RATIONING ACCORDING TO SEX

Considered in respect of quality, the food has just disclosed our profound

ignorance of the origins of instinct. Success falls to the blusterers, to

the imperturbable dogmatists, from whom anything is accepted if only they

make a little noise. Let us discard this bad habit and admit that really,

if we go to the bottom of things, we know nothing about anything.

Scientifically speaking, nature is a riddle to which human curiosity fin s

no definite solution. Hypothesis follows hypothesis; the theoretical

rubbish-heap grows bigger and bigger; and still truth escapes us. To know

how to know nothing might well be the last word of wisdom.



Considered in respect of quantity, the food sets us other problems, no less

obscure. Those of us who devote ourselves assiduously to studying the

customs of the game-hunting Wasps soon find our attention arrested by a

very remarkable fact, at the time when our mind, refusing to be satisfied

with sweeping generalities, which our indolence too readily makes shift

with, seeks to enter as far as possible into the secret of the details, so

curious and sometimes so important, as and when they become better-known to

us. This fact, which has preoccupied me for many a long year, is the

variable quantity of the provisions packed into the burrow as food for the

larva.



Each species is scrupulously faithful to the diet of its ancestors. For

more than a quarter of a century I have been exploring my district; and I

have never known the diet to vary. To-day, as thirty years ago, each

huntress must have the game which I first saw her pursuing. But, though the

nature of the victuals is constant, the quantity is not so. In this respect

the difference is so great that he would need to be a very superficial

observer who should fail to perceive it on his first examination of the

burrows. In the beginning, this difference, involving two, three, four

times the quantity and more, perplexed me extremely and led me to the

conclusions which I reject to-day.



Here, among the instances most familiar to me, are some examples of these

variations in the number of victims provided for the larva, victims, of

course, very nearly identical in size. In the larder of the Yellow-winged

Sphex, after the victualling is completed and the house shut up, two or

three Crickets are sometimes found and sometimes four. Stizus ruficornis

(Cf. "The Hunting Wasps": chapter 20; also "Bramble-bees and Others":

chapter 9.--Translator's Note.), established in some vein of soft

sandstone, places three Praying Mantes in one cell and five in another. Of

the caskets fashioned by Amedeus' Eumenes (Cf." The Mason-wasps": chapter

1.--Translator's Note.) out of clay and bits of stone, the more richly

endowed contain ten small caterpillars, the more poorly furnished five. The

Sand Cerceris (Cf. "The Hunting Wasps": chapter 2.--Translator's Note.)

will sometimes provide a ration of eight Weevils and sometimes one of

twelve or even more. My notes abound in abstracts of this kind. It is

unnecessary for the purpose in hand to quote them all. It will serve our

object better if I give the detailed inventory of the Bee-eating Philanthus

and of the Mantis-hunting Tachytes, considered especially with regard to

the quantity of the victuals.



The slayer of Hive-bees is frequently in my neighbourhood; and I can obtain

from her with the least trouble the greatest number of data. In September I

see the bold filibuster flying from clump to clump of the pink heather

pillaged by the Bee. The bandit suddenly arrives, hovers, makes her choice

and swoops down. The trick is done: the poor worker, with her tongue

lolling from her mouth in the death-struggle, is carried through the air to

the underground den, which is often a very long way from the spot of the

capture. The trickling of earthy refuse, on the bare banks, or on the

slopes of footpaths, instantly reveals the dwellings of the ravisher; and,

as the Philanthus always works in fairly populous colonies, I am able, by

noting the position of the communities, to make sure of fruitful

excavations during the forced inactivity of winter.



The sapping is a laborious task, for the galleries run to a great depth.

Favier wields the pick and spade; I break the clods which he brings down

and open the cells, whose contents--cocoons and remnants of provisions--I

at once pour into a little screw of paper. Sometimes, when the larva is not

developed, the stack of Bees is intact; more often the victuals have been

consumed; but it is always possible to tell the number of items provided.

The heads, abdomens and thoraxes, emptied of their fleshy substance and

reduced to the tough outer skin, are easily counted. If the larva has

chewed these overmuch, the wings at least are left; these are sapless

organs which the Philanthus absolutely scorns. They are likewise spared by

moisture, putrefaction and time, so much so that it is no more difficult to

take an inventory of a cell several years old than one of a recent cell.

The essential thing is not to overlook any of these tiny relics while

placing them in the paper bag, amid the thousand incidents of the

excavation. The rest of the work will be done in the study, with the aid of

the lens, taking the remains heap by heap; the wings will be separated from

the surrounding refuse and counted in sets of four. The result will give

the amount of the provisions. I do not recommend this task to any one who

is not endowed with a good stock of patience, nor above all to any one who

does not start with the conviction that results of great interest are

compatible with very modest means.



My inspection covers a total of one hundred and thirty-six cells, which are

divided as in the table below:



2 cells each containing 1 Bee

52 cells each containing 2 Bees

36 cells each containing 3 Bees

36 cells each containing 4 Bees

9 cells each containing 5 Bees

1 cell containing 6 Bees

---

136



The Mantis-hunting Tachytes consumes its heap of Mantes, the horny envelope

included, without leaving any remains but scanty crumbs, quite insufficient

to establish the number of items provided. After the meal is completed, any

inventory of the rations becomes impossible. I therefore have recourse to

the cells which still contain the egg or the very young larva and, above

all, to those whose provisions have been invaded by a tiny parasitic Gnat,

a Tachina (Cf. "The Hunting Wasps": chapters 4 and 16.--Translator's

Note.), which drains the game without cutting it up and leaves the whole

skin intact. Twenty-five larders, put to the count, give me the following

result:



8 cells each containing 3 items

5 cells each containing 4 items

4 cells each containing 6 items

3 cells each containing 7 items

2 cells each containing 8 items

1 cell containing 9 items

1 cell containing 12 items

1 cell containing 16 items

---

25



The predominant game is the Praying Mantis, green; next comes the Grey

Mantis, ash-coloured. A few Empusae make up the total. The specimens vary

in dimensions within fairly elastic limits: I measure some which are a

third to a half inch long, averaging two-thirds to one inch long, and some

which are two-fifths, averaging three quarters. I see pretty plainly that

their number increases in proportion as their size diminishes, as though

the Tachytes were seeking to make up for the smallness of the game by

increasing the amount; none the less I find it quite impossible to detect

the least equivalence by combining the two factors of number and size. If

the huntress really estimates the provisions, she does so very roughly; her

household accounts are not at all well kept; each head of game, large or

small, must always count as one in her eyes.



Put on my guard, I look to see whether the honey-gathering Bees have a

double service, like the game-hunting Wasps'. I estimate the amount of

honeyed paste; I gauge the cups intended to contain it. In many cases the

result resembles the first obtained: the abundance of provisions varies

from one cell to another. Certain Osmiae (O. cornuta and O. tricornis (Cf.

"Bramble-bees and Others": passim; and, in particular, chapters 3 to 5.--

Translator's Note.)) feed their larvae on a heap of pollen-dust moistened

in the middle with a very little disgorged honey. One of these heaps may be

three or four times the size of some other in the same group of cells. If I

detach from its pebble the nest of the Mason-bee, the Chalicodoma of the

Walls, I see cells of large capacity, sumptuously provisioned; close beside

these I see others, of less capacity, with victuals parsimoniously

allotted. The fact is general; and it is right that we should ask ourselves

the reason for these marked differences in the relative quantity of

foodstuffs and for these unequal rations.



I at last began to suspect that this is first and foremost a question of

sex. In many Bees and Wasps, indeed, the male and the female differ not

only in certain details of internal or external structure--a point of view

which does not affect the present problem--but also in length and bulk,

which depend in a high degree on the quantity of food.



Let us consider in particular the Bee-eating Philanthus. Compared with the

female, the male is a mere abortion. I find that he is only a third to half

the size of the other sex, as far as I can judge by sight alone. To obtain

exactly the respective quantities of substance, I should need delicate

balances, capable of weighing down to a milligramme. My clumsy villager's

scales, on which potatoes may be weighed to within a kilogramme or so, do

not permit of this precision. I must therefore rely on the evidence of my

sight alone, evidence, for that matter, which is amply sufficient in the

present instance. Compared with his mate, the Mantis-hunting Tachytes is

likewise a pigmy. We are quite astonished to see him pestering his giantess

on the threshold of the burrows.



We observe differences no less pronounced of size--and consequently of

volume, mass and weight--in the two sexes of many Osmiae. The differences

are less emphatic, but are still on the same side, in the Cerceres, the

Stizi, the Spheges, the Chalicodomae and many more. It is therefore the

rule that the male is smaller than the female. There are of course some

exceptions, though not many; and I am far from denying them. I will mention

certain Anthidia where the male is the larger of the two. Nevertheless, in

the great majority of cases the female has the advantage.



And this is as it should be. It is the mother, the mother alone, who

laboriously digs underground galleries and chambers, kneads the plaster for

coating the cells, builds the dwelling-house of cement and bits of grit,

bores the wood and divides the burrow into storeys, cuts the disks of leaf

which will be joined together to form honey-pots, works up the resin

gathered in drops from the wounds in the pine-trees to build ceilings in

the empty spiral of a Snail-shell, hunts the prey, paralyses it and drags

it indoors, gathers the pollen-dust, prepares the honey in her crop, stores

and mixes the paste. This severe labour, so imperious and so active, in

which the insect's whole life is spent, manifestly demands a bodily

strength which would be quite useless to the male, the amorous trifler.

Thus, as a general rule, in the insects which carry on an industry the

female is the stronger sex.



Does this pre-eminence imply more abundant provisions during the larval

stage, when the insect is acquiring the physical growth which it will not

exceed in its future development? Simple reflection supplies the answer:

yes, the aggregate growth has its equivalent in the aggregate provisions.

Though so slight a creature as the male Philanthus finds a ration of two

Bees sufficient for his needs, the female, twice or thrice as bulky, will

consume three to six at least. If the male Tachytes requires three Mantes,

his consort's meal will demand a batch of something like ten. With her

comparative corpulence, the female Osmia will need a heap of paste twice or

thrice as great as that of her brother, the male. All this is obvious; the

animal cannot make much out of little.



Despite this evidence, I was anxious to enquire whether the reality

corresponded with the previsions of the most elementary logic. Instances

are not unknown in which the most sagacious deductions have been found to

disagree with the facts. During the last few years, therefore, I have

profited by my winter leisure to collect, from spots noted as favourable

during the working-season, a few handfuls of cocoons of various Digger-

wasps, notably of the Bee-eating Philanthus, who has just furnished us with

an inventory of provisions. Surrounding these cocoons and thrust against

the wall of the cell were the remnants of the victuals--wings, corselets,

heads, wing-cases--a count of which enabled me to determine how many head

of game had been provided for the larva, now enclosed in its silken abode.

I thus obtained the correct list of provisions for each of the huntress'

cocoons. On the other hand, I estimated the quantities of honey, or rather

I gauged the receptacles, the cells, whose capacity is proportionate to the

mass of the provisions stored. After making these preparations, registering

the cells, cocoons and rations and putting all my figures in order, I had

only to wait for the hatching-season to determine the sex.



Well, I found that logic and experiment were in perfect agreement. The

Philanthus-cocoons with two Bees gave me males, always males; those with a

larger ration gave me females. From the Tachytes-cocoons with double or

treble that ration I obtained females. When fed upon four or five Nut-

weevils, the Sand Cerceris was a male; when fed upon eight or ten, a

female. In short, abundant provisions and spacious cells yield females;

scanty provisions and narrow cells yield males. This is a law upon which I

may henceforth rely.



At the stage which we have now reached a question arises, a question of

major importance, touching the most nebulous aspect of embryogeny. How is

it that the larva of the Philanthus, to take a particular case, receives

three to five Bees from its mother when it is to become a female and not

more than two when it is to become a male? Here the various head of game

are identical in size, in flavour, in nutritive properties. The food-value

is precisely in proportion to the number of items supplied, a helpful

detail which eliminates the uncertainties wherein we might be left by the

provision of game of different species and varying sizes. How is it, then,

that a host of Bees and Wasps, of honey-gatherers as well as huntresses,

store a larger or smaller quantity of victuals in their cells according as

the nurselings are to become females or males?



The provisions are stored before the eggs are laid; and these provisions

are measured by the needs of the sex of an egg still inside the mother's

body. If the egg-laying were to precede the rationing, which occasionally

takes place, as with the Odyneri (Cf. "The Hunting Wasps": chapters 2 and

8.--Translator's Note.), for example, we might imagine that the gravid

mother enquires into the sex of the egg, recognizes it and stacks victuals

accordingly. But, whether destined to become a male or a female, the egg is

always the same; the differences--and I have no doubt that there are

differences--are in the domain of the infinitely subtle, the mysterious,

imperceptible even to the most practised embryogenist. What can a poor

insect see--in the absolute darkness of its burrow, moreover--where science

armed with optical instruments has not yet succeeded in seeing anything?

And besides, even were it more discerning than we are in these genetic

obscurities, its visual discernment would have nothing whereupon to

practice. As I have said, the egg is laid only when the corresponding

provisions are stored. The meal is prepared before the larva which is to

eat it has come into the world. The supply is generously calculated by the

needs of the coming creature; the dining-room is built large or small to

contain a giant or a dwarf still germinating in the ovarian ducts. The

mother, therefore, knows the sex of her egg beforehand.



A strange conclusion, which plays havoc with our current notions! The logic

of the facts leads us to it directly. And yet it seems so absurd that,

before accepting it, we seek to escape the predicament by another

absurdity. We wonder whether the quantity of food may not decide the fate

of the egg, originally sexless. Given more food and more room, the egg

would become a female; given less food and less room, it would become a

male. The mother, obeying her instincts, would store more food in this case

and less in that; she would build now a large and now a small cell; and the

future of the egg would be determined by the conditions of food and

shelter.



Let us make every test, every experiment, down to the absurd: the crude

absurdity of the moment has sometimes proved to be the truth of the morrow.

Besides, the well-known story of the Hive-bee should make us wary of

rejecting paradoxical suppositions. Is it not by increasing the size of the

cell, by modifying the quality and quantity of the food, that the

population of a hive transforms a worker larva into a female or royal

larva? It is true that the sex remains the same, since the workers are only

incompletely developed females. The change is none the less miraculous, so

much so that it is almost lawful to enquire whether the transformation may

not go further, turning a male, that poor abortion, into a sturdy female by

means of a plentiful diet. Let us therefore resort to experiment.



I have at hand some long bits of reed in the hollow of which an Osmia, the

Three-horned Osmia, has stacked her cells, bounded by earthen partitions. I

have related elsewhere (Cf. "Bramble-bees and Others": chapters 2 to 5.--

Translator's Note.) how I obtain as many of these nests as I could wish

for. When the reed is split lengthwise, the cells come into view, together

with their provisions, the egg lying on the paste, or even the budding

larva. Observations multiplied ad nauseam have taught me where to find the

males and where the females in this apiary. The males occupy the fore-part

of the reed, the end next to the opening; the females are at the bottom,

next to the knot which serves as a natural stopper to the channel. For the

rest, the quantity of the provisions in itself points to the sex: for the

females it is twice or thrice as great as for the males.



In the scantily-provided cells, I double or treble the ration with food

taken from other cells; in the cells which are plentifully supplied, I

reduce the portion to a half or a third. Controls are left: that is to say,

some cells remain untouched, with their provisions as I found them, both in

the part which is abundantly provided and in that which is more meagrely

rationed. The two halves of the reed are then restored to their original

position and firmly bound with a few turns of wire. We shall see, when the

time comes, whether these changes increasing or decreasing the victuals

have determined the sex.



Here is the result: the cells which at first were sparingly provided, but

whose supplies were doubled or trebled by my artifice, contain males, as

foretold by the original amount of victuals. The surplus which I added has

not completely disappeared, far from it: the larva has had more than it

needed for its evolution as a male; and, being unable to consume the whole

of its copious provisions, it has spun its cocoon in the midst of the

remaining pollen-dust. These males, so richly supplied, are of handsome but

not exaggerated proportions; you can see that the additional food has

profited them to some small extent.



The cells with abundant provisions, reduced to a half or a third by my

intervention, contain cocoons as small as the male cocoons, pale,

translucent and limp, whereas the normal cocoons are dark-brown, opaque and

firm to the touch. These, we perceive at once, are the work of starved,

anaemic weavers, who, failing to satisfy their appetite and having eaten

the last grain of pollen, have, before dying, done their best with their

poor little drop of silk. Those cocoons which correspond with the smallest

allowance of food contain only a dead and shrivelled larva; others, in

whose case the provisions were less markedly decreased, contain females in

the adult form, but of very diminutive size, comparable with that of the

males, or even smaller. As for the controls which I was careful to leave,

they confirm the fact that I had males in the part near the orifice of the

reed and females in the part near the knot closing the channel.



Is this enough to dispose of the very improbable supposition that the

determination of the sex depends on the quantity of food? Strictly

speaking, there is still one door open to doubt. It may be said that

experiment, with its artifices, does not succeed in realizing the delicate

natural conditions. To make short work of all objections, I cannot do

better than have recourse to facts in which the experimenter's hand has not

intervened. The parasites will supply us with these facts; they will show

us how alien the quantity and even the quality of the food are from either

specific or sexual characters. The subject of enquiry thus becomes double,

instead of single as it was when I plundered one cell in my split reeds to

enrich another. Let us follow this double current for a little while.



An Ammophila, the Silky Ammophila (Cf. "The Hunting Wasps": chapter 13.--

Translator's Note.), which feeds on Looper caterpillars (Known also as

Measuring-worms, Inchworms, Spanworms and Surveyors: the caterpillars of

the Geometrid Moths.--Translator's Note.), has just been reared in my

refectory on Spiders. Replete to the regulation point, it spins its cocoon.

What will emerge from this? If the reader expects to see any modifications,

caused by a diet which the species, left to itself, had never effected, let

him be undeceived and that quickly. The Ammophila fed on Spiders is

precisely the same as the Ammophila fed on caterpillars, just as man fed on

rice is the same as man fed on wheat. In vain I pass my lens over the

product of my art: I cannot distinguish it from the natural product; and I

defy the most meticulous entomologist to perceive any difference between

the two. It is the same with my other boarders who have had their diet

altered.



I see the objection coming. The differences may be inappreciable, for my

experiments touch only a first rung of the ladder. What would happen if the

ladder were prolonged, if the offspring of the Ammophila fed on Spiders

were given the same food generation after generation? These differences, at

first imperceptible, might become accentuated until they grew into distinct

specific characters; the habits and instincts might also change; and in the

end the caterpillar-huntress might become a Spider-huntress, with a shape

of her own. A species would be created, for, among the factors at work in

the transformation of animals, the most important of all is incontestably

the type of food, the nature of the thing wherewith the animal builds

itself. All this is much more important than the trivialities which Darwin

relies upon.



To create a species is magnificent in theory, so that we find ourselves

regretting that the experimenter is not able to continue the attempt. But,

once the Ammophila has flown out of the laboratory to slake her thirst at

the flowers in the neighbourhood, just to try to find her again and induce

her to entrust you with her eggs, which you would rear in the refectory, to

increase the taste for Spiders from generation to generation! Merely to

dream of it were madness. Shall we, in our helplessness, admit ourselves

beaten by the evolutionary effects of diet? Not a bit of it! One

experiment--and you could not wish for a more decisive--is continually in

progress, apart from all artifices, on an enormous scale. It is brought to

our notice by the parasites.



They must, we are told, have acquired the habit of living on others in

order to save themselves work and to lead an easier life. The poor wretches

have made a sorry blunder. Their life is of the hardest. If a few establish

themselves comfortably, dearth and dire famine await most of the rest.

There are some--look at certain of the Oil-beetles--exposed to so many

chances of destruction that, to save one, they are obliged to procreate a

thousand. They seldom enjoy a free meal. Some stray into the houses of

hosts whose victuals do not suit them; others find only a ration quite

insufficient for their needs; others--and these are very numerous--find

nothing at all. What misadventures, what disappointments do these needy

creatures suffer, unaccustomed as they are to work! Let me relate some of

their misfortunes, gleaned at random.



The Girdled Dioxys (D. cincta) loves the ample honey-stores of the

Chalicodoma of the Pebbles. There she finds abundant food, so abundant that

she cannot eat it all. I have already passed censure on this waste. (Cf.

"The Mason-bees": chapter 10.--Translator's Note.) Now a little Osmia (O.

cyanoxantha, Perez) makes her nest in the Mason's deserted cells; and this

Bee, a victim of her ill-omened dwelling, also harbours the Dioxys. This is

a manifest error on the parasite's part. The nest of the Chalicodoma, the

hemisphere of mortar on its pebble, is what she is looking for, to confide

her eggs to it. But the nest is now occupied by a stranger, by the Osmia, a

circumstance unknown to the Dioxys, who comes stealing up to lay her egg in

the mother's absence. The dome is familiar to her. She could not know it

better if she had built it herself. Here she was born; here is what her

family wants. Moreover, there is nothing to arouse her suspicions: the

outside of the home has not changed its appearance in any respect; the

stopper of gravel and green putty, which later will form a violent contrast

with its white front, is not yet constructed. She goes in and sees a heap

of honey. To her thinking this can be nothing but the Chalicodoma's

portion. We ourselves would be beguiled, in the Osmia's absence. She lays

her eggs in this deceptive cell.



Her mistake, which is easy to understand, does not in any way detract from

her great talents as a parasite, but it is a serious matter for the future

larva. The Osmia, in fact, in view of her small dimensions, collects but a

very scanty store of food: a little loaf of pollen and honey, hardly the

size of an average pea. Such a ration is insufficient for the Dioxys. I

have described her as a waster of food when her larva is established,

according to custom, in the cell of the Mason-bee. This description no

longer applies; not in the very least. Inadvertently straying to the

Osmia's table, the larva has no excuse for turning up its nose; it does not

leave part of the food to go bad; it eats up the lot without having had

enough.



This famine-stricken refectory can give us nothing but an abortion. As a

matter of fact, the Dioxys subjected to this niggardly test does not die,

for the parasite must have a tough constitution to enable it to face the

disastrous hazards which lie in wait for it; but it attains barely half its

ordinary dimensions, which means one-eighth of its normal bulk. To see it

thus diminished, we are surprised at its tenacious vitality, which enables

it to reach the adult form in spite of the extreme deficiency of food.

Meanwhile, this adult is still the Dioxys; there is no change of any kind

in her shape or colouring. Moreover, the two sexes are represented; this

family of pigmies has its males and females. Dearth and the farinaceous

mess in the Osmia's cell has had no more influence over species or sex than

abundance and flowing honey in the Chalicodoma's home.



The same may be said of the Spotted Sapyga (S. punctata (A parasitic Wasp.

Cf. "The Mason-bees": chapters 9 and 10.--Translator's Note.)), which, a

parasite of the Three-pronged Osmia, a denizen of the bramble, and of the

Golden Osmia, an occupant of empty Snail-shells, strays into the house of

the Tiny Osmia (O. parvula (This bee makes her home in the brambles. Cf.

"Bramble-dwellers and Others": chapters 2 and 3.--Translator's Note.)),

where, for lack of sufficient food, it does not attain half its normal

size.



A Leucopsis (Cf. "The Mason-bees": chapter 11.--Translator's Note.) inserts

her eggs through the cement wall of our three Chalicodomae. I know her

under two names. When she comes from the Chalicodoma of the Pebbles or

Walls, whose opulent larva saturates her with food, she deserves by her

large size the name of Leucopsis gigas, which Fabricius bestows upon her;

when she comes from the Chalicodoma of the Sheds, she deserves no more than

the name of L. grandis, which is all that Klug grants her. With a smaller

ration "the giant" is to some degree diminished and becomes no more than

"the large." When she comes from the Chalicodoma of the Shrubs, she is

smaller still; and, if some nomenclator were to seek to describe her, she

would no longer deserve to be called more than middling. From dimension 2

she has descended to dimension 1 without ceasing to be the same insect,

despite the change of diet; and at the same time both sexes are present in

the three nurselings, despite the variation in the quantity of victuals.



I obtain Anthrax sinuata ("The Mason-bees": chapters 8, 10 and 11.--

Translator's Note.) from various bees' nests. When she issues from the

cocoons of the Three-horned Osmia, especially the female cocoons, she

attains the greatest development that I know of. When she issues from the

cocoons of the Blue Osmia (O. cyanea, KIRB.), she is sometimes hardly one-

third the length which the other Osmia gives her. And we still have the two

sexes--that goes without saying--and still identically the same species.



Two Anthidia, working in resin, A. septemdentatum, LATR., and A.

bellicosum, LEP. (For these Resin-bees, cf. "Bramble-bees and Others":

chapter 10.--Translator's Note.), establish their domicile in old Snail-

shells. The second harbours the Burnt Zonitis (Z. proeusta (Cf. "The Glow-

worm and Other Beetles": chapter 6.--Translator's Note.)). Amply nourished

this Meloe then acquires her normal size, the size in which she usually

figures in the collections. A like prosperity awaits her when she usurps

the provisions of Megachile sericans. (For this Bee, the Silky Leaf-cutter,

cf. "Bramble-bees and Others": chapter 8.--Translator's Note.) But the

imprudent creature sometimes allows itself to be carried away to the meagre

table of the smallest of our Anthidia (A. scapulare, LATR. (A Cotton-bee,

cf. idem: chapter 9.--Translator's Note.)), who makes her nests in dry

bramble-stems. The scanty fare makes a wretched dwarf of the offspring

belonging to either sex, without depriving them of any of their racial

features. We still see the Burnt Zonitis, with the distinctive sign of the

species: the singed patch at the tip of the wing-cases.



And the other Meloidae--Cantharides, Cerocomae, Mylabres (For these

Blister-beetles or Oil-beetles, cf. "The Glow-worm and Other Beetles":

chapter 6.--Translator's Note.)--to what inequalities of size are they not

subject, irrespective of sex! There are some--and they are numerous--whose

dimensions fall to a half, a third, a quarter of the regular dimensions.

Among these dwarfs, these misbegotten ones, these victims of atrophy, there

are females as well as males; and their smallness by no means cools their

amorous ardour. These needy creatures, I repeat, have a hard life of it.

Whence do they come, these diminutive Beetles, if not from dining-rooms

insufficiently supplied for their needs? Their parasitical habits expose

them to harsh vicissitudes. No matter: in dearth as well as in abundance

the two sexes appear and the specific features remain unchanged.



It is unnecessary to linger longer over this subject. The demonstration is

completed. The parasites tell us that changes in the quantity and quality

of food do not lead to any transformation of species. Fed upon the larva of

the Three-horned Osmia or of the Blue Osmia, Anthrax sinuata, whether of

handsome proportions or a dwarf, is still Anthrax sinuata; fed upon the

allowance of the Anthidium of the empty Snail-shells, the Anthidium of the

brambles, the Megachile or doubtless many others, the Burnt Zonitis is

still the Burnt Zonitis. Yet variation of diet ought to be a very potential

factor in the problem of progress towards another form. Is not the world of

living creatures ruled by the stomach? And the value of this factor is

unity, changing nothing in the product.



The same parasites tell us--and this is the chief object of my digression--

that excess or deficiency of nutriment does not determine the sex. So we

are once more confronted with the strange proposition, which is now more

positive than ever, that the insect which amasses provisions in proportion

to the needs of the egg about to be laid knows beforehand what the sex of

this egg will be. Perhaps the reality is even more paradoxical still. I

shall return to the subject after discussing the Osmiae, who are very

weighty witnesses in this grave affair. (Cf. "Bramble-bees and Others":

chapters 3 to 5. The student is recommended to read these three chapters in

conjunction with the present chapter, to which they form a sequel, with

that on the Osmiae (chapter 2 of the above volume) intervening.--

Translator's Note.)