Chapter XIII: Section 2: Cenobites (Dwellers in Community)

Subsection 1. SPURRED.

† _Parasitical._

Genus 25. APATHUS.

†† _Collectors._

_Temporarily social._

Genus 26. BOMBUS.

Subsection 2. UNSPURRED.

_Permanently social._

Genus 27. APIS.

The primary division of the bees into two large branches, viz. into the _Andrenidæ_, or abnormal bees, and the _Apidæ_, or normal bees, is effected by the mode in which they fold the cibarial apparatus in repose. In the description of the structure of the imago, I have enlarged upon these organs, and for their explanation I must refer to that chapter where diagrams exhibit the structure of the different kinds of trophi of the bees, as well as their mode of folding. Here it is only necessary to notice that in the _Andrenidæ_, the joint at the base draws back the basal portion when protruded, and this basal portion is further jointed at the point of the insertion of the paraglossæ and labial palpi, and parallel with which joint the maxillæ are likewise jointed close to the sinus where the maxillary palpi are inserted laterally upon it. The basal portion thus throws the anterior part forward or retracts it, at the will of the insect, and in the latter case, being then in repose, it lies in contiguous parallelism to the basal half, but beneath it. When thus withdrawn, the short tongue itself, with its paraglossæ and labial palpi are sheltered beneath the coping of the labrum and the lateral protection of the mandibles, whilst the horny sheathing of the maxillæ protect the softer parts folding underneath.

In the _Apidæ_, or normal bees, the basal joint has the same action in withdrawing the entire organ into its place of rest; but the joint which gives it this power is not in an analogous situation to that in the _Andrenidæ_, for it is seated short of the joint which lies at the base of the several organs of the cibarial apparatus. By bending these downwards, it carries their apex backwards towards the basal fulcrum through the action of these two joints, and, when there, the more delicate ones are protected from abrasion or injury, by the lateral overlapping of the horny skin of the maxillæ. All being thus withdrawn within this covering, upon the joint which folds them back, seated at the base of the tongue, the labrum falls, and further to strengthen this protection, the mandibles close over it like forceps.

That this difference in the arrangement of the cibarial apparatus points to any distinctive peculiarities of economy has not been ascertained, for the habits of the _Scopulipedes_ greatly resemble those of the _Andrenidæ_; although the habits of one of them, _Anthophora furcata_, are remarkably like those of the foreign genus _Xylocopa_, in its mode of drilling wood. But the _Apidæ_ have cross affinities amongst themselves, thus _Ceratina_ resembles _Heriades_, and some of the _Osmiæ_, in the way in which it nidificates.

The tongues of the _Andrenidæ_ are always shorter, broader, and flatter than those of the _Apidæ_, in which they are always long, cylindrical, and tapering. In the first section of the _Andrenidæ_, the paraglossæ are obtusely terminated at the apex, thence called lacerated, and where they are fringed with brief bristles. The peculiar form of the tongue in this section suggests its being separated into two subsections, that organ being in the first subsection very broad and bilobated, which gives those insects their position in the series by approximating them to the preceding family of the _Diploptera_, or wasps, whose tongues have the same bilobate form, but each lobe in them is furnished with a gland. These tongues, in both cases of the wasps and these bees, may conduce to the building or plastering habits of the insects. The form may aid the wasp and the _Colletes_, the first in the moulding of its hexagonal _papier-mâché_ cells, as it may the second in shaping and embroidering the silk-lined abode of its embryonic progeny. Why _Prosopis_ should have this organization is difficult to conceive, unless it be from an analogy of structure incidentally previously referred to, beyond which any special object has hitherto escaped detection.

In the second section of the _Andrenidæ_, which have the paraglossæ entire and terminating in a point, the tongues all also terminate acutely with a lateral inclination inwards. In the lanceolate-tongued tribe they bulge outwards laterally, although pointed at the apex.

All this subfamily of _Andrenidæ_, excepting only the two genera reputed parasites, viz. _Prosopis_ and _Sphecodes_, are essentially _Scopulipedes_, densely brush-legged, for the conveyance of pollen which they vigorously collect; but from the brevity of their tongues they are restricted to flowers with shallow petals and apparent nectaria, their favourite plants being the abounding _Compositæ_ and _Umbelliferæ_, as well as the _Rosaceæ_, whence they derive the agreeable odours which many of them emit upon being captured.

Their peculiar mode of collecting is a further reason for bringing the brush-legged _Apidæ_ collectively to the top of the normal bees, in juxtaposition to the _Andrenidæ_, where the transition is made very naturally from _Dasypoda_ to _Panurgus_.

The whole of the cibarial apparatus, or trophi, is always complete in all its constituent parts throughout the _Andrenidæ_; and it is only with _Ceratina_, in the group of _scopuliped Apidæ_, that it begins to show the tendency it has to abnormal deficiencies, by the paraglossæ, in that genus, being obsolete. This characteristic, then, exhibits itself in the _Nudipedes_ with two submarginal cells who are parasitical upon the _Dasygasters_, in whom also the maxillary palpi participate in a deficiency in the authentic number of their joints, whilst in _Apis_ both maxillary palpi and paraglossæ are unapparent. This shows that the numerical completion of the organs of the mouth have nothing to do with the qualifications of the creature, the best endowed in other respects being thus curtailed, the final cause of which is not yet understood.

The shape of the tongue itself thus separates the _Andrenidæ_ into three well-defined divisions readily perceptible. These, as I have just observed with respect to the differences in the mode of closing the oral apparatus in both cases, yield no clue to economy and habits, for which observation must supervene to illustrate it. This, patiently carried out, is very desirable, as it is still in discussion whether, notwithstanding the elucidation structure affords, _Prosopis_ and _Sphecodes_ are or are not parasitical. Structure says they are, for, like the cuckoo-bees forming the group _Nudipedes_ in the _Apidæ_, they are destitute of the requisite apparatus for collecting pollen. Mr. Kirby, however, gives direct testimony in favour of _Sphecodes_ being a burrower, in the case of which bee it ought not to be a matter of much difficulty to determine, for on sandy plateaus I have occasionally found it very abundant, especially where there was ragwort (_Senecio_) in flower in the vicinity, to which the males resorted; but being at the time more intent on other matters, I neglected the opportunity. Other observers concur with Mr. Kirby as regards _Sphecodes_, and also say as much for _Prosopis_ (better known as _Hylæus_). I strongly incline to the opinion enunciated by Latreille and Le Pelletier de St. Fargeau, that they are parasites. My opinion is based upon peculiarities in them other than, although strengthened by, the negative characteristic of absence of polliniferous organs. A negative cannot be proved, it is true, yet what has been positively asserted may as certainly result either from defective observation, or from too strong a desire to find no parasites among the _Andrenidæ_. My reasons occur elsewhere in this work, and I need not repeat them. It is still an open question, and the young entomologist, if entering the arena unprepossessed, might win his spurs in determining it. It would be well worth the trouble of attending to for those who have leisure, and if decided in favour of the independency of these genera, which must be corroborated by a plurality of observations, and not confined to one locality, they would form strong and remarkable instances of a defective analogy in nature’s workmanship, and suggest looking further for the causes of so extraordinary an anomaly, and urge us to endeavour to trace the equivalent which supersedes it.

The main subdivision of the _Apidæ_ results from the habits of the insects, which divides them into SOCIAL and SOLITARY. The only tangible characters the social tribes present to distinguish them from the solitary is the glabrous surface of the posterior tibiæ, with their lateral edges fringed with bristles slightly curved inwards, and which form, with the slightly indented surface of the limb, a sort of natural basket for the conveyance of pollen or other stores to the nest. This, however, has not been made use of as a main feature for scientific distribution, although they might follow the _Dasygasters_, as _corbiculated bees_, or little basket bearers, in which case they would form as pertinent a group as any of the rest, and the whole distribution of the bees, _Apidæ_, would then rest upon the absence of, or the mode in which the polliniferous organs were present. But the wonderful attribute of their extraordinary instinct prohibits their being treated with the rest in a consecutive line, and renders it rationally imperative that all the _Cenobites_ should group together in a section by themselves, and separate from the rest. Therefore in my arrangement I have not availed myself of this very natural character, and here indicate it, to show that I have not passed it from not noticing it.

Although the division into social and solitary yields in itself no tangible character whereby the insects may be separated, it being wholly empirical, yet is it so natural and necessary that it is impossible to gainsay it. We find the solitary section readily resolve itself into groups or subsections, determined by positive structural characters, indicative of certain habits, and having a conforming economy, besides which they are equivalents.

Thus the first subsection presents us with the brush-legged _Apidæ_ (_Scopulipedes_), which collect pollen upon their posterior legs. These are further subdivided into those which collect it upon the whole limb, viz. the coxa, the femur, the tibia, and first joint of the tarsus, (the _femoriferæ_), and those which gather it merely upon the shank and basal joint of the foot (the _cruriferæ_). These collectively form a well-defined group, and why _Panurgus_ should be separated from the brush-legged bees, when it is a most conspicuous instance of the faculty, even more so than any other of the _Scopulipedes_, I have yet to learn. It is true its mode of collecting closely resembles that practised by the _Andrenidæ_, as does also the furniture for the purpose of its posterior legs, but being essentially collocated with the _Apidæ_ or normal bees by its tongue, it fittingly links itself to the other brush-legged _Apidæ_ (which have hitherto been placed between the _Dasygasters_ and the Social Bees), by means of the genus _Eucera_, by reason of its two submarginal cells, the structure of its maxillary palpi, its mode of burrowing, and by each being infested by a similar parasite—a _Nomada_, which in accommodation to the size of the sitos is the largest of the genus. _Nomada_ does not occur as a parasite upon any other of the brush-legged bees, or indeed upon any other of the true bees at all, which peculiarity brings these two genera into close contiguity to all non-parasitical _Andrenidæ_, all of which have their legs furnished with polliniferous brushes, and upon which subfamily, exclusively of these two instances of _Panurgus_ and _Eucera_, _Nomada_ is solely parasitical.

With respect to the two submarginal cells to the wings, nature must have some reason for the limitation, for we find it prevalent also throughout the _Dasygasters_, or hairy-bellied bees.

The next very natural group is consistently central. It comprises the cuckoo-bees, which are naked-legged (_Nudipedes_), by reason of their parasitism, they not requiring organs to collect what they have no occasion to use. Their parasitism extends both upwards and downwards, those with three submarginal cells being parasitical upon all the brush-legged bees, whether subnormal _Andrenidæ_ or the _Scopulipedes_, those with two submarginal cells being restricted in their parasitism to the _Dasygasters_.

These _Dasygasters_, or hairy-bellied bees, form the next very natural group. Their general peculiarity of structure I have had occasion to advert to, in treating, in a former section of the work, upon the structure of the imago, and to which I now refer to avoid repetition. This group contains the majority of the artisan bees, whose habits I shall particularize when I speak of the genera specially; but we find carpenters amongst the _Scopulipedes_, and essentially builders amongst the _Cenobites_, which form a further and the last of our natural groups. A true cuckoo-bee (_Apathus_) consorts amongst these _Cenobites_, and properly so, from many causes. The anomaly would have been too great to have removed it to a place amongst the _Nudipedes_, for although in obsolete paraglossæ, and in a deficiency in the normal number of the joints of the maxillary palpi, it resembles some of these, its general habit and general structure, bating that controlled by its parasitical habits, are so like _Bombus_, that it cannot well be separated far from the latter,—especially as we know too little of its habits to say that it does not regularly dwell in the nest of its sitos, which may well mistake it for one of its own community, it resembling the species it infests so closely; it therefore consistently associates systematically with the temporarily social societies.

Having thus cursorily skimmed the surface of the method I suggest, I have next to give my reasons for proposing it in lieu of adopting any yet extant.

My exhibition of Kirby’s grouping, in the preceding section, where I treat of the scientific cultivation of British bees, will fully explain why I could not adopt that arrangement.

Why I cannot follow Latreille’s, is, that in his last elaboration, in his ‘Families Naturelles,’ published in 1825, which must be considered as his final view, he does not satisfactorily divide the _Andrenidæ_, of the genera of which he has made a complete jumble. With the _Apidæ_ in his group of _Dasygasters_, he intermixes _Ceratina_, separating it from the group of _Scopulipedes_, where it truly belongs by every characteristic, and he mingles also with them the two cuckoo genera _Stelis_ and _Cœlioxys_, which are merely parasites upon these _Dasygasters_, and can only be associated by the structural conformity of the two submarginal cells to the superior wings, and the length of the labrum, the latter being a character of very secondary importance; and further, he dissevers the _Scopulipedes_ in placing _Panurgus_ at the commencement of the _Apidæ_, and the rest proximate to the social bees.

Westwood, in his modification of Latreille’s system, certainly divides the _Andrenidæ_ better than his master had done, but he does not go far enough. Besides, he interposes _Halictus_ and _Lasioglossum_, (the latter admitted as a genus merely out of courtesy to Curtis, who had elevated it to that rank in his ‘British Entomology,’ although it is nothing more than a male _Halictus_), between _Sphecodes_ and _Andrena_ with _Cilissa_, these having lanceolate tongues with lacerate paraglossæ, whereas _Halictus_ has a very acute tongue, and its paraglossæ are entire, as is also the case with _Dasypoda_, from which _Halictus_ is thus divided. In the _Apidæ_, he does not separate the cuckoo-bees, but with Latreille intermixes _Cœlioxys_ and _Stelis_ with the artisan bees, although without retaining Latreille’s convenient and suitable name of _Dasygasters_, for this group of mechanics. The same objection I take to his _Scopulipedes_ as that expressed above, relative to Latreille’s.

Precisely the same fault I find with the _Andrenidæ_ of Smith, as that urged above with respect to Westwood’s. He is more careful with his _Apidæ_, his _Cuculinæ_ being all genuine parasites, but he includes _Ceratina_ with the _Dasygasters_, with which it has no affinity of structure, and only a slight analogy in the _form_ merely of its abdomen without its hairiness beneath, to that of _Osmia_, from whose proximity he takes it to place it near _Heriades_, when it is certainly intimately allied in every respect with the _Scopulipedes_, and by reason of its subclavate antennæ might suitably be brought into juxtaposition with _Panurgus_, did not its obsolete paraglossæ and three submarginal cells interfere with its occupying this position. To his _Scopulipedes_ the same objection is valid as that taken to Latreille’s and Westwood’s disposition of them. Amongst the social bees he separates _Bombus_ from _Apis_, by the intervention of _Apathus_, which is scarcely consistent.

It is in no spirit of captiousness that these objections are made; they are deduced from collocations whose conspicuous incoherence is patent to the most superficial observation. The distribution I have here introduced has been made merely to ameliorate, and make more cogent, what was so palpably defective and feeble.

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