Part 4

These varying habits in the same species {60} show pretty clearly that these little creatures are not driven by any blind instinct in the adoption of their methods of nest building: they appear to have a distinct power of choice and adaptation according to their environment, unless of course it can be shown that the offspring of, say, a snail shell inhabitant follows its parents' habits, and that that of a ground borer does the same--but even that would not explain the case given by F. Smith, and quoted above, where an _Osmia_ had filled up the whorls of a shell and then, finding the final whorl too large, placed two cells horizontally to fill it: that seems to indicate distinct design on the part of the bee and would be hard to explain as due to instinct. Unfortunately, with the exception of a very few, the species of _Osmia_ are rare in this country, so that few opportunities are available for studying their habits, which are certainly amongst the most interesting of any genus.

{61}

A COLONY OF ANTHOPHORA

_Anthophora pilipes_ (pl. D, 24, 25), one of our early spring bees, often forms enormous colonies. I have sometimes seen sandpits in which the sides were riddled all over with holes of this species, and where the insects were in such numbers that a distinct hum was audible from the vibration of their wings. In such colonies one is sure to detect some of their cuckoo associates, _Melecta armata_ (pl. D, 26). They are deep black bees, much of the same size as their hosts but with more pointed tails and with a small spot of snow-white hairs on the side of each segment of the body; like other cuckoos they sail about in a more demure way than their hosts, but a more lively scene than a large colony of _Anthophora_ can hardly be found. The _Anthophora_ provisions its cells with honey and pollen, and its egg in consequence floats on the top--the {62} number of cells varies from five or six up to ten or eleven.

_Anthophora pilipes_ has a very close relative in _Anthophora retusa_, which also forms large colonies, but it is as a rule less common. These two species are exceedingly alike, in fact it requires some skill on the part of the observer to differentiate their females. They are both black and clothed with black hairs, and both have yellow pollen-brushes, but in _retusa_ the hairs are shorter and not quite of such a deep black as those of _pilipes_, and the spurs of the tibiae are pale, whereas in _pilipes_ they are black. The males, however, differ widely, although much alike in colour; in _pilipes_ the feet of the middle pair of legs are clothed with enormously long hairs, the basal joint has a dense fringe of black hairs in front and some long black hairs behind (see pl. D, fig. 24); in _retusa_ the basal joint of the middle pair of feet have a fan-shaped fringe of black hairs, and the rest of the joints are clothed with longer hairs, but not long enough to be specially noticeable. _A. retusa_ is visited by the same cuckoo as _A. pilipes_ and also by its rare ally _Melecta luctuosa_, which only differs from _armata_ {63} (pl. D, 26) in the larger and squarer spots of the body and various small structural characters hardly appreciable except by specialists. The Anthophoras have other parasites besides their cuckoos; one is a beetle, which, however, is rare, and which lays its egg in the _Anthophora_ cells; the other is a very minute member of the Hymenopterous family, whose larva when hatched feeds upon the larva of the bee. Notwithstanding these disadvantages both species are abundant, although _retusa_ is more local than _pilipes_. A very interesting fact connected with this genus has just been communicated to me by the Rev. F. D. Morice. John Ray, who lived in the seventeenth century, mentions in his book _Historia Insectorum_ (published posthumously in 1710), p. 243, that a large colony of a bee, which from his description was clearly an _Anthophora_, as he specially calls attention to the great difference between the males and females, inhabited a certain locality at Kilby near "Hill Morton" in Northamptonshire. Mr. Morice, who for many years resided at Rugby, knew Hillmorton, as it is now spelled, well, and tells me that a large colony of _Anthophora_ was in that same locality when he knew it only {64} a few years ago. Of course there is no proof that it has been there throughout the intervening period, but there seems to be no reason to doubt it, and if so it is a most interesting case of a persistent colony.

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{65}

BEES AND POLLEN-COLLECTING

Bees whether solitary or social enter flowers for the sake of the honey in their nectaries and the pollen on their anthers. In some cases the flowers automatically deposit pollen on the bees during the operation, which enables them to fertilize other flowers of the same species, but the pollen which the bee requires for its own use has to be worked for and collected on organs specially adapted for the purpose. These vary very much in the different families and genera; they exist only in the females, and, if the males get covered with pollen, as they often do, it is probably more by chance than purpose, and it is doubtful if it is of any value to the brood, although no doubt useful in fertilizing other flowers. All our bees, as has been pointed out before, are clothed more or less with branched or feather-like hairs, which would appear to be admirably adapted for the collecting of pollen. {66} At the same time some species which have their bodies clothed with branched hairs have simple or spirally grooved hairs on the collecting organ--others collect on very much branched hairs--so that there seems to be no exact relationship between the plumosity of the hairs and their utility in collecting. The collecting brushes are either on the hind legs or, as in some cases, on the ventral surface of the body. In a female _Andrena_, the hind leg has a tuft of curled hairs near the base of the leg, and a more or less heavy brush on the outside of the tibia or shin (fig. 8). When a female returns after a collecting expedition these specially hairy regions are a mass of pollen grains, and the "beautiful yellow legs", so often remarked upon in some bees, are not always due to the colour of the hairs but to that of the grains of pollen adhering to them. The genera which collect on the under surface of the body have to visit flowers where the anthers lie in such a position that they can transfer the pollen on to it; the pea flower tribe are favourites with them, and also the _Compositae_. All this section have long tongues so that they are able to reach the nectaries of {67} [Illustration: FIG. 8.] [Illustration: FIG. 9.] plants with long tubular flowers. In visiting these the pollen is often deposited on the back of the bee; this it is able to transfer to its under side by means of the brushes on its feet or tarsi. The arrangements of the humble bees for pollen gathering are altogether different from those mentioned above. They have the hind shin outwardly shining and rather concave, with a series of long curved hairs running down each side of it and partly curving over it, so that they carry their mass of pollen in a sort of basket, scientifically called the "corbicula" (fig. 9); this would be impossible if the pollen were gathered dry, as it is by most of the solitary bees, so the bee moistens it on the flower with the nectar she has been sucking so as to make it sticky, and then transfers it into her basket by means of her foot brushes. The pollen therefore on the hind leg of a humble bee is all in one mass and can be {68} removed as such. When the bee reaches her nest this must of course save her the trouble which the solitary bee must have of cleaning off all the separate grains of pollen which are mixed up among the hairs.

A word or two may be convenient here on the combs and cleaning apparatus of bees. Any one who has watched a bee clean itself will have noticed that the front legs work more or less horizontally--a bee will lower its head and bring its front leg over it with a curved motion--and that it will clean the sides of the face with a sort of shaving-like action, also that the antennae are apparently pulled through the foot-joint in a remarkable way, often many times in succession. Now the foot of a bee consists of five joints, and is clothed with bristly looking hairs. If these hairs be examined through a microscope they will be found to be more or less razor-shaped, having a thick back and a dilated wing or knife-like blade (fig. 10). In some the blade is of some width, and the edge is evidently very sharp: these hairs or spines no doubt do the cleaning work, and admirably adapted they are to the purpose. The antennae-cleaner {69} [Illustration: FIG. 10.] [Illustration: FIG. 11.] [Illustration: FIG. 12.] (it may possibly be used for other purposes too) is a still more wonderful adaptation; in the basal joint of the foot there is a semicircular incision, which, when examined under the microscope, is seen to be a small toothed comb. The foot itself fits into the tibia or shin, and at the apex of the latter is a modified spine which is dilated on one side into a wing, or knife-like blade; this shuts down on to the semicircular comb, and the insect by passing the antennae between the two can clean off anything which may have stuck to it (fig. 11). When we come to examine the other legs we find that the inner surface of their tibiae and tarsi, i.e. that which is nearest the body, is clothed with hairs which have the points dilated and spade-like (fig. 12), which {70} allowing for the different action of the hind legs makes them just as good cleaners as the razors of the front pair; the spurs at the apex of the tibiae, which are known as the _calcaria_, are also doubtless useful for cleaning purposes, and this is specially suggested by the beautiful saw-like form which they assume in some species; although there is no actual semicircular comb in the first joint of the tarsi, yet there can be little doubt that the spur and this joint in conjunction can act as a cleaning organ very much in the same way as the more elaborate arrangement in the front legs. Any one who has the opportunity of examining the hairs of bees under a microscope will be amply repaid for the trouble in noticing the beautiful shapes and structures which these organs assume. (Figs. 13-18; 17 showing pollen grains adhering.) At one time, when I was specially examining bee hairs, I shaved the various parts of a large number of species and mounted their hairs dry in microscopic slides, merely securing the cover glass with liquid glue; this was twenty years ago, and many are still quite good. It may seem a difficult operation to shave a bee, but {71} the hairs come off very easily, and with a sharp dissecting knife for a razor as many hairs as one wants are almost immediately at one's disposal.

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{72}

ON BEES' TONGUES, AND HOW THEY SUCK HONEY

In order to understand how a bee sucks honey it will be necessary to go into some rather careful details as to the construction of its tongue and mouth organs. These I will make as short and simple as I can, but the apparatus is a very complicated one, and it will be impossible to describe it without a good deal of technical phraseology.

The tongue has always been considered such an important feature in a bee's structure that it has been made the chief basis of their classification. On this subject I will only say that there are three principal types of tongues--a short bifid tongue (fig. 19, 3[1]), resembling those of the fossors; a short pointed one, shaped somewhat like a spear head (fig. 19, 2, 2a); and a long parallel-sided, ribbon-like tongue (fig. 19, 1, 1a). The bees are classified on what is considered to be an {73} ascending scale, beginning with the bifid-tongued species, through those with the short spear shaped tongues to the higher forms, which have this organ elongate and parallel-sided.

The tongue is the central organ of an elaborate combination of mouth parts, which I will now try to explain. If we turn a bee's head over and look at its underside we shall find a deep cavity, filled up with the base of this combination which fits into it. If we extend the tongue (a humble bee is a good subject on account of its large size, fig. 20) so as to draw its base out of the cavity, we shall find that in the edge of each side of the cavity there is articulated a short rod (20, A), more or less dilated at its apex, called {74} the _stipes_; on the flattened ends of these rods there swings a joint shaped something like the "merrythought" bone of a chicken, called the _lora_ or reins (20, B), to the central angle of which are suspended the pieces of the apparatus which terminate in the tongue. This V-shaped joint can swing over on its feet, and can therefore lie either between the _stipites_ or rods with its angle pointing towards the tail of the bee, or in the opposite direction with its angle projecting beyond them and pointing forwards. It will at once be seen that by this turn of the V the tongue can be projected a distance equivalent to twice the length of the V.

This V-shaped joint varies much in the length of its arms, which are much longer in the long-tongued than in the short-tongued bees.

When we examine the parts that are suspended from this joint, we shall find that the actual tongue is separated from it by two distinct pieces; the first (i.e. that next to the _lora_) a short joint (the _submentum_, 20, C), the second (the _mentum_, 20, D) a long semi-cylindrical joint which holds as in a trough the softer parts at the base of the tongue. From the apex of the _mentum_ {75} project three organs; the central one is the actual tongue (or _ligula_, 20, E), and on each side are the organs which are called the _labial palpi_ (20, F); these in the long-tongued bees more or less fold over the base of the tongue and protect it. There are two other large and important mouth parts called the _maxillae_ (20, G); these articulate on to the flattened apices of the _cardines_, outside the articulation of the feet of the _lora_, and extend on each side of the _mentum_; they also have flattened blades sheathing, when closed, the whole of the _mentum_ above, as well as the base of the tongue.

So far we have been looking at the back of the head and mouth parts; if we now look at the front we shall see the _maxillae_; if we open these we shall see the tongue lying between the {76} labial palpi, and at the base of the tongue we shall see two little sheaths called the _paraglossae_; above these the softer parts lying in the trough of the _mentum_; from the base of the _mentum_, connecting with the _maxillae_, there extends a membrane which entirely invests the spaces between the bases of these organs and extends up to the mouth. A membrane also extends between the _stipites_ and _lora_, and closes the cavity at the back of the head. The back of the tongue in the act of sucking can be formed into a tube through which, partly, probably by capillary action, partly by the pumping action caused by the dilating and contracting of certain parts of the mechanism, the liquid food is drawn up into the aesophagus. This, I believe, has been shown to be the principle on which all bees, short- or long-tongued, suck up their honey. The subject could be treated at much greater length, and many other structures connected with the mouth parts discussed, but more minute details are unnecessary in an elementary work such as this, and I have therefore limited myself to a description of the broad principles of the process.

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{77}

A DREADFUL PARASITE

Of all the evils to which bee flesh is heir, there can hardly be any so terrible as the effects of the parasite _Stylops_ on the species of _Andrena_ and _Halictus_ which it attacks. This very extraordinary creature, which is now considered to be a beetle, lives during the early stages of both sexes in the body of the bee, which it enters when the bee is in the larval state. Its head protrudes like a minute flat seed between the body segments (fig. 21), and so is visible externally, but the rest of the creature, which is a grub-like larva, rests amongst the intestines of the bee; the female matures in the bee's body and never leaves it. The male, however, when mature, escapes, leaving the {78} [Illustration: FIG. 22. Stylops larva in abdominal cavity: after Perez.] great hole which he inhabited open; he is provided with wings, and I have more than once caught one flying in the open--but to return to our afflicted bee. This may be attacked in either sex, and by one to five of the parasites. I have specimens myself with four parasites in them, and a case of five has been recorded. Mr. R. C. L. Perkins, writing on this subject, says: "On removing the integument dorsally from the bee, the large body of the female parasite will be seen lying above the viscera, often almost entirely concealing them". If this is the condition of a bee nourishing only one parasite, I must leave it to my readers to imagine the state of the poor wretch who is supporting five! The outward appearance of one with several parasites is generally much distorted; the abdomen is very much inflated, and the poor creature is unable to fly any {79} distance, and can only crawl about, or perhaps take short flights of a foot or so. The effects, however, seem to be very different in different cases. I have caught _Andrenas_ with two _Stylops_ in them, flying about as usual and apparently none the worse for their inmates. Probably the position the parasite occupies may make a great difference in its effects on the bee.

The most notable effect produced by _Stylops_ is the alteration in the structure and colour of certain of the bee's characteristic features. In _Andrena_ the males differ very considerably from the females both in form and colouring. They have no pollen-brushes on their legs, and in some few species the face above the mouth is white, whereas in the female it is black. Now the effect of the parasite seems to be to unsex as it were its victims so far as their outward appearance is concerned. This is no doubt due to the internal effects it has on the larva of the bee. Anyhow, if a female is attacked, in most cases the pollen-brush is much reduced, the face tends to become more hairy, and, if it be the female of a white-faced male, spots of white are often produced on the face. On the other hand, {80} if it be a male subject, the hairiness of the face is diminished, the white colour is often reduced or absent, and the hairiness of the legs is increased.

Before the effects of the parasite were recognized, several new species were described simply on specimens of unusual appearance in consequence of its presence.

These effects, however, like the effects produced on the activity of the bee, vary exceedingly in extent. On some the parasite seems to have no effect, in others the alteration in appearance is very great. This, again, is probably due to the position of the parasites and to the pressure they exert on the reproductive organs of the body in the larval state.

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{81}

AMONGST THE BEES AT WORK

Now I feel sure many will be thinking "It is all very well to talk about all these solitary and social bees, but I never see them. I certainly know a humble bee with a white tail and another with a red tail, and a wasp, and perhaps a hornet, but I never notice any others." The reason for this, no doubt, is that people are not as a rule observant, and even if they notice a creature one moment they probably forget all about it the next. If any one goes out on a bright spring morning, late in March or early in April, about 11 o'clock, into a garden well stocked with flowers, it will not, I think, be many minutes before an insect darts on the wing along some border, and, if attention be paid to the flowers, a little black hairy bee with yellow legs, like a small humble bee, will be seen diligently at work sucking honey from one of them. The darting bee, which is of a brownish red colour, gradually {82} fading to grey after a few days' exposure to the sun, is the male, and the black one the female. The male rarely settles, but flies about courting the female. Often two or three males may be seen dodging and crossing each other in their flight. The name of this bee is _Anthophora_. It is quite a harbinger of spring, and I mention it especially as it so forces itself on one's attention, and there are few who will not meet with it without going especially on its quest.