in their building and mining operations, and are worked like trowels to collect moist clay, and to apply it to the masonry of their habitations.

The mesothorax, or central division of the thorax, has inserted on each side near the centre the four wings, the anterior pair articulating beneath the squamulæ, or wing-scales, which cover their base like an epaulette, and this wing scale often yields a specific character. In repose the four wings lie, horizontally, along the body, over the abdomen, the superior above, the inferior beneath. The wings themselves are transparent membranes, intersected by threads darker than their own substance, called their nervures, which are supposed to be tubular. These nervures and the spaces they enclose, called cells, are used in the superior wing only, and only occasionally, as subsidiary generic characters, and their terminology it will be desirable to describe, as use will be made subsequently of it. At the same time, to facilitate the comprehension of the terms, an illustrative diagram is appended; but those parts only will be described which have positive generic application. I may, however, first observe that upon the expansion of the wings in flight, the insect has the voluntary power of making the inferior cling to the superior wing by a series of hooklets with which its anterior edge is furnished at about half the length of that wing, which gives to the thus consolidated combination of the two a greater force in beating the air to accelerate its progress. That the insect has a control over the operation of these hooklets is very evident, for, upon settling, it usually unlocks them, and the anterior are often seen separated and raised perpendicularly over the insect; but that this can be mechanically effected also is shown sometimes in pinning a bee for setting, when by a lucky accident the pin catches the muscles which act upon the wings, and they become distended, as in flight, closely linked together. Both the diagram and the description of this superior wing I borrow from an elaborate paper of my own in the first volume of the ‘Transactions of the Entomological Society of London,’ wherein I gave a tabulated view, in chronological order, of the nomenclature introduced by successive entomologists in the use they made of the anterior wing of the Hymenoptera for generic subdivision, and which I subsequently applied to my own work upon the ‘Fossorial Hymenoptera of Great Britain.’

Fig. 12.—Superior wing.
a, marginal cell;
b, first cubital or submarginal cell;
c, second ditto;
d, third ditto;
e and f, first and second recurrent nervures.

Attached to the mesothorax in the centre, above and behind, are the scutellum and post-scutellum, which in colouring or form often yield subsidiary generic or specific characters. On each side of the mesothorax in front, above the pectus, or breast, and just below and before the articulation of the anterior wings, there is a small tubercle, or boss, separated from the surrounding integument by a suture, the colouring of which frequently yields a specific character, but its uses are not known.

Fig. 13.—Posterior legs:
1, of abnormal bee (Andrena);
2, scopuliped normal bee (Eucera);
3, parasitic bee (Nomada).
a, coxa;
b, trochanter, with flocculus;
c, femur;
d, tibia;
e, planta;
f, spinulæ;
g, tarsus, with its claws.

The metathorax carries the posterior legs laterally beneath, and in the centre, behind, the abdomen. The posterior legs are the chief organs used by the majority of bees for the conveyance of pollen to store in their cells, or, as in the case of humble-bees or the hive bee, the bee bread for the food for the young, or the requisite materials, in the majority of other bees, for nidification. To this end they are either densely clothed with hair throughout their whole extent,—usually externally only,—or this is limited to the external surface of the posterior shank. In the social bees this shank is edged externally with stiff bristles. In these, as in most of the bees, this limb greatly and gradually expands towards its articulation with the planta, or first joint of the tarsus; and this surface, which is perfectly smooth, serves to the social bee as a sort of basket to hold and convey the collected materials. The first joint of the tarsus, or planta, of this leg is also used in the domestic economy of the insect to assist in the same object. In the domestic bee the under side of the posterior plantæ have a very peculiar structure, consisting of a series of ten transverse broad parallel lines of minute dense but short brushes, which are used in the manipulations within the hive. Neither the Queen-bee nor the drone have this structure, and in the humble-bee and scopuliped bees the same joint is uniformly covered with this brush without its being separated into lines.

The Abdomen of bees has many shapes, its form being elliptical, cylindrical, subcylindrical, clavate, conical or subconical, and sometimes semicircular, or concavo-convex. It consists of six imbricated plates, called segments, in the female, and of seven in the male; in the latter sex, in several genera, it takes beneath at its base and at its apex, as well as at the extremity of the latter, remarkable forms and armature. It is very variously clothed and coloured, and sometimes extremely gaily and elegantly so; these various markings often giving the insects their specific characteristics; the clothing of the under side of this segment of the body, likewise, furnishes subsidiary generic characters, especially in the artisan bees, in whom it takes the place of the posterior legs as a polliniferous organ. This is possibly because were the supply conveyed upon their posterior legs it would be rubbed away as they entered the narrow apertures of their nests. Nature does nothing in vain, and there is evidently a purpose in this arrangement.