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To illustrate the methods of those who batten on others' goods, the

plunderers who know no rest till they have wrought the destruction of

the worker, it would be difficult to find a better instance than the

tribulations suffered by the Chalicodoma of the Walls. The Mason who

builds on the pebbles may fairly boast of being an industrious

workwoman. Throughout the month of May, we see her black squads, in

the full heat o
the sun, digging with busy teeth in the mortar-quarry

of the road hard by. So great is her zeal that she hardly moves out of

the way of the passer-by; more than one allows herself to be crushed

underfoot, absorbed as she is in collecting her cement.

The hardest and driest spots, which still retain the compactness

imparted by the steam-roller, are the favourite veins; and the work of

making the pellet is slow and painful. It is scraped up atom by atom;

and, by means of saliva, turned into mortar then and there. When it is

all well kneaded and there is enough to make a load, the Mason sets

off with an impetuous flight, in a straight line, and makes for her

pebble, a few hundred paces away. The trowel of fresh mortar is soon

spent, either in adding another storey to the turret-shaped edifice,

or in cementing into the wall lumps of gravel that give it greater

solidity. The journeys in search of cement are renewed until the

structure attains the regulation height. Without a moment's rest, the

Bee returns a hundred times to the stone-yard, always to the one spot

recognized as excellent.

The victuals are now collected: honey and flower-dust. If there is a

pink carpet of sainfoin anywhere in the neighbourhood, 'tis there that

the Mason goes plundering by preference, though it cost her a four

hundred yards' journey every time. Her crop swells with honeyed

exudations, her belly is floured with pollen. Back to the cell, which

slowly fills; and back straightway to the harvest-field. And all day

long, with not a sign of weariness, the same activity is maintained as

long as the sun is high enough. When it is late, if the house is not

yet closed, the Bee retires to her cell to spend the night there, head

downwards, tip of her abdomen outside, a habit foreign to the

Chalicodoma of the Sheds. Then and then alone the Mason rests; but it

is a rest that is in a sense equivalent to work, for, thus placed, she

blocks the entrance to the honey-store and defends her treasure

against twilight or night marauders.

Being anxious to form some estimate of the total distance covered by

the Bee in the construction and provisioning of a single cell, I

counted the number of steps from a nest to the road where the mortar

was mixed and from the same nest to the sainfoin-field where the

harvest was gathered. I took such note as my patience permitted of the

journeys made in both directions; and, completing these data with a

comparison between the work done and that which remained to do, I

arrived at nine and a half miles as the result of the total

travelling. Of course, I give this figure only as a rough calculation;

greater precision would have demanded more perseverance than I can


Such as it is, the result, which is probably under the actual figure

in many cases, is of a kind that gives us a vivid idea of the Mason-

bee's activity. The complete nest will comprise about fifteen cells.

Moreover, the heap of cells will be coated at the end with a layer of

cement a good finger's-breadth thick. This massive fortification,

which is less finished than the rest of the work but more expensive in

materials, represents perhaps in itself one half of the complete task,

so that, to establish her dome, Chalicodoma muraria, coming and going

across the arid table-land, traverses altogether a distance of 275

miles, which is nearly half of the greatest dimension of France from

north to south. Afterwards, when, worn out with all this fatigue, the

Bee retires to a hiding-place to languish in solitude and die, she is

surely entitled to say:

'I have laboured, I have done my duty!'

Yes, certainly, the Mason has toiled with a vengeance. To ensure the

future of her offspring, she has spent her own life without reserve,

her long life of five or six weeks' duration; and now she breathes her

last, contented because everything is in order in the beloved house:

copious rations of the first quality; a shelter against the winter

frosts; ramparts against incursions of the enemy. Everything is in

order, at least so she thinks; but, alas, what a mistake the poor

mother is making! Here the hateful fatality stands revealed, aspera

fata, which ruins the producer to provide a living for the drone; here

we see the stupid and ferocious law that sacrifices the worker for the

idler's benefit. What have we done, we and the insects, to be ground

with sovran indifference under the mill-stone of such wretchedness?

Oh, what terrible, what heart-rending questions the Mason-bee's

misfortunes would bring to my lips, if I gave free scope to my sombre

thoughts! But let us avoid these useless whys and keep within the

province of the mere recorder.

There are some ten of them plotting the ruin of the peaceable and

industrious Bee; and I do not know them all. Each has her own tricks,

her own art of injury, her own exterminating tactics, so that no part

of the Mason's work may escape destruction. Some seize upon the

victuals, others feed on the larvae, others again convert the dwelling

to their own use. Everything has to submit: cell, provisions, scarce-

weaned nurselings.

The stealers of food are the Stelis-wasp (Stelis nasuta) and the

Dioxys-bee (Dioxys cincta). I have already said how, in the Mason's

absence, the Stelis perforates the dome of cell after cell, lays her

eggs there and afterwards repairs the breach with a mortar made of red

earth, which at once betrays the parasite's presence to a watchful

eye. The Stelis, who is much smaller than the Chalicodoma, finds

enough food in a single cell for the rearing of several of her grubs.

The mother lays a number of eggs, which I have seen vary between the

extremes of two and twelve, on the surface, next to the Mason's egg,

which itself undergoes no outrage whatever.

Things do not go so badly at first. The feasters swim--it is the only

word--in the midst of plenty; they eat and digest like brothers.

Presently, times become hard for the hostess' son; the food decreases,

dearth sets in; and at length not an atom remains, although the

Mason's larva has attained at most a quarter of its growth. The

others, more expeditious feeders, have exhausted the victuals long

before the victim has finished his normal repast. The swindled grub

shrivels up and dies, while the gorged larvae of the Stelis begin to

spin their strong little brown cocoons, pressed close together and

lumped into one mass, so as to make the best use of the scanty space

in the crowded dwelling. Should you inspect the cell later, you will

find, between the heaped cocoons on the wall, a little dried-up

corpse. It is the larva that was such an object of care to the mother

Mason. The efforts of the most laborious of lives have ended in this

lamentable relic. It has happened to me just as often, when examining

the secrets of the cell which is at once cradle and tomb, not to come

upon the deceased grub at all. I picture the Stelis, before laying her

own eggs, destroying the Chalicodoma's egg and eating it, as the

Osmiae do among themselves; or I picture the dying thing, an irksome

mass for the numerous spinners at work in a narrow habitation, being

cut to pieces to make room for the medley of cocoons. But to so many

deeds of darkness I would not like to add another by an oversight; and

I prefer to admit that I failed to perceive the grub that died of


Let us now show up the Dioxys. At the time when the work of

construction is in progress, she is an impudent visitor of the nests,

exploiting with the same effrontery the enormous cities of the Mason-

bee of the Sheds and the solitary cupolas of the Mason-bee of the

Pebbles. An innumerable population, coming and going, humming and

buzzing, strikes her with no awe. On the tiles hanging from the walls

of my porch I see her, with her red scarf round her body, stalking

with sublime assurance over the ridged expanse of nests. Her black

schemes leave the swarm profoundly indifferent; not one of the workers

dreams of chasing her off, unless she should come bothering too

closely. Even then, all that happens is a few signs of impatience on

the part of the hustled Bee. There is no serious excitement, no eager

pursuits such as the presence of a mortal enemy might lead us to

suspect. They are there in their thousands, each armed with her

dagger; any one of them is capable of slaying the traitress; and not

one attacks her. The danger is not suspected.

Meanwhile, she inspects the workyard, moves freely among the ranks of

the Masons and bides her time. If the owner be absent, I see her

diving into a cell, coming out again a moment later with her mouth

smeared with pollen. She has been to try the provisions. A dainty

connoisseur, she goes from one store to another, taking a mouthful of

honey. Is it a tithe for her personal maintenance, or a sample tested

for the benefit of her coming grub? I should not like to say. What I

do know is that, after a certain number of these tastings, I catch her

stopping in a cell, with her abdomen at the bottom and her head at the

orifice. This is the moment of laying, unless I am much mistaken.

When the parasite is gone, I inspect the home. I see nothing abnormal

on the surface of the mass. The sharper eye of the owner, when she

gets back, sees nothing either, for she continues the victualling

without betraying the least uneasiness. A strange egg, laid on the

provisions, would not escape her. I know how clean she keeps her

warehouse; I know how scrupulously she casts out anything introduced

by my agency: an egg that is not hers, a bit of straw, a grain of

dust. So, according to my evidence and that of the Chalicodoma, which

is more conclusive, the Dioxys's egg, if it is really laid then, is

not placed on the surface.

I suspect, without having yet verified my suspicion--and I reproach

myself for the neglect--I suspect that the egg is buried in the heap

of pollen-dust. When I see the Dioxys come out of a cell with her

mouth all over yellow flour, perhaps she has been surveying the ground

and preparing a hiding-place for her egg. What I take for a mere

tasting might well be a more serious act. Thus concealed, the egg

escapes the eagle eye of the Bee, whereas, if left uncovered, it would

inevitably perish, would be flung on the rubbish heap at once by the

owner of the nest. When the Spotted Sapyga lays her egg on that of the

Bramble-dwelling Osmia, she does the deed under cover of darkness, in

the gloom of a deep well to which not the least ray of light can

penetrate; and the mother, returning with her pellet of green putty to

build the closing partition, does not see the usurping germ and is

ignorant of the danger. But here everything happens in broad daylight;

and this demands more cunning in the method of installation.

Besides, it is the one favourable moment for the Dioxys. If she waits

for the Mason-bee to lay, it is too late, for the parasite is not able

to break down doors, as the Stelis does. As soon as her egg is laid,

the Mason-bee of the Sheds comes out of her cell and at once turns

round and proceeds to close it up with the pellet of mortar which she

holds ready in her mandibles. The material is employed with such

method that the actual sealing is done in a moment: the other pellets,

the object of repeated journeys, will serve merely to increase the

thickness of the lid. The chamber is inaccessible to the Dioxys from

the first touch of the trowel. Hence it is absolutely necessary for

her to see to her egg before the Mason-bee of the Sheds has disposed

of hers and no less necessary to conceal it from the Mason's watchful


The difficulties are not so great in the nests of the Mason-bee of the

Pebbles. After this Bee has laid her egg, she leaves it for a time to

go in search of the cement needed for closing the cell; or, if she

already holds a pellet in her mandibles, this is not enough to seal it

properly, as the orifice is larger. More pellets are needed to wall up

the entrance entirely. The Dioxys would have time to strike her blow

during the mother's absences; but everything seems to suggest that she

behaves on the pebbles as she does on the tiles. She steals a march by

hiding the egg in the mass of pollen and honey.

What becomes of the Mason's egg confined in the same cell with the egg

of the Dioxys? In vain have I opened nests at every season; I have

never found a vestige of the egg nor of the grub of either

Chalicodoma. The Dioxys, whether as a larva on the honey, or enclosed

in its cocoon, or as the perfect insect, was always alone. The rival

had disappeared without a trace. A suspicion thereupon suggests

itself; and the facts are so compelling that the suspicion is almost

equal to a certainty. The parasitic grub, which hatches earlier than

the other, emerges from its hiding-place, from the midst of the honey,

comes to the surface and, with its first bite, destroys the egg of the

Mason-bee, as the Sapyga does the egg of the Osmia. It is an odious,

but a supremely efficacious method. Nor must we cry out too loudly

against such foul play on the part of a new born infant: we shall meet

with even more heinous tactics later. The criminal records of life are

full of these horrors which we dare not search too deeply. An

infinitesimal creature, a barely-visible grub, with the swaddling-

clothes of its egg still clinging to it, is led by instinct, at its

first inspiration, to exterminate whatever is in its way.

So the Mason's egg is exterminated. Was it really necessary in the

Dioxys' interest? Not in the least. The hoard of provisions is too

large for its requirements in a cell of the Chalicodoma of the Sheds;

how much more so in a cell of the Chalicodoma of the Pebbles! She eats

not a half, hardly a third of it. The rest remains as it was,

untouched. We see here, in the destruction of the Mason's egg, a

flagrant waste which aggravates the crime. Hunger excuses many things;

for lack of food, the survivors on the raft of the Medusa indulged in

a little cannibalism; but here there is enough food and to spare. When

there is more than she needs, what earthly motive impels the Dioxys to

destroy a rival in the germ stage? Why cannot she allow the larva, her

mess-mate, to take advantage of the remains and afterwards to shift

for itself as best it can? But no: the Mason-bee's offspring must

needs be stupidly sacrificed on the top of provisions which will only

grow mouldy and useless! I should be reduced to the gloomy

lucubrations of a Schopenhauer if I once let myself begin on


Such is a brief sketch of the two parasites of the Chalicodoma of the

Pebbles, true parasites, consumers of provisions hoarded on behalf of

others. Their crimes are not the bitterest tribulations of the Mason-

bee. If the first starves the Mason's grub to death, if the second

makes it perish in the egg, there are others who have a more pitiable

ending in store for the worker's family. When the Bee's grub, all

plump and fat and greasy, has finished its provisions and spun its

cocoon wherein to sleep the slumber akin to death, the necessary

period of preparation for its future life, these other enemies hasten

to the nests whose fortifications are powerless against their

hideously ingenious methods. Soon on the sleeper's body lies a nascent

grub which feasts in all security on the luscious fare. The traitors

who attack the larvae in their lethargy are three in number: an

Anthrax, a Leucopsis and a microscopic dagger-wearer. (Monodontomerus

cupreus. For this and the Anthrax, cf. "The Life of the Fly": chapters

2 and 3. The Leucopsis is a Hymenopteron, the essay upon whom forms

the concluding chapter of the present volume.--Translator's Note.)

Their story deserves to be told without reticence; and I shall tell it

later. For the moment, I merely mention the names of the three


The provisions are stolen, the egg is destroyed. The young grub dies

of hunger, the larva is devoured. Is that all? Not yet. The worker

must be exploited thoroughly, in her work as well as in her family.

Here are some now who covet her dwelling. When the Mason is

constructing a new edifice on a pebble, her almost constant presence

is enough to keep the aspirants to free lodgings at a distance; her

strength and vigilance overawe whoso would annex her masonry. If, in

her absence, one greatly daring thinks of visiting the building, the

owner soon appears upon the scene and ousts her with the most

discouraging animosity. She has no need then to fear the entrance of

unwelcome tenants while the house is new. But the Bee of the Pebbles

also uses old dwellings for her laying, as long as they are not too

much dilapidated. In the early stages of the work, neighbours compete

for these with an eagerness which shows the value attached to them.

Face to face, at times with their mandibles interlocked, now both

rising into the air, now coming down again, then touching ground and

rolling over each other, next flying up again, for hours on end they

will wage battle for the property at issue.

A ready-made nest, a family heirloom which needs but a little

restoring, is a precious thing for the Mason, ever sparing of her

time. We find so many of the old homes repaired and restocked that I

suspect the Bee of laying new foundations only when there are no

secondhand nests to be had. To have the chambers of a dome occupied by

a stranger therefore means a serious privation.

Now several Bees, however industrious in gathering honey, building

party-walls and contriving receptacles for provisions, are less clever

at preparing the resorts in which the cells are to be stacked. The

abandoned chambers of the Chalicodoma, now larger than they were

originally, through the addition of the hall of exit, are first-rate

acquisitions for them. The great thing is to occupy these chambers

first, for here possession is nine parts of the law. Once established,

the Mason is not disturbed in her home, while she, in her turn, does

not disturb the stranger who has settled down before her in an old

nest, the patrimony of her family. The disinherited one leaves the

Bohemian to enjoy the ruined manor in peace and goes to another pebble

to establish herself at fresh expense.

In the first rank of these free tenants, I will place an Osmia (Osmia

cyanoxantha, PEREZ) and a Megachile, or Leaf-cutting Bee (Megachile

apicalis, SPIN.) (Cf. "Bramble-dwellers and Others": chapter 8.--

Translator's Note.), both of whom work in May, at the same time as the

Mason, while both are small enough to lodge from five to eight cells

in a single chamber of the Chalicodoma, a chamber increased by the

addition of an outer hall. The Osmia subdivides this space into very

irregular compartments by means of slanting, upright or curved

partitions, subject to the dictates of space. There is no art,

consequently, in the accumulation of little cells; the architect's

only task is to use the breadth at her disposal in a frugal manner.

The material employed for the partitions is a green, vegetable putty,

which the Osmia must obtain by chewing the shredded leaves of a plant

whose nature is still uncertain. The same green paste serves for the

thick plug that closes the abode. But in this case the insect does not

use it unadulterated. To give greater power of resistance to the work,

it mixes a number of bits of gravel with the vegetable cement. These

materials, which are easily picked up, are lavishly employed, as

though the mother feared lest she should not fortify sufficiently the

entrance to her dwelling. They form a sort of coarse stucco, on the

more or less smooth cupola of the Chalicodoma; and this unevenness, as

well as the green colouring of its mortar of masticated leaves, at

once betrays the Osmia's nest. In course of time, under the prolonged

action of the air, the vegetable putty turns brown and assumes a dead-

leaf tint, especially on the outside of the plug; and it would then be

difficult for any one who had not seen them when freshly made to

recognize their nature.

The old nests on the pebbles seem to suit other Osmiae. My notes

mention Osmia Morawitzi, PEREZ, and Osmia cyanea, KIRB., as having

been recognized in these dwellings, although they are not very

assiduous visitors. Lastly, to complete the enumeration of the Bees

known to me as making their homes in the Mason's cupolas, I must add

Megachile apicalis, who piles in each cell a half-dozen or more honey-

pots constructed with disks cut from the leaves of the wild rose, and

an Anthidium whose species I cannot state, having seen nothing of her

but her white cotton sacks.

The Mason-bee of the Sheds, on the other hand, supplies free lodgings

to two species of Osmiae, Osmia tricornis, LATR., and Osmia

Latreillii, SPIN., both of whom are quite common. The Three-horned

Osmia frequents by preference the habitations of the Bees that build

their nests in populous colonies, such as the Chalicodoma of the Sheds

and the Hairy-footed Anthophora. Latreille's Osmia is nearly always

found with the Three-horned Osmia at the Chalicodoma's.

The real builder of the city and the exploiter of the labour of others

work together, at the same period, form a common swarm and live in

perfect harmony, each Bee of the two species attending to her business

in peace. They share and share alike, as though by tacit agreement. Is

the Osmia discreet enough not to put upon the good-natured Mason and

to utilize only abandoned passages and waste cells? Or does she take

possession of the home of which the real owners could themselves have

made use? I lean in favour of usurpation, for it is not rare to see

the Chalicodoma of the Sheds clearing out old cells and using them as

does her sister of the Pebbles. Be this as it may, all this little

busy world lives without strife, some building anew, others dividing

up the old dwelling.

Those Osmiae, on the contrary, who are the self-invited guests of the

Mason-bee of the Pebbles are the sole occupants of the dome. The cause

of this isolation lies in the unsociable temper of the proprietress.

The old nest does not suit her from the moment that she sees it

occupied by another. Instead of going shares, she prefers to seek

elsewhere a dwelling where she can work in solitude. Her gracious

surrender of a most excellent lodging in favour of a stranger who

would be incapable of offering the least resistance if a dispute arose

proves the great immunity enjoyed by the Osmia in the home of the

worker whom she exploits. The common and peaceful swarming of the

Mason-bee of the Sheds and the two cell-borrowing Osmiae proves it in

a still more positive fashion. There is never a fight for the

acquisition of another's goods or the defence of one's own property;

never a brawl between Osmiae and Chalicodomae. Robber and robbed live

on the most neighbourly terms. The Osmia considers herself at home;

and the other does nothing to undeceive her. If the parasites, so

deadly to the workers, move about in their very ranks with impunity,

without arousing the faintest excitement, an equally complete

indifference must be shown by the dispossessed owners to the presence

of the usurpers in their old homes. I should be greatly put to it if I

were asked to reconcile this calmness on the part of the expropriated

one with the ruthless competition that is said to sway the world.

Fashioned so as to instal herself in the Mason's property, the Osmia

meets with a peaceful reception from her. My feeble eyes can see no


I have named the provision-thieves, the grub-murderers and the house-

grabbers who levy tribute on the Mason-bee. Does that end the list?

Not at all. The old nests are cities of the dead. They contain Bees

who, on achieving the perfect state, were unable to open the exit-door

through the cement and who withered in their cells; they contain dead

larvae, turned into black, brittle cylinders; untouched provisions,

both mouldy and fresh, on which the egg has come to grief; tattered

cocoons; shreds of skins; relics of the transformation.

If we remove the nest of the Chalicodoma of the Sheds from its tile--a

nest sometimes quite eight inches thick--we find live inhabitants only

in a thin outer layer. All the remainder, the catacombs of past

generations, is but a horrible heap of dead, shrivelled, ruined,

decomposed things. Into this sub-stratum of the ancient city the

unreleased Bees, the untransformed larvae fall as dust; here the

honey-stores of old go sour, here the uneaten provisions are reduced

to mould.

Three undertakers, all members of the Beetle tribe, a Clerus, a Ptinus

and an Anthrenus, batten on these remains. The larvae of the Anthrenus

and the Ptinus gnaw the ashes of the corpses; the larva of the Clerus,

with the black head and the rest of its body a pretty pink, appeared

to me to be breaking into the old jam-pots filled with rancid honey.

The perfect insect itself, garbed in vermilion with blue ornaments, is

fairly common on the surface of the clay slabs during the working

season, strolling leisurely through the yard to taste here and there

the drops of honey oozing from some cracked pot. Notwithstanding his

showy livery, so unlike the workers' sombre frieze, the Chalicodomae

leave him in peace, as though they recognized in him the scavenger

whose duty it is to keep the sewers wholesome.

Ravaged by the passing years, the Mason's home at last falls into ruin

and becomes a hovel. Exposed as it is to the direct action of wind and

weather, the dome built upon a pebble chips and cracks. To repair it

would be too irksome, nor would that restore the original solidity of

the shaky foundation. Better protected by the covering of a roof, the

city of the sheds resists longer, without however escaping eventual

decay. The storeys which each generation adds to those in which it was

born increase the thickness and the weight of the edifice in alarming

proportions. The moisture of the tile filters into the oldest layers,

wrecks the foundations and threatens the nest with a speedy fall. It

is time to abandon for good the house with its cracks and rents.

Thereupon the crumbling apartments, on the pebble as well as on the

tile, become the home of a camp of gypsies who are not particular

where they find a shelter. The shapeless hovel, reduced to a fragment

of a wall, finds occupants, for the Mason's work must be exploited to

the utmost limits of possibility. In the blind alleys, all that

remains of the former cells, Spiders weave a white-satin screen,

behind which they lie in wait for the passing game. In nooks which

they repair in summary fashion with earthen embankments or clay

partitions, Hunting Wasps--Pompili and Tripoxyla--store up small

members of the Spider tribe, including sometimes the Weaving Spiders

who live in the same ruins.

I have said nothing yet of the Chalicodoma of the Shrubs. My silence

is not due to negligence, but to the circumstance that I am almost

destitute of facts relating to her parasites. Of the many nests which

I have opened in order to study their inhabitants, only one so far has

been invaded by strangers. This nest, the size of a large walnut, was

fixed on a pomegranate-branch. It comprised eight cells, of which

seven were occupied by the Chalicodoma, and the eighth by a little

Chalcis, the plague of a whole host of the Bee-tribe. Apart from this

instance, which was not a very serious case, I have seen nothing. In

those aerial nests, swinging at the end of a twig, not a Dioxys, a

Stelis, an Anthrax, a Leucopsis, those dread ravagers of the other two

Masons; never any Osmiae, Megachiles or Anthidia, those lodgers in the

old buildings.

The absence of the latter is easily explained. The Chalicodoma's

masonry does not last long on its frail support. The winter winds,

when the shelter of the foliage has disappeared, must easily break the

twig, which is little thicker than a straw and liable to give way by

reason of its heavy burden. Threatened with an early fall, if it is

not already on the ground, last year's dwelling is not restored to

serve the needs of the present generation. The same nest does not

serve twice; and this does away with the Osmiae and with their rivals

in the art of utilizing old cells.

The elucidation of this point does not remove the obscurity of the

next. I can see nothing to account for the absence or at least the

extreme rareness of usurpers of provisions and consumers of grubs,

both of whom are very indifferent to the new or old conditions of the

nest, so long as the cells are well stocked. Can it be that the lofty

position of the edifice and the shaky support of the twig arouse

distrust in the Dioxys and other malefactors? For lack of a better

explanation, I will leave it at that.

If my idea is not an empty fancy, we must admit that the Chalicodoma

of the Shrubs was singularly well-inspired in building in mid-air. You

have seen of what misfortunes the other two are victims. If I take a

census of the population of a tile, many a time I find the Dioxys and

the Mason-bee in almost equal proportions. The parasite has wiped out

half the colony. To complete the disaster, it is not unusual for the

grub-eaters, the Leucopsis and her rival, the pygmy Chalcis, to have

decimated the other half. I say nothing of Anthrax sinuata, whom I

sometimes see coming from the nests of the Chalicodoma of the Sheds;

her larva preys on the Three-horned Osmia, the Mason-bee's visitor.

All solitary though she be on her boulder, which would seem the proper

thing to keep away exploiters, the scourge of dense populations, the

Chalicodoma of the Pebbles is no less sorely tried. My notes abound in

cases such as the following: of the nine cells in one dome, three are

occupied by the Anthrax, two by the Leucopsis, two by the Stelis, one

by the Chalcis and the ninth by the Mason. It is as though the four

miscreants had joined forces for the massacre: the whole of the Bee's

family has disappeared, all but one young mother saved from the

disaster by her position in the centre of the citadel. I have

sometimes stuffed my pockets with nests removed from their pebbles

without finding a single one that has not been violated by one or

other of the malefactors and oftener still by several of them at a

time. It is almost an event for me to find a nest intact. After these

funereal records, I am haunted by a gloomy thought: the weal of one

means the woe of another.